Performance of a high-resolution depth-encoding PET detector module using linearly-graded SiPM arrays

Area of Science:

• Nuclear Instrumentation
• Medical Imaging Physics

Background:

• Positron Emission Tomography (PET) imaging requires high spatial resolution for accurate diagnosis.
• Depth-of-Interaction (DOI) encoding is critical for improving PET scanner performance.
• Silicon Photomultipliers (SiPMs) offer excellent spatial resolution characteristics suitable for advanced detector designs.

Purpose of the Study:

• To develop a high-resolution DOI-encoding PET detector module.
• To leverage the spatial resolution of position-sensitive SiPMs for enhanced PET imaging.
• To create a detector module suitable for small-bore PET scanner designs, particularly for preclinical research.

Main Methods:

• Constructed a detector module with a 30x30 array of polished LYSO crystals.
• Coupled the crystal array to two linearly-graded SiPM (LG-SiPM) arrays at opposite ends.
• Evaluated detector performance including crystal identification, energy resolution, timing resolution, and DOI resolution.

Main Results:

• All individual crystals within the LYSO array were successfully resolved.
• Achieved energy resolution of 21.8 ± 5.8%, coincidence timing resolution of 1.23 ± 0.10 ns, and DOI resolution of 3.8 ± 1.2 mm at -10 °C.
• Demonstrated stable performance up to 130,000 counts s⁻¹, indicating robustness at high event rates.

Conclusions:

• The developed PET detector module exhibits excellent spatial and DOI resolution.
• The detector design is well-suited for small-bore PET scanners requiring high spatial resolution and detection efficiency.
• This technology holds significant promise for preclinical imaging, such as rodent brain studies with neuroreceptor ligands.