| gamma camera | Any one of several scintigraphic cameras that records simultaneously counts from the entire operative field of view. Synonym: scintillation camera. (05 Mar 2000) |
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| gamma cameras | Electronic instruments that produce photographs or cathode-ray tube images of the gamma-ray emissions from organs containing radionuclide tracers. (12 Dec 1998) |
| gamma cell of pancreas | A cell of the pancreatic islets of the guinea pig. Synonym: gamma cell of pancreas. Synonym: parafollicular cells. (05 Mar 2000) |
| gamma crystallin | The least rapidly mobile form of crystallin on electrophoresis. (05 Mar 2000) |
| gamma efferent | The thin axon of a gamma motor neuron innervating the intrafusal muscle fibres of a muscle spindle. (05 Mar 2000) |
| gamma emission | <physics> Nuclear decay process whereby the nucleus goes from an excited state to a more stable state by emitting a gamma ray. See: gamma ray. (09 Oct 1997) |
| gamma encephalography | Imaging of the encephalon by the administration of small amounts of gamma-emitting radionuclides; commonly called a brain scan; superseded by computed tomography and magnetic resonance imaging. (05 Mar 2000) |
| gamma fibres | Nerve fibre's that have a conduction rate of about 20 m/sec. See: gamma efferent. (05 Mar 2000) |
| gamma globulin | <immunology> A non-specific immunoglobulin (antibody) administered for the purpose of passive immunity. A common example is hepatitis A prophylaxis. (27 Sep 1997) |
| gamma knife | <radiobiology> A special multi-source irradiation machine which focus a high intesity of irradiation on a small area: it is used as local therapy in especially brain tumours. This is investigational and is not part of the routine array of cancer treatments. (16 Dec 1997) |
| gamma loop | The reflex arc consisting of small anterior horn cells and neuroma, their small fibres projecting to the intrafusal bundle producing its contraction, which initiates the afferent impulses that pass through the posterior root to the anterior horn cells, inducing a stretch reflex. Synonym: gamma motor neurons, gamma motor system, Granit's loop. (05 Mar 2000) |
| gamma motor neurons | The reflex arc consisting of small anterior horn cells and neuroma, their small fibres projecting to the intrafusal bundle producing its contraction, which initiates the afferent impulses that pass through the posterior root to the anterior horn cells, inducing a stretch reflex. Synonym: gamma motor neurons, gamma motor system, Granit's loop. (05 Mar 2000) |
| gamma motor system | The reflex arc consisting of small anterior horn cells and neuroma, their small fibres projecting to the intrafusal bundle producing its contraction, which initiates the afferent impulses that pass through the posterior root to the anterior horn cells, inducing a stretch reflex. Synonym: gamma motor neurons, gamma motor system, Granit's loop. (05 Mar 2000) |
| gamma radiation | Ionizing electromagnetic radiation resulting from nuclear processes, such as radioactive decay or fission. (05 Mar 2000) |
| gamma ray | <radiobiology> Electromagnetic radiation (photons) with energies greater than (roughly) 100 keV (that is, 100,000 electron volts). Gamma radiation frequently accompanies alpha and beta decays, and always accompanies fission. Gamma rays are highly penetrating and are best shielded against using dense materials, such as lead or depleted uranium. (Gamma rays are similar to X-rays, but are generally higher in energy and nuclear in origin.) Gamma rays have wavelengths of 1 nanometre or shorter. These are highly energised, deeply penetrating photons which can be emitted from an atomic nucleus during nuclear fission (the splitting of an atom) and during regular atomic decay (radioactivity). (13 Oct 1997) |