A method of attenuation map and emission activity reconstructions from emission data

An iterative algorithm that reconstructs of attenuation map and emission activity distribution from SPECT emission data only is proposed based on quasi-linearized attenuated Radon transform. At each iteration of the algorithm, emission activity distribution is first reconstructed, using the attenuation map from previous iteration. Then the attenuation map is estimated by using the current emission image. To find the attenuation map effectively in a possible class of solutions the attenuation map is constrained by an optimal basis set, derived from cross-correlation of a priory images or “knowledge set.” Computer simulations show that the proposed algorithm has the capacity to effectively reconstruct Emission activity distribution and transmission map without transmission measurements. The proposed method has been tested using clinically acquired data