Registration of whole-body scintillation camera images for conjugate view quantification

A registration method for whole-body (WB) scintillation camera images is presented, with application to conjugate view activity quantification. Accurate image registration is here required if the quantification is performed on an image basis, for (a) serial emission images, for analysis of the biokinetics, and (b) transmission and emission images, for a pixel-based attenuation correction. The spatial transformation used for registration is composed of both global and local transformations, including rigid, projective and one curved transformation. As similarity measure, the mutual information is used. An initial coarse solution is first calculated by cross-correlation. Optimization is then performed in a sequence, beginning with the legs position, followed by the abdomen and head. Evaluation has been performed for Monte Carlo simulated 131-I images of an anthropomorphic WB phantom. Obtained registration errors are within one pixel (<3.6 mm)