n. a diagram showing the distribution of radioactive *tracer in a part of the body, produced by recording the flashes of light given off by a *scintillator as it is struck by radiation of different intensities. This technique is called scintigraphy. By scanning the body, section by section, a ‘map’ of the radioactivity in various regions is built up, aiding the diagnosis of cancer or other disorders. Such a record is known as a scintiscan. These images are now usually obtained using a *gamma camera.
A compound introduced into the body, the progress of which can subsequently be followed and information obtained about the body’s metabolic activities. Radioactive tracers are compounds labelled with RADIONUCLIDE which give o? radiation. This can be measured with a gamma camera or a scintigram. The information is used in the investigation of suspected tumours in the BRAIN or malfunctioning of the THYROID GLAND.... tracer
diethylenetriaminepentaacetic acid, which when labelled with *technetium-99m is used as a tracer to obtain *scintigrams of the kidney over a period of time, by means of a *gamma camera. DTPA is filtered out of the blood by the kidneys and passes into the urine; it is used to show the function of the kidney and reflux from the bladder up the ureter. It is particularly useful in assessing obstruction to urinary drainage from the kidneys.... dtpa
an apparatus that detects gamma rays emitted by radioactive isotopes that have been introduced into the body as *tracers. It contains an activated sodium iodide crystal (see scintillator) and a large array of photomultiplier tubes. Using lead *collimators, the position of the source of the radioactivity can be plotted and displayed on a TV monitor or photographic film (see scintigram).... gamma camera
1. n. examination of the body or a part of the body using *ultrasonography, *computerized tomography (CT), *magnetic resonance imaging (MRI), or scintigraphy (see scintigram). 2. n. the image obtained from such an examination. 3. vb. to examine the body using any of these techniques.... scan
n. a substance that produces a fluorescent flash when struck by high-energy radiation, such as beta or gamma rays. In medicine the most commonly used scintillator is a crystal of thallium-activated sodium iodide, which forms the basis of a *gamma camera. See also scintigram.... scintillator
n. an isotope of the artificial radioactive element technetium. It emits gamma radiation only, with no beta particles, at a convenient energy for detection by a *gamma camera and has a short half-life. For these reasons it is widely used in nuclear medicine as a *tracer for the examination of many organs (see scintigram). Symbol: Tc-99m.... technetium-99m
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