Wavelength Shifting Phoswich Detectors for Superior Depth-of-Interaction Resolution

Melcher, Charles L ; Eriksson, Lars

关键词: detectors;    phoswich;    depth-of-interaction;    positron emission tomography;    resolution;   

DOI  :  10.2172/1054100
RP-ID  :  DOE/ER64678-1
PID  :  OSTI ID: 1054100

美国|英语

来源: SciTech Connect

【 摘 要 】

In order to simultaneously achieve both high spatial resolution and high sensitivity in small Positron Emission Tomography (PET) systems, scintillation detectors must be long in the radial direction as well as able to provide depth-of-interaction (DOI) information. DOI information is typically provided by constructing detectors from two or more layers of scintillators that are identifiable due to their different decay times. This approach has worked well in tomographs such as the High Resolution Research Tomograph (HRRT, CTI PET Systems, Inc.) in which the emission and excitation bands of the scintillator layers do not overlap each other. However, many potentially important pairs of scintillator crystals exist in which the emission of one crystal is, in fact, absorbed and re-emitted by the second crystal, thus impacting the pulse shape discrimination process used to identify the scintillator layers. These potentially useful pairs of scintillators are unlikely to be implemented in phoswich detectors without a comprehensive understanding of the complex emission that results when the light of one crystal is absorbed by the second crystal and then reemitted. Our objective is to develop a fundamental understanding of the optical phenomena that occur in phoswich detectors and to exploit these phenomena to achieve improved spatial resolution in small high sensitivity PET scanners.