Reconstruction of multiple line source attenuation maps

Abstract

A simple configuration for a transmission source for single photon emission computed tomography (SPECT) is proposed, which utilizes a series of collimated line sources parallel to the axis of rotation of the camera. The detector is equipped with a standard parallel hole collimator. The authors have demonstrated that this type of source configuration can be used to generate sufficient data for the reconstruction of the attenuation map when using 8-10 line sources spaced by 3.5-4.5 cm for a 30/spl times/40 cm detector placed 65 cm from the sources. Transmission data for a nonuniform thorax phantom was simulated, then binned and reconstructed using filtered backprojection (FBP) and iterative methods. It was found that optimum maps were obtained with data binned into 2-3 bins and FBP reconstruction. The activity in the source was investigated for uniform and exponential activity distributions. The effect of gaps and overlaps of the neighboring fan beams was also studied. A prototype of the line source system has been built and the experimental verification of the simulation results has started.