Electronics method to advance the coincidence time resolution with bismuth germanate

Area of Science:

• Medical Imaging
• Nuclear Instrumentation
• Materials Science

Background:

• Time-of-flight positron emission tomography (TOF-PET) requires high coincidence time resolution (CTR) for accurate imaging.
• Cherenkov light from bismuth germanate (BGO) scintillators offers potential for TOF-PET but is limited by single photon time resolution (SPTR).
• Silicon photomultipliers (SiPMs) are crucial for detecting Cherenkov light, and their performance, particularly SPTR, impacts CTR.

Purpose of the Study:

• To investigate the impact of a passive bootstrapping readout circuit on CTR in BGO crystals coupled with FBK NUV-HD SiPMs.
• To evaluate the effectiveness of reducing SiPM device capacitance for improving SPTR and subsequent CTR.
• To demonstrate a simple method for achieving state-of-the-art CTR for TOF-PET applications.

Main Methods:

• Utilized FBK near-ultra-violet high density (NUV-HD) SiPMs known for high photon detection efficiency in UV light.
• Employed a passive bootstrapping readout circuit to effectively reduce the SiPM device capacitance.
• Measured CTR for BGO crystals of varying dimensions (3x3x3 mm³ and 3x3x15 mm³) coupled to the SiPMs.

Main Results:

• Achieved sub-100 ps FWHM SPTR with the FBK NUV-HD SiPMs using optimized readout techniques.
• Measured CTR values ranging from 200 ± 3 ps FWHM to 277 ± 7 ps FWHM for the BGO crystals.
• Demonstrated that the passive bootstrapping readout effectively minimizes electronic noise influence on SPTR.

Conclusions:

• The passive bootstrapping readout circuit is a simple and effective method for enhancing CTR in BGO-based TOF-PET systems.
• The combination of BGO crystals and FBK NUV-HD SiPMs with this readout achieves state-of-the-art performance.
• This approach holds significant promise for advancing TOF-PET imaging capabilities.