• The expensive and potentially dangerous radioactive sources used in SPA and DPA have been replaced by single X-ray absorptiometry (SXA) and dual-energy X-ray absorptiometry (DXA) since the late 1980s. (wikipedia.org)
  • Dual energy X-ray absorptiometry is helpful in detecting low bone mineral density (BMD) caused by hyperparathyroidism. (wikidoc.org)
  • Another modality used in hyperparathyroidism is dual energy X-ray absorptiometry ( DXA ). (wikidoc.org)
  • Dual-energy x-ray absorptiometry (DEXA) detects small changes in bone mass by comparing the patient's bone density to that of healthy adults (T score) and to age-matched adults (Z score). (medscape.com)
  • [ 12 ] and dual-energy x-ray absorptiometry (DEXA). (medscape.com)
  • Dual-energy X-ray absorptiometry or DXA was based on low dose x-ray radiations has become the widely used procedure. (boneandspine.com)
  • Measures true density in gm/cm- 3 centimeter in contrast to dual-energy X-ray absorptiometry, which determines density measured in g/cm 2 . (boneandspine.com)
  • Common methods include conventional radiography, quantitative CT (QCT), single-photon absorptiometry (SPA), dual-photon absorptiometry (DPA), quantitative ultrasonography (QUS), and dual-energy x-ray absorptiometry (DEXA). (medscape.com)
  • Non-invasive imaging modalities for preoperative localization of hyper-functioning parathyroid glands include Tc-99m sestamibi scintigraphy ( sestamibi or MIBI ), single photon emission computed tomography ( SPECT ), positron emission tomography ( PET ). (wikidoc.org)
  • Single photon emission computed tomography may be used along with Tc-99m sestamibi scintigraphy for preoperative evaluation of hyper-functioning parathyroid gland. (wikidoc.org)
  • Quantitative computed tomography is a procedure which uses CT scan for quantitative assessment of the bones or bone mineral density. (boneandspine.com)
  • In recent years, better CT technology and the advantages of CT over DXA in the differentiation of cortical and trabecular bone mineral density and others, the use of quantitative computed tomography in musculoskeletal research studies is increasing. (boneandspine.com)
  • Quantitative computed tomography is used to quantify bone mineral density in the spine, proximal femur, forearm, and tibia. (boneandspine.com)
  • In spine, quantitative computed tomography gauges mineral density is gauged from analyzing the vertebral bones. (boneandspine.com)
  • SINGLE-PHOTON EMISSION-COMPUTED TOMOGRAPHY is closely related to positron emission tomography , but uses isotopes with longer half-lives and resolution is lower. (lookformedical.com)
  • Types of spiral computed tomography technology in which multiple slices of data are acquired simultaneously improving the resolution over single slice acquisition technology. (lookformedical.com)
  • A method of computed tomography that uses radionuclides which emit a single photon of a given energy. (lookformedical.com)
  • Osteoporosis is defined as a progressive systemic skeletal disorder characterized by low bone mineral density (BMD), deterioration of the microarchitecture of bone tissue, and susceptibility to fracture. (medscape.com)
  • By Osteoporosis is a skeletal disease, characterized by low bone mass and micro-architectural deterioration of bone tissue, with a consequent increase in bone fragility and susceptibility to fracture. (boneandspine.com)
  • The disadvantage is that, unlike positron-emission tomography where the positron-electron annihilation results in the emission of 2 photons at 180 degrees from each other, SPECT requires physical collimation to line up the photons, which results in the loss of many available photons and hence degrades the image. (lookformedical.com)
  • The single photon absorption method operates when a certain amount of gamma rays emitted by isotopes, pass through human tissues. (wikipedia.org)
  • In 1963, the single photon absorption Assay (SPA) invented by Cameron and Sorenson was the first quantitative analysis method applied to the diagnosis of osteoporosis. (wikipedia.org)
  • This method uses the principle that the absorption of radioactive substances by bone tissue is proportional to the bone mineral content. (wikipedia.org)
  • BMC (g/cm) can be obtained by synthesizing the measured bone gamma photon absorption energy. (wikipedia.org)
  • This method is called gamma-ray absorption method, which is also called single-photon absorption method. (wikipedia.org)
  • Single photon absorption is the earliest method to measure bone mineral density accurately. (wikipedia.org)
  • Its basic principle is that bone mineral density can be obtained by the law of absorption. (wikipedia.org)
  • In this law, the important parameters to be obtained are bone thickness, bone absorption coefficient and radiation intensity (or counting) after bone absorption. (wikipedia.org)
  • The thickness of soft tissue measured by single photon absorption method is the same. (wikipedia.org)
  • The next improvement in the field of bone mineral density is the single-photon absorption (SPA) method invented by Cameron and Sorenson in 1963. (wikipedia.org)
