All-optical Temporal Correlation for PET
PET requires temporal correlation of the two 511 keV “annihilation photons” simultaneously emitted for every PET tracer radioactive decay. Time-of-flight (TOF)-PET uses photon arrival time measurements that provide information on the two-photon emission location within the body to substantially increase image signal-to-noise ratio, enabling significant improvements in disease visualization and quantification, or large reduction in injected dose and/or scan time. Precise photon arrival time information requires very high temporal resolution, however. Our lab has developed a method of directly modulating vertical cavity surface emitting lasers (VCSELs) using the output of very fast photodetectors known as solid-state photomultipliers (SSPMs) coupled to fast scintillation crystals.