Radiotherapy
The use of IONIZING RADIATION to treat malignant NEOPLASMS and some benign conditions.
Radiotherapy Dosage
The total amount of radiation absorbed by tissues as a result of radiotherapy.
Computers
A computer in a medical context is an electronic device that processes, stores, and retrieves data, often used in medical settings for tasks such as maintaining patient records, managing diagnostic images, and supporting clinical decision-making through software applications and tools.
Radiotherapy, Conformal
Radiotherapy, Adjuvant
Radiotherapy given to augment some other form of treatment such as surgery or chemotherapy. Adjuvant radiotherapy is commonly used in the therapy of cancer and can be administered before or after the primary treatment.
Radiotherapy, Intensity-Modulated
CONFORMAL RADIOTHERAPY that combines several intensity-modulated beams to provide improved dose homogeneity and highly conformal dose distributions.
Radiotherapy Planning, Computer-Assisted
Computer-assisted mathematical calculations of beam angles, intensities of radiation, and duration of irradiation in radiotherapy.
Radiotherapy, High-Energy
Radiotherapy using high-energy (megavolt or higher) ionizing radiation. Types of radiation include gamma rays, produced by a radioisotope within a teletherapy unit; x-rays, electrons, protons, alpha particles (helium ions) and heavy charged ions, produced by particle acceleration; and neutrons and pi-mesons (pions), produced as secondary particles following bombardment of a target with a primary particle.
Combined Modality Therapy
The treatment of a disease or condition by several different means simultaneously or sequentially. Chemoimmunotherapy, RADIOIMMUNOTHERAPY, chemoradiotherapy, cryochemotherapy, and SALVAGE THERAPY are seen most frequently, but their combinations with each other and surgery are also used.
Dose Fractionation
Administration of the total dose of radiation (RADIATION DOSAGE) in parts, at timed intervals.
Radiation Injuries
Radiotherapy, Computer-Assisted
Computer systems or programs used in accurate computations for providing radiation dosage treatment to patients.
Radiotherapy, Image-Guided
Computer Simulation
Radiation Oncology
A subspecialty of medical oncology and radiology concerned with the radiotherapy of cancer.
Treatment Outcome
Radiosurgery
A radiological stereotactic technique developed for cutting or destroying tissue by high doses of radiation in place of surgical incisions. It was originally developed for neurosurgery on structures in the brain and its use gradually spread to radiation surgery on extracranial structures as well. The usual rigid needles or probes of stereotactic surgery are replaced with beams of ionizing radiation directed toward a target so as to achieve local tissue destruction.
Dose-Response Relationship, Radiation
Brachytherapy
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.
Head and Neck Neoplasms
Soft tissue tumors or cancer arising from the mucosal surfaces of the LIP; oral cavity; PHARYNX; LARYNX; and cervical esophagus. Other sites included are the NOSE and PARANASAL SINUSES; SALIVARY GLANDS; THYROID GLAND and PARATHYROID GLANDS; and MELANOMA and non-melanoma skin cancers of the head and neck. (from Holland et al., Cancer Medicine, 4th ed, p1651)
Neoplasm Recurrence, Local
The local recurrence of a neoplasm following treatment. It arises from microscopic cells of the original neoplasm that have escaped therapeutic intervention and later become clinically visible at the original site.
Neoplasm Staging
Chemoradiotherapy
Treatment that combines chemotherapy with radiotherapy.
Computer Peripherals
Various units or machines that operate in combination or in conjunction with a computer but are not physically part of it. Peripheral devices typically display computer data, store data from the computer and return the data to the computer on demand, prepare data for human use, or acquire data from a source and convert it to a form usable by a computer. (Computer Dictionary, 4th ed.)
Antineoplastic Combined Chemotherapy Protocols
The use of two or more chemicals simultaneously or sequentially in the drug therapy of neoplasms. The drugs need not be in the same dosage form.
Computer Literacy
Familiarity and comfort in using computers efficiently.
Brain Neoplasms
Neoplasms of the intracranial components of the central nervous system, including the cerebral hemispheres, basal ganglia, hypothalamus, thalamus, brain stem, and cerebellum. Brain neoplasms are subdivided into primary (originating from brain tissue) and secondary (i.e., metastatic) forms. Primary neoplasms are subdivided into benign and malignant forms. In general, brain tumors may also be classified by age of onset, histologic type, or presenting location in the brain.
