THE GEM MAP ALGORITHM WITH 3-D SPECT SYSTEM RESPONSE

In single photon emission computed tomography, every reconstruction algorithm must use some model for the response of the gamma camera to emitted gamma-rays. The true camera response is both spatially variant and object dependent. These two properties result from the effects of scatter, septal penetration, and attenuation and they forestall determination of the true response with any precision. This motivates our investigation of the performance of reconstruction algorithms when there are errors between the camera response used in the reconstruction algorithm and the true response of the gamma camera. In this regard, we compare the filtered backprojection algorithm, the expectation-maximization maximum likelihood algorithm, and the GEM MAP algorithm, a Bayesian algorithm which uses a Markov random field prior.