Speaker
Description
The ultrafast emission of Cherenkov photons offers a route to enhance the coincidence time resolution (CTR) of time-of-flight positron emission tomography (TOF-PET) detectors. Although the Cherenkov yield under 511 keV excitation is low, these photons increase the signal onset steepness and thus the achievable timing precision. Among common scintillators, bismuth germanate (BGO) emits more Cherenkov photons than lutetium-based crystals, but its slow scintillation component leads to large event-by-event variations in signal shape. Measuring the rise time at the signal onset, obtained from the time difference between two thresholds, allows classification of events by steepness and time-offset correction to improve CTR. While this principle has been demonstrated with dedicated fast electronics, scalable implementation remains a challenge. The new FastIC+ ASIC provides an integrated rise-time measurement correlated with CTR in BGO scintillators. We show event classification using rise time to mitigate time offsets and to improve the CTR by 32%, from 577 to 395 ps FWHM with 3×3×15 mm³ polished BGO with ESR on 3×3 mm² FBK NUV-MT SiPMs biased at 49 V. This work marks the first steps toward a scalable approach to exploiting BGO's mixed Cherenkov–scintillation emission in TOF-PET imaging.
| Track | FTMI |
|---|---|
| Presentation type | Oral |