Carcinoma, Squamous Cell
A carcinoma derived from stratified SQUAMOUS EPITHELIAL CELLS. It may also occur in sites where glandular or columnar epithelium is normally present. (From Stedman, 25th ed)
Disease-Free Survival
Retrospective Studies
Studies used to test etiologic hypotheses in which inferences about an exposure to putative causal factors are derived from data relating to characteristics of persons under study or to events or experiences in their past. The essential feature is that some of the persons under study have the disease or outcome of interest and their characteristics are compared with those of unaffected persons.
Radiation Tolerance
The ability of some cells or tissues to survive lethal doses of IONIZING RADIATION. Tolerance depends on the species, cell type, and physical and chemical variables, including RADIATION-PROTECTIVE AGENTS and RADIATION-SENSITIZING AGENTS.
Survival Rate
Organs at Risk
Follow-Up Studies
Radiation-Sensitizing Agents
Computer Systems
Systems composed of a computer or computers, peripheral equipment, such as disks, printers, and terminals, and telecommunications capabilities.
Survival Analysis
A class of statistical procedures for estimating the survival function (function of time, starting with a population 100% well at a given time and providing the percentage of the population still well at later times). The survival analysis is then used for making inferences about the effects of treatments, prognostic factors, exposures, and other covariates on the function.
Rectal Neoplasms
Tumors or cancer of the RECTUM.
Particle Accelerators
Chemotherapy, Adjuvant
Prognosis
Cisplatin
An inorganic and water-soluble platinum complex. After undergoing hydrolysis, it reacts with DNA to produce both intra and interstrand crosslinks. These crosslinks appear to impair replication and transcription of DNA. The cytotoxicity of cisplatin correlates with cellular arrest in the G2 phase of the cell cycle.
Cranial Irradiation
Radiometry
Radiation Dosage
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).
Computers, Handheld
Tomography, X-Ray Computed
Radiation Pneumonitis
Laryngeal Neoplasms
Mastectomy, Segmental
Hodgkin Disease
A malignant disease characterized by progressive enlargement of the lymph nodes, spleen, and general lymphoid tissue. In the classical variant, giant usually multinucleate Hodgkin's and REED-STERNBERG CELLS are present; in the nodular lymphocyte predominant variant, lymphocytic and histiocytic cells are seen.
Computer Terminals
Radiodermatitis
Heavy Ion Radiotherapy
Neoplasms, Radiation-Induced
Tumors, cancer or other neoplasms produced by exposure to ionizing or non-ionizing radiation.
Neoplasms, Second Primary
Abnormal growths of tissue that follow a previous neoplasm but are not metastases of the latter. The second neoplasm may have the same or different histological type and can occur in the same or different organs as the previous neoplasm but in all cases arises from an independent oncogenic event. The development of the second neoplasm may or may not be related to the treatment for the previous neoplasm since genetic risk or predisposing factors may actually be the cause.
Neoplasms
Dacarbazine
Organ Sparing Treatments
Procarbazine
An antineoplastic agent used primarily in combination with mechlorethamine, vincristine, and prednisone (the MOPP protocol) in the treatment of Hodgkin's disease.
Software
Fluorouracil
Antineoplastic Agents
Substances that inhibit or prevent the proliferation of NEOPLASMS.
Neoadjuvant Therapy
Radioisotope Teletherapy
A type of high-energy radiotherapy using a beam of gamma-radiation produced by a radioisotope source encapsulated within a teletherapy unit.
Computers, Analog
Spinal Neoplasms
Spinal neoplasms are abnormal growths or tumors that develop within the spinal column, which can be benign or malignant, and originate from cells within the spinal structure or spread to the spine from other parts of the body (metastatic).
Cobalt Radioisotopes
Carcinoma, Non-Small-Cell Lung
A heterogeneous aggregate of at least three distinct histological types of lung cancer, including SQUAMOUS CELL CARCINOMA; ADENOCARCINOMA; and LARGE CELL CARCINOMA. They are dealt with collectively because of their shared treatment strategy.
Lymphatic Irradiation
Mechlorethamine
A biologic alkylating agent that exerts its cytotoxic effects by forming DNA ADDUCTS and DNA interstrand crosslinks, thereby inhibiting rapidly proliferating cells. The hydrochloride is an antineoplastic agent used to treat HODGKIN DISEASE and LYMPHOMA.
Carcinoma
Algorithms
Feasibility Studies
Glioblastoma
A malignant form of astrocytoma histologically characterized by pleomorphism of cells, nuclear atypia, microhemorrhage, and necrosis. They may arise in any region of the central nervous system, with a predilection for the cerebral hemispheres, basal ganglia, and commissural pathways. Clinical presentation most frequently occurs in the fifth or sixth decade of life with focal neurologic signs or seizures.
