SPECT Reconstruction of Combined Cone Beam and Parallel Hole Collimation with Experimental Data

We have developed three methods to combine parallel and cone bean (P & CB) SPECT data using modified Maximum Likelihood-Expectation Maximization (ML-EM) algorithms. The first combination method applies both parallel and cone beam data sets to reconstruct a single intermediate image after each iteration using the ML-EM algorithm. The other two iterative methods combine the intermediate parallel beam (PB) and cone beam (CB) source estimates to enhance the uniformity of images. These two methods are ad hoc methods. In earlier studies using computer Monte Carlo simulation, we suggested that improved images might be obtained by reconstructing combined P&CB SPECT data. These combined collimation methods are qualitatively evaluated using experimental data. An attenuation compensation is performed by including the effects of attenuation in the transition matrix as a multiplicative factor. The combined P & CB images are compared with CB-only images and the results indicate that the combined P & CB approaches suppress artifacts caused by truncated projections and correct for the distortions of the CB-only images. © 1993 IEEE

Duke Scholars

Author Timothy Garvey Turkington Radiology