Simulated annealing image reconstruction method for a pinhole aperture single photon emission computed tomograph (SPECT)

Abstract

A series of computer experiments was performed to determine the relative performance of simulated annealing, quenched annealing, and a least-squares iterative technique for image reconstruction for single photon emission computed tomography (SPECT). The simulated SPECT geometry was of the pinhole aperture type, with 32 pinholes and 128 or 512 detectors. To test the robustness of the reconstruction techniques upon arbitrary geometries, a 360-detector geometry with a random pixel-detector-factor matrix was tested. Eight computer-simulated, 10-cm-diameter planar phantoms were used with 1961 2-mm(2) reconstruction bins and a range of 3000 to 50,000,000 detected photon counts. Reconstruction quality was measured by a normalized, squared error picture distance measure. Over a wide range of noise, the simulated annealing method had slightly better reconstruction quality than the iterative method, although requiring greater reconstruction time. Quenched annealing was faster than simulated annealing, with comparable reconstruction quality. Methods of efficiently controlling the simulated annealing algorithm are presented.