Detector Design using Block Scintillator with 4-Sided Light Sensor and MLPE for Achieving High Resolution and High Sensitivity in Small Animal PET/MRI

A detector utilizing a block scintillator and a semiconductor light sensor was designed for small animal positron emission tomography/magnetic resonance imaging (PET/MRI) applications that achieves high resolution and sensitivity without signal distortion in a magnetic field. The goal was to achieve high sensitivity by using a block scintillator rather than a pixelated scintillator, and high resolution by applying a maximum likelihood position estimation (MLPE). A DETECT2000 simulation was performed to evaluate the performance of the designed detector. Gamma-ray events, where the scintillator and gamma-rays interact, were generated at 1 mm intervals in all directions within the scintillator, and signals were collected by the light sensor. A look-up table (LUT) was created based on the collected signals, and the measurement accuracy of the gamma-ray interaction location was evaluated using the LUT and MLPE. The results showed an excellent measurement accuracy of approximately 85.7% on average. It is considered that this detector can achieve excellent sensitivity and resolution when used in small animal PET/MRI.