Due to little white (or lightly colored) spots that are slightly elevated on the surface of the iris. These spots, arranged in a ring concentric with the pupil, occur in normal children but are far more frequent in Down’s syndrome (trisomy 21). They were described in 1924 by Thomas Brushfield, are called Brushfield’s spots, and are due to aggregation of a normal iris element (connective tissue).
An acronym that stands for Single Photon Emission Computed Tomography, a nuclear medicine procedure in which a gamma camera rotates around the patient and takes pictures from many angles, which a computer then uses to form a tomographic (cross-sectional) image. The calculation process in SPECT is similar to that in CT (X-ray computed tomography) and […]
- SPECT scan
Single photon emission computed tomography scan, a nuclear medicine procedure in which a gamma camera rotates around the patient to produce images from many angles, which a computer then uses to form a tomographic (cross-‘sectional) image.
- Spectral karyotype (SKY)
A visualization of all of the chromosomes in the genome all together with each chromosome labeled with a different color. The SKY technique is useful for identifying chromosome abnormalities.
An abnormal and persistent fear of ghosts. Sufferers of spectrophobia experience undue anxiety even though they realize their fear is irrational. They may fear going into woods, empty houses or dark places and may react with alarm at strange or unexplained noises. No doubt Hollywood has enkindled spectrophobia with such films as Poltergeist, The Haunting […]
A device which measures the amount of ultraviolet light absorbed by a substance. For example, vitamin A absorbs ultraviolet light so that a spectrophotometer can measure within minutes with almost perfect accuracy the amount of vitamin A in a given food. The spectrophotometer, a key instrument today in biomedical laboratories, was invented in 1939 by […]