Distance-dependent restoration filtering of dual photopeak window scatter compensated SPECT images

A non-iterative SPECT reconstruction method is presented which consists of pre-processing the projection data for compensation of scatter, attenuation and the detector response prior to ramp filtered backprojection. Scatter is compensated for using the dual-photopeak window (DPW) method, attenuation is compensated for using Bellini´s method, and compensation for the non-stationary detector response and noise suppression is performed with a frequency distance principle (FDP) Wiener filter. This approach was compared to a number of different processing methods using a Monte Carlo simulation study of an anthropomorphic digitized phantom of the liver and spleen. Compared to Butterworth smoothing, the DPW/FDP Wiener filtering method can provide a substantial increase in contrast with a noise increase ranging from minimal to moderate depending on the cut-off frequency of the Butterworth filter