High-resolution PET detectors with dual-ended readout using cost-effective highly multiplexed readout circuit and...

Area of Science:

• Nuclear Instrumentation
• Medical Imaging Physics
• Biomedical Engineering

Background:

• Small-animal positron emission tomography (PET) is crucial for biomedical research, translating discoveries into clinical practice.
• PET detector and electronics performance significantly impact imaging capabilities and overall system cost.
• Existing PET electronics can be complex, motivating the development of simplified schemes.

Purpose of the Study:

• To evaluate a novel, simplified electronics scheme for high-resolution small-animal PET detectors.
• To assess the performance of dual-ended readout PET detectors utilizing the new electronics.
• To determine if the simplified electronics can maintain or improve key imaging metrics.

Main Methods:

• Two lutetium-yttrium oxyorthosilicate (LYSO) PET detectors with different crystal sizes (1.45mm² and 0.75mm²) were constructed.
• Both detectors featured dual-ended readout using 8x8 silicon photomultiplier (SiPM) arrays.
• A multiplexed row-column summation network converted 64 SiPM outputs to four signals, processed by a commercial ASIC, enabling measurement of flood maps, energy resolution, DOI resolution, and timing resolution.

Main Results:

• Both detectors successfully resolved individual crystals in flood map imaging.
• Detector 1 achieved an energy resolution of 14.2±0.4%, DOI resolution of 3.04±0.37mm, and detector timing resolution (DTR) of 2.24±0.10 ns.
• Detector 2 achieved an energy resolution of 15.3±0.7%, DOI resolution of 2.56±0.46mm, and DTR of 2.38±0.20 ns.

Conclusions:

• The evaluated electronics scheme provides competitive energy and DOI performance for high-resolution small-animal PET.
• The new scheme significantly reduces the electronics channel count, simplifying system design.
• This simplification contributes to potentially lower system costs without compromising key performance metrics.