STUDY OF MULTISPECTRAL FRAME-BY-FRAME CONVOLUTION SCATTER CORRECTION IN HIGH-RESOLUTION PET

High resolution PET scanners based on small individual detectors have a low sensitivity resulting from increased inter-detector scatter. It has been postulated that this limitation can be overcome by using enla rged discrimination windows to include more low-energy events and by d eveloping more efficient energy-dependent methods to correct for scatt er. In this work, we investigate one such method based on the frame-by -frame scatter correction of multispectral data. Images acquired in th e conventional (344-658 keV), broad (129-658 keV) and multispectral (1 29-658 keV) window modes were processed by stationary and nonstationar y convolution-restoration scatter correction methods. Broad and multis pectral window acquisition improved counting efficiency relative to th e conventional window. The degradation of image quality due to added s catter can be mostly recovered by the subtraction-restoration scatter correction. However, the multispectral frame-by-frame method was found to be more sensitive to the effects of the nonstationary scatter resp onse functions and its performance was not as good as that of the broa d window. It is concluded that more sophisticated scatter degradation models and correction methods need to be established to take full adva ntage of multispectral data.