Unstable isotopes of oxygen that decay or disintegrate emitting radiation. O atoms with atomic weights 13, 14, 15, 19, and 20 are radioactive oxygen isotopes.
An element with atomic symbol O, atomic number 8, and atomic weight [15.99903; 15.99977]. It is the most abundant element on earth and essential for respiration.
Isotopes that exhibit radioactivity and undergo radioactive decay. (From Grant & Hackh's Chemical Dictionary, 5th ed & McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
Unstable isotopes of zinc that decay or disintegrate emitting radiation. Zn atoms with atomic weights 60-63, 65, 69, 71, and 72 are radioactive zinc isotopes.
Method for assessing flow through a system by injection of a known quantity of radionuclide into the system and monitoring its concentration over time at a specific point in the system. (From Dorland, 28th ed)
Unstable isotopes of strontium that decay or disintegrate spontaneously emitting radiation. Sr 80-83, 85, and 89-95 are radioactive strontium isotopes.
The rate at which oxygen is used by a tissue; microliters of oxygen STPD used per milligram of tissue per hour; the rate at which oxygen enters the blood from alveolar gas, equal in the steady state to the consumption of oxygen by tissue metabolism throughout the body. (Stedman, 25th ed, p346)
Unstable isotopes of iodine that decay or disintegrate emitting radiation. I atoms with atomic weights 117-139, except I 127, are radioactive iodine isotopes.
Molecules or ions formed by the incomplete one-electron reduction of oxygen. These reactive oxygen intermediates include SINGLET OXYGEN; SUPEROXIDES; PEROXIDES; HYDROXYL RADICAL; and HYPOCHLOROUS ACID. They contribute to the microbicidal activity of PHAGOCYTES, regulation of signal transduction and gene expression, and the oxidative damage to NUCLEIC ACIDS; PROTEINS; and LIPIDS.
Unstable isotopes of krypton that decay or disintegrate emitting radiation. Kr atoms with atomic weights 74-77, 79, 81, 85, and 87-94 are radioactive krypton isotopes.
Unstable isotopes of indium that decay or disintegrate emitting radiation. In atoms with atomic weights 106-112, 113m, 114, and 116-124 are radioactive indium isotopes.
Unstable isotopes of sodium that decay or disintegrate emitting radiation. Na atoms with atomic weights 20-22 and 24-26 are radioactive sodium isotopes.
The spontaneous transformation of a nuclide into one or more different nuclides, accompanied by either the emission of particles from the nucleus, nuclear capture or ejection of orbital electrons, or fission. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)
Unstable isotopes of barium that decay or disintegrate emitting radiation. Ba atoms with atomic weights 126-129, 131, 133, and 139-143 are radioactive barium isotopes.
The production of an image obtained by cameras that detect the radioactive emissions of an injected radionuclide as it has distributed differentially throughout tissues in the body. The image obtained from a moving detector is called a scan, while the image obtained from a stationary camera device is called a scintiphotograph.
Unstable isotopes of yttrium that decay or disintegrate emitting radiation. Y atoms with atomic weights 82-88 and 90-96 are radioactive yttrium isotopes.
Unstable isotopes of tin that decay or disintegrate emitting radiation. Sn atoms with atomic weights 108-111, 113, 120-121, 123 and 125-128 are tin radioisotopes.
Unstable isotopes of carbon that decay or disintegrate emitting radiation. C atoms with atomic weights 10, 11, and 14-16 are radioactive carbon isotopes.
Unstable isotopes of iron that decay or disintegrate emitting radiation. Fe atoms with atomic weights 52, 53, 55, and 59-61 are radioactive iron isotopes.
Unstable isotopes of copper that decay or disintegrate emitting radiation. Cu atoms with atomic weights 58-62, 64, and 66-68 are radioactive copper isotopes.
Unstable isotopes of phosphorus that decay or disintegrate emitting radiation. P atoms with atomic weights 28-34 except 31 are radioactive phosphorus isotopes.
High energy POSITRONS or ELECTRONS ejected from a disintegrating atomic nucleus.
The first artificially produced element and a radioactive fission product of URANIUM. Technetium has the atomic symbol Tc, atomic number 43, and atomic weight 98.91. All technetium isotopes are radioactive. Technetium 99m (m=metastable) which is the decay product of Molybdenum 99, has a half-life of about 6 hours and is used diagnostically as a radioactive imaging agent. Technetium 99 which is a decay product of technetium 99m, has a half-life of 210,000 years.
Unstable isotopes of mercury that decay or disintegrate emitting radiation. Hg atoms with atomic weights 185-195, 197, 203, 205, and 206 are radioactive mercury isotopes.
A gamma-emitting radionuclide imaging agent used for the diagnosis of diseases in many tissues, particularly in the gastrointestinal system, liver, and spleen.
Stable cesium atoms that have the same atomic number as the element cesium, but differ in atomic weight. Cs-133 is a naturally occurring isotope.
Unstable isotopes of cerium that decay or disintegrate emitting radiation. Ce atoms with atomic weights 132-135, 137, 139, and 141-148 are radioactive cerium isotopes.
Stable cobalt atoms that have the same atomic number as the element cobalt, but differ in atomic weight. Co-59 is a stable cobalt isotope.
Hafnium. A metal element of atomic number 72 and atomic weight 178.49, symbol Hf. (From Dorland, 28th ed)
Inhalation of oxygen aimed at restoring toward normal any pathophysiologic alterations of gas exchange in the cardiopulmonary system, as by the use of a respirator, nasal catheter, tent, chamber, or mask. (From Dorland, 27th ed & Stedman, 25th ed)
Unstable isotopes of gold that decay or disintegrate emitting radiation. Au 185-196, 198-201, and 203 are radioactive gold isotopes.
Techniques for labeling a substance with a stable or radioactive isotope. It is not used for articles involving labeled substances unless the methods of labeling are substantively discussed. Tracers that may be labeled include chemical substances, cells, or microorganisms.
An excited state of molecular oxygen generated photochemically or chemically. Singlet oxygen reacts with a variety of biological molecules such as NUCLEIC ACIDS; PROTEINS; and LIPIDS; causing oxidative damages.
Unstable isotopes of lead that decay or disintegrate emitting radiation. Pb atoms with atomic weights 194-203, 205, and 209-214 are radioactive lead isotopes.
Any diagnostic evaluation using radioactive (unstable) isotopes. This diagnosis includes many nuclear medicine procedures as well as radioimmunoassay tests.
Stable zinc atoms that have the same atomic number as the element zinc, but differ in atomic weight. Zn-66-68, and 70 are stable zinc isotopes.
Unstable isotopes of sulfur that decay or disintegrate spontaneously emitting radiation. S 29-31, 35, 37, and 38 are radioactive sulfur isotopes.
Unstable isotopes of cadmium that decay or disintegrate emitting radiation. Cd atoms with atomic weights 103-105, 107, 109, 115, and 117-119 are radioactive cadmium isotopes.
Astatine. A radioactive halogen with the atomic symbol At, atomic number 85, and atomic weight 210. Its isotopes range in mass number from 200 to 219 and all have an extremely short half-life. Astatine may be of use in the treatment of hyperthyroidism.
Radiotherapy where cytotoxic radionuclides are linked to antibodies in order to deliver toxins directly to tumor targets. Therapy with targeted radiation rather than antibody-targeted toxins (IMMUNOTOXINS) has the advantage that adjacent tumor cells, which lack the appropriate antigenic determinants, can be destroyed by radiation cross-fire. Radioimmunotherapy is sometimes called targeted radiotherapy, but this latter term can also refer to radionuclides linked to non-immune molecules (see RADIOTHERAPY).
Lutetium. An element of the rare earth family of metals. It has the atomic symbol Lu, atomic number 71, and atomic weight 175.
Rhenium. A metal, atomic number 75, atomic weight 186.2, symbol Re. (Dorland, 28th ed)
Samarium. An element of the rare earth family of metals. It has the atomic symbol Sm, atomic number 62, and atomic weight 150.36. The oxide is used in the control rods of some nuclear reactors.
Compounds that are used in medicine as sources of radiation for radiotherapy and for diagnostic purposes. They have numerous uses in research and industry. (Martindale, The Extra Pharmacopoeia, 30th ed, p1161)
Pollutants, present in soil, which exhibit radioactivity.
Unstable isotopes of bromine that decay or disintegrate emitting radiation. Br atoms with atomic weights 74-78, 80, and 82-90 are radioactive bromine isotopes.
Detection and counting of scintillations produced in a fluorescent material by ionizing radiation.
Leakage and accumulation of CEREBROSPINAL FLUID in the subdural space which may be associated with an infectious process; CRANIOCEREBRAL TRAUMA; BRAIN NEOPLASMS; INTRACRANIAL HYPOTENSION; and other conditions.
Stable calcium atoms that have the same atomic number as the element calcium, but differ in atomic weight. Ca-42-44, 46, and 48 are stable calcium isotopes.
Liquid, solid, or gaseous waste resulting from mining of radioactive ore, production of reactor fuel materials, reactor operation, processing of irradiated reactor fuels, and related operations, and from use of radioactive materials in research, industry, and medicine. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
Normal human serum albumin mildly iodinated with radioactive iodine (131-I) which has a half-life of 8 days, and emits beta and gamma rays. It is used as a diagnostic aid in blood volume determination. (from Merck Index, 11th ed)
Unstable isotopes of ruthenium that decay or disintegrate emitting radiation. Ru atoms with atomic weights 93-95, 97, 103, and 105-108 are radioactive ruthenium isotopes.
Techniques used to determine the age of materials, based on the content and half-lives of the RADIOACTIVE ISOTOPES they contain.
Positively charged particles composed of two protons and two NEUTRONS, i.e. equivalent to HELIUM nuclei, which are emitted during disintegration of heavy ISOTOPES. Alpha rays have very strong ionizing power, but weak penetrability.
Unstable isotopes of selenium that decay or disintegrate emitting radiation. Se atoms with atomic weights 70-73, 75, 79, 81, and 83-85 are radioactive selenium isotopes.
Atomic species differing in mass number but having the same atomic number. (Grant & Hackh's Chemical Dictionary, 5th ed)
A gamma-emitting radionuclide imaging agent used for the diagnosis of diseases in many tissues, particularly in the gastrointestinal system, cardiovascular and cerebral circulation, brain, thyroid, and joints.
A class of organic compounds containing a ring structure made up of more than one kind of atom, usually carbon plus another atom. The ring structure can be aromatic or nonaromatic.
Tungsten. A metallic element with the atomic symbol W, atomic number 74, and atomic weight 183.85. It is used in many manufacturing applications, including increasing the hardness, toughness, and tensile strength of steel; manufacture of filaments for incandescent light bulbs; and in contact points for automotive and electrical apparatus.
An iron chelating agent with properties like EDETIC ACID. DTPA has also been used as a chelator for other metals, such as plutonium.
Accumulation of a drug or chemical substance in various organs (including those not relevant to its pharmacologic or therapeutic action). This distribution depends on the blood flow or perfusion rate of the organ, the ability of the drug to penetrate organ membranes, tissue specificity, protein binding. The distribution is usually expressed as tissue to plasma ratios.
A type of high-energy radiotherapy using a beam of gamma-radiation produced by a radioisotope source encapsulated within a teletherapy unit.
Stable oxygen atoms that have the same atomic number as the element oxygen, but differ in atomic weight. O-17 and 18 are stable oxygen isotopes.
Determination of the energy distribution of gamma rays emitted by nuclei. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
A series of steps taken in order to conduct research.
A specialty field of radiology concerned with diagnostic, therapeutic, and investigative use of radioactive compounds in a pharmaceutical form.
A technetium imaging agent used in renal scintigraphy, computed tomography, lung ventilation imaging, gastrointestinal scintigraphy, and many other procedures which employ radionuclide imaging agents.
The measurement of radiation by photography, as in x-ray film and film badge, by Geiger-Mueller tube, and by SCINTILLATION COUNTING.
Tritium is an isotope of hydrogen (specifically, hydrogen-3) that contains one proton and two neutrons in its nucleus, making it radioactive with a half-life of about 12.3 years, and is used in various applications including nuclear research, illumination, and dating techniques due to its low energy beta decay.
Compounds that contain the triphenylmethane aniline structure found in rosaniline. Many of them have a characteristic magenta color and are used as COLORING AGENTS.
A form species of spore-producing CYANOBACTERIA, in the family Nostocaceae, order Nostocales. It is an important source of fixed NITROGEN in nutrient-depleted soils. When wet, it appears as a jelly-like mass.
Measurement of radioactivity in the entire human body.
Unstable isotopes of potassium that decay or disintegrate emitting radiation. K atoms with atomic weights 37, 38, 40, and 42-45 are radioactive potassium isotopes.
Stable carbon atoms that have the same atomic number as the element carbon, but differ in atomic weight. C-13 is a stable carbon isotope.
The therapeutic intermittent administration of oxygen in a chamber at greater than sea-level atmospheric pressures (three atmospheres). It is considered effective treatment for air and gas embolisms, smoke inhalation, acute carbon monoxide poisoning, caisson disease, clostridial gangrene, etc. (From Segen, Dictionary of Modern Medicine, 1992). The list of treatment modalities includes stroke.
An iodine-containing compound used in pyelography as a radiopaque medium. If labeled with radioiodine, it can be used for studies of renal function.
Elements of limited time intervals, contributing to particular results or situations.
The pressure that would be exerted by one component of a mixture of gases if it were present alone in a container. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)
A class of compounds of the type R-M, where a C atom is joined directly to any other element except H, C, N, O, F, Cl, Br, I, or At. (Grant & Hackh's Chemical Dictionary, 5th ed)
The amount of radiation energy that is deposited in a unit mass of material, such as tissues of plants or animal. In RADIOTHERAPY, radiation dosage is expressed in gray units (Gy). In RADIOLOGIC HEALTH, the dosage is expressed by the product of absorbed dose (Gy) and quality factor (a function of linear energy transfer), and is called radiation dose equivalent in sievert units (Sv).
An imaging technique using compounds labelled with short-lived positron-emitting radionuclides (such as carbon-11, nitrogen-13, oxygen-15 and fluorine-18) to measure cell metabolism. It has been useful in study of soft tissues such as CANCER; CARDIOVASCULAR SYSTEM; and brain. SINGLE-PHOTON EMISSION-COMPUTED TOMOGRAPHY is closely related to positron emission tomography, but uses isotopes with longer half-lives and resolution is lower.
Uptake of substances through the lining of the INTESTINES.
The rate dynamics in chemical or physical systems.
A cobalt-containing coordination compound produced by intestinal micro-organisms and found also in soil and water. Higher plants do not concentrate vitamin B 12 from the soil and so are a poor source of the substance as compared with animal tissues. INTRINSIC FACTOR is important for the assimilation of vitamin B 12.
Relatively complete absence of oxygen in one or more tissues.
A strong oxidizing agent used in aqueous solution as a ripening agent, bleach, and topical anti-infective. It is relatively unstable and solutions deteriorate over time unless stabilized by the addition of acetanilide or similar organic materials.
A diagnostic procedure used to determine whether LYMPHATIC METASTASIS has occurred. The sentinel lymph node is the first lymph node to receive drainage from a neoplasm.
A chemical reaction in which an electron is transferred from one molecule to another. The electron-donating molecule is the reducing agent or reductant; the electron-accepting molecule is the oxidizing agent or oxidant. Reducing and oxidizing agents function as conjugate reductant-oxidant pairs or redox pairs (Lehninger, Principles of Biochemistry, 1982, p471).
A gamma-emitting radionuclide imaging agent used primarily in skeletal scintigraphy. Because of its absorption by a variety of tumors, it is useful for the detection of neoplasms.
The physical or physiological processes by which substances, tissue, cells, etc. take up or take in other substances or energy.
A disturbance in the prooxidant-antioxidant balance in favor of the former, leading to potential damage. Indicators of oxidative stress include damaged DNA bases, protein oxidation products, and lipid peroxidation products (Sies, Oxidative Stress, 1991, pxv-xvi).
A metallic element that has the atomic symbol Bi, atomic number 83 and atomic weight 208.98.
Antibodies produced by a single clone of cells.
A specific protein in egg albumin that interacts with BIOTIN to render it unavailable to mammals, thereby producing biotin deficiency.
The determination of oxygen-hemoglobin saturation of blood either by withdrawing a sample and passing it through a classical photoelectric oximeter or by electrodes attached to some translucent part of the body like finger, earlobe, or skin fold. It includes non-invasive oxygen monitoring by pulse oximetry.
Stable phosphorus atoms that have the same atomic number as the element phosphorus, but differ in atomic weight. P-31 is a stable phosphorus isotope.
The making of a radiograph of an object or tissue by recording on a photographic plate the radiation emitted by radioactive material within the object. (Dorland, 27th ed)
Unstable isotopes of cesium that decay or disintegrate emitting radiation. Cs atoms with atomic weights of 123, 125-132, and 134-145 are radioactive cesium isotopes.
A collective term for interstitial, intracavity, and surface radiotherapy. It uses small sealed or partly-sealed sources that may be placed on or near the body surface or within a natural body cavity or implanted directly into the tissues.
Unstable isotopes of iridium that decay or disintegrate emitting radiation. Ir atoms with atomic weights 182-190, 192, and 194-198 are radioactive iridium isotopes.
Studies determining the effectiveness or value of processes, personnel, and equipment, or the material on conducting such studies. For drugs and devices, CLINICAL TRIALS AS TOPIC; DRUG EVALUATION; and DRUG EVALUATION, PRECLINICAL are available.
Tomography using radioactive emissions from injected RADIONUCLIDES and computer ALGORITHMS to reconstruct an image.
A metallic element with atomic symbol Fe, atomic number 26, and atomic weight 55.85. It is an essential constituent of HEMOGLOBINS; CYTOCHROMES; and IRON-BINDING PROTEINS. It plays a role in cellular redox reactions and in the transport of OXYGEN.
An analytical method used in determining the identity of a chemical based on its mass using mass analyzers/mass spectrometers.
A potent, long-acting synthetic SOMATOSTATIN octapeptide analog that inhibits secretion of GROWTH HORMONE and is used to treat hormone-secreting tumors; DIABETES MELLITUS; HYPOTENSION, ORTHOSTATIC; HYPERINSULINISM; hypergastrinemia; and small bowel fistula.
The time it takes for a substance (drug, radioactive nuclide, or other) to lose half of its pharmacologic, physiologic, or radiologic activity.

