Analytic pulse height correction in dual-ended readout PET detectors

We propose an analytical method for pulse height correction to enable a global energy spectrum and to restore uniformity of signal asymmetry used for extraction of depth of interaction (DOI) information in PET detectors with dual-ended readout configuration. The method is based on empirically modifying the pulse heights obtained from two ends of crystals to correct for non-linear dependency of light output on DOI before calculating energy or DOI. Experiments with saw-cut, high aspect ratio crystals (1×1×20 mm³ LYSO) showed that an improvement in global energy resolution from 48% to 18% is obtained using our method without any calibration of the energy spectrum based on DOI. We also observed improvement in uniformity of signal asymmetry along the crystal by correcting pulse heights using the proposed method. Details of correction method, its effect on energy resolution and signal asymmetry and/or DOI profile, as well as results of optimization of the method based on maximizing the peak-to-valley ratio of the photopeak are presented and discussed. The proposed method finds application in calibration and signal processing of DOI PET detectors based on dual-ended readout configuration.