Information analysis for 3D SPECT imaging of radionuclide distributions in attenuating objects
A mutual information formula is developed for the imaging of radionuclide distributions in attenuating objects using single photon emission computed tomography (SPECT) collimators. The formula is expressed in terms of the source distribution, attenuation coefficients, and collimator parameters such as collimator thickness, hole size, septal thickness, and hole shape factor. The polyhedral collimator is employed for our mutual information analysis in this report. Based on imaging surface decomposition, the analysis of the polyhedral collimator is reduced to the analysis of a single-headed collimator for planar imaging. Conventional collimators including parallel and cone beam collimators are used for the analysis of the single-headed collimator. The information loss due to attenuation is evaluated for myocardial imaging using technetium-99m.