Modeling electronic processing in GATE

An important feature of the GATE simulation tool for the complete simulation of PET or SPECT scans is the modeling of signal processing after energy deposit in the detector crystal. In GATE electronic processing is modeled as a list of elementary processors, called pulse processors, through which signal (i.e. energy deposit within a sensitive detector element) is transformed and filtered-out. This structure of control, so-called digitizer in GATE, yields the signal as it will be measured, given the physical signal as an input. This manuscript describes the models used in the digitizer, like energy response modeling and count rate processing. In order to improve the simulation of PET count rates with GATE, new developments have been integrated in the second GATE release regarding the modeling of electronic noise, the dead time of the coincidence processor, the input and output bandwidth and the random estimation methods. Using these newly developed models for electronic processing, GATE appears more and more appropriate to study the potentialities of different scanner designs and to optimize quantitative analysis of PET data.