Real time Method based on SVM for Depth-of-‎Interaction Identification in PET Scanners

Document Type : Original Article

Authors

1 Radiation enginerring department, national ceter fro radiation research and technology, Egyptian Atomic Energy Authority

2 Radiation Engineering Dept.,

3 Radiation Engineering Department, National Center for Radiation Research and Technology, Cairo, Egypt

Abstract

‎ Positron Emission Tomography (PET) scanners are based on a ring of scintillation ‎detectors where each detector is comprised of an array of crystals usually coupled to a ‎photosensor. The parallax error is the common error that degrades the spatial resolution of ‎the reconstructed image in the PET scanners. This error resulted from the misidentification ‎of the exact depth-of-interaction (DOI). Phoswich based detector has been used as a ‎solution to accurately identifying the DOI. The pulses emitted from the scintillation crystal ‎layer of this detector are discriminated based on the Pulse Shape Discrimination (PSD) ‎method. In this paper, a high rate merged PSD method which depends on only half of the ‎scintillation pulse is proposed to enhance the performance of PET scanners. The ‎frequency transform (discrete cosine transform or discrete sine transform) is merged with ‎the supportvector machine (SVM) classifier. The PSD method is verified by ‎discriminating 100 000 scintillation pulses of both LSO and LuYAP crystal. The event rate ‎was 24.5 M events/sec. Therefore, the proposed method realizes a high real-time event ‎rate which nominates it for a ClearPET small animal PET scanner. The discrimination ‎efficiency was kept as 91.36% by merging DST4 with the linear kernel of SVM.‎

Keywords

Arab Journal of Nuclear Sciences and Applications
Volume 55, Issue 2
April 2022
Pages 104-112

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