Design of a Depth-Encoding Detector for PET Through Insertion of Light Guide Between Crystal Arrays

To improve the spatial resolution of preclinical positron emission tomography (PET), a detector consisting of a two-layer scintillator pixel array was designed. A light guide was inserted between the arrays of scintillators to change the distribution of light generated in each layer. By analyzing the different light distributions, it is possible to track where the gamma rays interacted. To this end, a gamma ray event was generated at the center of the flashing pixel and a lookup table was created based on the signal obtained from the light sensor. The optimal position of the scintillation pixel was tracked through comparison and analysis of the newly detected signal with the look-up table through maximum likelihood position estimation. As a result, excellent accuracy was shown. If this detector is used in a preclinical PET system, it is expected to show excellent spatial resolution, and since an optical sensor that is not affected by magnetic fields is used, it is considered that it can be applied to PET/MRI in the future.