Current Status of Single Photon Emission Computerised Tomography

Gamma-ray imaging is a well-established procedure in medical diagnosis. In single photon ECT we wish to measure and display the concentration of radio activity within a thin transverse slice of the body while still retaining the simple, atraumatic, non-invasive nature of the iadionuclide investigation. When Kuhl and Edwards introduced the technique in 1963, it did not involve any fundamental change in the detection-display equipment nor in the accuracy of measurement, as for example with X-ray transmission imaging, but simply pointed the way to develop the emission imaging equipment into a more sophisticated tool for the accurate measurement of in-vivo concentration of radionuclide. This paper attempts to examine the technique and to review the physics and engineering aspects of current ECT systems.