  • The main effects of parathyroid hormone are to increase the concentration of plasma calcium by increasing the release of calcium and phosphate from bone matrix, increasing calcium reabsorption by the kidney, and increasing renal production of 1,25-dihydroxyvitamin D-3 (calcitriol), which increases intestinal absorption of calcium. (medscape.com)
  • Moreover, the Kerr nonlinearity and the lack of two-photon absorption in the near infrared enable efficient nonlinear optics, e.g., frequency comb generation. (bvsalud.org)
  • Skeletal manifestations include a selective cortical bone loss. (medscape.com)
  • In quantitative terms, BMD is the amount of calcium hydroxyapatite, or Ca 10 (PO 4 ) 6 (OH) 2 , per unit volume of bone tissue examined. (medscape.com)
  • The basic principle of single-photon bone mineral density measuring instrument is to calculate the attenuation degree of single-energy gamma photon beam through bone tissue. (wikipedia.org)
  • The more attenuation degree is, the more absorbed by bone minerals, the more bone mineral content and the higher bone mineral density are. (wikipedia.org)
  • Two of the most frequently used methods are based on measuring the attenuation of a beam of electromagnetic radiation or ultrasound when it passes through the bone. (medscape.com)
  • This method is mainly used for bone measurements of limbs and population census with the aid of the water bath. (wikipedia.org)
  • Density measurements of the spine or hip are used. (medscape.com)
  • Bone-density measurements can be performed by using X-ray methods, such as DEXA, QCT, and ultrasonic methods. (medscape.com)
  • After being absorbed by the bone and soft tissue, NaI (Tl) crystal is used to detect the radioactivity counts parallel to the light source. (wikipedia.org)
  • The location of measurement is usually located at the 1/3 junction of the ulna and distal radius, or at the less soft tissue sites such as calcaneus and hand bone, wrapped in a water bag and placed between light source and detector. (wikipedia.org)
  • Soft tissue does not affect the results of bone tissue measurement. (wikipedia.org)
  • The basis of "single-isotope, double-phase technique" is that sestamibi washes out of the thyroid more rapidly than from abnormal parathyroid tissue. (wikidoc.org)
  • Bone mineral density (BMD) is determined by measuring the amount of bone mineral (calcium hydroxyapatite) per unit volume of bone tissue. (medscape.com)
  • If the isotope source is changed to X-ray source, that is, single energy X-ray absorptiometer (SXA), the principle and determination method is the same as SPA, but the radiation source is different. (wikipedia.org)
  • Dedicated peripheral CT scanners to measure BMD and bone morphology in the radius and tibia are smaller, more mobile and less expensive that whole-body CT scanners. (boneandspine.com)
  • Therefore, the influence of soft tissues can be eliminated by a water bath, and the number of gamma rays absorbed by bone tissues can be measured, and then calculated. (wikipedia.org)
  • Iodine or Americium gamma photons are used as a light source to penetrate the forearm. (wikipedia.org)
  • DXA is helpful in detecting low bone mineral density (BMD) caused by hyperparathyroidism. (wikidoc.org)
  • An early attempt which used conventional X-rays to measure bone mineral density (BMD) uses stepped wedges made of aluminum or ivory phantom as a calibration tool. (wikipedia.org)
  • The goal is the measurement of bone strength, to predict fractures, and to differentially assess the effects of aging and treatment. (boneandspine.com)
  • The bone mineral density was calculated by visually comparing the bone mineral density and the known density at each step of the phantom. (wikipedia.org)
  • To transform HU into bone mineral equivalents an appropriate bone mineral phantom is included in the scan field. (boneandspine.com)
  • Bone loss in women accelerates quickly during the first years following menopause. (medscape.com)
  • However, linear and nonlinear operations require distinct engineering of the waveguide core geometry, resulting in a tradeoff between optical loss and single-mode behavior, which hinders the development of high-performance, ultralow-loss linear processing blocks on a single layer. (bvsalud.org)
  • Single photon absorptiometry is a measuring method for bone density invented by John R. Cameron and James A. Sorenson in 1963. (wikipedia.org)
  • This method can only measure the bone mineral content of limbs. (wikipedia.org)
  • According to the WHO definition, a patient is osteoporotic if the patient's BMD is 2.5 standard deviations (SDs) below typical peak bone mass of young, healthy white women. (medscape.com)
  • BMC and BMD are obtained by calculating the density of photon energy emitted and emitted. (wikipedia.org)
  • Single and dual-energy photon absorptiometry utilized radionuclide sources. (boneandspine.com)
  • Single-isotope, double-phase technique is used. (wikidoc.org)
  • It is a sensitive technique and can detect changes in bone density only 6-12 months after a previous measurement is obtained. (medscape.com)
  • In 1976, it was an important tool for quantifying bone mineralization in infants. (wikipedia.org)