Abstract
A new method for processing signals from Anger position-sensitive detectors used in gamma cameras and positron emission tomography (PET) is proposed for very high count-rate imaging. It has a same concept as high yield pileup-event recover (HYPER) method we introduced before by using 1) dynamically integrating a present event, the integrating will stop immediately before the next event is detected; 2) estimating a weighted-value to indicate the total energy inside the scintillation detector; and 3) remnant correction to remove the residual energy of all the previous events from the weighted-value. This paper introduces two improved practical techniques to get a better weighted-value with low noise sensitivity in order to improve the final pileup-free energy resolution. One is applying a low-pass filter combined with multiple sampling to a weight-sum of the instantaneous signal and integrated signal. The other one is weighting the integration value of the income signal; the weighting also includes exponential distortion compensation. This paper also describes the application of the HYPER electronics in a high resolution low cost PET camera with 12 photomultipliers (PMTs)-quadrant-sharing (PQS) detector modules that can decode 38016 bismuth-germanate (BGO) crystal elements using 924 PMTs. Each detector module has four Anger-HYPER circuits to further increase the count-rate. To use the HYPER circuit in coincidence imaging applications, there is a serious synchronization problem between the arrival time of an event and the end time of integration that is variable from event to event. This synchronization problem is solved by a field programmable gate array (FPGA) circuit with real time remnant correction and a high-resolution trigger delay unit with a small dead-time for recovering the synchronization of data and the event-trigger.
Original language | English (US) |
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Pages (from-to) | 2051-2056 |
Number of pages | 6 |
Journal | IEEE Transactions on Nuclear Science |
Volume | 49 I |
Issue number | 5 |
DOIs | |
State | Published - Oct 2002 |
Keywords
- High count rate
- High-speed electronics
- Nuclear imaging
- Positron emission tomography
ASJC Scopus subject areas
- Nuclear and High Energy Physics
- Nuclear Energy and Engineering
- Electrical and Electronic Engineering