Speaker
Description
We have developed a bismuth germanate (BGO) Cherenkov and Scintillation photon counting time-of-flight positron emission tomography (TOF-PET) detector which can count and provide unique timestamps for detected optical photons. This allows 511 keV photon time of interaction estimators to be derived from the prompt Cherenkov light without influence from scintillation light, which has a much higher variance from time of detection. This detector concept is also capable of three-dimensional positioning of 511 keV photon interactions, allowing for position and depth-of-interaction dependent optical transit time skew corrections to be applied to the prompt estimators. Information from this detector concept can be used to classify each detected optical photon as Cherenkov or scintillation. In this work, we show how labeling each detected photon as Cherenkov/scintillation and only incorporating prompt information into a timing estimator that averages timestamps for events with more than one detected Cherenkov photon significantly improves both achievable coincidence time resolution with BGO and also the TOF kernel shape by significantly reducing the long tails from time pickoff on scintillation light. We constructed a 16x16x15 mm3 BGO photon counting detector prototype and evaluated its performance in coincidence with a fast reference detector. Incorporating the information from multiple labeled Cherenkov photons improved CTR from 159 ps to 137 ps FWHM, and the long scintillation tail was reduced to a small fraction of the total coincidence distribution. When considering all events with at least one Cherenkov photon detected, CTR was 122 ps FWHM with a Gaussian kernel shape. CTR improved to ≤100 ps for events containing 2 or more detected Cherenkov photons. We present methods for these methods, along with a new detector concept with high Cherenkov photon detection efficiency to enable ≤100 ps CTR in a BGO TOF-PET detectors that also have high 511 keV photon detection efficiency.
| Track | FTMI |
|---|---|
| Presentation type | Oral |