Radiation-Protective Agents
Prospective Studies
Pelvis
Diagnosis, Computer-Assisted
Salvage Therapy
A therapeutic approach, involving chemotherapy, radiation therapy, or surgery, after initial regimens have failed to lead to improvement in a patient's condition. Salvage therapy is most often used for neoplastic diseases.
Bleomycin
A complex of related glycopeptide antibiotics from Streptomyces verticillus consisting of bleomycin A2 and B2. It inhibits DNA metabolism and is used as an antineoplastic, especially for solid tumors.
Kaplan-Meier Estimate
A nonparametric method of compiling LIFE TABLES or survival tables. It combines calculated probabilities of survival and estimates to allow for observations occurring beyond a measurement threshold, which are assumed to occur randomly. Time intervals are defined as ending each time an event occurs and are therefore unequal. (From Last, A Dictionary of Epidemiology, 1995)
Iridium Radioisotopes
Patient Positioning
Glioma
Benign and malignant central nervous system neoplasms derived from glial cells (i.e., astrocytes, oligodendrocytes, and ependymocytes). Astrocytes may give rise to astrocytomas (ASTROCYTOMA) or glioblastoma multiforme (see GLIOBLASTOMA). Oligodendrocytes give rise to oligodendrogliomas (OLIGODENDROGLIOMA) and ependymocytes may undergo transformation to become EPENDYMOMA; CHOROID PLEXUS NEOPLASMS; or colloid cysts of the third ventricle. (From Escourolle et al., Manual of Basic Neuropathology, 2nd ed, p21)
Lymphatic Metastasis
Antineoplastic Agents, Alkylating
A class of drugs that differs from other alkylating agents used clinically in that they are monofunctional and thus unable to cross-link cellular macromolecules. Among their common properties are a requirement for metabolic activation to intermediates with antitumor efficacy and the presence in their chemical structures of N-methyl groups, that after metabolism, can covalently modify cellular DNA. The precise mechanisms by which each of these drugs acts to kill tumor cells are not completely understood. (From AMA, Drug Evaluations Annual, 1994, p2026)
Thoracic Neoplasms
Thoracic neoplasms are a broad category of abnormal growths or tumors that originate within the thorax, encompassing malignant (cancerous) and benign (non-cancerous) forms, which can affect structures such as the lungs, pleura, mediastinum, and chest wall.
Tumor Burden
Doxorubicin
Computer Communication Networks
A system containing any combination of computers, computer terminals, printers, audio or visual display devices, or telephones interconnected by telecommunications equipment or cables: used to transmit or receive information. (Random House Unabridged Dictionary, 2d ed)
Radiotherapy Setup Errors
Mistakes committed in the preparations for radiotherapy, including errors in positioning of patients, alignment radiation beams, or calculation of radiation doses.
Sarcoma
Cyclophosphamide
Precursor of an alkylating nitrogen mustard antineoplastic and immunosuppressive agent that must be activated in the LIVER to form the active aldophosphamide. It has been used in the treatment of LYMPHOMA and LEUKEMIA. Its side effect, ALOPECIA, has been used for defleecing sheep. Cyclophosphamide may also cause sterility, birth defects, mutations, and cancer.
Computer Graphics
The process of pictorial communication, between human and computers, in which the computer input and output have the form of charts, drawings, or other appropriate pictorial representation.
Drug Administration Schedule
Positron-Emission Tomography
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.
Heavy Ions
Supratentorial Neoplasms
Primary and metastatic (secondary) tumors of the brain located above the tentorium cerebelli, a fold of dura mater separating the CEREBELLUM and BRAIN STEM from the cerebral hemispheres and DIENCEPHALON (i.e., THALAMUS and HYPOTHALAMUS and related structures). In adults, primary neoplasms tend to arise in the supratentorial compartment, whereas in children they occur more frequently in the infratentorial space. Clinical manifestations vary with the location of the lesion, but SEIZURES; APHASIA; HEMIANOPSIA; hemiparesis; and sensory deficits are relatively common features. Metastatic supratentorial neoplasms are frequently multiple at the time of presentation.
Proton Therapy
The use of an external beam of PROTONS as radiotherapy.