Correlation of regional cerebral blood flow and change of plasma sodium concentration during genesis and satiation of thirst. (1/380)

Positron emission tomography studies were conducted during genesis of moderate thirst by rapid i.v. infusion of hypertonic saline (0.51 M) and after satiation of thirst by drinking water. The correlation of regional cerebral blood flow with the change in the plasma Na concentration showed a significant group of cerebral activations in the anterior cingulate region and also a site in the middle temporal gyrus and in the periaqueductal gray. Strongest deactivations occurred in the parahippocampal and frontal gyri. The data are consistent with an important role of the anterior cingulate in the genesis of thirst.  (+info)

Command-related distribution of regional cerebral blood flow during attempted handgrip. (2/380)

To localize a central nervous feed-forward mechanism involved in cardiovascular regulation during exercise, brain activation patterns were measured in eight subjects by employing positron emission tomography and oxygen-15-labeled water. Scans were performed at rest and during rhythmic handgrip before and after axillary blockade with bupivacaine. After the blockade, handgrip strength was reduced to 25% (range 0-50%) of control values, whereas handgrip-induced heart rate and blood pressure increases were unaffected (13 +/- 3 beats/min and 12 +/- 5 mmHg, respectively; means +/- SE). Before regional anesthesia, handgrip caused increased activation in the contralateral sensory motor area, the supplementary motor area, and the ipsilateral cerebellum. We found no evidence for changes in the activation pattern due to an interaction between handgrip and regional anesthesia. This was true for both the blocked and unblocked arm. It remains unclear whether the activated areas are responsible for the increase in cardiovascular variables, but neural feedback from the contracting muscles was not necessary for the activation in the mentioned areas during rhythmic handgrip.  (+info)

Brain activation during maintenance of standing postures in humans. (3/380)

The regulatory mechanism of bipedal standing in humans remains to be elucidated. We investigated neural substrates for maintaining standing postures in humans using PET with our mobile gantry PET system. Normal volunteers were instructed to adopt several postures: supine with eyes open toward a target; standing with feet together and eyes open or eyes closed; and standing on one foot or with two feet in a tandem relationship with eyes open toward the target. Compared with the supine posture, standing with feet together activated the cerebellar anterior lobe and the right visual cortex (Brodmann area 18/19), and standing on one foot increased cerebral blood flow in the cerebellar anterior vermis and the posterior lobe lateral cortex ipsilateral to the weight-bearing side. Standing in tandem was accompanied by activation within the visual association cortex, the anterior and posterior vermis as well as within the midbrain. Standing with eyes closed activated the prefrontal cortex (Brodmann area 8/9). Our findings confirmed that the cerebellar vermis efferent system plays an important role in maintenance of standing posture and suggested that the visual association cortex may subserve regulating postural equilibrium while standing.  (+info)

Brief vibrotactile stimulation does not increase cortical oxygen consumption when measured by single inhalation of positron emitting oxygen. (4/380)

Vibrotactile stimulation of the hand elicits no increase in oxygen consumption commensurate with the increase in blood flow measured in human sensory cortex. To test the hypothesis that previous failures to detect a proportionate increase in oxygen consumption could be an artefact of the sequential bolus, or three-step, method used to measure this parameter in the human brain in vivo, the authors compared the measurements with the results of a novel single bolus, or one-step, method of measuring oxygen consumption. The time of completion of the three-step method was 40 to 50 minutes, whereas the one-step method lasted only 3 minutes. The baseline whole-brain oxygen consumption averaged 185 +/- 32 micromol hg(-1) min(-1) by the three-step method and 153 +/- 15 micromol hg(-1) min(-1) by the one-step method. Vibrotactile stimulation did not elicit a significant increase in oxygen consumption measured by either method. This finding rejects the hypothesis that failure to detect an increase of oxygen consumption could be an artefact caused by limitations of the method used previously. Conversely, it also rejects the hypothesis that observations of an increase of oxygen consumption by the new method are artefacts caused by limitations of the one-step method.  (+info)

Oxygen consumption of cerebral cortex fails to increase during continued vibrotactile stimulation. (5/380)

The coupling of oxidative metabolism to the blood flow of the sensory motor hand area is uncertain. The authors tested the hypothesis that continued vibrotactile stimulation ultimately must lead to increased oxygen consumption consumption. Twenty-two healthy right-handed young volunteers underwent positron emission tomography (PET) with the [(15)O]water bolus injection method to measure water clearance (K1H2O an index of blood flow (CBF), and with the [(15)O]oxygen bolus inhalation method to measure CMR(O2). The CMR(O2) was measured 30 seconds and 20 minutes after onset of intermittent (1 second on, 1 second off) vibrotactile stimulation (110 Hz) and compared with baseline measurements without stimulation. The K1H2O and CMR(O2) changes (delta K1H2O and delta CMR(O2)) were determined using intersubject averaging, together with magnetic resonance imaging based stereotaxic registration technique. The K1H2O increase was 21 +/- 4% and 12 +/- 4% at 30 seconds and 20 minutes after onset of stimulation, respectively. No significant increase of CMR(O2) was found until 30 minutes after the onset of stimulation. The authors conclude that blood flow and oxidative metabolism undergo uncoupling during sustained phasic stimulation of the sensory hand area. Therefore, neuronal activity stimulated in this manner does not rely on significantly increased oxidative phosphorylation.  (+info)

Frequency-dependent changes in cerebral metabolic rate of oxygen during activation of human visual cortex. (6/380)

To test the hypothesis that brain oxidative metabolism is significantly increased upon adequate stimulation, we varied the presentation of a visual stimulus to determine the frequency at which the metabolic response would be at maximum. The authors measured regional CMR(O2) in 12 healthy normal volunteers with the ECAT EXACT HR+ (CTI/Siemens, Knoxville, TN, U.S.A.) three-dimensional whole-body positron emission tomograph (PET). In seven successive activating conditions, subjects viewed a yellow-blue annular checkerboard reversing its contrast at frequencies of 0, 1, 4, 8, 16, 32, and 50 Hz. Stimulation began 4 minutes before and continued throughout the 3-minute dynamic scan. In the baseline condition, the subjects began fixating a cross hair 30 seconds before the scan and continued to do so for the duration of the 3-minute scan. At the start of each scan, the subjects inhaled 20 mCi of (15)O-O2 in a single breath. The CMR(O2) value was calculated using a two-compartment, weighted integration method. Normalized PET images were averaged across subjects and coregistered with the subjects' magnetic resonance imaging in stereotaxic space. Mean subtracted image volumes (activation minus baseline) of CMR(O2) then were obtained and converted to z statistic volumes. The authors found a statistically significant focal change of CMR(O2) in the striate cortex (x = 9; y = -89; z = -1) that reached a maximum at 4 Hz and dropped off sharply at higher stimulus frequencies.  (+info)

Identification of the cerebral loci processing human swallowing with H2(15)O PET activation. (7/380)

Lesional and electrophysiological data implicate a role for the cerebral cortex in the initiation and modulation of human swallowing, and yet its functional neuroanatomy remains undefined. We therefore conducted a functional study of the cerebral loci processing human volitional swallowing with 15O-labeled water positron emission tomography (PET) activation imaging. Regional cerebral activation was investigated in 8 healthy right handed male volunteers with a randomized 12-scan paradigm of rest and water swallows (5 ml/bolus, continuous infusion) at increasing frequencies of 0.1, 0.2, and 0.3 Hz, which were visually cued and monitored with submental electromyogram (EMG). Group and individual linear covariate analyses were performed with SPM96. In five of eight subjects, the cortical motor representation of pharynx was subsequently mapped with transcranial magnetic stimulation (TMS) in a posthoc manner to substantiate findings of hemispheric differences in sensorimotor cortex activation seen with PET. During swallowing, group PET analysis identified increased regional cerebral blood flow (rCBF) (P < 0.001) within bilateral caudolateral sensorimotor cortex [Brodmann's area (BA) 3, 4, and 6], right anterior insula (BA 16), right orbitofrontal and temporopolar cortex (BA 11 and 38), left mesial premotor cortex (BA 6 and 24), left temporopolar cortex and amygdala (BA 38 and 34), left superiomedial cerebellum, and dorsal brain stem. Decreased rCBF (P < 0.001) was also observed within bilateral posterior parietal cortex (BA 7), right anterior occipital cortex (BA 19), left superior frontal cortex (BA 8), right prefrontal cortex (BA 9), and bilateral superiomedial temporal cortex (BA 41 and 42). Individual PET analysis revealed asymmetric representation within sensorimotor cortex in six of eight subjects, four lateralizing to right hemisphere and two to left hemisphere. TMS mapping in the five subjects identified condordant interhemisphere asymmetries in the motor representation for pharynx, consistent with the PET findings. We conclude that volitional swallowing recruits multiple cerebral regions, in particular sensorimotor cortex, insula, temporopolar cortex, cerebellum, and brain stem, the sensorimotor cortex displaying strong degrees of interhemispheric asymmetry, further substantiated with TMS. Such findings may help explain the variable nature of swallowing disorders after stroke and other focal lesions to the cerebral cortex.  (+info)

Iterative reconstruction based on median root prior in quantification of myocardial blood flow and oxygen metabolism. (8/380)

The aim of this study was to compare reproducibility and accuracy of two reconstruction methods in quantification of myocardial blood flow and oxygen metabolism with 15O-labeled tracers and PET. A new iterative Bayesian reconstruction method based on median root prior (MRP) was compared with filtered backprojection (FBP) reconstruction method, which is traditionally used for image reconstruction in PET studies. METHODS: Regional myocardial blood flow (rMBF), oxygen extraction fraction (rOEF) and myocardial metabolic rate of oxygen consumption (rMMRO2) were quantified from images reconstructed in 27 subjects using both MRP and FBP methods. For each subject, regions of interest (ROIs) were drawn on the lateral, anterior and septal regions on four planes. To test reproducibility, the ROI drawing procedure was repeated. By using two sets of ROIs, variability was evaluated from images reconstructed with the MRP and the FBP methods. RESULTS: Correlation coefficients of mean values of rMBF, rOEF and rMMRO2 were significantly higher in the images reconstructed with the MRP reconstruction method compared with the images reconstructed with the FBP method (rMBF: MRP r = 0.896 versus FBP r = 0.737, P < 0.001; rOEF: 0.915 versus 0.855, P < 0.001; rMMRO2: 0.954 versus 0.885, P < 0.001). Coefficient of variation for each parameter was significantly lower in MRP images than in FBP images (rMBF: MRP 23.5% +/- 11.3% versus FBP 30.1% +/- 14.7%, P < 0.001; rOEF: 21.0% +/- 11.1% versus 32.1% +/- 19.8%, P < 0.001; rMMRO2: 23.1% +/- 13.2% versus 30.3% +/- 19.1%, P < 0.001). CONCLUSION: The MRP reconstruction method provides higher reproducibility and lower variability in the quantitative myocardial parameters when compared with the FBP method. This study shows that the new MRP reconstruction method improves accuracy and stability of clinical quantification of myocardial blood flow and oxygen metabolism with 15O and PET.  (+info)

Oxygen radioisotopes are unstable isotopes of the element oxygen that emit radiation as they decay to a more stable form. These isotopes can be used in medical imaging and treatment, such as positron emission tomography (PET) scans. Common oxygen radioisotopes used in medicine include oxygen-15 and oxygen-18. Oxygen-15 has a very short half-life of about 2 minutes, while oxygen-18 has a longer half-life of about 2 hours. These isotopes can be incorporated into molecules such as water or carbon dioxide, which can then be used to study blood flow, metabolism and other physiological processes in the body.

Oxygen is a colorless, odorless, tasteless gas that constitutes about 21% of the earth's atmosphere. It is a crucial element for human and most living organisms as it is vital for respiration. Inhaled oxygen enters the lungs and binds to hemoglobin in red blood cells, which carries it to tissues throughout the body where it is used to convert nutrients into energy and carbon dioxide, a waste product that is exhaled.

Medically, supplemental oxygen therapy may be provided to patients with conditions such as chronic obstructive pulmonary disease (COPD), pneumonia, heart failure, or other medical conditions that impair the body's ability to extract sufficient oxygen from the air. Oxygen can be administered through various devices, including nasal cannulas, face masks, and ventilators.

Radioisotopes, also known as radioactive isotopes or radionuclides, are variants of chemical elements that have unstable nuclei and emit radiation in the form of alpha particles, beta particles, gamma rays, or conversion electrons. These isotopes are formed when an element's nucleus undergoes natural or artificial radioactive decay.

Radioisotopes can be produced through various processes, including nuclear fission, nuclear fusion, and particle bombardment in a cyclotron or other types of particle accelerators. They have a wide range of applications in medicine, industry, agriculture, research, and energy production. In the medical field, radioisotopes are used for diagnostic imaging, radiation therapy, and in the labeling of molecules for research purposes.

It is important to note that handling and using radioisotopes requires proper training, safety measures, and regulatory compliance due to their ionizing radiation properties, which can pose potential health risks if not handled correctly.

Zinc radioisotopes are unstable isotopes or variants of the element zinc that undergo radioactive decay, emitting radiation in the process. These isotopes have a different number of neutrons than the stable isotope of zinc (zinc-64), which contributes to their instability and tendency to decay.

Examples of zinc radioisotopes include zinc-65, zinc-70, and zinc-72. These isotopes are often used in medical research and diagnostic procedures due to their ability to emit gamma rays or positrons, which can be detected using specialized equipment.

Zinc radioisotopes may be used as tracers to study the metabolism and distribution of zinc in the body, or as therapeutic agents to deliver targeted radiation therapy to cancer cells. However, it is important to note that the use of radioisotopes carries potential risks, including exposure to ionizing radiation and the potential for damage to healthy tissues.

The Radioisotope Dilution Technique is a method used in nuclear medicine to measure the volume and flow rate of a particular fluid in the body. It involves introducing a known amount of a radioactive isotope, or radioisotope, into the fluid, such as blood. The isotope mixes with the fluid, and samples are then taken from the fluid at various time points.

By measuring the concentration of the radioisotope in each sample, it is possible to calculate the total volume of the fluid based on the amount of the isotope introduced and the dilution factor. The flow rate can also be calculated by measuring the concentration of the isotope over time and using the formula:

Flow rate = Volume/Time

This technique is commonly used in medical research and clinical settings to measure cardiac output, cerebral blood flow, and renal function, among other applications. It is a safe and reliable method that has been widely used for many years. However, it does require the use of radioactive materials and specialized equipment, so it should only be performed by trained medical professionals in appropriate facilities.

Strontium radioisotopes are radioactive isotopes of the element strontium. Strontium is an alkaline earth metal that is found in nature and has several isotopes, some of which are stable and some of which are radioactive. The radioactive isotopes of strontium, also known as strontium radionuclides, decay and emit radiation in the form of beta particles.

Strontium-89 (^89Sr) and strontium-90 (^90Sr) are two common radioisotopes of strontium that are used in medical applications. Strontium-89 is a pure beta emitter with a half-life of 50.5 days, which makes it useful for the treatment of bone pain associated with metastatic cancer. When administered, strontium-89 is taken up by bones and irradiates the bone tissue, reducing pain and improving quality of life in some patients.

Strontium-90, on the other hand, has a longer half-life of 28.8 years and emits more powerful beta particles than strontium-89. It is used as a component in radioactive waste and in some nuclear weapons, but it is not used in medical applications due to its long half-life and high radiation dose.

It's important to note that exposure to strontium radioisotopes can be harmful to human health, especially if ingested or inhaled. Therefore, handling and disposal of strontium radioisotopes require special precautions and regulations.

Oxygen consumption, also known as oxygen uptake, is the amount of oxygen that is consumed or utilized by the body during a specific period of time, usually measured in liters per minute (L/min). It is a common measurement used in exercise physiology and critical care medicine to assess an individual's aerobic metabolism and overall health status.

In clinical settings, oxygen consumption is often measured during cardiopulmonary exercise testing (CPET) to evaluate cardiovascular function, pulmonary function, and exercise capacity in patients with various medical conditions such as heart failure, chronic obstructive pulmonary disease (COPD), and other respiratory or cardiac disorders.

During exercise, oxygen is consumed by the muscles to generate energy through a process called oxidative phosphorylation. The amount of oxygen consumed during exercise can provide important information about an individual's fitness level, exercise capacity, and overall health status. Additionally, measuring oxygen consumption can help healthcare providers assess the effectiveness of treatments and rehabilitation programs in patients with various medical conditions.

Iodine radioisotopes are radioactive isotopes of the element iodine, which decays and emits radiation in the form of gamma rays. Some commonly used iodine radioisotopes include I-123, I-125, I-131. These radioisotopes have various medical applications such as in diagnostic imaging, therapy for thyroid disorders, and cancer treatment.

For example, I-131 is commonly used to treat hyperthyroidism and differentiated thyroid cancer due to its ability to destroy thyroid tissue. On the other hand, I-123 is often used in nuclear medicine scans of the thyroid gland because it emits gamma rays that can be detected by a gamma camera, allowing for detailed images of the gland's structure and function.

It is important to note that handling and administering radioisotopes require specialized training and safety precautions due to their radiation-emitting properties.

Reactive Oxygen Species (ROS) are highly reactive molecules containing oxygen, including peroxides, superoxide, hydroxyl radical, and singlet oxygen. They are naturally produced as byproducts of normal cellular metabolism in the mitochondria, and can also be generated by external sources such as ionizing radiation, tobacco smoke, and air pollutants. At low or moderate concentrations, ROS play important roles in cell signaling and homeostasis, but at high concentrations, they can cause significant damage to cell structures, including lipids, proteins, and DNA, leading to oxidative stress and potential cell death.

Krypton is a noble gas with the symbol Kr and atomic number 36. It exists in various radioisotopes, which are unstable isotopes of krypton that undergo radioactive decay. A few examples include:

1. Krypton-81: This radioisotope has a half-life of about 2.1 x 10^5 years and decays via electron capture to rubidium-81. It is produced naturally in the atmosphere by cosmic rays.
2. Krypton-83: With a half-life of approximately 85.7 days, this radioisotope decays via beta decay to bromine-83. It can be used in medical imaging for lung ventilation studies.
3. Krypton-85: This radioisotope has a half-life of about 10.7 years and decays via beta decay to rubidium-85. It is produced as a byproduct of nuclear fission and can be found in trace amounts in the atmosphere.
4. Krypton-87: With a half-life of approximately 76.3 minutes, this radioisotope decays via beta decay to rubidium-87. It is not found naturally on Earth but can be produced artificially.

