single-photon emission computed tomography

tomography /to·mog·ra·phy/ (to-mog´rah-fe) the recording of internal body images at a predetermined plane by means of the tomograph.

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computed tomography  (CT), computerized axial tomography (CAT) an imaging method in which a cross-sectional image of the structures in a body plane is reconstructed by a computer program from the x-ray absorption of beams projected through the body in the image plane.

positron emission tomography  (PET) a nuclear medicine imaging method similar to computed tomography, except that the image shows the tissue concentration of a positron-emitting radioisotope.

single-photon emission computed tomography  (SPECT) a type in which gamma photon–emitting radionuclides are administered and then detected by one or more gamma cameras rotated around the patient, using the series of two-dimensional images to recreate a three-dimensional view.

ultrasonic tomography  the ultrasonographic visualization of a cross-section of a predetermined plane of the body.

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single-photon emission computed tomography (SPECT),

a variation of computed tomography in which the ray sum is defined by the collimator holes on the gamma-ray detector rotating around the patient. SPECT units usually consist of large crystal gamma cameras mounted on a gantry that permits rotation of the camera around the patient. Multiple detectors are used to reduce the imaging time.