A comparison of three systems for performing single-photon emission tomography

A comparison is made between the performance of three transverse axial single-photon emission tomographic machines, namely a rotating gamma-camera and two different scanning systems. Each system has been evaluation in terms of the spatial resolution, sensitivity and efficiency. The functional dependence of the volume sensitivity on the size of the emitting object has been derived using a theoretical model of the photon emission, attenuation and detection. The model is shown to predict this size dependence well and is consistent with the experimental observations.