Exploring spatiotemporal information in a Cherenkov and scintillation photon counting BGO TOF-PET semi-monolithic...

Area of Science:

• Medical Physics
• Instrumentation
• Nuclear Medicine

Background:

• Bismuth germanate (BGO) crystals offer potential for time-of-flight positron emission tomography (TOF-PET) detectors.
• Accurate timestamping of Cherenkov photons is crucial for enhancing TOF-PET performance.
• Existing TOF-PET detectors require improved timing resolution and spatial accuracy.

Purpose of the Study:

• To demonstrate a BGO-based optical photon counting detector concept for TOF-PET.
• To characterize a prototype detector utilizing Cherenkov signatures and silicon photomultiplier (SiPM) arrays.
• To explore the use of spatiotemporal photon information for improved detector performance.

Main Methods:

• Developed a prototype detector with a thick, semi-monolithic BGO crystal coupled to a 16-channel SiPM array.
• Implemented a 16-channel signal processing chain for digital photon timestamping.
• Utilized 3D position calibration and first photon delay distribution (FPDD) for data-driven corrections.

Main Results:

• Achieved unique first photon timestamping for approximately 77% of events with 1.8 ns signal shaping.
• FPDD analysis effectively parameterized Cherenkov and scintillation contributions to photon arrival.
• Attained a coincidence time resolution of 172 ps FWHM by correcting for 3D position dependence using FPDD.

Conclusions:

• The photon counting BGO detector is feasible for TOF-PET, showing promising timing and positioning capabilities.
• Rich photon timing information enables data-driven Cherenkov identification and event-by-event corrections.
• This approach provides a foundation for further advancements in TOF-PET detector technology.