G - Glossary of Terms

Glossary of terms index - A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z

G - Glossary of Terms

gall	(gawl) Bitter, brownish or greenish yellow fluid secreted by liver; bile.
gallbladder	A pouchlike organ attached to the underside of the liver in which bile secreted by the liver is stored and concentrated.
gamma	The gradient (slope) of the steepest portion of the characteristic curve.
ganglion	(gang´gle-un) Greek = swelling, an aggregation of nerve cell bodies occurring outside the central nervous system.
gangrene	(gang'green) Necrosis of tissue caused by interference with blood supply to part, usually accompanied with putrefaction.
gantry	The portion of the computed tomographic or magnetic resonance imaging system that accommodates the patient and source or the detector assemblies.
gas gangrene	(gang'green) Gangrene occurring chiefly in lacerated wounds and in which tissues become impregnated with gas produced by a mixed infection of bacteria, including gas bacillus.
gastr	(gas'tr-) Prefix signifying relation to stomach; as gastritis„gastroenterostorny.
gastric	(gas'trik) Of or pertaining to stomach.
gastroentero	(gas"tro-enter-o-) Prefix denoting relation to stomach and intestine; as gastroenteroptosis, prolapse or downward displacement of stomach and intestines.
gastrointestinal syndrome	A form of acute radiation syndrome that appears in humans at a threshold dose of about 10 Gy (1000 rad). It is characterized by nausea, diarrhea, and damage to the cells lining the intestines.
gastrointestinal tract	(GI tract) (gas´´tro-in-tes´tu1-nal) The portion of the digestive tract that includes the stomach and the small and large intestines.
gavage	(gah"vahzh') Feeding by stomach tube.
Geiger-Muller counter	Radiation-detection and radiation-measuring instrument that detects individual ionisations. It is the primary radiation survey instrument for nuclear medicine facilities.
gelatin	The part of the emulsion that provides mechanical support for the silver halide crystals by holding them uniformly dispersed in place.
generation time	See cell cycle time.
genetic cell	The oogonium or the spermatogonium.
genetic effect	Effects of radiation that affects and in dividual and subsequent unexposed generations.
genetically significant dose (GSD)	The average gonadal dose to members of the population who are of childbearing age.
genic	(-jen'ik) Combining form meaning causing, giving origin to, or arising from; as osteogenic, originating in bone.
geometric unsharpness	The loss of detail due to penumbral effects of the finite focal spot size. Increases with greater magnification.
germ cell	A reproductive cell.
german horizontal plane	Base line of cranium; anthropologic base line.
germicide	(jermi-side) Any agent that destroys germs; cf. antiseptic and disinfectant
gigantism	(ji-gan´tiz´´em) Abnormal body growth as a result of the excessive secretion of growth hormone.
gingivae	(jin´ji-va) The fleshy covering over the mandible and maxilla through which the teeth protrude within the mouth; also called the gum.
glabella	(glah-bel'ah). Smooth space on forehead between superciliary arches, which corresponds in position with eyebrows.
glabelloalveolar line	(glah-bero al v 'o lar) Imaginary line extending from glabella to upper alveolus; localisation plane of face.
glabellomeatal line	(glah-bero al v 'o lar) Imaginary line extending from glabella to external auditory meatus; localisation line used in skull radiography.
gland	An organ that produces a specific substance or secretion.
glandular dose	The average radiation dose to glandular tissue.
glans penis	(glanz pe´nis) The enlarged, sensitive, distal end of the penis.
glenoid	(gle'noid) Smooth, shallow depression; specifically, glenoid fossa of scapula.
gliding joint	A type of synovial joint in which the articular surfaces are flat, permitting only side-to-side and back-and-forth movements.
glioma	(gIi-o'mah) Malignant tumor originating in supportive or connective tissue of central nervous system.
glomerular capsule	(glo-mer´yuu-lar) The double-walled proximal portion of a renal tubule that encloses the glomerulus of a nephron; also called Bowman's capsule.
glossa	(glos'ah) Greek for tongue.
glossal	(glos'aI) Of or pertaining to tongue; lingual.
glottis	(glot´is) A slitlike opening into the larynx, positioned between the true vocal cords.
glow curve	Graph that shows the relationship of light output to temperature change.
glycogen	A human polysaccharide.