It's important to note that while krypton radioisotopes have medical applications, they are also associated with potential health risks due to their radioactivity. Proper handling and safety precautions must be taken when working with these substances.

Indium radioisotopes refer to specific types of radioactive indium atoms, which are unstable and emit radiation as they decay. Indium is a chemical element with the symbol In and atomic number 49. Its radioisotopes are often used in medical imaging and therapy due to their unique properties.

For instance, one commonly used indium radioisotope is Indium-111 (^111In), which has a half-life of approximately 2.8 days. It emits gamma rays, making it useful for diagnostic imaging techniques such as single-photon emission computed tomography (SPECT). In clinical applications, indium-111 is often attached to specific molecules or antibodies that target particular cells or tissues in the body, allowing medical professionals to monitor biological processes and identify diseases like cancer.

Another example is Indium-113m (^113mIn), which has a half-life of about 99 minutes. It emits low-energy gamma rays and is used as a source for in vivo counting, typically in the form of indium chloride (InCl3) solution. This radioisotope can be used to measure blood flow, ventilation, and other physiological parameters.

It's important to note that handling and using radioisotopes require proper training and safety measures due to their ionizing radiation properties.

Sodium radioisotopes are unstable forms of sodium, an element naturally occurring in the human body, that emit radiation as they decay over time. These isotopes can be used for medical purposes such as imaging and treatment of various diseases. Commonly used sodium radioisotopes include Sodium-22 (^22Na) and Sodium-24 (^24Na).

It's important to note that the use of radioisotopes in medicine should be under the supervision of trained medical professionals, as improper handling or exposure can pose health risks.

Radioactivity is not typically considered within the realm of medical definitions, but since it does have medical applications and implications, here is a brief explanation:

Radioactivity is a natural property of certain elements (referred to as radioisotopes) that emit particles or electromagnetic waves due to changes in their atomic nuclei. This process can occur spontaneously without any external influence, leading to the emission of alpha particles, beta particles, gamma rays, or neutrons. These emissions can penetrate various materials and ionize atoms along their path, which can cause damage to living tissues.

In a medical context, radioactivity is used in both diagnostic and therapeutic settings:

1. Diagnostic applications include imaging techniques such as positron emission tomography (PET) scans and single-photon emission computed tomography (SPECT), where radioisotopes are introduced into the body to visualize organ function or detect diseases like cancer.
2. Therapeutic uses involve targeting radioisotopes directly at cancer cells, either through external beam radiation therapy or internal radiotherapy, such as brachytherapy, where a radioactive source is placed near or within the tumor.

While radioactivity has significant medical benefits, it also poses risks due to ionizing radiation exposure. Proper handling and safety measures are essential when working with radioactive materials to minimize potential harm.

Barium radioisotopes are radioactive forms of the element barium, which are used in medical imaging procedures to help diagnose various conditions. The radioisotopes emit gamma rays that can be detected by external devices, allowing doctors to visualize the inside of the body. Barium sulfate is often used as a contrast agent in X-rays and CT scans, but when combined with a radioisotope such as barium-133, barium-198, or barium-207, it can provide more detailed images of specific organs or systems.

For example, barium sulfate mixed with barium-133 may be used in a lung scan to help diagnose pulmonary embolism or other respiratory conditions. Barium-207 is sometimes used in bone scans to detect fractures, tumors, or infections.

It's important to note that the use of radioisotopes carries some risks, including exposure to radiation and potential allergic reactions to the barium compound. However, these risks are generally considered low compared to the benefits of accurate diagnosis and effective treatment.

Radionuclide imaging, also known as nuclear medicine, is a medical imaging technique that uses small amounts of radioactive material, called radionuclides or radiopharmaceuticals, to diagnose and treat various diseases and conditions. The radionuclides are introduced into the body through injection, inhalation, or ingestion and accumulate in specific organs or tissues. A special camera then detects the gamma rays emitted by these radionuclides and converts them into images that provide information about the structure and function of the organ or tissue being studied.

Radionuclide imaging can be used to evaluate a wide range of medical conditions, including heart disease, cancer, neurological disorders, gastrointestinal disorders, and bone diseases. The technique is non-invasive and generally safe, with minimal exposure to radiation. However, it should only be performed by qualified healthcare professionals in accordance with established guidelines and regulations.

Yttrium radioisotopes are radioactive isotopes or variants of the element Yttrium, which is a rare earth metal. These radioisotopes are artificially produced and have unstable nuclei that emit radiation in the form of gamma rays or high-speed particles. Examples of yttrium radioisotopes include Yttrium-90 and Yttrium-86, which are used in medical applications such as radiotherapy for cancer treatment and molecular imaging for diagnostic purposes.

Yttrium-90 is a pure beta emitter with a half-life of 64.1 hours, making it useful for targeted radionuclide therapy. It can be used to treat liver tumors, leukemia, and lymphoma by attaching it to monoclonal antibodies or other targeting agents that selectively bind to cancer cells.

Yttrium-86 is a positron emitter with a half-life of 14.7 hours, making it useful for positron emission tomography (PET) imaging. It can be used to label radiopharmaceuticals and track their distribution in the body, providing information on the location and extent of disease.

It is important to note that handling and use of radioisotopes require specialized training and equipment due to their potential radiation hazards.

Tin radioisotopes refer to specific variants of the element tin that have unstable nuclei and emit radiation as they decay towards a more stable state. These isotopes are often produced in nuclear reactors or particle accelerators and can be used in a variety of medical applications, such as:

1. Medical Imaging: Tin-117m, for example, is used as a radiopharmaceutical in medical imaging studies to help diagnose various conditions, including bone disorders and liver diseases.
2. Radiation Therapy: Tin-125 can be used in the treatment of certain types of cancer, such as prostate cancer, through brachytherapy - a type of radiation therapy that involves placing a radioactive source directly into or near the tumor.
3. Radioisotope Production: Tin-106 is used as a parent isotope in the production of other medical radioisotopes, such as iodine-125 and gallium-67.

It's important to note that handling and using radioisotopes requires specialized training and equipment due to their potential radiation hazards.

Carbon radioisotopes are radioactive isotopes of carbon, which is an naturally occurring chemical element with the atomic number 6. The most common and stable isotope of carbon is carbon-12 (^12C), but there are also several radioactive isotopes, including carbon-11 (^11C), carbon-14 (^14C), and carbon-13 (^13C). These radioisotopes have different numbers of neutrons in their nuclei, which makes them unstable and causes them to emit radiation.

Carbon-11 has a half-life of about 20 minutes and is used in medical imaging techniques such as positron emission tomography (PET) scans. It is produced by bombarding nitrogen-14 with protons in a cyclotron.

Carbon-14, also known as radiocarbon, has a half-life of about 5730 years and is used in archaeology and geology to date organic materials. It is produced naturally in the atmosphere by cosmic rays.

Carbon-13 is stable and has a natural abundance of about 1.1% in carbon. It is not radioactive, but it can be used as a tracer in medical research and in the study of metabolic processes.

"Iron radioisotopes" refer to specific forms of the element iron that have unstable nuclei and emit radiation. These isotopes are often used in medical imaging and treatment procedures due to their ability to be detected by specialized equipment. Common iron radioisotopes include Iron-52, Iron-55, Iron-59, and Iron-60. They can be used as tracers to study the distribution, metabolism, or excretion of iron in the body, or for targeted radiation therapy in conditions such as cancer.

Copper radioisotopes are radioactive isotopes or variants of the chemical element copper. These isotopes have an unstable nucleus and emit radiation as they decay over time. Copper has several radioisotopes, including copper-64, copper-67, and copper-60, among others. These radioisotopes are used in various medical applications such as diagnostic imaging, therapy, and research. For example, copper-64 is used in positron emission tomography (PET) scans to help diagnose diseases like cancer, while copper-67 is used in targeted radionuclide therapy for cancer treatment. The use of radioisotopes in medicine requires careful handling and regulation due to their radiation hazards.

Phosphorus radioisotopes are radioactive isotopes or variants of the element phosphorus that emit radiation. Phosphorus has several radioisotopes, with the most common ones being phosphorus-32 (^32P) and phosphorus-33 (^33P). These radioisotopes are used in various medical applications such as cancer treatment and diagnostic procedures.

Phosphorus-32 has a half-life of approximately 14.3 days and emits beta particles, making it useful for treating certain types of cancer, such as leukemia and lymphoma. It can also be used in brachytherapy, a type of radiation therapy that involves placing a radioactive source close to the tumor.

Phosphorus-33 has a shorter half-life of approximately 25.4 days and emits both beta particles and gamma rays. This makes it useful for diagnostic procedures, such as positron emission tomography (PET) scans, where the gamma rays can be detected and used to create images of the body's internal structures.

It is important to note that handling and using radioisotopes requires specialized training and equipment to ensure safety and prevent radiation exposure.

Beta particles, also known as beta rays, are a type of ionizing radiation that consist of high-energy electrons or positrons emitted from the nucleus of certain radioactive isotopes during their decay process. When a neutron in the nucleus decays into a proton, it results in an excess energy state and one electron is ejected from the atom at high speed. This ejected electron is referred to as a beta particle.

Beta particles can have both positive and negative charges, depending on the type of decay process. Negative beta particles (β−) are equivalent to electrons, while positive beta particles (β+) are equivalent to positrons. They possess kinetic energy that varies in range, with higher energies associated with greater penetrating power.

Beta particles can cause ionization and excitation of atoms and molecules they encounter, leading to chemical reactions and potential damage to living tissues. Therefore, appropriate safety measures must be taken when handling materials that emit beta radiation.

Technetium is not a medical term itself, but it is a chemical element with the symbol Tc and atomic number 43. However, in the field of nuclear medicine, which is a branch of medicine that uses small amounts of radioactive material to diagnose or treat diseases, Technetium-99m (a radioisotope of technetium) is commonly used for various diagnostic procedures.

Technetium-99m is a metastable nuclear isomer of technetium-99, and it emits gamma rays that can be detected outside the body to create images of internal organs or tissues. It has a short half-life of about 6 hours, which makes it ideal for diagnostic imaging since it decays quickly and reduces the patient's exposure to radiation.

Technetium-99m is used in a variety of medical procedures, such as bone scans, lung scans, heart scans, liver-spleen scans, brain scans, and kidney scans, among others. It can be attached to different pharmaceuticals or molecules that target specific organs or tissues, allowing healthcare professionals to assess their function or identify any abnormalities.

Mercury radioisotopes refer to specific variants of the element mercury that have unstable nuclei and emit radiation as they decay towards a more stable state. These isotopes are often produced in nuclear reactors or particle accelerators for various medical, industrial, and research applications. In the medical field, mercury-203 (^203Hg) and mercury-207 (^207Hg) are used as gamma emitters in diagnostic procedures and therapeutic treatments. However, due to environmental and health concerns associated with mercury, its use in medical applications has significantly decreased over time.

Technetium Tc 99m Sulfur Colloid is a radioactive tracer used in medical imaging procedures, specifically in nuclear medicine. It is composed of tiny particles of sulfur colloid that are labeled with the radioisotope Technetium-99m. This compound is typically injected into the patient's body, where it accumulates in certain organs or tissues, depending on the specific medical test being conducted.

The radioactive emissions from Technetium Tc 99m Sulfur Colloid are then detected by a gamma camera, which produces images that can help doctors diagnose various medical conditions, such as liver disease, inflammation, or tumors. The half-life of Technetium-99m is approximately six hours, which means that its radioactivity decreases rapidly and is eliminated from the body within a few days.

Cesium is a chemical element with the atomic number 55 and the symbol Cs. There are several isotopes of cesium, which are variants of the element that have different numbers of neutrons in their nuclei. The most stable and naturally occurring cesium isotope is cesium-133, which has 78 neutrons and a half-life of more than 3 x 10^20 years (effectively stable).

However, there are also radioactive isotopes of cesium, including cesium-134 and cesium-137. Cesium-134 has a half-life of about 2 years, while cesium-137 has a half-life of about 30 years. These isotopes are produced naturally in trace amounts by the decay of uranium and thorium in the Earth's crust, but they can also be produced artificially in nuclear reactors and nuclear weapons tests.

Cesium isotopes are commonly used in medical research and industrial applications. For example, cesium-137 is used as a radiation source in cancer therapy and industrial radiography. However, exposure to high levels of radioactive cesium can be harmful to human health, causing symptoms such as nausea, vomiting, diarrhea, and potentially more serious effects such as damage to the central nervous system and an increased risk of cancer.

Cerium is a naturally occurring element found in the Earth's crust, and it has several radioisotopes, which are radioactive isotopes or forms of cerium. These isotopes have unstable nuclei that emit radiation as they decay into more stable forms. Here are some examples of cerium radioisotopes:

* Cerium-134: This radioisotope has a half-life of about 3.12 days, which means that half of its atoms will decay into other elements in this time period. It decays by emitting beta particles and gamma rays.
* Cerium-137: This is a long-lived radioisotope with a half-life of about 2.5 years. It decays by emitting beta particles and gamma rays, and it can be used in medical imaging and cancer treatment. However, if released into the environment, it can pose a radiation hazard to humans and other organisms.
* Cerium-141: This radioisotope has a half-life of about 32.5 days, and it decays by emitting beta particles and gamma rays. It is produced in nuclear reactors and can be used for research purposes.
* Cerium-144: This radioisotope has a half-life of about 284 days, and it decays by emitting beta particles and gamma rays. It is produced in nuclear reactors and can be used for research purposes.

It's important to note that handling and working with radioisotopes requires proper training and protective measures to ensure safety and prevent radiation exposure.

Cobalt isotopes are variants of the chemical element Cobalt (Co) that have different numbers of neutrons in their atomic nuclei. This results in the different isotopes having slightly different masses and varying levels of stability.

The most naturally occurring stable cobalt isotope is Co-59, which contains 27 neutrons in its nucleus. However, there are also several radioactive isotopes of cobalt, including Co-60, which is a commonly used medical and industrial radioisotope.

Co-60 has 30 neutrons in its nucleus and undergoes beta decay, emitting gamma rays and becoming Nickel-60. It has a half-life of approximately 5.27 years, making it useful for a variety of applications, including cancer treatment, industrial radiography, and sterilization of medical equipment.

Other radioactive isotopes of cobalt include Co-57, which has a half-life of 271.8 days and is used in medical imaging, and Co-56, which has a half-life of just 77.2 seconds and is used in research.

I'm sorry for any confusion, but Hafnium is not a medical term. It is a chemical element with the symbol Hf and atomic number 72. Hafnium is a lustrous, silvery, tetravalent transition metal that chemically resembles zirconium and is found in zirconium minerals.

It has no relevance to medical terminology or healthcare. If you have any questions related to medical definitions or health-related topics, I'd be happy to try to help with those instead!

Oxygen inhalation therapy is a medical treatment that involves the administration of oxygen to a patient through a nasal tube or mask, with the purpose of increasing oxygen concentration in the body. This therapy is used to treat various medical conditions such as chronic obstructive pulmonary disease (COPD), pneumonia, heart failure, and other conditions that cause low levels of oxygen in the blood. The additional oxygen helps to improve tissue oxygenation, reduce work of breathing, and promote overall patient comfort and well-being. Oxygen therapy may be delivered continuously or intermittently, depending on the patient's needs and medical condition.

Gold radioisotopes are unstable forms of gold that emit radiation as they decay into more stable elements. They are not typically used for medical purposes, but there have been some experimental uses in the treatment of cancer. For example, Gold-198 is a radioisotope that has been used in the brachytherapy (internal radiation therapy) of certain types of tumors. It releases high-energy gamma rays and is often used as a sealed source for the treatment of cancer.

It's important to note that the use of radioisotopes in medicine, including gold radioisotopes, should only be performed under the supervision of trained medical professionals and radiation safety experts due to the potential risks associated with radiation exposure.

Isotope labeling is a scientific technique used in the field of medicine, particularly in molecular biology, chemistry, and pharmacology. It involves replacing one or more atoms in a molecule with a radioactive or stable isotope of the same element. This modified molecule can then be traced and analyzed to study its structure, function, metabolism, or interaction with other molecules within biological systems.

Radioisotope labeling uses unstable radioactive isotopes that emit radiation, allowing for detection and quantification of the labeled molecule using various imaging techniques, such as positron emission tomography (PET) or single-photon emission computed tomography (SPECT). This approach is particularly useful in tracking the distribution and metabolism of drugs, hormones, or other biomolecules in living organisms.

Stable isotope labeling, on the other hand, employs non-radioactive isotopes that do not emit radiation. These isotopes have different atomic masses compared to their natural counterparts and can be detected using mass spectrometry. Stable isotope labeling is often used in metabolic studies, protein turnover analysis, or for identifying the origin of specific molecules within complex biological samples.

In summary, isotope labeling is a versatile tool in medical research that enables researchers to investigate various aspects of molecular behavior and interactions within biological systems.

Singlet oxygen, also known as excited oxygen or oxygen triplet state, is a variant of molecular oxygen (O2) with unusual chemical and physical properties. In its ground state, molecular oxygen consists of two atoms with parallel spins, forming a triplet state. However, singlet oxygen has both atoms in a spin-paired configuration, which makes it more reactive than the ground state oxygen.

In biomedical terms, singlet oxygen is often generated during normal cellular metabolism or under pathological conditions such as inflammation and oxidative stress. It can react with various biological molecules, including lipids, proteins, and DNA, leading to damage and dysfunction of cells and tissues. Therefore, singlet oxygen has been implicated in the development and progression of several diseases, such as atherosclerosis, neurodegenerative disorders, and cancer.

It is worth noting that singlet oxygen can also be used in medical applications, such as photodynamic therapy (PDT), where it is generated by light-activated drugs to selectively destroy cancer cells or bacteria.

Lead radioisotopes refer to specific types of radioactive isotopes (or radionuclides) of the element lead. These isotopes have unstable nuclei and emit radiation as they decay over time, changing into different elements in the process. Examples of lead radioisotopes include lead-210, lead-212, and lead-214. These isotopes are often found in the decay chains of heavier radioactive elements such as uranium and thorium, and they have various applications in fields like nuclear medicine, research, and industrial radiography. However, exposure to high levels of radiation from lead radioisotopes can pose significant health risks, including damage to DNA and increased risk of cancer.

Diagnostic techniques using radioisotopes, also known as nuclear medicine, are medical diagnostic procedures that use small amounts of radioactive material, called radioisotopes or radionuclides, to diagnose and monitor various diseases and conditions. The radioisotopes are introduced into the body through different routes (such as injection, inhalation, or ingestion) and accumulate in specific organs or tissues.

