emission+of+rays
21positron emission tomography scanner — noun a tomograph that produces cross sectional X rays of metabolic processes in the body • Syn: ↑PET scanner • Hypernyms: ↑tomograph * * * positron emission tomography scanner ● positron …
22positron emission tomography — the process of producing a PET scan. Cf. PET scanner. * * * ▪ imaging technique imaging technique used in diagnosis and biomedical research. It has proved particularly useful for studying brain and heart functions and certain biochemical… …
23positron emission tomography — noun A medical imaging technique which detects the gamma rays produced by positrons emitted from injected radionuclides …
24positron emission — a form of radioactive decay in which a positron (β+) and neutrino are ejected from the nucleus as a proton is transformed into a neutron. Collision of the positron with an electron causes annihilation of both particles and conversion of… …
25Positron Emission Tomography — technique for creating detailed images of bodily tissues by injecting positron laden material into the body and recording the gamma rays emitted over a period of about two hours (Medicine) …
26gamma decay — Type of radioactivity in the most common form of which an unstable atomic nucleus dissipates energy by gamma emission, producing gamma rays. Gamma decay also includes two other processes, internal conversion and internal pair production. In… …
27bright — adj 1 Bright, brilliant, radiant, luminous, lustrous, effulgent, refulgent, beaming, lambent, lucent, incandescent are comparable when they mean actually or seemingly shining or glowing with light. Bright implies an opposition to dim or dull; it… …
28ray gun — noun : a hypothetical future weapon releasing deadly or stunning rays of unknown nature * * * 1. a gun that can fire bursts of usually destructive or lethal rays: a science fiction novel whose hero has a ray gun made of gold. 2. a child s… …
29ray — 1. n. & v. n. 1 a single line or narrow beam of light from a small or distant source. 2 a straight line in which radiation travels to a given point. 3 (in pl.) radiation of a specified type (gamma rays; X rays). 4 a trace or beginning of an… …
30bright — I. adjective Etymology: Middle English, from Old English beorht; akin to Old High German beraht bright, Sanskrit bhrājate it shines Date: before 12th century 1. a. radiating or reflecting light ; shining, sparkling < bright lights > < bright eyes …
