Post-reconstruction correction in quantitative single photon ECT

This paper describes a post-reconstruction correction method to compensate the distance-dependent system distortion function of the imaging system in single photon emission computed tomography (SPECT). After the projection data have been reconstructed by an attenuation-compensation algorithm, the preliminary reconstruction is then corrected using a space-varying iterative restoration scheme. The positivity contraint of the reconstructed image is incorporated into the restoration procedure. This post-reconstruction correction algorithm is verified by computer simulation. The corrected image is compared with the result of attenuation-corrected convolution backprojection and another post-reconstruction correction schemes.