Pet Scanning: From 2 Different Sources
The abbreviation for positron emission tomography, a diagnostic technique based on the detection of positrons (a type of subatomic particle) that are emitted by radioactively labelled substances introduced into the body. scanning produces 3-dimensional images of the metabolic and chemical activity of tissues.
Substances used in biochemical processes in the body are labelled with radioisotopes and then injected into the bloodstream. The substances are taken up in greater concentrations by tissues that are more metabolically active. The substances emit positrons, which release photons that are detected by the scanner. scans are used to detect brain tumours, locate epileptic activity within the brain, and examine brain function.
Positron-emission tomography is a NUCLEAR MEDICINE diagnostic technique that works by identifying positrons – positively charged electrons – given o? by substances labelled with radioactive varieties of elements. The result is three-dimensional images that identify metabolic and chemical activities of tissues, especially brain tissues. The images provide information about tissue and organ functions, and can be collated with structural images using COMPUTED TOMOGRAPHY or magnetic resonance imaging (MRI). The equipment is very expensive and available only in selected hospitals in the United Kingdom. The technique is especially valuable in the assessment of neurological disorders.
A speech disorder in which articulated syllables are wrongly spaced and each is given the same vocal emphasis. The condition occurs as a result of disease in the cerebellum (see BRAIN) or its connecting nerves. (See also VOICE AND SPEECH.)... scanning speech
Ways of producing images of body organs that record, process and analyse sound waves, radio waves or X-RAYS passing through or generated by the body’s tissues. ULTRASOUND scanning using high-frequency, inaudible sound waves directed at the area of the body being studied is the most generally used scanning procedure. Sound waves are re?ected more powerfully by some structures than others, and a pattern of those re?ections is detected and shown on a screen. Other screening methods include COMPUTED TOMOGRAPHY, magnetic resonance imaging (MRI), positron emission tomography (PET SCANNING) and RADIONUCLIDE scanning, which measures the di?erential uptake of radioactive materials in the body’s tissues.... scanning techniques
An abbreviation for computerized axial tomographic scanning, commonly known as CT scanning.... cat scanning
See radionuclide scanning.... isotope scanning
See radionuclide scanning.... radioisotope scanning
Techniques, such as radionuclide scanning and ultrasound scanning, that are used to provide information about the location, anatomy, and function of the thyroid gland.... thyroid scanning
(NT scanning) an ultrasound screening test performed during pregnancy at 11 weeks of gestation that measures the maximum thickness of the translucency between the skin and the soft tissue overlying the cervical (neck) region of the spine of the fetus. Increased NT is associated with an increased risk of chromosomal abnormalities and of a wide variety of structural abnormalities (e.g. heart defects). See also ultrasound marker.... nuchal translucency scanning
an imaging system that allows a PET scan (see positron emission tomography) and a CT scan (see computerized tomography) to be performed very close together, with minimal movement of the patient between scans. This means that the images produced can be co-registered (see co-registration), giving very accurate anatomical localization (from the CT scan) of areas of increased activity (identified on the PET scan). This is very important for determining the site of disease in order to plan treatment.... pet/ct scanning
see ophthalmoscope.... scanning laser ophthalmoscope
(single photon emission computing tomography) (in nuclear medicine) a *cross-sectional imaging technique for observing an organ or part of the body using a *gamma camera; images are produced after injecting a radioactive *tracer. The camera is rotated around the patient being scanned. Using a computer reconstruction *algorithm similar to that of a *computerized tomography scanner, multiple ‘slices’ are made through the area of interest. SPECT scanning is used particularly in cardiac nuclear medicine imaging (see MUGA scan). It differs from PET scanning in that radioactive decay gives off only a single gamma ray.... spect scanning
(helical CT scanning) a development of conventional *computerized tomography (CT) scanning in which the X-ray tube rotates continuously around the patient as he or she passes through the scanner. This allows the acquisition of images throughout a specified volume of tissue much more quickly. Since these images are digitally acquired (see digitization), *post-processing can produce images in numerous planes, without further exposure of the patient to ionizing radiation. See also multidetector computerized tomography.... spiral ct scanning
(V/Q scanning) a nuclear medicine technique in which two different isotopes are used, one inhaled (usually *xenon-133 or *krypton-81m), to examine lung ventilation, and the other injected into a vein, to examine lung perfusion. In *pulmonary embolism, the area of lung supplied by the blocked artery is not being perfused with blood – which gives a perfusion defect on the film – but has normal ventilation. This technique is highly sensitive for pulmonary embolism.... ventilation-perfusion scanning
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