The gamma rays or photons emitted by these radioisotopes are then detected by specialized imaging devices, such as gamma cameras or PET scanners, which generate images that provide information about the structure and function of the organ or tissue being examined. This information helps healthcare professionals to make accurate diagnoses, monitor disease progression, assess treatment response, and plan appropriate therapies.

Common diagnostic techniques using radioisotopes include:

1. Radionuclide imaging (also known as scintigraphy): A gamma camera is used to produce images of specific organs or tissues after the administration of a radioisotope. Examples include bone scans, lung scans, heart scans, and brain scans.
2. Positron emission tomography (PET) scans: A PET scanner detects pairs of gamma rays emitted indirectly by a positron-emitting radionuclide, such as fluorodeoxyglucose (FDG), which is often used in oncology to assess metabolic activity and identify cancerous lesions.
3. Single-photon emission computed tomography (SPECT): A specialized gamma camera rotates around the patient, acquiring multiple images from different angles that are then reconstructed into a 3D image, providing detailed information about organ function and structure.

Diagnostic techniques using radioisotopes offer several advantages, including high sensitivity, non-invasiveness, and the ability to assess both anatomical and functional aspects of organs and tissues. However, they also involve exposure to ionizing radiation, so their use should be balanced against potential risks and benefits, and alternative diagnostic methods should be considered when appropriate.

Zinc isotopes refer to variants of the chemical element zinc, each with a different number of neutrons in their atomic nucleus. Zinc has five stable isotopes: zinc-64, zinc-66, zinc-67, zinc-68, and zinc-70. These isotopes have naturally occurring abundances that vary, with zinc-64 being the most abundant at approximately 48.6%.

Additionally, there are also several radioactive isotopes of zinc, including zinc-65, zinc-71, and zinc-72, among others. These isotopes have unstable nuclei that decay over time, emitting radiation in the process. They are not found naturally on Earth and must be produced artificially through nuclear reactions.

Medical Definition: Zinc isotopes refer to variants of the chemical element zinc with different numbers of neutrons in their atomic nucleus, including stable isotopes such as zinc-64, zinc-66, zinc-67, zinc-68, and zinc-70, and radioactive isotopes such as zinc-65, zinc-71, and zinc-72.

Sulfur radioisotopes are unstable forms of the element sulfur that emit radiation as they decay into more stable forms. These isotopes can be used in medical imaging and treatment, such as in the detection and treatment of certain cancers. Common sulfur radioisotopes used in medicine include sulfur-35 and sulfur-32. Sulfur-35 is used in research and diagnostic applications, while sulfur-32 is used in brachytherapy, a type of internal radiation therapy. It's important to note that handling and usage of radioisotopes should be done by trained professionals due to the potential radiation hazards they pose.

Cadmium radioisotopes are unstable forms of the heavy metal cadmium that emit radiation as they decay into more stable elements. These isotopes can be created through various nuclear reactions, such as bombarding a cadmium atom with a high-energy particle. Some common cadmium radioisotopes include cadmium-109, cadmium-113, and cadmium-115.

These radioisotopes have a wide range of applications in medicine, particularly in diagnostic imaging and radiation therapy. For example, cadmium-109 is used as a gamma ray source for medical imaging, while cadmium-115 has been studied as a potential therapeutic agent for cancer treatment.

However, exposure to cadmium radioisotopes can also be hazardous to human health, as they can cause damage to tissues and organs through ionizing radiation. Therefore, handling and disposal of these materials must be done with care and in accordance with established safety protocols.

Astatine is a naturally occurring, radioactive, semi-metallic chemical element with the symbol At and atomic number 85. It is the rarest naturally occurring element in the Earth's crust, and the heaviest of the halogens. Astatine is not found free in nature, but is always found in combination with other elements, such as uranium and thorium.

Astatine is a highly reactive element that exists in several allotropic forms and is characterized by its metallic appearance and chemical properties similar to those of iodine. It has a short half-life, ranging from a few hours to a few days, depending on the isotope, and emits alpha, beta, and gamma radiation.

Due to its rarity, radioactivity, and short half-life, astatine has limited practical applications. However, it has been studied for potential use in medical imaging and cancer therapy due to its ability to selectively accumulate in tumors.

Radioimmunotherapy (RIT) is a medical treatment that combines the specificity of antibodies and the therapeutic effects of radiation to target and destroy cancer cells. It involves the use of radioactive isotopes, which are attached to monoclonal antibodies, that recognize and bind to antigens expressed on the surface of cancer cells. Once bound, the radioactivity emitted from the isotope irradiates the cancer cells, causing damage to their DNA and leading to cell death. This targeted approach helps minimize radiation exposure to healthy tissues and reduces side effects compared to conventional radiotherapy techniques. RIT has been used in the treatment of various hematological malignancies, such as non-Hodgkin lymphoma, and is being investigated for solid tumors as well.

Lutetium is a chemical element with the symbol Lu and atomic number 71. It is a rare earth metal that belongs to the lanthanide series. In its pure form, lutetium is a silvery-white metal that is solid at room temperature.

Medically, lutetium is used in the form of radioactive isotopes for diagnostic and therapeutic purposes. For example, lutetium-177 (^177Lu) is a radiopharmaceutical agent that can be used to treat certain types of cancer, such as neuroendocrine tumors. The radioactivity of ^177Lu can be harnessed to destroy cancer cells while minimizing damage to healthy tissue.

It's important to note that the use of lutetium in medical treatments should only be performed under the supervision of trained medical professionals, and with appropriate safety measures in place to protect patients and healthcare workers from radiation exposure.

I'm sorry for any confusion, but "Rhenium" is not a medical term. It is a chemical element with the symbol "Re" and atomic number 75. Rhenium is a heavy, silvery-white, metallic element that is highly resistant to corrosion and is used in high-temperature alloys and electronics.

It does not have any direct medical relevance or application as a drug, treatment, or diagnostic tool in human medicine. However, like many other elements, rhenium compounds are being studied for their potential medicinal uses, such as in cancer therapy. But it's important to note that these are still in the research phase and have not yet been approved for use in humans.

Samarium is not a medical term itself, but it is a chemical element with the symbol Sm and atomic number 62. It is a silvery-white metallic element that belongs to the lanthanide series in the periodic table.

However, samarium-153 (Sm-153) is a radioactive isotope of samarium that has medical applications. It is used as a therapeutic agent for the treatment of painful bone metastases, particularly in patients with prostate or breast cancer. Sm-153 is combined with a chelating agent to form a complex that can be injected into the patient's bloodstream. The chelating agent helps to ensure that the samarium is distributed throughout the body and is not taken up by healthy tissues. Once inside the body, Sm-153 emits beta particles, which can destroy cancer cells in the bones and relieve pain.

Therefore, while samarium is not a medical term itself, it does have medical applications as a therapeutic agent for the treatment of bone metastases.

Radiopharmaceuticals are defined as pharmaceutical preparations that contain radioactive isotopes and are used for diagnosis or therapy in nuclear medicine. These compounds are designed to interact specifically with certain biological targets, such as cells, tissues, or organs, and emit radiation that can be detected and measured to provide diagnostic information or used to destroy abnormal cells or tissue in therapeutic applications.

The radioactive isotopes used in radiopharmaceuticals have carefully controlled half-lives, which determine how long they remain radioactive and how long the pharmaceutical preparation remains effective. The choice of radioisotope depends on the intended use of the radiopharmaceutical, as well as factors such as its energy, range of emission, and chemical properties.

Radiopharmaceuticals are used in a wide range of medical applications, including imaging, cancer therapy, and treatment of other diseases and conditions. Examples of radiopharmaceuticals include technetium-99m for imaging the heart, lungs, and bones; iodine-131 for treating thyroid cancer; and samarium-153 for palliative treatment of bone metastases.

The use of radiopharmaceuticals requires specialized training and expertise in nuclear medicine, as well as strict adherence to safety protocols to minimize radiation exposure to patients and healthcare workers.

Radioactive soil pollutants refer to radioactive substances that contaminate and negatively impact the chemical, physical, and biological properties of soil. These pollutants can arise from various sources such as nuclear accidents, industrial activities, agricultural practices, and military testing. They include radionuclides such as uranium, plutonium, cesium-137, and strontium-90, among others.

Exposure to radioactive soil pollutants can have serious health consequences for humans and other living organisms. Direct contact with contaminated soil can result in radiation exposure, while ingestion or inhalation of contaminated soil particles can lead to internal radiation exposure. This can increase the risk of cancer, genetic mutations, and other health problems.

Radioactive soil pollutants can also have negative impacts on the environment, such as reducing soil fertility, disrupting ecosystems, and contaminating water sources. Therefore, it is essential to monitor and regulate radioactive soil pollution to protect human health and the environment.

Bromine radioisotopes are unstable forms of the element bromine that emit radiation as they decay into more stable forms. These isotopes can be used in various medical applications, such as diagnostic imaging and cancer treatment. Some commonly used bromine radioisotopes include Bromine-75, Bromine-76, and Bromine-77.

Bromine-75 is a positron-emitting radionuclide that can be used in positron emission tomography (PET) scans to image and diagnose various diseases, including cancer. It has a half-life of about 97 minutes.

Bromine-76 is also a positron-emitting radionuclide with a longer half-life of approximately 16.2 hours. It can be used in PET imaging to study the pharmacokinetics and metabolism of drugs, as well as for tumor imaging.

Bromine-77 is a gamma-emitting radionuclide with a half-life of about 57 hours. It can be used in various medical applications, such as in the labeling of antibodies and other biomolecules for diagnostic purposes.

It's important to note that handling and using radioisotopes require specialized training and equipment due to their potential radiation hazards.

Scintillation counting is a method used in medical physics and nuclear medicine to detect and quantify radioactivity. It relies on the principle that certain materials, known as scintillators, emit light flashes (scintillations) when they absorb ionizing radiation. This light can then be detected and measured to determine the amount of radiation present.

In a scintillation counting system, the sample containing radioisotopes is placed in close proximity to the scintillator. When radiation is emitted from the sample, it interacts with the scintillator material, causing it to emit light. This light is then detected by a photomultiplier tube (PMT), which converts the light into an electrical signal that can be processed and counted by electronic circuits.

The number of counts recorded over a specific period of time is proportional to the amount of radiation emitted by the sample, allowing for the quantification of radioactivity. Scintillation counting is widely used in various applications such as measuring radioactive decay rates, monitoring environmental radiation levels, and analyzing radioisotopes in biological samples.

A subdural effusion is an abnormal accumulation of fluid in the potential space between the dura mater (the outermost layer of the meninges that covers the brain and spinal cord) and the arachnoid membrane (one of the three layers of the meninges that surround the brain and spinal cord) in the subdural space.

Subdural effusions can occur due to various reasons, including head trauma, infection, or complications from neurosurgical procedures. The fluid accumulation may result from bleeding (subdural hematoma), inflammation, or increased cerebrospinal fluid pressure. Depending on the underlying cause and the amount of fluid accumulated, subdural effusions can cause various symptoms, such as headaches, altered mental status, or neurological deficits.

Subdural effusions are often asymptomatic and may resolve independently; however, in some cases, medical intervention might be necessary to alleviate the pressure on the brain or address the underlying condition. Imaging techniques like computed tomography (CT) or magnetic resonance imaging (MRI) scans are typically used to diagnose and monitor subdural effusions.

Calcium isotopes refer to variants of the chemical element calcium (ca) that have different numbers of neutrons in their atomic nuclei, and therefore differ in their atomic masses while having the same number of protons. The most common and stable calcium isotope is Calcium-40, which contains 20 protons and 20 neutrons. However, calcium has several other isotopes, including Calcium-42, Calcium-43, Calcium-44, and Calcium-46 to -52, each with different numbers of neutrons. Some of these isotopes are radioactive and decay over time. The relative abundances of calcium isotopes can vary in different environments and can provide information about geological and biological processes.

Radioactive waste is defined in the medical context as any material that contains radioactive nuclides in sufficient concentrations or for such durations that it is considered a threat to human health and the environment. It includes materials ranging from used hospital supplies, equipment, and substances contaminated with radionuclides, to liquids and gases released during the reprocessing of spent nuclear fuel.

Radioactive waste can be classified into two main categories:

1. Exempt waste: Waste that does not require long-term management as a radioactive waste due to its low activity and short half-life.
2. Radioactive waste: Waste that requires long-term management as a radioactive waste due to its higher activity or longer half-life, which can pose a threat to human health and the environment for many years.

Radioactive waste management is a critical aspect of nuclear medicine and radiation safety, with regulations in place to ensure proper handling, storage, transportation, and disposal of such materials.

Radio-iodinated serum albumin refers to human serum albumin that has been chemically bonded with radioactive iodine isotopes, typically I-125 or I-131. This results in a radiolabeled protein that can be used in medical imaging and research to track the distribution and movement of the protein in the body.

In human physiology, serum albumin is the most abundant protein in plasma, synthesized by the liver, and it plays a crucial role in maintaining oncotic pressure and transporting various molecules in the bloodstream. Radio-iodination of serum albumin allows for non-invasive monitoring of its behavior in vivo, which can be useful in evaluating conditions such as protein losing enteropathies, nephrotic syndrome, or liver dysfunction.

It is essential to handle and dispose of radio-iodinated serum albumin with proper radiation safety protocols due to its radioactive nature.

Ruthenium radioisotopes refer to unstable isotopes of the element ruthenium, which decays or disintegrates spontaneously emitting radiation. Ruthenium is a rare transition metal with the atomic number 44 and has several radioisotopes, including ruthenium-97, ruthenium-103, ruthenium-105, and ruthenium-106. These radioisotopes have medical applications in diagnostic imaging, radiation therapy, and brachytherapy (a type of internal radiation therapy).

For instance, ruthenium-106 is used as a radiation source in ophthalmic treatments for conditions such as neovascular age-related macular degeneration and diabetic retinopathy. Ruthenium-103 is also used in brachytherapy seeds for the treatment of prostate cancer.

It's important to note that handling and using radioisotopes require specialized training, equipment, and safety measures due to their radiation hazards.

Radiometric dating is a method used to determine the age of objects, including rocks and other fossilized materials, based on the decay rates of radioactive isotopes. This technique relies on the fact that certain elements, such as carbon-14, potassium-40, and uranium-238, are unstable and gradually decay into different elements over time.

By measuring the ratio of the remaining radioactive isotope to the stable end product, scientists can calculate the age of a sample using the following formula:

age = (ln(Nf/N0)) / λ

where Nf is the number of atoms of the decayed isotope, N0 is the initial number of atoms of the radioactive isotope, and λ is the decay constant.

Radiometric dating has been used to date objects ranging from a few thousand years old to billions of years old, making it an essential tool for archaeologists, geologists, and other scientists who study the history of our planet.

Alpha particles are a type of radiation that consist of two protons and two neutrons. They are essentially the nuclei of helium atoms and are produced during the decay of radioactive isotopes, such as uranium or radon. When an alpha particle is emitted from a radioactive atom, it carries away energy and causes the atom to transform into a different element with a lower atomic number and mass number.

Alpha particles have a positive charge and are relatively massive compared to other types of radiation, such as beta particles (which are high-energy electrons) or gamma rays (which are high-energy photons). Because of their charge and mass, alpha particles can cause significant ionization and damage to biological tissue. However, they have a limited range in air and cannot penetrate the outer layers of human skin, making them generally less hazardous than other forms of radiation if exposure is external.

Internal exposure to alpha-emitting radionuclides, however, can be much more dangerous because alpha particles can cause significant damage to cells and DNA when they are emitted inside the body. This is why inhaling or ingesting radioactive materials that emit alpha particles can pose a serious health risk.

Selenium radioisotopes are unstable forms of the element selenium that emit radiation as they decay into more stable forms. These isotopes can be produced through various nuclear reactions, such as irradiating a stable selenium target with protons or alpha particles. Some examples of selenium radioisotopes include selenium-75, selenium-79, and selenium-81.

Selenium-75 is commonly used in medical imaging to study the function of the thyroid gland, as it accumulates in this gland and can be detected using a gamma camera. Selenium-79 and selenium-81 have potential uses in cancer treatment, as they can be incorporated into compounds that selectively target and destroy cancer cells. However, more research is needed to fully understand the potential benefits and risks of using these radioisotopes in medical treatments.

It's important to note that handling and using radioisotopes requires special training and precautions, as they can be dangerous if not handled properly. Exposure to radiation from radioisotopes can increase the risk of cancer and other health problems, so it's essential to use them only under controlled conditions and with appropriate safety measures in place.

Isotopes are variants of a chemical element that have the same number of protons in their atomic nucleus, but a different number of neutrons. This means they have different atomic masses, but share similar chemical properties. Some isotopes are stable and do not decay naturally, while others are unstable and radioactive, undergoing radioactive decay and emitting radiation in the process. These radioisotopes are often used in medical imaging and treatment procedures.

Sodium Pertechnetate Tc 99m is a radioactive pharmaceutical preparation used in medical diagnostic imaging. It is a technetium-99m radiopharmaceutical, where technetium-99m is a metastable nuclear isomer of technetium-99, which emits gamma rays and has a half-life of 6 hours. Sodium Pertechnetate Tc 99m is used as a contrast agent in various diagnostic procedures, such as imaging of the thyroid, salivary glands, or the brain, to evaluate conditions like inflammation, tumors, or abnormalities in blood flow. It is typically administered intravenously, and its short half-life ensures that the radiation exposure is limited.

Heterocyclic compounds are organic molecules that contain a ring structure made up of at least one atom that is not carbon, known as a heteroatom. These heteroatoms can include nitrogen, oxygen, sulfur, or other elements. In the case of "1-ring" heterocyclic compounds, the molecule contains a single ring structure composed of these heteroatoms and carbon atoms. Examples of 1-ring heterocyclic compounds include pyridine (contains one nitrogen atom in the ring), furan (contains one oxygen atom in the ring), and thiophene (contains one sulfur atom in the ring). These compounds play important roles in various biological processes and are also found in many drugs, dyes, and materials.

I'm sorry for any confusion, but 'Tungsten' is not a medical term. It is a chemical element with the symbol W and atomic number 74. Tungsten is a rare metal found naturally on Earth, and it has many industrial uses due to its hardness, high density, and high melting point.

In the context of medicine or healthcare, tungsten may be encountered in certain medical devices, such as X-ray tubes and electrodes, where its properties are utilized for their durability and heat resistance. However, it is not a term that would typically have a formal medical definition.