Nimustine
Antineoplastic agent especially effective against malignant brain tumors. The resistance which brain tumor cells acquire to the initial effectiveness of this drug can be partially overcome by the simultaneous use of membrane-modifying agents such as reserpine, calcium antagonists such as nicardipine or verapamil, or the calmodulin inhibitor, trifluoperazine. The drug has also been used in combination with other antineoplastic agents or with radiotherapy for the treatment of various neoplasms.
Radiopharmaceuticals
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)
Reproducibility of Results
The statistical reproducibility of measurements (often in a clinical context), including the testing of instrumentation or techniques to obtain reproducible results. The concept includes reproducibility of physiological measurements, which may be used to develop rules to assess probability or prognosis, or response to a stimulus; reproducibility of occurrence of a condition; and reproducibility of experimental results.
Amifostine
Remission Induction
Neoplasm Metastasis
Prednisone
Magnetic Resonance Imaging
Quality of Life
Mucositis
An INFLAMMATION of the MUCOSA with burning or tingling sensation. It is characterized by atrophy of the squamous EPITHELIUM, vascular damage, inflammatory infiltration, and ulceration. It usually occurs at the mucous lining of the MOUTH, the GASTROINTESTINAL TRACT or the airway due to chemical irritations, CHEMOTHERAPY, or radiation therapy (RADIOTHERAPY).
Central Nervous System Neoplasms
Imaging, Three-Dimensional
The process of generating three-dimensional images by electronic, photographic, or other methods. For example, three-dimensional images can be generated by assembling multiple tomographic images with the aid of a computer, while photographic 3-D images (HOLOGRAPHY) can be made by exposing film to the interference pattern created when two laser light sources shine on an object.
Skull Base Neoplasms
Computer-Assisted Instruction
Radiation, Ionizing
ELECTROMAGNETIC RADIATION or particle radiation (high energy ELEMENTARY PARTICLES) capable of directly or indirectly producing IONS in its passage through matter. The wavelengths of ionizing electromagnetic radiation are equal to or smaller than those of short (far) ultraviolet radiation and include gamma and X-rays.
Chemoradiotherapy, Adjuvant
Combined chemotherapy and radiotherapy given to augment some other form of treatment such as surgery. It is commonly used in the therapy of cancer.
Etoposide
A semisynthetic derivative of PODOPHYLLOTOXIN that exhibits antitumor activity. Etoposide inhibits DNA synthesis by forming a complex with topoisomerase II and DNA. This complex induces breaks in double stranded DNA and prevents repair by topoisomerase II binding. Accumulated breaks in DNA prevent entry into the mitotic phase of cell division, and lead to cell death. Etoposide acts primarily in the G2 and S phases of the cell cycle.
Minicomputers
Small computers that lack the speed, memory capacity, and instructional capability of the full-size computer but usually retain its programmable flexibility. They are larger, faster, and more flexible, powerful, and expensive than microcomputers.
Preoperative Care
Care given during the period prior to undergoing surgery when psychological and physical preparations are made according to the special needs of the individual patient. This period spans the time between admission to the hospital to the time the surgery begins. (From Dictionary of Health Services Management, 2d ed)
Postoperative Care
Models, Biological
Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.
Esthesioneuroblastoma, Olfactory
A malignant olfactory neuroblastoma arising from the olfactory epithelium of the superior nasal cavity and cribriform plate. It is uncommon (3% of nasal tumors) and rarely is associated with the production of excess hormones (e.g., SIADH, Cushing Syndrome). It has a high propensity for multiple local recurrences and bony metastases. (From Holland et al., Cancer Medicine, 3rd ed, p1245; J Laryngol Otol 1998 Jul;112(7):628-33)
Vindesine
Vinblastine derivative with antineoplastic activity against CANCER. Major side effects are myelosuppression and neurotoxicity. Vindesine is used extensively in chemotherapy protocols (ANTINEOPLASTIC COMBINED CHEMOTHERAPY PROTOCOLS).
Meningeal Neoplasms
Proportional Hazards Models
Statistical models used in survival analysis that assert that the effect of the study factors on the hazard rate in the study population is multiplicative and does not change over time.
Astrocytoma
Neoplasms of the brain and spinal cord derived from glial cells which vary from histologically benign forms to highly anaplastic and malignant tumors. Fibrillary astrocytomas are the most common type and may be classified in order of increasing malignancy (grades I through IV). In the first two decades of life, astrocytomas tend to originate in the cerebellar hemispheres; in adults, they most frequently arise in the cerebrum and frequently undergo malignant transformation. (From Devita et al., Cancer: Principles and Practice of Oncology, 5th ed, pp2013-7; Holland et al., Cancer Medicine, 3d ed, p1082)
Pilot Projects
Treatment Failure
Prostate-Specific Antigen
Health Physics
Risk Factors
Actuarial Analysis
The application of probability and statistical methods to calculate the risk of occurrence of any event, such as onset of illness, recurrent disease, hospitalization, disability, or death. It may include calculation of the anticipated money costs of such events and of the premiums necessary to provide for payment of such costs.
