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Glossary

Starting with A for "ACE inhibitor" and continuing through to Y for "Yolk Sac Tumour", we give you succinct explanations for scientific and medical terms in clear and simple words.




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Computer tomography
Abbreviation CT

X-Ray diagnostic and computer-based imaging procedure. A narrow fan-shaped beam is produced with an X-ray tube and a special filter system. This is attenuated (weakened) to various degrees by the structures present in the layer of the patient who is irradiated. The signal from this attenuated X-ray beam is detected with an array of multiple detectors and electronically processed. During computer tomography, the system of tube and detectors rotates together round the middle of the circular measurement field. In this way, many different projections of the same layer are produced and processed in the computer to an image which depicts the distribution of the attenuation values in the irradiated body layer. CT images have much better contrast resolution but poorer structural and form resolution than conventional X-rays. CT is particularly useful in the detection of restricted and diffuse morphological changes, such as tumours, metastases and abscesses. It complements ultrasound diagnosis, conventional X-ray diagnosis and nuclear spin tomography.

Glossary entries:  Roche and Walter de Gruyter, Berlin