Detector Light Response Modeling for a Thick Continuous Slab Detector

Abstract

We investigate a method to improve the position decoding for thick crystal versions (i.e., ≥8 mm) of the continuous miniature crystal element (cMiCE) PET detector by more accurately modeling the detector light response function (LRF). The LRF for continuous detectors varies with the depth of interaction (DOI) of the detected photon. This variation in LRF can result in a positioning error for two-dimensional positioning algorithms. We explore a method to improve positioning performance by deriving two lookup tables, corresponding to the front and back regions of the crystal. The DETECT2000 simulation package was used to investigate the light response characteristics for a 48.8 mm by 48.8 mm by 10 (8) mm slab of LSO coupled to a 64-channel, flat-panel PMT. The data are then combined to produce the two-dimensional light collection histograms. Light collection histograms that have markedly non-Gaussian distributions are characterized as a combination of two Gaussian functions, where each Gaussian function corresponds to a DOI region of the crystal. The results indicate that modest gains in positioning accuracy are achieved near the central region of the crystal. However, significant improvements in spatial resolution and positioning bias are achieved for the corner section of the detector.

Preclinical positron emission tomography scanner based on a monolithic annulus of scintillator: initial design study

“…Specifically, the x-and y-coordinates can be calculated by determining the center-of-mass of the scintillation light distribution recorded by the SiPMs. 67 The DOI of events could be calculated by applying (N∕I)-based modeling method used in this study. Note that nonuniformities of light output in the scintillator, which could affect the calculation of DOI, are normalized due to the use of the N∕I ratio at the first stage of the depth calculation.…”

“…65,66 For example, Miyaoka et al 67 used DETECT2000 to model continuousscintillator detectors to aid in improving event position determination. To reduce reflection of photons into the detector volume from the two end caps (an effect that could distort the photon distributions at the ends of the detector), these surfaces were blackened.…”

Monte carlo simulation of four-layer DOI detector with relative offset in animal PET

“…3). A total of 2,500 light photons were produced per event accounting for the light conversion efficiency of LYSO and the quantum efficiency of the PMT's photocathode [6]. Each scintillation photon is then propagated within the crystal, subject to reflection conditions assumed for crystal surfaces.…”