Four-Dimensional Computed Tomography
Prostatectomy
Complete or partial surgical removal of the prostate. Three primary approaches are commonly employed: suprapubic - removal through an incision above the pubis and through the urinary bladder; retropubic - as for suprapubic but without entering the urinary bladder; and transurethral (TRANSURETHRAL RESECTION OF PROSTATE).
Image Processing, Computer-Assisted
Radiobiology
Clinical Trials as Topic
Works about pre-planned studies of the safety, efficacy, or optimum dosage schedule (if appropriate) of one or more diagnostic, therapeutic, or prophylactic drugs, devices, or techniques selected according to predetermined criteria of eligibility and observed for predefined evidence of favorable and unfavorable effects. This concept includes clinical trials conducted both in the U.S. and in other countries.
Phantoms, Imaging
Devices or objects in various imaging techniques used to visualize or enhance visualization by simulating conditions encountered in the procedure. Phantoms are used very often in procedures employing or measuring x-irradiation or radioactive material to evaluate performance. Phantoms often have properties similar to human tissue. Water demonstrates absorbing properties similar to normal tissue, hence water-filled phantoms are used to map radiation levels. Phantoms are used also as teaching aids to simulate real conditions with x-ray or ultrasonic machines. (From Iturralde, Dictionary and Handbook of Nuclear Medicine and Clinical Imaging, 1990)
Multivariate Analysis
A set of techniques used when variation in several variables has to be studied simultaneously. In statistics, multivariate analysis is interpreted as any analytic method that allows simultaneous study of two or more dependent variables.
Mastectomy, Modified Radical
Total mastectomy with axillary node dissection, but with preservation of the pectoral muscles.
Cone-Beam Computed Tomography
Information Systems
Testicular Neoplasms
Tumors or cancer of the TESTIS. Germ cell tumors (GERMINOMA) of the testis constitute 95% of all testicular neoplasms.
Meningioma
A relatively common neoplasm of the CENTRAL NERVOUS SYSTEM that arises from arachnoidal cells. The majority are well differentiated vascular tumors which grow slowly and have a low potential to be invasive, although malignant subtypes occur. Meningiomas have a predilection to arise from the parasagittal region, cerebral convexity, sphenoidal ridge, olfactory groove, and SPINAL CANAL. (From DeVita et al., Cancer: Principles and Practice of Oncology, 5th ed, pp2056-7)
Soft Tissue Neoplasms
Methotrexate
Carcinoma, Small Cell
An anaplastic, highly malignant, and usually bronchogenic carcinoma composed of small ovoid cells with scanty neoplasm. It is characterized by a dominant, deeply basophilic nucleus, and absent or indistinct nucleoli. (From Stedman, 25th ed; Holland et al., Cancer Medicine, 3d ed, p1286-7)
Fluorodeoxyglucose F18
The compound is given by intravenous injection to do POSITRON-EMISSION TOMOGRAPHY for the assessment of cerebral and myocardial glucose metabolism in various physiological or pathological states including stroke and myocardial ischemia. It is also employed for the detection of malignant tumors including those of the brain, liver, and thyroid gland. (From Martindale, The Extra Pharmacopoeia, 30th ed, p1162)
Spinal Cord Neoplasms
Benign and malignant neoplasms which occur within the substance of the spinal cord (intramedullary neoplasms) or in the space between the dura and spinal cord (intradural extramedullary neoplasms). The majority of intramedullary spinal tumors are primary CNS neoplasms including ASTROCYTOMA; EPENDYMOMA; and LIPOMA. Intramedullary neoplasms are often associated with SYRINGOMYELIA. The most frequent histologic types of intradural-extramedullary tumors are MENINGIOMA and NEUROFIBROMA.
Disease Progression
The worsening of a disease over time. This concept is most often used for chronic and incurable diseases where the stage of the disease is an important determinant of therapy and prognosis.
Monte Carlo Method
In statistics, a technique for numerically approximating the solution of a mathematical problem by studying the distribution of some random variable, often generated by a computer. The name alludes to the randomness characteristic of the games of chance played at the gambling casinos in Monte Carlo. (From Random House Unabridged Dictionary, 2d ed, 1993)
Abdominal Neoplasms
Abdominal neoplasms refer to abnormal growths or tumors occurring within the abdominal cavity, which can be benign or malignant, and affect various organs such as the pancreas, liver, kidneys, or intestines.
