Title :
A high count rate position decoding and energy measuring method for nuclear cameras using Anger logic detectors
Author :
Wong, Wai-Hoi ; Li, Hongdi ; Uribe, Jorge
Author_Institution :
M.D. Anderson Cancer Center, Texas Univ., Houston, TX, USA
fDate :
6/1/1998 12:00:00 AM
Abstract :
A new method for processing signals from Anger position-sensitive detectors used in gamma cameras and PET is proposed for very high count-rate imaging where multiple-event pileups are the norm. This method is designed to sort out and recover every impinging event from multiple-event pileups while maximizing the collection of scintillation signal for every event to achieve optimal accuracy in the measurement of energy and position. For every detected event, this method cancels the remnant signals from previous events, and excludes the pileup of signals from following events. The remnant subtraction is exact even for multiple pileup events. A prototype circuit for energy recovery demonstrated that the maximum count rates can be increased by more than 10 times comparing to the pulse-shaping method, and the energy resolution is as good as pulse shaping (or fixed integration) at low count rates. At 2×106 events/sec on NaI(Tl), the true counts acquired with this method is 3.3 times more than the delay-line clipping method (256 ns clipping) due to events recovered from pileups. Pulse-height spectra up to 3.5×106 events/sec have been studied. Monte Carlo simulation studies have been performed for image-quality comparisons between different processing methods
Keywords :
Monte Carlo methods; biomedical electronics; biomedical equipment; cameras; medical image processing; positron emission tomography; radioisotope imaging; 256 ns; Anger logic detectors; Monte Carlo simulation studies; energy recovery; energy resolution; high count rate position decoding/energy measuring method; image-quality comparisons; medical diagnostic imaging; multiple pileup events; nuclear cameras; nuclear medicine; prototype circuit; Cameras; Decoding; Energy measurement; Gamma ray detection; Gamma ray detectors; Position measurement; Position sensitive particle detectors; Pulse shaping methods; Signal processing; Solid scintillation detectors;
Journal_Title :
Nuclear Science, IEEE Transactions on