Sinogram resolution recovery using information gained through detector motion

Positron emission tomography (PET), as a biomedical imaging modality, is unique in its ability to provide quantitative information regarding biological function in a living subject. Unfortunately, its use has been hampered by the poor spatial resolution of the images produced, resulting primarily from the relatively large detectors used to acquire the tomographic measurements. In this paper, we show that by applying signal recovery to the data obtained by moving the detection system during the course of the measurement process, dramatic improvement in image quality can be obtained when detector size is, indeed, the factor limiting spatial resolution. The method of projections onto convex sets is used to recover (deblur) the sinogram, from which the image is reconstructed by conventional filtered backprojection. By making use of filtered backprojection in the reconstruction step, the computational burden commonly associated with iterative signal recovery is avoided; the proposed method adds only a few seconds to the total processing time. Simulation results demonstrate that the method is robust to misspecification of the point spread functions of the detection system as well as to the high levels of quantum noise inherent in PET.