Study of PET Detector Performance with Varying SiPM Parameters and Readout Schemes.

Area of Science:

• Medical Imaging
• Detector Physics
• Nuclear Instrumentation

Background:

• Monolithic crystal Positron Emission Tomography (PET) detectors offer improved performance.
• Sensor on the Entrance Surface (SES) design requires advanced readout strategies.
• Silicon Photomultiplier (SiPM) arrays are crucial for high-resolution PET imaging.

Purpose of the Study:

• To characterize the spatial resolution of a monolithic crystal PET detector with a 2D SiPM array.
• To investigate the impact of various SiPM parameters and readout schemes on detector performance.
• To identify optimal parameters for a practical PET detector design.

Main Methods:

• Simulated a 49.2mm x 49.2mm x 15mm LYSO crystal PET detector using a 12x12 SiPM array.
• Employed a statistics-based positioning (SBP) method for event positioning and depth of interaction (DOI) decoding.
• Analyzed the effects of photon detection efficiency (PDE), gain variability, instability, and dark count noise on spatial resolution.

Main Results:

• Individual channel readout yielded better spatial resolution than row-column summing.
• PDE and gain shifts between testing and calibration significantly degraded spatial resolution and introduced positioning bias.
• Dark count noise impacted intrinsic spatial resolution.
• No data normalization is needed for PDE variability up to 12% FWHM and gain variability up to 15% FWHM.

Conclusions:

• A row-column summing readout scheme without data normalization is proposed for efficiency.
• Cooling detectors below room temperature will reduce dark count noise.
• Active temperature control of SiPMs will minimize PDE and gain drifts, enhancing detector stability and performance.