Many of the scientific terms found in the abstracts, articles and lay translations presented on our site are included in this section. We are continually adding terminology found in both new and existing documents.
| R | ramification |
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Symbol for rate, expiratory exchange ratio, resistance, respiration, rhythm, right, roentgen, rough (colony), Rankine scale, Réaumur scale, and Behnken's unit; chemical symbol for an organic radical.
1. Distribution in branches.
2. A branch or set of branches.
3. The manner of branching.
4. Consequence, outgrowth.
Symbol for rate, expiratory exchange ratio, resistance, respiration, rhythm, right, roentgen, rough (colony), Rankine scale, Réaumur scale, and Behnken's unit; chemical symbol for an organic radical.
1. The condition of being subjected to extremes of radiation, which may have a harmful effect.
2. In radiology, a measure of the x-ray or gamma radiation at a certain place based on its ability to cause ionization. The unit of exposure is the roentgen. Symbol X. Called also exposure dose .
3. In radiology, the product of the intensity of x-rays and the time the film is exposed.
An isotope which is radioactive; one having an unstable nucleus and emitting characteristic radiation during its decay to a stable form. Radioisotopes have important diagnostic and therapeutic uses in clinical medicine and research.
Differential staining of chromosomes to elicit chromosome bands (R bands), consisting of pretreatment with hot alkali before staining; the banding pattern shown is the reverse of that of G and Q banding—darkly stained R bands are G and Q light and vice versa. Also called reverse banding .
Radiotherapy.
Marked by incorporation of a radioisotope. See also radioactive tracer .
See R band .
1. Directed to the cause; directed to the root or source of a morbid process, as radical surgery.
2. A group of atoms which enters into and goes out of chemical combination without change, and which forms one of the fundamental constituents of a molecule. Organic radicals are symbolized R.
Pertaining to radiology.
The initial upward deflection of the QRS complex, following the Q wave in the normal electrocardiogram and representing early depolarization of the ventricles.
Electromagnetic radiation of wavelength between 10–1 and 106 [["cm":2967]] and frequency of about 1011 to 104 hertz.
Pertaining to radiology.
A temperature scale with the ice point at 0 degrees and the normal boiling point of water at 80 degrees Rankine (oR).
Having the property of radioactivity.
That branch of the health sciences dealing with radioactive substances and radiant energy and with the diagnosis and treatment of disease by means of both ionizing (e.g., x-rays) and nonionizing (e.g., ultrasound) radiations.
As r - Symbol for ring chromosome and drug resistance ; formerly symbol for roentgen , officially replaced by R (See below).
As r - Symbol for correlation coefficient , distance , radius , and drug resistance .
As R - Symbol for rate , expiratory exchange ratio , resistance , respiration , rhythm , right , roentgen , rough (colony), Rankine scale , Réaumur scale, and Behnken's unit ; chemical symbol for an organic radical .
As R - Symbol for resistance and the gas constant .
Radioisotope.
The property of being radiolucent.
1. An ethnic stock or division of humankind; in a narrower sense, a national or tribal stock; in a still narrower sense, a genealogic line of descent; a class of persons of a common lineage. In genetics, races are considered as populations having different distributions of gene frequencies.
2. A class or breed of animals; a group of individuals having certain characteristics in common, owing to a common inheritance; a subspecies.
See radionuclide .
Permitting the passage of x-rays or other forms of radiant energy with little attenuation; radiolucent areas appear dark on the exposed film.
Pertaining to a particular race.
A radioactive isotope replacing a stable chemical element in a compound (said to be radiolabeled ) and so able to be followed or tracked through one or more reactions or systems by means of a radiation detector; used especially for such a compound that is introduced into the body for study of the compound's metabolism, distribution, and passage through the body.
A radioactive nuclide; one that disintegrates with the emission of corpuscular or electromagnetic radiations.
1. Acronym for radiation absorbed dose - a unit of measurement of the absorbed dose of ionizing radiation; it corresponds to an energy transfer of 100 ergs per gram of any absorbing material (including tissues). The biological effect of 1 rad varies with the kind of radiation the tissue is exposed to.
2. Abbreviation for "radian."
The quality of emitting or the emission of corpuscular or electromagnetic radiations consequent to nuclear disintegration, a natural property of all chemical elements of atomic number above 83, and possible of induction in all other known elements.
The determination of measurement of various factors, the specific data being transmitted by radio waves from the object of measurement to the recording apparatus.
1. Pertaining to the radius of the forearm or to the radial (lateral) aspect of the arm as opposed to the ulnar (medial) aspect; pertaining to a radius.
2. Radiating; spreading outward from a common center.
A film produced by radiography.
The treatment of disease by ionizing radiation. Called also "irradiation therapy" and "radiation therapy."
(Rad) The SI unit of measurement of plane angles, equal to the angle subtended to the center of a circle by an arc whose length is equal to the radius of the circle. One radian equals 360°/2π or approximately 57.296°.
Pertaining to or produced by radiography.
1. A line segment from the center to the circumference of a circle or the surface of a sphere; the length of such a segment. Symbol r.
2. The bone on the outer or thumb side of the forearm, articulating proximally with the humerus and ulna and distally with the ulna and carpus.
1. Diverging from a common center.
2. Emitting radiation or heat.
3. Transmitted by radiation.
The making of film records (radiographs) of internal structures of the body by passage of x-rays or gamma rays through the body to act on specially sensitized film. Formerly called roentgenography .
Root: a general term for the most inferior part, or a part by which a structure is anchored, as the portion of a hair, nail, or tooth that is buried in the tissues, or the part of a nerve adjacent to the center to which it is connected.
The energy of electromagnetic waves, such as radio waves, visible light, x-rays, and gamma rays.
A highly sensitive and specific assay method that uses the competition between radiolabeled and unlabeled substances in an antigen-antibody reaction to determine the concentration of the unlabeled substance; it can be used to determine antibody concentrations or to determine the concentration of any substance against which specific antibody can be produced. Abbreviated RIA.
Discontinuous sounds consisting of a series of short nonmusical noises, heard primarily during inhalation; called also crackle .
1. Divergence from a common center.
2. A structure made up of divergent elements, as one of the fiber tracts in the brain.
3. Energy transmitted by waves through space or through some medium; usually referring to electromagnetic radiation when used without a modifier. By extension, a stream of particles, such as electrons, neutrons, protons, or alpha particles.
Involving the use of a radioiodine.
Recurrent meningeal branch of the lacrimal artery.
Any device for converting radiant energy to a form more readily observable.
Any of the nine radioactive isotopes of iodine; 131I, 125I, and 123I are the most commonly used in the diagnosis and treatment of both benign and malignant disease of the thyroid gland and in the scintiscanning of such organs as the lung, liver, and kidney. Called also radioactive iodine .
1. Distribution in branches.
2. A branch or set of branches.
3. The manner of branching.
4. Consequence, outgrowth.