An LSO scintillator array for a PET detector module with depth of interaction measurement

Abstract

Abstract--We present construction methods and performance results for a production scintillator array of 6 4 optically isolated, 3 mm x 3 mm x 30 mm sized LSO crystals. This scintillator array has been developed for a PET detector module consisting of the 8x8 LSO array coupled on one end to a single photomultiplier tube (PMT) and on the opposite end to a 64 pixel array of silicon photodiodes (PD). The PMT provides an accurate timing pulse and initial energy discrimination, the PD identifies the crystal of interaction, the sum provides a total energy signal, and the PD/(PD+PMT) ratio determines the depth of interaction (DOI). Unlike the previous LSO array prototypes, we now glue Lumirror reflector material directly onto 4 sides of each crystal to obtain an easily manufactured, mechanically rugged array with our desired depth dependence. With 511 keV excitation, we obtain a total energy signal of 3600 electrons, pulse-height resolution of 25% fwhm, and 6-15 mm fwhm DOI resolution.

Calibration of a PEM detector with depth of interaction measurement

“…This degradation is also due to the decreased signal to noise ratio as described for energy resolution in the previous section. The DOI resolution has improved in comparison to a previous prototype module, which had 6 to 15 mm DOI resolution [4]. This improvement may be attributed to the lower electronic noise of the PETRIC.…”

“…The LBNL PEM detector consists of 64 3 mm × 3 mm × 30 mm LSO crystals coupled to a single photomultiplier tube and an 8×8 silicon photodiode array [4]. The photomultiplier tube provides accurate timing.…”

“…With the correct calibration, the position of the interaction pixels should lie on a 45-degree beam line in the x-y plane. We process the data using the calibration factors derived from our algorithms, and determine the depth bin i using equation (4). The events are assigned to three dimensional positions within the module, and the number of events at each position is stored in an 8×8×8 array (8×8 crystals, and another 8 depth bins for each crystal).…”

“…However, in situ calibration is the only practical solution for ongoing calibration of the installed detectors. Such calibration is necessary to accommodate the effects of drift in photomultiplier tube gains, temperature sensitivity, and electronic aging.The LBNL PEM detector consists of 64 3 mm × 3 mm × 30 mm LSO crystals coupled to a single photomultiplier tube and an 8×8 silicon photodiode array [4]. The photomultiplier tube provides accurate timing.…”

Development of a data acquisition architecture with distributed synchronization for a Positron Emission Tomography system with integrated front-end.

“…For instance, light sharing detectors are based on the deployment of photodetectors on both the back and the front side of the scintillator crystal ( Fig. 4.18d) and estimate DOI depending on the ratio of total energy collected in both sides [249,250]. Also, continuous cubic detectors have been proposed with photodetectors coupled to side borders ( Fig.…”