Modeling scatter in multiple energy windows for incorporating scattered radiation information in SPECT imaging

The scatter in single photon emission computed tomography (SPECT) contains activity information and some reports showed that it is possible to use this information for improving image quantity. The method is modeling scatter in multiple energy windows in reconstruction. However, what the performance and what noise behavior will be when using scattered radiation in reconstruction are the problems remaining unanswered. Here, the authors investigate the method of modeling scatter in multiple energy windows in the cases of few projection views. The system performance is analyzed by using singular value decomposition (SVD). For investigating noise behavior, the reconstruction is accomplished by estimating the variance of reconstructed voxel values. The effectiveness of using scatter in noise cases is evaluated by resolution kernel analysis. The results show that the improvements due to using scatter are shown in normalized mean square error (NMEM) of reconstructed images and the resolution kernels. When photon counts fall below about one million, there is still some effectiveness of using scatter in the cases of few projection views