Pentetic Acid, also known as DTPA (Diethylenetriaminepentaacetic acid), is not a medication itself but a chelating agent used in the preparation of pharmaceutical products. A chelating agent is a compound that can form multiple bonds with metal ions, allowing them to be excreted from the body.

Pentetic Acid is used in medical treatments to remove or decrease the levels of certain toxic metals, such as lead, plutonium, americium, and curium, from the body. It can be given intravenously or orally, depending on the specific situation and the formulation of the medication.

It is important to note that the use of Pentetic Acid should be under the supervision of a healthcare professional, as it can also bind to essential metals like zinc, calcium, and iron, which can lead to deficiencies if not properly managed.

Tissue distribution, in the context of pharmacology and toxicology, refers to the way that a drug or xenobiotic (a chemical substance found within an organism that is not naturally produced by or expected to be present within that organism) is distributed throughout the body's tissues after administration. It describes how much of the drug or xenobiotic can be found in various tissues and organs, and is influenced by factors such as blood flow, lipid solubility, protein binding, and the permeability of cell membranes. Understanding tissue distribution is important for predicting the potential effects of a drug or toxin on different parts of the body, and for designing drugs with improved safety and efficacy profiles.

Radioisotope teletherapy is a type of cancer treatment that uses high-energy radiation from a radioisotope to destroy cancer cells. In this procedure, the radioisotope is placed outside the body and aimed at the tumor site, rather than being inserted into the body like in brachytherapy. The radiation travels through space and penetrates the tissue to reach the tumor, where it damages the DNA of cancer cells and inhibits their ability to divide and grow. This type of radiotherapy is often used for larger or more difficult-to-reach tumors, as well as for palliative care in advanced stages of cancer. Examples of radioisotopes commonly used in teletherapy include cobalt-60 and cesium-137.

Oxygen isotopes are different forms or varieties of the element oxygen that have the same number of protons in their atomic nuclei, which is 8, but a different number of neutrons. The most common oxygen isotopes are oxygen-16 (^{16}O), which contains 8 protons and 8 neutrons, and oxygen-18 (^{18}O), which contains 8 protons and 10 neutrons.

The ratio of these oxygen isotopes can vary in different substances, such as water molecules, and can provide valuable information about the origins and history of those substances. For example, scientists can use the ratio of oxygen-18 to oxygen-16 in ancient ice cores or fossilized bones to learn about past climate conditions or the diets of ancient organisms.

In medical contexts, oxygen isotopes may be used in diagnostic tests or treatments, such as positron emission tomography (PET) scans, where a radioactive isotope of oxygen (such as oxygen-15) is introduced into the body and emits positrons that can be detected by specialized equipment to create detailed images of internal structures.

Gamma spectrometry is a type of spectrometry used to identify and measure the energy and intensity of gamma rays emitted by radioactive materials. It utilizes a device called a gamma spectrometer, which typically consists of a scintillation detector or semiconductor detector, coupled with electronic circuitry that records and analyzes the energy of each detected gamma ray.

Gamma rays are a form of ionizing radiation, characterized by their high energy and short wavelength. When they interact with matter, such as the detector in a gamma spectrometer, they can cause the ejection of electrons from atoms or molecules, leading to the creation of charged particles that can be detected and measured.

In gamma spectrometry, the energy of each detected gamma ray is used to identify the radioactive isotope that emitted it, based on the characteristic energy levels associated with different isotopes. The intensity of the gamma rays can also be measured, providing information about the quantity or activity of the radioactive material present.

Gamma spectrometry has a wide range of applications in fields such as nuclear medicine, radiation protection, environmental monitoring, and nuclear non-proliferation.

In the context of medical research, "methods" refers to the specific procedures or techniques used in conducting a study or experiment. This includes details on how data was collected, what measurements were taken, and what statistical analyses were performed. The methods section of a medical paper allows other researchers to replicate the study if they choose to do so. It is considered one of the key components of a well-written research article, as it provides transparency and helps establish the validity of the findings.

Nuclear medicine is a branch of medical imaging that uses small amounts of radioactive material, called radiopharmaceuticals, to diagnose and treat various diseases. The radiopharmaceuticals are taken internally, usually through injection or oral administration, and accumulate in specific organs or tissues. A special camera then detects the radiation emitted by these substances, which helps create detailed images of the body's internal structures and functions.

The images produced in nuclear medicine can help doctors identify abnormalities such as tumors, fractures, infection, or inflammation. Additionally, some radiopharmaceuticals can be used to treat certain conditions, like hyperthyroidism or cancer, by delivering targeted doses of radiation directly to the affected area. Overall, nuclear medicine provides valuable information for the diagnosis, treatment planning, and monitoring of many medical conditions.

Technetium Tc 99m Pentetate is a radioactive pharmaceutical preparation used as a radiopharmaceutical agent in medical imaging. It is a salt of technetium-99m, a metastable nuclear isomer of technetium-99, which emits gamma rays and has a half-life of 6 hours.

Technetium Tc 99m Pentetate is used in various diagnostic procedures, including renal imaging, brain scans, lung perfusion studies, and bone scans. It is distributed throughout the body after intravenous injection and is excreted primarily by the kidneys, making it useful for evaluating renal function and detecting abnormalities in the urinary tract.

The compound itself is a colorless, sterile, pyrogen-free solution that is typically supplied in a lead shielded container to protect against radiation exposure. It should be used promptly after preparation and handled with care to minimize radiation exposure to healthcare workers and patients.

Radiometry is the measurement of electromagnetic radiation, including visible light. It quantifies the amount and characteristics of radiant energy in terms of power or intensity, wavelength, direction, and polarization. In medical physics, radiometry is often used to measure therapeutic and diagnostic radiation beams used in various imaging techniques and cancer treatments such as X-rays, gamma rays, and ultraviolet or infrared light. Radiometric measurements are essential for ensuring the safe and effective use of these medical technologies.

Tritium is not a medical term, but it is a term used in the field of nuclear physics and chemistry. Tritium (symbol: T or 3H) is a radioactive isotope of hydrogen with two neutrons and one proton in its nucleus. It is also known as heavy hydrogen or superheavy hydrogen.

Tritium has a half-life of about 12.3 years, which means that it decays by emitting a low-energy beta particle (an electron) to become helium-3. Due to its radioactive nature and relatively short half-life, tritium is used in various applications, including nuclear weapons, fusion reactors, luminous paints, and medical research.

In the context of medicine, tritium may be used as a radioactive tracer in some scientific studies or medical research, but it is not a term commonly used to describe a medical condition or treatment.

Rosaniline dyes are a type of basic dye that were first synthesized in the late 19th century. They are named after rosaniline, which is a primary chemical used in their production. Rosaniline dyes are characterized by their ability to form complexes with metal ions, which can then bind to proteins and other biological molecules. This property makes them useful as histological stains, which are used to highlight specific structures or features within tissues and cells.

Rosaniline dyes include a range of different chemicals, such as methyl violet, crystal violet, and basic fuchsin. These dyes are often used in combination with other staining techniques to provide contrast and enhance the visibility of specific cellular components. For example, they may be used to stain nuclei, cytoplasm, or other structures within cells, allowing researchers and clinicians to visualize and analyze tissue samples more effectively.

It's worth noting that some rosaniline dyes have been found to have potential health hazards, particularly when used in certain forms or concentrations. Therefore, it's important to follow proper safety protocols when handling these chemicals and to use them only under the guidance of trained professionals.

"Nostoc commune" is not a medical term, but a scientific name for a type of cyanobacteria (blue-green algae). It's commonly found in various environments such as freshwater, soil, and on rocks. This organism can form colonies that appear as slimy, dark green or black mats.

While not a direct medical term, certain species of cyanobacteria, including Nostoc commune, can produce toxins that may pose health risks to humans and animals if ingested, inhaled, or contact skin. These toxins can cause various symptoms, such as rashes, nausea, vomiting, diarrhea, and liver damage. However, not all strains of Nostoc commune produce toxins, and the health risks associated with this specific species are relatively low compared to other cyanobacteria.

Nonetheless, it is essential to be aware of potential health hazards when encountering cyanobacterial blooms in recreational water bodies or drinking water sources and follow local guidelines for reporting and managing such incidents.

Whole-body counting is a non-invasive nuclear medicine technique used for the detection and measurement of radioactivity in the human body. It involves the use of sensitive radiation detectors that can measure the gamma rays emitted by radionuclides present within the body tissues.

The individual lies on a table or sits in a chair with their entire body inside a large detector, which is typically a scintillation camera or a NaI(Tl) crystal. The detector measures the number and energy of gamma rays emitted from the body, allowing for the identification and quantification of specific radionuclides present within the body.

Whole-body counting has several clinical applications, including monitoring patients who have received therapeutic radioisotopes, evaluating the effectiveness of radiation therapy, detecting and measuring internal contamination due to accidental exposure or intentional intake, and assessing the distribution and retention of radionuclides in research studies.

It is important to note that whole-body counting does not provide anatomical information like other imaging techniques (e.g., CT, MRI), but rather offers functional data on the presence and quantity of radioactivity within the body.

Potassium radioisotopes refer to unstable isotopes or variants of the element potassium that emit radiation as they decay towards a stable form. A common example is Potassium-40 (40K), which occurs naturally in small amounts in potassium-containing substances. It decays through beta decay and positron emission, as well as electron capture, with a half-life of approximately 1.25 billion years.

Radioisotopes like 40K have medical applications such as in dating archaeological artifacts or studying certain biological processes. However, exposure to high levels of radiation from potassium radioisotopes can be harmful and potentially lead to health issues like radiation sickness or cancer.

Carbon isotopes are variants of the chemical element carbon that have different numbers of neutrons in their atomic nuclei. The most common and stable isotope of carbon is carbon-12 (^{12}C), which contains six protons and six neutrons. However, carbon can also come in other forms, known as isotopes, which contain different numbers of neutrons.

Carbon-13 (^{13}C) is a stable isotope of carbon that contains seven neutrons in its nucleus. It makes up about 1.1% of all carbon found on Earth and is used in various scientific applications, such as in tracing the metabolic pathways of organisms or in studying the age of fossilized materials.

Carbon-14 (^{14}C), also known as radiocarbon, is a radioactive isotope of carbon that contains eight neutrons in its nucleus. It is produced naturally in the atmosphere through the interaction of cosmic rays with nitrogen gas. Carbon-14 has a half-life of about 5,730 years, which makes it useful for dating organic materials, such as archaeological artifacts or fossils, up to around 60,000 years old.

Carbon isotopes are important in many scientific fields, including geology, biology, and medicine, and are used in a variety of applications, from studying the Earth's climate history to diagnosing medical conditions.

Hyperbaric oxygenation is a medical treatment in which a patient breathes pure oxygen in a pressurized chamber, typically at greater than one atmosphere absolute (ATA). This process results in increased levels of oxygen being dissolved in the blood and delivered to body tissues, thereby promoting healing, reducing inflammation, and combating infection. Hyperbaric oxygen therapy is used to treat various medical conditions, including carbon monoxide poisoning, decompression sickness, gangrene, and wounds that are slow to heal due to diabetes or radiation injury.

Iodohippuric acid is not typically defined in medical textbooks, but it is a radiocontrast agent used in imaging studies. Here's the definition from a chemistry perspective:

Iodohippuric acid, also known as iodine-131 hippuran or Hippuran, is an organic compound with the formula C6H5IO2 + . It is a derivative of hippuric acid, where one hydrogen atom has been replaced by radioactive iodine-131.

In medical imaging, it is used as a radiocontrast agent for renal function studies, such as renography, to assess the functioning and anatomy of the kidneys. The compound is excreted primarily by the kidneys, so its clearance rate can be used to estimate the glomerular filtration rate (GFR), which is a measure of kidney function.

Therefore, while not a medical definition per se, iodohippuric acid is an essential compound in nuclear medicine for evaluating renal function.

In the field of medicine, "time factors" refer to the duration of symptoms or time elapsed since the onset of a medical condition, which can have significant implications for diagnosis and treatment. Understanding time factors is crucial in determining the progression of a disease, evaluating the effectiveness of treatments, and making critical decisions regarding patient care.

For example, in stroke management, "time is brain," meaning that rapid intervention within a specific time frame (usually within 4.5 hours) is essential to administering tissue plasminogen activator (tPA), a clot-busting drug that can minimize brain damage and improve patient outcomes. Similarly, in trauma care, the "golden hour" concept emphasizes the importance of providing definitive care within the first 60 minutes after injury to increase survival rates and reduce morbidity.

Time factors also play a role in monitoring the progression of chronic conditions like diabetes or heart disease, where regular follow-ups and assessments help determine appropriate treatment adjustments and prevent complications. In infectious diseases, time factors are crucial for initiating antibiotic therapy and identifying potential outbreaks to control their spread.

Overall, "time factors" encompass the significance of recognizing and acting promptly in various medical scenarios to optimize patient outcomes and provide effective care.

In the context of medicine, and specifically in physiology and respiratory therapy, partial pressure (P or p) is a measure of the pressure exerted by an individual gas in a mixture of gases. It's commonly used to describe the concentrations of gases in the body, such as oxygen (PO2), carbon dioxide (PCO2), and nitrogen (PN2).

The partial pressure of a specific gas is calculated as the fraction of that gas in the total mixture multiplied by the total pressure of the mixture. This concept is based on Dalton's law, which states that the total pressure exerted by a mixture of gases is equal to the sum of the pressures exerted by each individual gas.

For example, in room air at sea level, the partial pressure of oxygen (PO2) is approximately 160 mmHg (mm of mercury), which represents about 21% of the total barometric pressure (760 mmHg). This concept is crucial for understanding gas exchange in the lungs and how gases move across membranes, such as from alveoli to blood and vice versa.

Organometallic compounds are a type of chemical compound that contain at least one metal-carbon bond. This means that the metal is directly attached to carbon atom(s) from an organic molecule. These compounds can be synthesized through various methods, and they have found widespread use in industrial and medicinal applications, including catalysis, polymerization, and pharmaceuticals.

It's worth noting that while organometallic compounds contain metal-carbon bonds, not all compounds with metal-carbon bonds are considered organometallic. For example, in classical inorganic chemistry, simple salts of metal carbonyls (M(CO)n) are not typically classified as organometallic, but rather as metal carbonyl complexes. The distinction between these classes of compounds can sometimes be subtle and is a matter of ongoing debate among chemists.

Radiation dosage, in the context of medical physics, refers to the amount of radiation energy that is absorbed by a material or tissue, usually measured in units of Gray (Gy), where 1 Gy equals an absorption of 1 Joule of radiation energy per kilogram of matter. In the clinical setting, radiation dosage is used to plan and assess the amount of radiation delivered to a patient during treatments such as radiotherapy. It's important to note that the biological impact of radiation also depends on other factors, including the type and energy level of the radiation, as well as the sensitivity of the irradiated tissues or organs.

Positron-Emission Tomography (PET) is a type of nuclear medicine imaging that uses small amounts of radioactive material, called a radiotracer, to produce detailed, three-dimensional images. This technique measures metabolic activity within the body, such as sugar metabolism, to help distinguish between healthy and diseased tissue, identify cancerous cells, or examine the function of organs.

During a PET scan, the patient is injected with a radiotracer, typically a sugar-based compound labeled with a positron-emitting radioisotope, such as fluorine-18 (^18^F). The radiotracer accumulates in cells that are metabolically active, like cancer cells. As the radiotracer decays, it emits positrons, which then collide with electrons in nearby tissue, producing gamma rays. A special camera, called a PET scanner, detects these gamma rays and uses this information to create detailed images of the body's internal structures and processes.

PET is often used in conjunction with computed tomography (CT) or magnetic resonance imaging (MRI) to provide both functional and anatomical information, allowing for more accurate diagnosis and treatment planning. Common applications include detecting cancer recurrence, staging and monitoring cancer, evaluating heart function, and assessing brain function in conditions like dementia and epilepsy.

Intestinal absorption refers to the process by which the small intestine absorbs water, nutrients, and electrolytes from food into the bloodstream. This is a critical part of the digestive process, allowing the body to utilize the nutrients it needs and eliminate waste products. The inner wall of the small intestine contains tiny finger-like projections called villi, which increase the surface area for absorption. Nutrients are absorbed into the bloodstream through the walls of the capillaries in these villi, and then transported to other parts of the body for use or storage.

In the context of medicine and pharmacology, "kinetics" refers to the study of how a drug moves throughout the body, including its absorption, distribution, metabolism, and excretion (often abbreviated as ADME). This field is called "pharmacokinetics."

1. Absorption: This is the process of a drug moving from its site of administration into the bloodstream. Factors such as the route of administration (e.g., oral, intravenous, etc.), formulation, and individual physiological differences can affect absorption.

2. Distribution: Once a drug is in the bloodstream, it gets distributed throughout the body to various tissues and organs. This process is influenced by factors like blood flow, protein binding, and lipid solubility of the drug.

3. Metabolism: Drugs are often chemically modified in the body, typically in the liver, through processes known as metabolism. These changes can lead to the formation of active or inactive metabolites, which may then be further distributed, excreted, or undergo additional metabolic transformations.

4. Excretion: This is the process by which drugs and their metabolites are eliminated from the body, primarily through the kidneys (urine) and the liver (bile).

Understanding the kinetics of a drug is crucial for determining its optimal dosing regimen, potential interactions with other medications or foods, and any necessary adjustments for special populations like pediatric or geriatric patients, or those with impaired renal or hepatic function.

Vitamin B12, also known as cobalamin, is a water-soluble vitamin that plays a crucial role in the synthesis of DNA, formation of red blood cells, and maintenance of the nervous system. It is involved in the metabolism of every cell in the body, particularly affecting DNA regulation and neurological function.

Vitamin B12 is unique among vitamins because it contains a metal ion, cobalt, from which its name is derived. This vitamin can be synthesized only by certain types of bacteria and is not produced by plants or animals. The major sources of vitamin B12 in the human diet include animal-derived foods such as meat, fish, poultry, eggs, and dairy products, as well as fortified plant-based milk alternatives and breakfast cereals.

Deficiency in vitamin B12 can lead to various health issues, including megaloblastic anemia, fatigue, neurological symptoms such as numbness and tingling in the extremities, memory loss, and depression. Since vitamin B12 is not readily available from plant-based sources, vegetarians and vegans are at a higher risk of deficiency and may require supplementation or fortified foods to meet their daily requirements.

Anoxia is a medical condition that refers to the absence or complete lack of oxygen supply in the body or a specific organ, tissue, or cell. This can lead to serious health consequences, including damage or death of cells and tissues, due to the vital role that oxygen plays in supporting cellular metabolism and energy production.

