Restoration of detector scatter in quantitative Rat-PET studies

The potential of positron emission tomography (PET) to provide quantitative physiological parameters in vivo is of great importance in medicine as well as in pharmacology. However, the PET data need to be previously corrected for the physical image degrading effects. In this work, we demonstrate the effect of detector scatter restoration on image quality in small animal imaging as measured with individual detectors. The detector scatter is shown to affect the spatial resolution and the partial volume. Its effect on object scatter correction is also discussed. The spatial resolution was found to increase by about 2.5% after restoration of detector scatter as assessed in the projections of the sinograms. The gain in amplitude of a small size measured structure corresponding to this ratio should be considered to subsequently accurately correct for partial volume effect. Application of the detector scatter restoration prior to the assessment of tumor and myocardium glucose metabolism in the rat as well as perfusion in the rat heart was found to slightly increase these parameter values.