Medical Conditions Terminology in Category R

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Random Allocation

A process involving chance used in therapeutic trials or other research endeavor for allocating experimental subjects, human or animal, between treatment and control groups, or among treatment groups. It may also apply to experiments on inanimate objects.

Rectal Drug Administration

The insertion of drugs into the rectum, usually for confused or incompetent patients, like children, infants, and the very old or comatose.

Radiation Accident

Accidental dispersal of radioactive materials from a radiation source. Accidents at nuclear reactors can involve large groups of the population from dispersion of radioactivity into the environment and through fallout or a few individuals with high injurious doses.

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Radiation Induced Abnormalities

Congenital changes in the morphology of organs produced by exposure to ionizing or non-ionizing radiation.

Radiation Protective Agents

Drugs used to protect against ionizing radiation. They are usually of interest for use in radiation therapy but have been considered for other, e.g. military, purposes.

Radiation Sensitizing Agents

Drugs used to potentiate the effectiveness of radiation therapy in destroying unwanted cells.

Radiation-Induced Abnormality

Congenital changes in the morphology of organs produced by exposure to ionizing or non-ionizing radiation.

Radioactive Air Pollutants

Pollutants, present in air, which exhibit radioactivity.

Radiofrequency Catheter Ablation

Removal of tissue with electrical current delivered via electrodes positioned at the distal end of a catheter. Energy sources are commonly direct current (DC-shock) or alternating current at radiofrequencies (usually 750 kHz). The technique is used most often to ablate the AV junction and/or accessory pathways in order to interrupt AV conduction and produce AV block in the treatment of various tachyarrhythmias.

Radio-Iodinated Serum Albumin

Normal human serum albumin mildly iodinated with radioactive iodine (131-I) which has a half-life of 8 days, and emits beta and gamma rays. It is used as a diagnostic aid in blood volume determination. (from Merck Index, 11th ed)