Design of DOI Detector Through Analysis of Light Distribution Change According to the Depth Direction of the Scintillation Pixel

초록

A detector for measuring the interaction depth was designed to improve the spatial resolution of a positron-emission tomography (PET) for small animals. The detector composed of a scintillation pixel array was designed and performance-evaluated in accordance with DETECT2000. The interaction depth was measured by analyzing the light distribution change in the photosensor according to the depth direction of the scintillation pixel interacting with gamma rays. The scintillation pixel of the designed detector was composed of a 4 × 4 array with a size of 3 mm × 3 mm and two layers of 5 mm and 15 mm in the depth direction. Various lights generated by interaction with gamma rays were generated by varying the height of the scintillation pixel to obtain light distribution in the photosensor and determine the layer interacting with gamma rays. A lookup table was prepared with the average and standard deviation of the signals obtained from each photosensor. The light at the new location was acquired from the photosensor, and the interaction depth was measured through comparison and analysis with the lookup table using maximum likelihood position estimation. Results showed an accuracy of 89.2%. Given the excellent spatial resolution to apply this detector to the PET for small animals, images with improved performance can be obtained. © 2022 The Korean Physical Society. All rights reserved.

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