Body deformation correction for SPECT imaging

Body bending and body twisting are kinds of non- rigid and non-periodic patient motion which may occur during SPECT imaging. We have developed a body- deformation correction method to account for these motions in 3D SPECT reconstructions. In this paper, we describe the underlying body-deformation model and also demonstrate its application within a modified MLEM iterative reconstruction algorithm. The deformation model proposed here has three degrees of freedom, defined by the twist angle, the bend angle, and the bending direction. We estimate these deformation parameters using a set of skin- based marker coordinates. Our experiments show that this body model works well for real patients. A comparison of simulated images reconstructed with and without the deformation correction indicates the improvement that our method can bring to 3D SPECT reconstructions.