Implementation of simultaneous attenuation and detector response correction in SPECT

Simultaneous correction of nonuniform attenuation and detector response was implemented in single-photon-emission computed tomography (SPECT) image reconstruction. A ray-driven projector-backprojector that exactly models attenuation in the reconstructed image slice and the spatially variant detector response was developed and used in the iterative maximum-likelihood algorithm for the correction. A computer-generated heart-lung phantom was used in simulation studies to compare the simultaneous correction method with an intrinsic attenuation correction method using a smoothing filter, and intrinsic attenuation correction method using a deconvolution filter, and a modified Chang attenuation correction method using a nonuniform attenuation distribution. The results demonstrate that the present method provides more-accurate quantitation and superior image quality.<>