an imaging technique in which a radioactive substance is introduced into the body and the radiation emitted by the substance is detected by a camera and is transformed into cross-sectional images by a computer

A method in which images are generated by using radionuclides that emit single photons of a given energy. Images are captured at multiple positions by rotating the sensor around the subject; the three-dimensional distribution of radionuclides is then used to reconstruct the images. SPECT can be used to observe biochemical and physiological processes, as well as the size and volume of structures. Unlike positron emission tomography, SPECT requires the physical alignment of the photons for their detection, resulting in the loss of many available photons and the degradation of the image.

See SPECT

A computer scan which using radioactive isotopes as tracers, that can visualise the damage to the basal ganglia seen in Parkinson's. It follows similar principles to PET but uses different isotopes and tracers. It is more practical and less expensive than PET, but the spatial resolution achieved is not as good.