Simultaneous attenuation and depth-dependent resolution compensation for 180° myocardial perfusion SPECT

A method has been developed that combines filtered backprojection (FBP) with an iterative 3-D attenuation and resolution compensation method for Tc-99m myocardial perfusion single photon emission computed tomography (SPECT), and dual-window scatter correction performed on projection data. The 3-D compensation is accomplished by including both the attenuation and depth-dependent resolution variation in a reprojection procedure and using the difference between the reprojection and the scatter-corrected projection data to revise the previous estimate of tracer distribution. The method was evaluated with both simulated and experimental data using clinical protocols with a homomorphic thorax phantom with cardiac insert. Significant improvements in image resolution and defect-to-normal contrast were observed. A significant improvement in uniformity of maximum pixel count values was also observed where uniform distribution was expected. The method provides the potential for more accurate lesion detection and quantitation of tracer concentration in the myocardium