Oligodendroglioma
A relatively slow-growing glioma that is derived from oligodendrocytes and tends to occur in the cerebral hemispheres, thalamus, or lateral ventricle. They may present at any age, but are most frequent in the third to fifth decades, with an earlier incidence peak in the first decade. Histologically, these tumors are encapsulated, relatively avascular, and tend to form cysts and microcalcifications. Neoplastic cells tend to have small round nuclei surrounded by unstained nuclei. The tumors may vary from well-differentiated to highly anaplastic forms. (From DeVita et al., Cancer: Principles and Practice of Oncology, 5th ed, p2052; Adams et al., Principles of Neurology, 6th ed, p655)
Lymphoma, Non-Hodgkin
Any of a group of malignant tumors of lymphoid tissue that differ from HODGKIN DISEASE, being more heterogeneous with respect to malignant cell lineage, clinical course, prognosis, and therapy. The only common feature among these tumors is the absence of giant REED-STERNBERG CELLS, a characteristic of Hodgkin's disease.
Eye Enucleation
Deoxycytidine
Spinal Cord Compression
Acute and chronic conditions characterized by external mechanical compression of the SPINAL CORD due to extramedullary neoplasm; EPIDURAL ABSCESS; SPINAL FRACTURES; bony deformities of the vertebral bodies; and other conditions. Clinical manifestations vary with the anatomic site of the lesion and may include localized pain, weakness, sensory loss, incontinence, and impotence.
Risk Assessment
Photons
Discrete concentrations of energy, apparently massless elementary particles, that move at the speed of light. They are the unit or quantum of electromagnetic radiation. Photons are emitted when electrons move from one energy state to another. (From Hawley's Condensed Chemical Dictionary, 11th ed)
Karnofsky Performance Status
A performance measure for rating the ability of a person to perform usual activities, evaluating a patient's progress after a therapeutic procedure, and determining a patient's suitability for therapy. It is used most commonly in the prognosis of cancer therapy, usually after chemotherapy and customarily administered before and after therapy. It was named for Dr. David A. Karnofsky, an American specialist in cancer chemotherapy.
Computers, Molecular
Medulloblastoma
A malignant neoplasm that may be classified either as a glioma or as a primitive neuroectodermal tumor of childhood (see NEUROECTODERMAL TUMOR, PRIMITIVE). The tumor occurs most frequently in the first decade of life with the most typical location being the cerebellar vermis. Histologic features include a high degree of cellularity, frequent mitotic figures, and a tendency for the cells to organize into sheets or form rosettes. Medulloblastoma have a high propensity to spread throughout the craniospinal intradural axis. (From DeVita et al., Cancer: Principles and Practice of Oncology, 5th ed, pp2060-1)
Seminoma
A radiosensitive, malignant neoplasm of the testis, thought to be derived from primordial germ cells of the sexually undifferentiated embryonic gonad. There are three variants: classical (typical), the most common type; anaplastic; and spermatocytic. The classical seminoma is composed of fairly well differentiated sheets or cords of uniform polygonal or round cells (seminoma cells), each cell having abundant clear cytoplasm, distinct cell membranes, a centrally placed round nucleus, and one or more nucleoli. In the female, a grossly and histologically identical neoplasm, known as dysgerminoma, occurs. (Dorland, 27th ed)
Brain Stem Neoplasms
Benign and malignant intra-axial tumors of the MESENCEPHALON; PONS; or MEDULLA OBLONGATA of the BRAIN STEM. Primary and metastatic neoplasms may occur in this location. Clinical features include ATAXIA, cranial neuropathies (see CRANIAL NERVE DISEASES), NAUSEA, hemiparesis (see HEMIPLEGIA), and quadriparesis. Primary brain stem neoplasms are more frequent in children. Histologic subtypes include GLIOMA; HEMANGIOBLASTOMA; GANGLIOGLIOMA; and EPENDYMOMA.
Tumor Markers, Biological
Molecular products metabolized and secreted by neoplastic tissue and characterized biochemically in cells or body fluids. They are indicators of tumor stage and grade as well as useful for monitoring responses to treatment and predicting recurrence. Many chemical groups are represented including hormones, antigens, amino and nucleic acids, enzymes, polyamines, and specific cell membrane proteins and lipids.