| AF | abnormal frequency; acid-fast; adult female; afebrile; aflatoxin; albumin-free; albumose-free; aldeh... |
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| FTC | Federal Trade Commission; follicular thyroid carcinoma; frequency threshold curve; frequency tuning ... |
| HFO | high-frequency oscillator; high-frequency oscillatory [ventilation] |
| Hfr | heart frequency; high frequency |
| HFT | high-frequency transduction; high-frequency transfer |
| frequency distribution | A statistical description of raw data in terms of the number or frequency of items characterised by each of a series or range of values of a continuous variable. (05 Mar 2000) |
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| frequency domain | The expression of a function by its amplitude and phase at each component frequency, usually as determined by Fourier analysis. (05 Mar 2000) |
| frequency encoding | In magnetic resonance imaging, a method of varying the magnetic field strength with location to encode the location of each voxel uniquely in one direction. (05 Mar 2000) |
| frequency of micturition | Micturition at short intervals; it may result from increased urine formation, decreased bladder capacity, or lower urinary tract irritation. (05 Mar 2000) |
| frequency of occurrence | The number of times a given event occurs at specified sample points during a defined period. (07 Apr 1998) |
| frequency spectrum | The range of frequencies in a signal, used to describe the resolving power of an imaging system in radiology. (05 Mar 2000) |
| frequency, urinary | Urinating too often, at too frequent intervals, not due to an unusually large volume of urine, but rather to a decrease in the capacity of the bladder to hold urine. (12 Dec 1998) |
| fundamental frequency | The principal component of a sound wave, which has the greatest wavelength, tone produced by the vibration of the vocal folds before the air reaches any cavities. (05 Mar 2000) |
| low frequency transduction | Specialised transduction in which only a small portion of the prophage particles, because of their defectiveness, are able to develop sufficiently to serve as effective transducing agents. (05 Mar 2000) |
| adrenal imaging | <radiology> Cortex, I-131 iodo-cholesterol, not widely used due to high rad dose and 4-15 day delayed imaging, medulla, search for pheo, MIBG (I-131 meta-iodobenzylguanidine) (12 Dec 1998) |
| adrenal medullary imaging | <investigation, radiology> A nuclear scan that images the adrenal glands after a radioactive tracer is injected into the bloodstream. This test is useful in detecting a pheochromocytoma, particularly if it not within the adrenal gland. (27 Sep 1997) |
| backscattered electron imaging | <microscopy> The production of backscattered electrons from a sample varies directly with the specimen's average atomic number, higher atomic number elements produce more backscattered electrons than lower atomic number ones. Detection of Backscattered Electrons is achieved by using a donut shaped solid state saemiconductor device mounted on the bottom of the objective lens. When Backscattered Electrons strike the detector electron-hole pairs are created which are then counted. This quantity is translated into a pixel intensity and displayed on the CRT, forming the image. By splitting the detector into halves (or quadrants) differences in the signal level on the individual detector segments provide surface topography information. (05 Aug 1998) |
| blood pool imaging | Nuclear medicine study using a radionuclide that is confined to the vascular compartment. (05 Mar 2000) |
| bone: gallium imaging | <radiology> Increased activity in: active osteomyelitis (90% sensitivity: better than Tc-99m MDP), sarcoma, cellulitis, septic arthritis, rheumatoid arthritis, Paget disease, metastases (65% sensitivity: than for bone agents) see: gallium: indications (12 Dec 1998) |
| bright field imaging | <microscopy> An imaging mode in a transmission electron microscopy that uses only unscattered Electrons to form the image. Contrast in such an image is due entirely to mass-thickness variations in amorphous samples, and may include diffraction contrast in crystalline samples. (05 Aug 1998) |