An affordable ultrahigh-resolution detector design must decode a significantly larger number of crystals per PMT. The increased number of crystals to be served by each PMT will inevitably increase the chance of signal pileup in the detection system. Pileups degrade image quality and create image distortions. Hence, to fully realize the benefits of the PQS detector design, we will apply the High-Yield Pileup Event Recovery (HYPER) processing electronics developed by us to process the scintillation signal to prevent and correct for signal pileup for each detected count in real time.
HYPER is a new electronic design for processing the detector signal in gamma cameras so that the individual y energies and positions of pileup events, including multiple pileups, can be resolved and recovered despite the mixing of signals. The HYPER electronics have been demonstrated to increase the count rate or imaging rate of NaI by 10 times and that of Bismuth Germanate (BGO) by six to eight times. A new prototype PET system is being designed implementing the HYPER circuit, which will allow each BGO module to operate at 800,000 events/second, allowing the system to process 40,000,000 events/second.
Crystal Signal Output
Illustration of Scintillation-crystal signal output in situation of continuous pileups or multiple pileups in high counting rates
99m Tc Energy Spectra of Gamma Camera as Function of Counting Rates
Effects of Remnant Subtraction