Anoxia can occur due to various reasons, such as respiratory failure, cardiac arrest, severe blood loss, carbon monoxide poisoning, or high altitude exposure. Prolonged anoxia can result in hypoxic-ischemic encephalopathy, a serious condition that can cause brain damage and long-term neurological impairments.

Medical professionals use various diagnostic tests, such as blood gas analysis, pulse oximetry, and electroencephalography (EEG), to assess oxygen levels in the body and diagnose anoxia. Treatment for anoxia typically involves addressing the underlying cause, providing supplemental oxygen, and supporting vital functions, such as breathing and circulation, to prevent further damage.

Hydrogen peroxide (H2O2) is a colorless, odorless, clear liquid with a slightly sweet taste, although drinking it is harmful and can cause poisoning. It is a weak oxidizing agent and is used as an antiseptic and a bleaching agent. In diluted form, it is used to disinfect wounds and kill bacteria and viruses on the skin; in higher concentrations, it can be used to bleach hair or remove stains from clothing. It is also used as a propellant in rocketry and in certain industrial processes. Chemically, hydrogen peroxide is composed of two hydrogen atoms and two oxygen atoms, and it is structurally similar to water (H2O), with an extra oxygen atom. This gives it its oxidizing properties, as the additional oxygen can be released and used to react with other substances.

A sentinel lymph node biopsy is a surgical procedure used in cancer staging to determine if the cancer has spread beyond the primary tumor to the lymphatic system. This procedure involves identifying and removing the sentinel lymph node(s), which are the first few lymph nodes to which cancer cells are most likely to spread from the primary tumor site.

The sentinel lymph node(s) are identified by injecting a tracer substance (usually a radioactive material and/or a blue dye) near the tumor site. The tracer substance is taken up by the lymphatic vessels and transported to the sentinel lymph node(s), allowing the surgeon to locate and remove them.

The removed sentinel lymph node(s) are then examined under a microscope for the presence of cancer cells. If no cancer cells are found, it is unlikely that the cancer has spread to other lymph nodes or distant sites in the body. However, if cancer cells are present, further lymph node dissection and/or additional treatment may be necessary.

Sentinel lymph node biopsy is commonly used in the staging of melanoma, breast cancer, and some types of head and neck cancer.

Oxidation-Reduction (redox) reactions are a type of chemical reaction involving a transfer of electrons between two species. The substance that loses electrons in the reaction is oxidized, and the substance that gains electrons is reduced. Oxidation and reduction always occur together in a redox reaction, hence the term "oxidation-reduction."

In biological systems, redox reactions play a crucial role in many cellular processes, including energy production, metabolism, and signaling. The transfer of electrons in these reactions is often facilitated by specialized molecules called electron carriers, such as nicotinamide adenine dinucleotide (NAD+/NADH) and flavin adenine dinucleotide (FAD/FADH2).

The oxidation state of an element in a compound is a measure of the number of electrons that have been gained or lost relative to its neutral state. In redox reactions, the oxidation state of one or more elements changes as they gain or lose electrons. The substance that is oxidized has a higher oxidation state, while the substance that is reduced has a lower oxidation state.

Overall, oxidation-reduction reactions are fundamental to the functioning of living organisms and are involved in many important biological processes.

Technetium Tc 99m Medronate is a radiopharmaceutical agent used in nuclear medicine for bone scintigraphy. It is a technetium-labeled bisphosphonate compound, which accumulates in areas of increased bone turnover and metabolism. This makes it useful for detecting and evaluating various bone diseases and conditions, such as fractures, tumors, infections, and arthritis.

The "Tc 99m" refers to the radioisotope technetium-99m, which has a half-life of approximately 6 hours and emits gamma rays that can be detected by a gamma camera. The medronate component is a bisphosphonate molecule that binds to hydroxyapatite crystals in bone tissue, allowing the radiolabeled compound to accumulate in areas of active bone remodeling.

Overall, Technetium Tc 99m Medronate is an important tool in nuclear medicine for diagnosing and managing various musculoskeletal disorders.

In medicine, "absorption" refers to the process by which substances, including nutrients, medications, or toxins, are taken up and assimilated into the body's tissues or bloodstream after they have been introduced into the body via various routes (such as oral, intravenous, or transdermal).

The absorption of a substance depends on several factors, including its chemical properties, the route of administration, and the presence of other substances that may affect its uptake. For example, some medications may be better absorbed when taken with food, while others may require an empty stomach for optimal absorption.

Once a substance is absorbed into the bloodstream, it can then be distributed to various tissues throughout the body, where it may exert its effects or be metabolized and eliminated by the body's detoxification systems. Understanding the process of absorption is crucial in developing effective medical treatments and determining appropriate dosages for medications.

Oxidative stress is defined as an imbalance between the production of reactive oxygen species (free radicals) and the body's ability to detoxify them or repair the damage they cause. This imbalance can lead to cellular damage, oxidation of proteins, lipids, and DNA, disruption of cellular functions, and activation of inflammatory responses. Prolonged or excessive oxidative stress has been linked to various health conditions, including cancer, cardiovascular diseases, neurodegenerative disorders, and aging-related diseases.

Bismuth is a heavy, brittle, white metallic element (symbol: Bi; atomic number: 83) that is found in various minerals and is used in several industrial, medical, and household products. In medicine, bismuth compounds are commonly used as antidiarrheal and anti-ulcer agents due to their antibacterial properties. They can be found in medications like Pepto-Bismol and Kaopectate. It's important to note that bismuth itself is not used medically, but its compounds have medical applications.

Monoclonal antibodies are a type of antibody that are identical because they are produced by a single clone of cells. They are laboratory-produced molecules that act like human antibodies in the immune system. They can be designed to attach to specific proteins found on the surface of cancer cells, making them useful for targeting and treating cancer. Monoclonal antibodies can also be used as a therapy for other diseases, such as autoimmune disorders and inflammatory conditions.

Monoclonal antibodies are produced by fusing a single type of immune cell, called a B cell, with a tumor cell to create a hybrid cell, or hybridoma. This hybrid cell is then able to replicate indefinitely, producing a large number of identical copies of the original antibody. These antibodies can be further modified and engineered to enhance their ability to bind to specific targets, increase their stability, and improve their effectiveness as therapeutic agents.

Monoclonal antibodies have several mechanisms of action in cancer therapy. They can directly kill cancer cells by binding to them and triggering an immune response. They can also block the signals that promote cancer growth and survival. Additionally, monoclonal antibodies can be used to deliver drugs or radiation directly to cancer cells, increasing the effectiveness of these treatments while minimizing their side effects on healthy tissues.

Monoclonal antibodies have become an important tool in modern medicine, with several approved for use in cancer therapy and other diseases. They are continuing to be studied and developed as a promising approach to treating a wide range of medical conditions.

Avidin is a protein found in the white of eggs (egg whites) and some other animal tissues. It has a high binding affinity for biotin, also known as vitamin B7 or vitamin H, which is an essential nutrient for humans and other organisms. This property makes avidin useful in various biochemical and medical applications, such as immunohistochemistry, blotting techniques, and drug delivery systems.

Biotin-avidin interactions are among the strongest non-covalent interactions known in nature, with a dissociation constant (Kd) of approximately 10^-15 M. This means that once biotin is bound to avidin, it is very difficult to separate them. In some cases, this property can be exploited to create stable and specific complexes for various applications.

However, it's worth noting that the high affinity of avidin for biotin can also have negative effects in certain contexts. For example, raw egg whites contain large amounts of avidin, which can bind to biotin in the gut and prevent its absorption if consumed in sufficient quantities. This can lead to biotin deficiency, which can cause various health problems. Cooking egg whites denatures avidin and reduces its ability to bind to biotin, making cooked eggs a safe source of biotin.

Pulse oximetry is a noninvasive method for monitoring a person's oxygen saturation (SO2) and pulse rate. It uses a device called a pulse oximeter, which measures the amount of oxygen-carrying hemoglobin in the blood compared to the amount of hemoglobin that is not carrying oxygen. This measurement is expressed as a percentage, known as oxygen saturation (SpO2). Normal oxygen saturation levels are generally 95% or above at sea level. Lower levels may indicate hypoxemia, a condition where there is not enough oxygen in the blood to meet the body's needs. Pulse oximetry is commonly used in hospitals and other healthcare settings to monitor patients during surgery, in intensive care units, and in sleep studies to detect conditions such as sleep apnea. It can also be used by individuals with certain medical conditions, such as chronic obstructive pulmonary disease (COPD), to monitor their oxygen levels at home.

Phosphorus isotopes are different forms of the element phosphorus that have different numbers of neutrons in their atomic nuclei, while the number of protons remains the same. The most common and stable isotope of phosphorus is 31P, which contains 15 protons and 16 neutrons. However, there are also several other isotopes of phosphorus that exist, including 32P and 33P, which are radioactive and have 15 protons and 17 or 18 neutrons, respectively. These radioactive isotopes are often used in medical research and treatment, such as in the form of radiopharmaceuticals to diagnose and treat various diseases.

Autoradiography is a medical imaging technique used to visualize and localize the distribution of radioactively labeled compounds within tissues or organisms. In this process, the subject is first exposed to a radioactive tracer that binds to specific molecules or structures of interest. The tissue is then placed in close contact with a radiation-sensitive film or detector, such as X-ray film or an imaging plate.

As the radioactive atoms decay, they emit particles (such as beta particles) that interact with the film or detector, causing chemical changes and leaving behind a visible image of the distribution of the labeled compound. The resulting autoradiogram provides information about the location, quantity, and sometimes even the identity of the molecules or structures that have taken up the radioactive tracer.

Autoradiography has been widely used in various fields of biology and medical research, including pharmacology, neuroscience, genetics, and cell biology, to study processes such as protein-DNA interactions, gene expression, drug metabolism, and neuronal connectivity. However, due to the use of radioactive materials and potential hazards associated with them, this technique has been gradually replaced by non-radioactive alternatives like fluorescence in situ hybridization (FISH) or immunofluorescence techniques.

Cesium radioisotopes are different forms of the element cesium that have unstable nuclei and emit radiation. Some commonly used medical cesium radioisotopes include Cs-134 and Cs-137, which are produced from nuclear reactions in nuclear reactors or during nuclear weapons testing.

In medicine, cesium radioisotopes have been used in cancer treatment for the brachytherapy of certain types of tumors. Brachytherapy involves placing a small amount of radioactive material directly into or near the tumor to deliver a high dose of radiation to the cancer cells while minimizing exposure to healthy tissues.

Cesium-137, for example, has been used in the treatment of cervical, endometrial, and prostate cancers. However, due to concerns about potential long-term risks associated with the use of cesium radioisotopes, their use in cancer therapy is becoming less common.

It's important to note that handling and using radioactive materials requires specialized training and equipment to ensure safety and prevent radiation exposure.

Brachytherapy is a type of cancer treatment that involves placing radioactive material directly into or near the tumor site. The term "brachy" comes from the Greek word for "short," which refers to the short distance that the radiation travels. This allows for a high dose of radiation to be delivered directly to the tumor while minimizing exposure to healthy surrounding tissue.

There are two main types of brachytherapy:

1. Intracavitary brachytherapy: The radioactive material is placed inside a body cavity, such as the uterus or windpipe.
2. Interstitial brachytherapy: The radioactive material is placed directly into the tumor or surrounding tissue using needles, seeds, or catheters.

Brachytherapy can be used alone or in combination with other cancer treatments such as surgery, external beam radiation therapy, and chemotherapy. It may be recommended for a variety of cancers, including prostate, cervical, vaginal, vulvar, head and neck, and skin cancers. The specific type of brachytherapy used will depend on the size, location, and stage of the tumor.

The advantages of brachytherapy include its ability to deliver a high dose of radiation directly to the tumor while minimizing exposure to healthy tissue, which can result in fewer side effects compared to other forms of radiation therapy. Additionally, brachytherapy is often a shorter treatment course than external beam radiation therapy, with some treatments lasting only a few minutes or hours.

However, there are also potential risks and side effects associated with brachytherapy, including damage to nearby organs and tissues, bleeding, infection, and pain. Patients should discuss the benefits and risks of brachytherapy with their healthcare provider to determine if it is an appropriate treatment option for them.

Iridium radioisotopes are unstable isotopes or variants of the element iridium that emit radiation as they decay into more stable forms. These isotopes can be used in various medical applications, such as brachytherapy, a type of cancer treatment where a small amount of radioactive material is placed inside the body near the tumor site to deliver targeted radiation therapy.

Iridium-192 is one commonly used iridium radioisotope for this purpose. It has a half-life of 74.2 days and emits gamma rays, making it useful for treating various types of cancer, including breast, gynecological, prostate, and head and neck cancers.

It's important to note that handling and using radioisotopes requires specialized training and equipment due to the potential radiation hazards associated with them.

"Evaluation studies" is a broad term that refers to the systematic assessment or examination of a program, project, policy, intervention, or product. The goal of an evaluation study is to determine its merits, worth, and value by measuring its effects, efficiency, and impact. There are different types of evaluation studies, including formative evaluations (conducted during the development or implementation of a program to provide feedback for improvement), summative evaluations (conducted at the end of a program to determine its overall effectiveness), process evaluations (focusing on how a program is implemented and delivered), outcome evaluations (assessing the short-term and intermediate effects of a program), and impact evaluations (measuring the long-term and broad consequences of a program).

In medical contexts, evaluation studies are often used to assess the safety, efficacy, and cost-effectiveness of new treatments, interventions, or technologies. These studies can help healthcare providers make informed decisions about patient care, guide policymakers in developing evidence-based policies, and promote accountability and transparency in healthcare systems. Examples of evaluation studies in medicine include randomized controlled trials (RCTs) that compare the outcomes of a new treatment to those of a standard or placebo treatment, observational studies that examine the real-world effectiveness and safety of interventions, and economic evaluations that assess the costs and benefits of different healthcare options.

Emission computed tomography (ECT) is a type of tomographic imaging technique in which an emission signal from within the body is detected to create cross-sectional images of that signal's distribution. In Emission-Computed Tomography (ECT), a radionuclide is introduced into the body, usually through injection, inhalation or ingestion. The radionuclide emits gamma rays that are then detected by external gamma cameras.

The data collected from these cameras is then used to create cross-sectional images of the distribution of the radiopharmaceutical within the body. This allows for the identification and quantification of functional information about specific organs or systems within the body, such as blood flow, metabolic activity, or receptor density.

One common type of Emission-Computed Tomography is Single Photon Emission Computed Tomography (SPECT), which uses a single gamma camera that rotates around the patient to collect data from multiple angles. Another type is Positron Emission Tomography (PET), which uses positron-emitting radionuclides and detects the coincident gamma rays emitted by the annihilation of positrons and electrons.

Overall, ECT is a valuable tool in medical imaging for diagnosing and monitoring various diseases, including cancer, heart disease, and neurological disorders.

In the context of medicine, iron is an essential micromineral and key component of various proteins and enzymes. It plays a crucial role in oxygen transport, DNA synthesis, and energy production within the body. Iron exists in two main forms: heme and non-heme. Heme iron is derived from hemoglobin and myoglobin in animal products, while non-heme iron comes from plant sources and supplements.

The recommended daily allowance (RDA) for iron varies depending on age, sex, and life stage:

* For men aged 19-50 years, the RDA is 8 mg/day
* For women aged 19-50 years, the RDA is 18 mg/day
* During pregnancy, the RDA increases to 27 mg/day
* During lactation, the RDA for breastfeeding mothers is 9 mg/day

Iron deficiency can lead to anemia, characterized by fatigue, weakness, and shortness of breath. Excessive iron intake may result in iron overload, causing damage to organs such as the liver and heart. Balanced iron levels are essential for maintaining optimal health.

Mass spectrometry (MS) is an analytical technique used to identify and quantify the chemical components of a mixture or compound. It works by ionizing the sample, generating charged molecules or fragments, and then measuring their mass-to-charge ratio in a vacuum. The resulting mass spectrum provides information about the molecular weight and structure of the analytes, allowing for identification and characterization.

In simpler terms, mass spectrometry is a method used to determine what chemicals are present in a sample and in what quantities, by converting the chemicals into ions, measuring their masses, and generating a spectrum that shows the relative abundances of each ion type.

Octreotide is a synthetic analogue of the natural hormone somatostatin, which is used in medical treatment. It is a octapeptide with similar effects to somatostatin, but with a longer duration of action. Octreotide is primarily used in the management of acromegaly, gastroenteropancreatic neuroendocrine tumors (GEP-NETs), and diarrhea and flushing associated with carcinoid syndrome.

It works by inhibiting the release of several hormones, including growth hormone, insulin, glucagon, and gastrin. This results in a decrease in symptoms caused by excessive hormone secretion, such as reduced growth hormone levels in acromegaly, decreased tumor size in some GEP-NETs, and improved diarrhea and flushing in carcinoid syndrome.

Octreotide is available in several forms, including short-acting subcutaneous injections (Sandostatin®), long-acting depot intramuscular injections (Sandostatin LAR®), and a slow-release formulation for the treatment of diarrhea associated with AIDS (Mycapssa™).

The medical definition of Octreotide is:

A synthetic octapeptide analogue of somatostatin, used in the management of acromegaly, gastroenteropancreatic neuroendocrine tumors (GEP-NETs), and diarrhea and flushing associated with carcinoid syndrome. Octreotide inhibits the release of several hormones, including growth hormone, insulin, glucagon, and gastrin, leading to symptomatic improvement in these conditions. It is available as short-acting subcutaneous injections, long-acting depot intramuscular injections, and a slow-release formulation for diarrhea associated with AIDS.

In the context of pharmacology, "half-life" refers to the time it takes for the concentration or amount of a drug in the body to be reduced by half during its elimination phase. This is typically influenced by factors such as metabolism and excretion rates of the drug. It's a key factor in determining dosage intervals and therapeutic effectiveness of medications, as well as potential side effects or toxicity risks.

