Scintillation and Cherenkov Photon Counting Detectors with Analog
Silicon Photomultipliers for TOF-PET
Abstract
Standard signal processing approaches for scintillation detectors in
positron emission tomography (PET) derive accurate estimates for 511 keV
photon time of interaction and energy imparted to the detection media
from aggregate characteristics of electronic pulse shapes. The ultimate
realization of a scintillation detector for PET is one that provides a
unique timestamp and position for each detected scintillation photon.
Detectors with these capabilities enable advanced concepts for
three-dimensional (3D) position and time of interaction estimation with
methods that exploit the spatiotemporal arrival time kinetics of
individual scintillation photons. In this work, we show that taking into
consideration the temporal photon emission density of a scintillator,
the channel density of an analog silicon photomultiplier (SiPM) array,
and employing fast electronic readout with digital signal processing, a
detector that counts and timestamps scintillation photons can be
realized. To demonstrate this approach, a prototype detector was
constructed, comprising multichannel electronic readout for a bismuth
germanate (BGO) scintillator coupled to a 4x4 SiPM array. In
proof-of-concept measurements with this detector configuration, we are
able to count and provide a timestamp for all optical photons produced
by 511 keV photoelectric interactions. We show that this photon counting
detector concept can implement 3D positioning of 511 keV photon
interactions and thereby enable advanced corrections for time of
interaction estimators. We outline the methodology, readout, and
approach for achieving this detector capability in first-ever,
proof-of-concept measurements for scintillation photon counting detector
with analog silicon photomultipliers.