Promising results on PSF correction applied in the reconstruction process of a small animal PET image

In this work we present the effects on the spatial resolution of a small animal Positron Emission Tomography (PET) using continuous crystals when their Point Spread Function (PSF) information is considered in an iterative reconstruction algorithm. The PET system consisted of eight detector modules with slight differences in their detection efficiency and intrinsic resolution. We have experimentally determined the PSF for each detector using a grid of 7×7 uniformly distributed holes. An image reconstruction algorithm including the PSF information has been implemented. The quantitative performance of PSF reconstruction was compared with the one obtained with a standard reconstruction algorithm. This comparative analysis was carried out with a phantom formed by 9×9 ²²Na point-like sources. They had 1 mm in diameter and the distance between adjacent centers was 5 mm. We obtained a resolution improvement of up to 13% when the PSF information was considered in the reconstruction process.