Oxygen-15 is a radioisotope, often used in positron emission tomography (PET). It can be used in, among other things, water for ... Oxygen isotopes are also used to trace ocean composition and temperature which seafood is from. Thirteen radioisotopes have ... About 109 kelvin is needed to fuse oxygen into sulfur. An atomic mass of 16 was assigned to oxygen prior to the definition of ... Heaviest particle-bound isotope of oxygen, see Nuclear drip line Natural oxygen is made of three stable isotopes, 16 O , 17 O ...
... while that of oxygen-17 is 0.037%. The reduction of the oxygen-17 and oxygen-18 present in the plutonium dioxide will result in ... neutron reaction with the oxygen-18 and oxygen-17 present in the oxide. The normal amount of oxygen-18 present in the natural ... A radioisotope thermoelectric generator (RTG, RITEG), sometimes referred to as a radioisotope power system (RPS), is a type of ... NASA Radioisotope Power Systems website - RTG page NASA JPL briefing, Expanding Frontiers with Radioisotope Power Systems - ...
Fifteen radioisotopes have been characterized, ranging from 11O to 28O. The most stable are 15O with a half-life of 122.24 ... a lack of oxygen Limiting oxygen concentration Oxygen compounds Oxygen plant Oxygen sensor Portals: Chemistry Medicine Oxygen ... Oxygen Oxygen (O2) Properties, Uses, Applications Roald Hoffmann article on "The Story of O" WebElements.com - Oxygen Oxygen on ... Oxygen tents were once commonly used in oxygen supplementation, but have since been replaced mostly by the use of oxygen masks ...
The radioisotopes used in clinics are normally 18F (fluoride), 11C (carbon) and 15O (oxygen). The labeled compound, called a ... PET imaging with oxygen-15 indirectly measures blood flow to the brain. In this method, increased radioactivity signal ... Some traces used for ischemic stroke are Oxygen-15 labelled water, [18F]FMISO. The development of a number of novel probes for ... Example: Brain pathologies such as Alzheimer's disease greatly decrease brain metabolism of both glucose and oxygen in tandem. ...
Many isotopes are produced in cyclotrons, for example fluorine-18 and oxygen-15 which are widely used for positron emission ... A synthetic radioisotope is a radionuclide that is not found in nature: no natural process or mechanism exists which produces ... Most synthetic radioisotopes have a short half-life. Though a health hazard, radioactive materials have many medical and ... Several radioisotopes and compounds are used for medical treatment, usually by bringing the radioactive isotope to a high ...
In the presence of oxygen, it reacts with cyanide salts. Traditional oxidants also react, including the halogens and oxygen at ... The radioisotope iridium-192 is one of the two most important sources of energy for use in industrial γ-radiography for non- ... At least 37 radioisotopes have also been synthesized, ranging in mass number from 164 to 202. 192Ir, which falls between the ... A radioisotope of iridium, 192 Ir, is dangerous, like other radioactive isotopes. The only reported injuries related to iridium ...
Both modes of decay yield stable oxygen-18. 18 F is a natural trace radioisotope produced by cosmic ray spallation of ... The organic oxygen-18 pharmaceutical molecule is not made before the production of the radiopharmaceutical, as high energy ... Fluorine-18 (18F) is a fluorine radioisotope which is an important source of positrons. It has a mass of 18.0009380(6) u and ... atmospheric argon as well as by reaction of protons with natural oxygen: 18O + p → 18F + n. In the radiopharmaceutical industry ...
Of particular interest is the use of a Mn-O cluster, the oxygen-evolving complex, in the production of oxygen by plants. ... Several radioisotopes have been isolated and described, ranging in atomic weight from 46 u (46Mn) to 72 u (72Mn). The most ... Dismukes, G. Charles; Willigen, Rogier T. van (2006). "Manganese: The Oxygen-Evolving Complex & Models". Manganese: The Oxygen- ... The oxygen-evolving complex (OEC), containing four atoms of manganese, is a part of photosystem II contained in the thylakoid ...
The surface habitat would have two 5 kilowatt radioisotope Stirling generators and an ISRU oxygen generator. Unlike DRA 5.0 or ... Advanced Stirling radioisotope generator Mars Design Reference Mission NASA - Austere Human Missions to Mars Austere Human ... The pressurized rovers would be powered by a 5 kilowatt Stirling radioisotope generator on each rover. The P/L module would ... transferred once in advance to provide basic surface machinery A standardized liquid oxygen/liquid hydrogen (LOX/LH2) ...
A radiopharmaceutical - a radioisotope attached to a drug - is injected into the body as a tracer. When the radiopharmaceutical ... PET imaging with oxygen-15 indirectly measures blood flow to the brain. In this method, increased radioactivity signal ... As the radioisotope undergoes positron emission decay (also known as positive beta decay), it emits a positron, an antiparticle ... For example: 18 F -FDG is commonly used to detect cancer; Na18 F is widely used for detecting bone formation; Oxygen-15 is ...
SPECT scan is another radiotracer based imaging technique that uses oxygen radio-isotope to assess blood flow. This imaging is ...
Hydrogen, nitrogen, oxygen and chlorine are cheapest by volume at atmospheric pressure. When there is no public data on the ... The price listing for radioisotopes is not exhaustive. 2000s commodities boom Density for 0 °C, 101.325 kPa. For individual ... Per-kilogram prices of some synthetic radioisotopes range to trillions of dollars. While the difficulty of obtaining ...
PMMA is used as a shield to stop beta radiation emitted from radioisotopes. Small strips of PMMA are used as dosimeter devices ... Smooth PMMA surface can be easily nanostructured by treatment in oxygen radio-frequency plasma and nanostructured PMMA surface ...
Carbon-14, the radioisotope of carbon, is naturally developed in trace amounts in the atmosphere and it can be detected in all ... These neutrons collide with 14N to produce 14C which then combines with oxygen to form 14CO2. This radioactive CO2 spreads ... The radioisotope 14C thus becomes part of the biosphere so that all living organisms contain a certain amount of 14C. Nuclear ... The radioisotope carbon-14 is constantly formed from nitrogen-14 (14N) in the higher atmosphere by incoming cosmic rays which ...
A 'thiosemicarbazone' contains a sulfur atom in lieu of the ketonic oxygen in semicarbazone. Bisthiosemicarbazones are known to ... They have also been identified as potential ligands for radioisotope delivery, with selectivity towards hypoxic tissues, ...
They were then thermalized and oxidized in a mixture of helium and oxygen gases to form hassium tetroxide molecules. Hs + 2 O2 ... using the synthetic osmium radioisotopes 172Os and 173Os as a reference. During the experiment, seven hassium atoms were ... Chemistry experiments have confirmed that hassium behaves as the heavier homologue to osmium, reacting readily with oxygen to ...
In biological contexts, use of radioisotope tracers are sometimes called radioisotope feeding experiments. Radioisotopes of ... When a sulfur atom replaces an oxygen atom in a phosphate group on a nucleotide a thiophosphate is produced, so 35S can also be ... 99mTc is a very versatile radioisotope, and is the most commonly used radioisotope tracer in medicine. It is easy to produce in ... The commonly used radioisotopes have short half lives and so do not occur in nature in large amounts. They are produced by ...
The 18O constitutes about 0.20% of ordinary oxygen (mostly oxygen-16), from which it is extracted. The 18F is then typically ... The most commonly used radioisotope in PET, 18F, is not produced in a nuclear reactor, but rather in a circular accelerator ... The cyclotron is used to accelerate protons to bombard the stable heavy isotope of oxygen 18O. ...
... a shortage of oxygen-18, a raw material for FDG, made it necessary to ration isotope supplies. Israel's oxygen-18 facility had ... Subsequently, a "nucleophilic synthesis" was devised with the same radioisotope. As with all radioactive 18F-labeled ... "heavy oxygen" in the hydroxyl at the C-2 position. The new presence of a 2-hydroxyl now allows it to be metabolized normally in ... after nuclear transmutation of the fluorine to oxygen ceases to prevent metabolism). Another fraction of [18F]FDG, representing ...
Organofluorine in the form of its radioisotope 18F is also at the heart of a modern medical imaging technique known as positron ... They can hold more oxygen or carbon dioxide than blood does. For that reason, they have attracted ongoing interest related to ... Application to oxygen solubility, partition coefficient, viscosity, vapor pressure, and density". ASAIO Journal. 42 (6): 968- ... Perfluorocarbons are banned from sports, where they may be used to increase oxygen use for endurance athletes. One cyclist, ...
The radioisotope iodine-131, which has a high fission product yield, concentrates in the thyroid, and is one of the most ... If it does come in contact with water, though, it will combine with the atoms of both oxygen and hydrogen to form strontium ... A number of iodine radioisotopes are also used in medical applications. Iodine is found on Earth mainly as the highly water- ... Palladium plays a key role in the technology used for fuel cells, which combine hydrogen and oxygen to produce electricity, ...
Air, freshwater and seawater contain mostly oxygen-16 ( 16O). Oxygen-18 (18O) occurs in approximately one oxygen atom in every ... Natural radioisotopes like tritium (3-H) and radiocarbon (14-C) are also used as natural clocks to determine the residence ... The most commonly used isotope application in hydrology uses hydrogen and oxygen isotopes to evaluate sources or age of water, ... Water molecules carry unique isotopic "fingerprints", based in part on differing ratios of the oxygen and hydrogen isotopes ...
Of the 10 radioisotopes of beryllium, the most stable are 10 Be with a half-life of 1.387(12) million years and 7 Be with a ... The 1:1 neutron-proton ratio seen in stable isotopes of many light elements (up to oxygen, and in elements with even atomic ... These two radioisotopes of beryllium in the atmosphere track the sunspot cycle and solar activity, since this affects the ... half-life of 53.22(6) d. All other radioisotopes have half-lives under 15 s, most under 30 milliseconds. The least stable ...
They were depleted in the early eras of the Solar System, while oxygen forms numerous oxides. Oxygen isotope studies had been ... However, isotope differences in individual samples (excepting radioisotopes) had once been widely held to be local effects, ... These are the macroscopic samples with the heaviest oxygen in the Solar System. Oxygen isotope studies and classification have ... Oxygen is the chief element in CI- and many other- meteorites. Despite the Solar agreement, the common elements carbon and ...
... naturally occurring radioisotopes like Thorium isotopes to reconstruct particle flux, and redox-sensitive metals such as ... manganese and uranium to reconstruct ocean oxygen levels. She is also involved in research to improve our understanding of ...
Hydrogen requires a double capture to attain instability as tritium (hydrogen-3), while natural oxygen (oxygen-16) requires ... Salted bomb Table of nuclides Manual for reactor produced radioisotopes from the International Atomic Energy Agency Neeb, Karl ... The activated oxygen-16 nucleus emits a proton (hydrogen nucleus), and transmutes to nitrogen-16, which has a very short life ( ... Water, for example, is made up of hydrogen and oxygen. ... as a result of the production of neutron-rich radioisotopes.[ ...
... mercury radioisotopes MeSH D01.496.586.520 - nitrogen radioisotopes MeSH D01.496.625.600 - oxygen radioisotopes MeSH D01.496. ... mercury radioisotopes MeSH D01.496.749.615 - nitrogen radioisotopes MeSH D01.496.749.635 - oxygen radioisotopes MeSH D01.496. ... iron radioisotopes MeSH D01.496.749.540 - krypton radioisotopes MeSH D01.496.749.560 - lead radioisotopes MeSH D01.496.749.590 ... xenon radioisotopes MeSH D01.496.749.960 - yttrium radioisotopes MeSH D01.496.749.980 - zinc radioisotopes MeSH D01.496.807.800 ...
He soon realized that radioisotope transport was influenced by the metabolism of species and ecosystems, and he soon became ... Oxygen Consumption, and Trace Element Metabolism in Forest Floor Arthropods". Ecology. 49 (3): 538-542. doi:10.2307/1934119. ... Reichle, David E. (November 1969). "Measurement of Elemental Assimilation by Animals from Radioisotope Retention Patterns". ...
In a long-term project, Harmon Craig and Valerie Craig (his wife) used carbon and oxygen isotopes to identify the sources of ... Craig developed new methods in radiocarbon dating and applied radioisotope and isotope distribution to various topics in marine ... Craig, H.; Gordon, L.I. (1965). "Deuterium and oxygen 18 variations in the ocean and the marine atmosphere". In Tongiorgi, E. ( ... doi:10.1007/s12520-017-0556-8. Herz, N. (April 17, 2013). "The oxygen and carbon isotopic data base for classical marble". In ...
Traces of 40 K are found in all potassium, and it is the most common radioisotope in the human body. Potassium ions are vital ... With oxygen it forms potassium peroxide. With water potassium forms potassium hydroxide (KOH). The reaction of potassium with ... These are nuclear fusion reactions, not to be confused with chemical burning of potassium in oxygen.) 40 K is also formed in s- ... Unlike lithium and sodium, potassium should not be stored under oil for longer than six months, unless in an inert (oxygen-free ...
The decomposition of chlorate to chloride and oxygen is a common way to produce oxygen in the laboratory on a small scale. ... The most stable chlorine radioisotope is 36Cl. The primary decay mode of isotopes lighter than 35Cl is electron capture to ... Hyperchloremia can affect oxygen transport. Chlorine is a toxic gas that attacks the respiratory system, eyes, and skin. ... Common chemical theory at that time held that an acid is a compound that contains oxygen (remnants of this survive in the ...
Oxygen-15 is a radioisotope, often used in positron emission tomography (PET). It can be used in, among other things, water for ... Oxygen isotopes are also used to trace ocean composition and temperature which seafood is from. Thirteen radioisotopes have ... About 109 kelvin is needed to fuse oxygen into sulfur. An atomic mass of 16 was assigned to oxygen prior to the definition of ... Heaviest particle-bound isotope of oxygen, see Nuclear drip line Natural oxygen is made of three stable isotopes, 16 O , 17 O ...
Iodine Radioisotopes * Male * Oxygen / pharmacology * Pulmonary Alveoli / metabolism* * RNA, Messenger / analysis * Rats ...
... cerebral responses to differing neurobehavioral tasks in normal subjects studied with positron computed tomography and oxygen- ... of oxygen-15-labeled water in the brain were the most accurate for identifying such relative changes between radioisotope ... A noninvasive positron computed tomography technique using oxygen-15--labeled water for the evaluation of neurobehavioral task ... Visual stimulation studies in normal volunteers demonstrated relative radioisotope concentration changes between control and ...
The diagnosis is based on clinical suspicion, diagnostic imaging, and radio-isotope cisternography. Treatment usually consists ... Hyperbaric Oxygen Therapy for Traumatic Brain Injury: Promising or Wishful Thinking? * 2001/viewarticle/996802 ...
CI: (c) 2006; JID: 0400654; 0 (Oxygen Isotopes); 0 (Strontium Radioisotopes); 0 (Trace Elements); ppublish ... Oxygen Isotopes/analysis, Peru, Population Dynamics, Spectrophotometry, Atomic, Strontium Radioisotopes/analysis, Tooth/ ... While oxygen isotope data could clearly distinguish the high-altitude sites from others, more data is needed to characterize ... Analyzing oxygen isotope and trace element concentration data and comparing it with strontium isotope data from the same ...
Using radioactive xenon, a first report in 1966 has demonstrated a reduction in the radioisotope clearance in obese scWAT [47 ... Indeed in order to provide oxygen and nutrients to adipocytes, the WAT vascularization is highly developed and each adipocyte ... However, several studies have suggested abnormal oxygen supply in obese WAT for example by measuring the Adipose Tissue Blood ... The HIF1 proteins regulate the response to oxygen availability at the transcriptional level [52]. HIF1 is also tightly ...
Episodic growth of the Gondwana supercontinent from hafnium and oxygen isotopes in zircons, Nature 439(7076):580-583, 2006 , ... Austin, S.A., Do radioisotope clocks need repair? Testing the assumptions of isochron dating using K-Ar, Rb-Sr, Sm-Nd, and Pb- ... Baumgardner, J., Do radioisotope methods yield trustworthy relative ages for the earths rocks?, J. Creation 26(3):68-75, 2012 ... Snelling, A.A., Isochron discordances and the role of inheritance and mixing of radioisotopes in the mantle and crust; in: ...
For example, the isotope oxygen-18 can help scientists assess rainfall patterns over decades; natural radioisotopes such as ...
They were then thermalized and oxidized in a mixture of helium and oxygen gases to form hassium tetroxide molecules.[128][130][ ... The first chemistry experiments were performed using gas thermochromatography in 2001, using the synthetic osmium radioisotopes ... Chemistry experiments have confirmed that hassium behaves as the heavier homologue to osmium, reacting readily with oxygen to ...
... tens of millions of patients each year are diagnosed and treated with accelerator-based radioisotopes. ... reach an energy of about 10 million to 15 million electronvolts they slam into a water target enriched with the oxygen-18 ... While radioisotopes with long half-lives are often formed in nuclear reactors, more than 300 cyclotrons across the United ... Physicists hope to develop accelerators in the United States to reliably mass-produce Moly-99 and other radioisotopes.. Brad ...
... and Martian settlers are going to need LOTS of Oxygen. They will be able to choose between Oxygen extracted on site and Oxygen ... Can the Moon and the Mars import nuclear waste from Earth to power Radioisotope thermoelectric generators? That electricity ... and Martian settlers are going to need LOTS of Oxygen. They will be able to choose between Oxygen extracted on site and Oxygen ... It took around 50 hours to extract 96 percent of the oxygen bound up in the regolith sample, but 75 percent of the oxygen ...
Oxygen Radioisotopes. *Oxygen Consumption. *Nuclear Medicine & Medical Imaging. *Macaca nemestrina. *Inhalation. * ... measurement of cerebral oxygen extraction and cerebral oxygen metabolism under pathologic conditions of reduced cerebral oxygen ... The absolute error in oxygen extraction measured with PET was small (mean 0.03 +/- 0.04, range -0.03 to 0.12) and was ... Altman, D. I., Lich, L. L., & Powers, W. J. (1991). Brief inhalation method to measure cerebral oxygen extraction fraction with ...
The effects of solution variables such as ph, oxygen partial pressure, and ferric iron concentration at different temperatures ... High-grade transvaal chalcopyrite was neutron-irradiated to produce radioisotopes copper- 64, iron-59, and sulfur-35. ...
In addition, the space agency developed hydrogen oxygen rocket engines, multi-staged heavy-lift launch vehicles, nuclear rocket ... engines, space nuclear reactors, radioisotope power generators, spacesuits, in-space life support systems, orbital rendezvous ...
A new manuscript of the Récits dun ChemoStrat Introduction Chemostratigraphy Oxygen Isotopes Carbon Isotopes Radioisotopes ...
... secure handling of radioisotopes, current advances in immunoassay, separation methods, high quality control and approaches to ... Respiratory support with oxygen or mechanical ventilation is commonly required in cyanotic newborns herbs mill [url=https:// ...
