| 131I | radioactive Iodine(used in Thyroid uptake, Liver & Kidney Scans & Treatment of malignant & nonmalig... |
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| 99mTc | radioactive Technetium(used in Brain Skull, Thyroid, Liver, Spleen, Bone & Lung scans) |
| RA | radioactive; ragocyte; ragweed antigen; rapidly adapting [receptors]; reactive arthritis; reciprocal... |
| RAIU | radioactive iodine uptake |
| RAMP | radioactive antigen microprecipitin; right atrial mean pressure |
| intra-aortic balloon pumping | Counterpulsation in which a pumping unit synchronised with the patient's electrocardiogram rapidly fills a balloon in the aorta with helium or carbon dioxide in early diastole and evacuates the balloon at the onset of systole. As the balloon inflates, it raises aortic diastolic pressure, and as it deflates, it lowers aortic systolic pressure. The result is a decrease in left ventricular work and increased myocardial and peripheral perfusion. (12 Dec 1998) |
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| laser-assisted balloon angioplasty | <cardiology, procedure> Techniques using laser energy in combination with a balloon catheter to perform angioplasty. These procedures can take several forms including: 1. Laser fibre delivering the energy while the inflated balloon centres the fibre and occludes the blood flow. 2. Balloon angioplasty immediately following laser angioplasty. 3. Laser energy transmitted through angioplasty balloons that contain an internal fibre. (05 Mar 2000) |
| air pollutants, radioactive | Pollutants, present in air, which exhibit radioactivity. (12 Dec 1998) |
| radioactive | Giving off radiation. (12 Dec 1998) |
| radioactive atom | <chemistry, physics> An atom with an unstable nucleus, which emits particulate or electromagnetic radiation (radioactive emission) to achieve greater stability. See: radionuclide, half-life, Becquerel. (05 Mar 2000) |
| radioactive constant | <physics, radiobiology> The fraction of the amount of a radionuclide that undergoes transition per unit time. Formally: Lamda=dP/dt Where dP is the probability of a given nucleus undergoing spontaneous nuclear transition in the time interval dt. (16 Dec 1997) |
| radioactive contamination | <radiobiology> Radioactive substance dispersed in material or places where it is undesirable. (16 Dec 1997) |
| radioactive cow | Colloquialism for radionuclide generator. See: cow. (05 Mar 2000) |
| radioactive decay | <physics> The process by which a spontaneous change in nuclear state takes place. This process is accompanied by the emission of energy in various specific combinations of electromagnetic and corpuscular radiation and neutrinos. (16 Dec 1997) |
| radioactive equilibrium | <radiobiology> That condition in which the activities of the members of a radioactive chain decrease exponentially in time with the half-life of the chain precursor. Such radioactive equilibrium is only possible when the half-life of the precursor is longer than that of any other chain member. If the precursor half-life is so long that the change in the precursor population during the period of interest can be ignored, all the activities become sensibly equal and the equilibrium is said to be secular, otherwise it is said to be transient. (16 Dec 1997) |
| radioactive fallout | The material that descends to the earth or water well beyond the site of a surface or subsurface nuclear explosion. (12 Dec 1998) |
| radioactive iodide uptake test | A test of thyroid function in which 131I-iodide is given orally; after 24 hours, the amount present in the thyroid gland is measured and compared with normal values. Synonym: radioactive iodide uptake test, RAI test. (05 Mar 2000) |
| radioactive iodine | Iodine that gives off radiation. See radioiodine. (12 Dec 1998) |
| radioactive isotope | <physics, radiobiology> An isotope of an element that has an unstable nucleus, it tries to stabilise itself by giving off ionising radiation. (09 Oct 1997) |
| radioactive pollutants | Radioactive substances which act as pollutants. They include chemicals whose radiation is released via radioactive waste, nuclear accidents, fallout from nuclear explosions, and the like. (12 Dec 1998) |