| cathode ray tube | An evacuated tube containing a beam of electrons which can be deflected to various parts of a fluorescent screen; used in the cathode ray oscilloscope. (05 Mar 2000) |
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| pa X-ray | An X-ray picture in which the beams pass from back-to-front (posteroanterior). As opposed to an ap (anteroposterior) film in which the rays pass through the body from front-to-back. (12 Dec 1998) |
| medullary ray | The centre of the renal lobule, which has the shape of a small, steep pyramid, consisting of straight tubular parts; these may be either ascending or descending limbs of the nephronic loop or collecting tubules. Synonym: pars radiata lobuli corticalis renis, Ferrein's pyramid, processus ferreini. (05 Mar 2000) |
| characteristic X-ray | <microscopy> An X-ray having a unique energy that is emitted by an atom in the sample during its de-energization after ionization of one of its electrons by an incident electron. (05 Aug 1998) |
| chemical ray | A light ray toward and beyond the violet end of the spectrum that acts upon a photographic plate and produces other chemical effects. Synonym: chemical ray. (05 Mar 2000) |
| chest X-ray | Commonly used to detect abnormalities in the lungs, but can also detect abnormalities in the heart, aorta, and the bones of the thoracic area. Metallic objects, such as jewelry are removed from the chest and neck areas for a chest X-ray to avoid interference with x-ray penetration and improve accuracy of the interpretation. (12 Dec 1998) |
| grenz ray | Very soft X-ray's, closely allied to the ultraviolet ray's in their wavelength (i.e., long) and in their biologic action upon tissues; they are produced by a specially built vacuum tube with a hot cathode operating from a transformer delivering not more than 8 kw. Origin: Ger. Grenze, borderline, boundary (05 Mar 2000) |
| roentgen ray | <investigation> A type of irradiation used for imaging purposes that uses energy beams of very short wavelengths (0.1 to 1000 angstroms) that can penetrate most substances except heavy metals. This is the commonest form of imaging technique used in clinical practice everywhere in the world with the image captured on photographic film. An AP film is when the beams pass from front-to-back (anteroposterior) and is used for mobile film, particularly on the ward or in casualty. This is the oposite to a PA film (posteroanterior) in which the rays pass through the body from back-to-front. Most films taken in the main radiology department are PA. (20 Jun 2000) |
| microscope, X-ray | <microscopy> A device for producing enlarged images of a specimen by means of X rays. Dioptric systems, analogous to light microscopes, are not available, but contact microradiography, point-projection, and reflection techniques (which see) provide practical alternatives. (05 Aug 1998) |
| crystallography, X-ray | The study of crystal structure using X-ray diffraction techniques. (12 Dec 1998) |
| half-ray | <geometry> A straight line considered as drawn from a center to an indefinite distance in one direction, the complete ray being the whole line drawn to an indefinite distance in both directions. Source: Websters Dictionary (01 Mar 1998) |
| Harris and Ray test | A test for vitamin C in the urine; a microtitration test of the urine against a known amount of 0.05% aqueous solution of the dye 2,6-dichloroindophenol in 10% acetic acid (usually 0.05 ml of dye is used, roughly equivalent to 0.025 mg of ascorbic acid). Synonym: Harris test. (05 Mar 2000) |
| X-ray | <investigation> A type of irradiation used for imaging purposes that uses energy beams of very short wavelengths (0.1 to 1000 angstroms) that can penetrate most substances except heavy metals. This is the commonest form of imaging technique used in clinical practice everywhere in the world with the image captured on photographic film. An AP film is when the beams pass from front-to-back (anteroposterior) and is used for mobile film, particularly on the ward or in casualty. This is the oposite to a PA film (posteroanterior) in which the rays pass through the body from back-to-front. Most films taken in the main radiology department are PA. (20 Jun 2000) |
| X-ray computed tomography | <radiology> Tomography using X-ray transmission and a computer to reconstruct the image. See: computed tomography. (20 Jun 2000) |
| X-ray crystallography | <investigation> A technique of determining the three-dimensional structure of a molecule by analysing the X-ray diffraction patterns of crystals made up of the molecule in question. (06 May 1997) |