... and the radioisotopes tritium (3H), carbon-14 (TIC), and radon (222~. Because the stable isotopes oxygen-18 and deuterium are ... Owing to differences of mass between hydrogen and deuterium, and between oxygen-16 and oxygen-18, one isotope is enriched ( ... con The environmental isotopes in most common use today include the stable isotopes deuterium (2H), oxygen-18 (~80), and carbon ... identification and differentiation of water masses that have unique mixtures of different isotopes of hydrogen or oxygen in the ...
... radioisotope milk scans, and echocardiograms. Assessment of hypoxia included either random pulse oximetry oxygen saturation or ... Home oxygen was required in five patients. At follow up all patients are alive at a median age of 6 years (range 1 to 12 years ... Four patients were born preterm; three required oxygen in the first week of life. Patient 11 was one of twins. On antenatal ... Patients 10 and 11 have been weaned to flow rates between 1 and 0.5 litres per minute while patient 5 needs nocturnal oxygen ...
Not to mention its almost imperceptible atmosphere with similar chemical composition as Earths!!(including oxygen). ... A clue given by the oxygen and CO2 particles liberation going on.. We ponder & wonder: Could Rhea harbor some type of crude ... a national competition for elementary through high school students featuring the power of radioisotopes for space exploration. ...
Real-Time Detection of Reactive Oxygen Species Production in Immune Response in Rice with a Chemiluminescence Assay… ... An Alternative to Radioisotope Assays… ... Real-Time Detection of Reactive Oxygen Species Production in ...
... this paper will discuss radioisotope tracers (e.g. tritium, carbon-14 and radon-222), as robust and proven tools to help ... stable isotopes of oxygen and hydrogen, industrial compounds (CFCs and SF6) and dissolved carbon isotopes (i.e. inorganic and ... stable isotopes of oxygen and hydrogen, industrial compounds (CFCs and SF6) and dissolved carbon isotopes (i.e. inorganic and ... organic forms). In addition, this paper will discuss radioisotope tracers (e.g. tritium, carbon-14 and radon-222), as robust ...
115 Radioisotope X-Ray Fluorescence Spectrometry INTERNATIONAL ATOMIC ENERGY AGENCY, VIENNA,1970 RADIOISOTOPE ... 0, ,525 Oxygen 8 2, ,85 x10~4 "s80» 0, ,677 Fluorine 9 CFj 5, .82 xlO"4 ... C., "The analysis of tin and copper ores using a portable radioisotope X-ray fluorescence analyser", Radioisotope Instruments ... No radiation damage to the windows occurs because of the low X-ray intensities from radioisotope sources. Both radioisotope X- ...
As water is the source of oxygen, food and fuel; it is our target. The question is how to get this water! Lets put some facts ... a national competition for elementary through high school students featuring the power of radioisotopes for space exploration. ... a national competition for K-12 students featuring the enabling power of radioisotopes. ... a national competition for K-12 students featuring the enabling power of radioisotopes. ...
Oxygen-15 water. Positron emission tomography (PET) scans after intravenous (IV) administration of 25 mCi of [15O] water as a ... The regional cerebral blood flow (rCBF) is estimated by radioisotope brain imaging. Hexamethylpropyleneamine oxide (HMPAO), a ... and dopamine D2 receptor binding in 6 children aged 3-5 years utilizing oxygen-15 [15O] water (12 MBq/kg), carbon-11-labeled ...
The applications of radioisotopes to various fields are valuable assets worth noting. Without their use, our high standard of ... To give a detailed instance, plants use photosynthesis to synthesize CO2 and H2O to produce oxygen. But yet, how are scientists ... Radioisotopes have a variety of unique aspects. What makes these radioactive isotopes extraordinary is their capabilities for ... Radiochemists put radioisotopes through various procedures and practices in areas outside of the field of chemistry. ...
iv) Oxygen.. Oxygen and equipment for its administration are covered. Benefits are limited to providing a tank unit at one ... viii) Anesthetics and oxygen.. Anesthetics and oxygen and their administration are considered a service or supply if furnished ... Includes radioisotopes.. (xi) Physical therapy.. (xii) Oxygen.. Includes equipment for its administration. ... location with oxygen limited to a 30-day supply at any one time. Repair and adjustment of CHAMPUS-purchased oxygen equipment ...
Oxygen,Piperazines,Potassium,Radioisotopes;Rats,Rats;ReperfusionRubidiumSodiumSodium,Sodium-CalciumSodium-Potassium-Exchanging ...
In positron emission tomography (PET), the use of ionizing radioisotopes is required. The most well-known technique for ... During plastic and reconstructive surgery, the oxygen saturation can be monitored to predict survival of flaps.. ... Measuring the oxygen saturation is of great value in a wide range of medical fields. For instance, tumor progression and ... Monitoring of cerebral oxygen saturation can be used in the diagnosis of cerebral desaturations in stroke patients. In ...
  • To produce the isotope fluorine-18, for example, when the particles reach an energy of about 10 million to 15 million electronvolts they slam into a water target enriched with the oxygen-18 isotope. (symmetrymagazine.org)
  • An imaging technique using compounds labelled with short-lived positron-emitting radionuclides (such as carbon-11, nitrogen-13, oxygen-15 and fluorine-18) to measure cell metabolism. (lookformedical.com)
  • Oxygen-18 is used as a precursor to producing the medical radioisotope fluorine-18 [18F], which is used in the PET / CT scan (positron emission tomography). (irisotope.com)
  • There are three known stable isotopes of oxygen (8O): 16 O , 17 O , and 18 O . Radioactive isotopes ranging from 11 O to 28 O have also been characterized, all short-lived. (wikipedia.org)
  • These include: field parameters (e.g. electrical conductivity, temperature), major and trace ions (e.g. metals), stable isotopes of oxygen and hydrogen, industrial compounds (CFCs and SF6) and dissolved carbon isotopes (i.e. inorganic and organic forms). (edu.au)
  • The initial validation of the brief inhalation method to measure cerebral oxygen extraction fraction (OEF) with positron emission tomography (PET) was performed in non-human primates with predominantly normal cerebral oxygen metabolism (CMRO2). (duke.edu)
  • In positron emission tomography (PET), the use of ionizing radioisotopes is required. (lu.se)
  • Assessment of hypoxia included either random pulse oximetry oxygen saturation or overnight oxygen saturation studies. (bmj.com)
  • Measuring the oxygen saturation is of great value in a wide range of medical fields. (lu.se)
  • Monitoring of cerebral oxygen saturation can be used in the diagnosis of cerebral desaturations in stroke patients. (lu.se)
  • During plastic and reconstructive surgery, the oxygen saturation can be monitored to predict survival of flaps. (lu.se)
  • Several techniques have been developed to monitor oxygen saturation, but they all have limitations. (lu.se)
  • The most well-known technique for measuring oxygen saturation is pulse oximetry that uses the physiologic activity of the cardiac pulse, in combination with the difference in spectroscopic reflectance at wavelength of 660 nm and 940 nm defining the concentration of oxyhemo and deoxyhema, to determine oxygen saturation. (lu.se)
  • PAI thus has the potential of measuring oxygen saturation non-invasively with spatial resolution. (lu.se)
  • To date, PA imaging has mainly been developed for measuring oxygen saturation mainly in phantoms and numerous preclinical studies in animals have exploited the oxygenated and deoxygenated hemoglobin components to characterize tumour microenvironment. (lu.se)
  • In our studies, the feasibility of using PAI for estimating the spatial distribution of oxygen saturation is examined, in models of occlusion reperfusion and adrenalin-dependent vasoconstriction in humans. (lu.se)
  • During the apnea test continuous monitoring of oxygen saturation, pulse, and … The Patient Can't Breathe on Their Own. (dinpoker.se)
  • Postoperatively, he became febrile, tachypneic, and hypoxemic, requiring up to 6 L/min supplemental oxygen by nasal prongs. (bvsalud.org)
  • Supplemental oxygen is often required to manage the symptoms of HPS, but this may not be necessary in milder cases. (rarediseases.org)
  • Handheld radioisotope identification instruments (RIIDs) are an important, front-line tool for passively detecting, locating, and characterizing radioactive materials and thereby helping to prevent the spread of illicit nuclear materials. (sbir.gov)
  • A radionuclide ( radioactive nuclide , radioisotope or radioactive isotope ) is a nuclide that has excess nuclear energy, making it unstable. (wikipedia.org)
  • Radioactive SnF is used as a marker for bone infection radioisotope imagery, proving the affinity of this molecule to the site of the infection. (ra-infection-connection.com)
  • Scholars@Duke publication: Brief inhalation method to measure cerebral oxygen extraction fraction with PET: accuracy determination under pathologic conditions. (duke.edu)
  • These data indicate that the brief inhalation method can be used for measurement of cerebral oxygen extraction and cerebral oxygen metabolism under pathologic conditions of reduced cerebral oxygen metabolism, with these limitations borne in mind. (duke.edu)
  • A technique is described that provides information about relative cerebral responses to differing neurobehavioral tasks in normal subjects studied with positron computed tomography and oxygen-15-labeled water. (nih.gov)
  • These interventions include placing the patient in high Fowler's position and administering oxygen, diuretics, and positive inotropic drugs as prescribed. (rnpedia.com)
  • Visual stimulation studies in normal volunteers demonstrated relative radioisotope concentration changes between control and stimulated states that are in good agreement with similar results obtained using the same stimulation paradigm but with the use of fluorodeoxyglucose to determine cerebral glucose metabolism. (nih.gov)
  • For example, it was proven, that the oxygen released in photosynthesis originates in H2O, rather than in the also consumed CO2, by isotope tracing experiments. (wikipedia.org)
  • But yet, how are scientists aware of exactly where that oxygen originates from? (moravek.com)
  • The longest-lived radioisotope is 15 O with a half-life of 122.266(43) s, while the shortest-lived isotope is the unbound 11 O with a half-life of 198(12) yoctoseconds, though half-lives have not been measured for the unbound heavy isotopes 27 O and 28 O . mO - Excited nuclear isomer. (wikipedia.org)
  • Heaviest particle-bound isotope of oxygen, see Nuclear drip line Natural oxygen is made of three stable isotopes, 16 O , 17 O , and 18 O , with 16 O being the most abundant (99.762% natural abundance). (wikipedia.org)
  • Therefore facilities which remove tritium from heavy water used in nuclear reactors often also remove or at least reduce the amount of heavier isotopes of oxygen. (wikipedia.org)
  • While radioisotopes with long half-lives are often formed in nuclear reactors, more than 300 cyclotrons across the United States produce short-lived isotopes for hospitals. (symmetrymagazine.org)
  • Produced abroad by only three nuclear reactors devoted to radioisotope production, Moly-99 is involved in more than 50,000 procedures worldwide each day. (symmetrymagazine.org)
  • Can the Moon and the Mars import nuclear waste from Earth to power Radioisotope thermoelectric generators? (newmars.com)
  • The strengths of these resonances and, therefore, the 21 Na ( p , γ ) 22 Mg nuclear reaction rate, were hitherto unknown, creating significant uncertainty in the expected yield of 22 Na from an oxygen-neon nova event. (triumf.ca)
  • For on-line measurement in particular, the combination of radioisotope X-ray fluorescence with neutron activation analysis (using radioisotope neutron sources) is now being developed. (docslib.org)
  • The oxygen contained in CO2 in turn is used to make up the sugars formed by photosynthesis. (wikipedia.org)
  • To give a detailed instance, plants use photosynthesis to synthesize CO2 and H2O to produce oxygen. (moravek.com)
  • The effects of solution variables such as ph, oxygen partial pressure, and ferric iron concentration at different temperatures were measured. (cdc.gov)
  • As some methods of isotope separation enrich not only heavier isotopes of hydrogen but also heavier isotopes of oxygen when producing heavy water, the concentration of 17 O and 18 O can be measurably higher. (wikipedia.org)
  • Furthermore the 17 O(n,α)14 C reaction is a further undesirable result of an elevated concentration of heavier isotopes of oxygen. (wikipedia.org)
  • The wastewater from hospitals is a hotbed of emerging contaminants like pharmaceutically active compounds (PhACs), heavy metals, surfactants, radioisotopes and other hazardous substances. (sciforum.net)
  • Solid samples (organic and inorganic) for oxygen isotopic ratios are usually stored in silver cups and measured with pyrolysis and mass spectrometry. (wikipedia.org)
  • Chemistry experiments have confirmed that hassium behaves as the heavier homologue to osmium , reacting readily with oxygen to form a volatile tetroxide . (wikipedia.org)
  • Although these worlds are rich in oxygen, all of the oxygen present in the atmosphere and ocean is found in combination with hydrogen. (orionsarm.com)
  • Hospital effluent is characterized by a high chemical oxygen demand (COD) ranging between 120 - 500 mg/L and an average Biochemical Oxygen demand (BOD) is around 200 mg/L along with the presence of Nitrogenous compounds, total organic carbon, suspended solids, epidemic vectors and other emerging contaminants. (sciforum.net)
  • High-grade transvaal chalcopyrite was neutron-irradiated to produce radioisotopes copper- 64, iron-59, and sulfur-35. (cdc.gov)
  • Examples: Iron (Fe), copper (Cu), and oxygen (O_2). (ontologyportal.org)
  • An atomic mass of 16 was assigned to oxygen prior to the definition of the unified atomic mass unit based on 12 C . Since physicists referred to 16 O only, while chemists meant the natural mix of isotopes, this led to slightly different mass scales. (wikipedia.org)
  • For instance, functional magnetic resonance imaging monitors the blood oxygen level dependent (BOLD) contrast but is sensitive only to deoxygenated hemoglobin and the MRI machine is bulky. (lu.se)
  • Some radiotherapy treatments implant metallic radioisotope seeds with relatively long half-lives directly into a tumor, where the emitted gamma rays destroy the cancer cells. (symmetrymagazine.org)
  • Image acquisition times of 60 s following the arrival of oxygen-15-labeled water in the brain were the most accurate for identifying such relative changes between radioisotope administrations and were not limited by statistical noise from total image counts. (nih.gov)
  • They occupy a middle ground between Panthalassic (smaller, cool-water ocean worlds with oxygen-rich atmospheres) and pyrothalassic (very hot magma-ocean worlds, where water only exists as steam). (orionsarm.com)
  • If time is the only factor for quick an not the tonnage to be moved then the shorter time would yield more oxygen. (newmars.com)
  • The first recorded description of a low level of oxygen in the blood (hypoxemia) with liver dysfunction was by Flückiger in 1884. (rarediseases.org)
  • NASA selected three winners out of nine finalists in the second annual Power to Explore Challenge, a national competition for elementary through high school students featuring the power of radioisotopes for space exploration. (nasa.gov)
  • To generate oxygen enriched gas for injured soldiers via separation from air, the oxygen production devices based on current high temperature membranes technologies are large and consume significant power because the ceramic materials have to operate at high temperatures (>800oC) to achieve acceptable conductivity. (sbir.gov)
  • Postoperatively, the patient remained persistently hypoxemic with partial response to high-flow oxygen. (bvsalud.org)
  • An innovative aspect of BULLE is the implementation of continuous measurements of O2/N2 and pCO2 concentrations respiration, and the deployment of In Situ Oxygen Dynamic Autosampler (IODA) instrumentation in the coastal NW Mediterranean Sea. (openaire.eu)
  • During this event production, and subsequent ejection into the interstellar medium, of the radioisotope 22 Na can ensue. (triumf.ca)
  • In particular, radiochemistry studies both artificial and natural radioisotopes. (moravek.com)
  • Oxygen isotopes are also used to trace ocean composition and temperature which seafood is from. (wikipedia.org)
  • The depth at which this ice mantle forms depends on the temperature of the ocean, which depends in turn on the heat received from the local star(s), tidal heating and radioisotope decay in the core. (orionsarm.com)
  • Three years postoperatively, the patient remained oxygen independent. (bvsalud.org)
  • The absolute error in oxygen extraction measured with PET was small (mean 0.03 +/- 0.04, range -0.03 to 0.12) and was independent of cerebral blood flow, cerebral blood volume, CMRO2, or OEF. (duke.edu)
  • The most prominent symptom of HPS is usually a severe shortness of breath and low blood oxygen levels. (rarediseases.org)
  • In return, I will transfer my experience in microbial metabolisms and radioisotopes tracking methods to the host team. (openaire.eu)
  • NASA selected 9 finalists out of the 45 semi-finalists student essays in the Power to Explore Challenge, a national competition for K-12 students featuring the enabling power of radioisotopes. (nasa.gov)
  • Sure we can hydrogenate the regolith, bake the hell out of it or you can add calcium chloride to it and turn on the current through it to get almost all of the oxygen in the ore with the ore still useable to smelt for the iron or other metals that are in it. (newmars.com)
  • Due to natural oxygen being mostly 16 O, samples enriched with the other stable isotopes can be used for isotope labeling. (wikipedia.org)
  • Physicists hope to develop accelerators in the United States to reliably mass-produce Moly-99 and other radioisotopes. (symmetrymagazine.org)
  • Some amount of oxygen supply settlers, the rest are released on Mars and converted to ozone that is also released on Mars? (newmars.com)
  • Comparison between radioisotope X-ray fluorescence and other analytical techniques 1 A.1.1. (docslib.org)
  • Comparison between radioisotope and conventional X-ray fluorescence analysis 4 A. 2.1. (docslib.org)
  • A great variety of portable equipment for the analysis of alloys, both in industrial plant laboratories and in the field, now uses radioisotope X-ray fluorescence techniques as a basic element in its design. (docslib.org)
  • If this is severe enough, the lungs can lose their ability to effectively transfer oxygen to the body. (rarediseases.org)
  • The report is based on Panel discussions and on written contributions from each Panel Member, as well as on a paper by B. Dziunikowski, Institute of Radioisotope Techniques, Academy of Mining and Metallurgy, Cracow, Poland. (docslib.org)
  • I noted that some of the Oxygen was lost in the process, but I would imagine that if the process is conducted in an enclosed space, the gas would not ** really ** be lost. (newmars.com)
  • Radioisotope X-ray fluorescence is one of the more recent techniques developed as a result of the general availability of sealed radioisotope sources. (docslib.org)
  • I can see an immediate market opportunity, in that launch from the Moon of a variety of materials would be less expensive that would be the case from Earth, and Martian settlers are going to need LOTS of Oxygen. (newmars.com)
  • The applications of radioisotopes to various fields are valuable assets worth noting. (moravek.com)
  • An oxygen-neon nova is presently understood to be the result of a thermonuclear runaway on the surface of an oxygen-neon white dwarf. (triumf.ca)