glycogenolysis	(gli´´ko-je-nol´i-sis) The hydrolysis of glycogen to glucose 1-phosphate, which can be converted to glucose 6-phosphate, which then may be oxidized via glycolysis or (in the liver) converted to free glucose.
goblet cell	A unicellular mucus-secreting gland that is associated with columnar epithelia; also called a mucous cell.
Golgi tendon organ	A sensory receptor found near the junction of tendons and muscles.
gomphosis	Fibrous joint between teeth and jaw.
gonad	(go´nad) A reproductive organ, testis or ovary, that produces gametes and sex hormones.
gonadal dose	The exposure to the reproductive organs. Gradient The slope of the tangent at any point on the characteristic curve.
gonion	(go'ne-on) Tip of angle of mandible.
gram method	Technique for staining microorganisms.
granulation	(gran-u-la'shun). Formation of small grains or particles; any small, granule-like mass of abnormal tissue projecting from surface of an organ; formation in a wound of small, rounded granules of new tissue during healing process.
granulocyte	A scavenger cell used to fight bacteria. Gray (Gy) Special name for the SI unit of absorbed dose and air kerma. 1 Gy = 1 J/kg = 100 rad.
granuloma	Tumorlike mass of tissue caused by a chronic inflammatory process.
gravel	(grav'eI) Deposit of small, stonelike concretions in kidneys and urinary bladder: calculi.
Graves' disease	A hyperthyroid condition believed to be caused by excessive stimulation of the thyroid gland by autoantibodies; it is associated with exophthalmos (bulging eyes), high pulse rate, high metabolic rate, and other symptoms of hyperthyroidism.
gravid	(grav'id) Pregnant. A condition containing a developing young.
gray scale	An image display in which intensity is recorded as variations in brightness.
grey matter	The region of the central nervous system composed of nonmyelinated nerve tissue.
greater omentum	(o-men´tum) A double-layered peritoneal membrane that originates on the greater curvature of the stomach. It hangs inferiorly like an apron over the contents of the abdominal cavity.
grid	A device used to reduce scatter radiation in the remnant X-ray beam. Constructed of alternating strips of lead and a radio-transparent medium (such as aluminum, wood, or plastic) which are oriented in such a way that most of the primary radiation will pass through the grid between the strips while most of the scattered radiation will intersect the lead strips and be absorbed.
grid clean-up	The ability of a grid to absorb scatter radiation.
grid-controlled tube	An X-ray tubes designed to be turned on and off very rapidly for situations requiring multiple exposures at precise exposure times.
grid cutoff	The absence of optical density on a radiograph because of unintended X-ray absorption in a grid.
grid frequency	The number of grid lines per inch or centimeter.
grid lines	A series of sections of radiopaque material.
grid ratio	The ratio of grid height to grid strip separation.
groin	(groin) Depression between lower part of abdomen and thigh, or region around depression; inguen, or inguinal region.
groove	(groov) Shallow, linear depression, or furrow in a part, especially in bone.
gross anatomy	The branch of anatomy concerned with structures of the body that can be studied without a microscope.
Grossman principle	Tomographic principle in which fulcrum or axis of rotation remains at a fixed height. The focal plane level is changed by raising or lowering the tabletop through this fixed point to the desired height.
ground glass	Any extended, finely granular pattern of pulmonary opacity within which normal anatomic details are partially (not completely) obscured. Compare with consolidation, in which the underlying anatomic details are completely obscured.
guanine	A nitrogenous organic base that attaches to a deoxyribose molecule.
guide shoe	A device in an automatic processor that is used for steering film around bends.
guidewire	A device that allows the safe introduction of the catheter into the vessel.
gumma	(gum'ah) Soft, gummy, granulomatous tumor of syphilitic origin, occurring in third stage of disease.
gustatory	(gus´ta-tor´´e) Pertaining to the sense of taste.
gut	(The GI tract or a portion thereof; generally used in reference to the embryonic digestive tube, consisting of the foregut, midgut, and hindgut.
gynecology	(gin"e-kol'o-je) Branch of medicine that treats women's diseases occurring in genital, urinary, and rectal regions.
gyrus	(ji´rus) Greek gyros = circle, a convoluted elevation or ridge.

Glossary of terms index - A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z


◄ .....Go back to the general radiography homepage