Analysis of time resolution in a dual head LSO+PSPMT PET system using low pass filter interpolation and digital constant fraction discriminator techniques

Research areas:
Authors:
Monzó, José M.; Lerche, Christoph W.; Martínez, Jorge D.; Esteve, Raúl; Toledo, José; Gadea, Rafael; Colom, Ricardo J.; Herrero, Vicente; Ferrando, Néstor; Aliaga, Ramón J.; Mateo, Fernando; Sánchez, Filomeno; Mora, Francisco J.; Benlloch, José M.; Sebastiá, Ángel
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2009
Article
Nuclear Instr and Meth in Physics A
604
1-2
347–350
June
Keywords:
Positron emission tomography, Event time detection, Digital algorithms, System simulation, Position sensitive detector

 

Abstract:
PET systems need good timeresolution to improve the true event rate, random event rejection, and pile-up rejection. In this study we propose adigital procedure for this task using alowpassfilterinterpolation plus aDigitalConstantFractionDiscriminator (DCFD). We analyzed the best way to implement this algorithm on our dualheadPETsystem and how varying the quality of the acquired signal and electronic noise analytically affects timing resolution. Our detector uses two continuous LSO crystals with a position sensitive PMT. Six signals per detector are acquired using an analog electronics front-end and these signals are processed using an in-house digital acquisition board. The test bench developed simulates the electronics and digital algorithms using Matlab®. Results show that electronic noise and other undesired effects have a significant effect on the timing resolution of the system. Interpolated DCFD gives better results than non-interpolated DCFD. In high noise environments, differences are reduced. An optimum delay selection, based on the environment noise, improves timeresolution.

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