방사선의학 웹진

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Abstract
An integrated dual-module Compton camera system (IDM-CCS) was developed to address the limitations of conventional Compton cameras, such as restricted field-of-view (FOV) and low intrinsic detection efficiency. The IDM-CCS, which comprises two single scintillator-based modules, operates both independently and interactively, using the multi-system weighted list-mode maximum likelihood expectation maximization (LM-MLEM) algorithms for enhanced image reconstruction. In the interactive (coincidence) mode, the first and second reactions occurred in different detector modules. This enabled the adjustment of the lever arm distance, which was the distance between the first and second reactions, by modifying the detector geometry; the experiments were performed at various lever arm distances.
A minimum resolvable angle assessment showed an improvement in the case of single scintillator modules, with a distinct source separation at 24°. The intrinsic imaging efficiency for the axial radiation source direction was determined to be 2.1 %, 1.3 %, and 0.8 % for short, medium, and long lever arm distances, respectively. Meanwhile, for the lateral direction, the efficiency remained stable at approximately 1.3 % across all lever arm distances. Field usability tests confirmed that when the pixel resolution of the IDM-CCS was aligned with that of standard cameras, such as those used in smartphones, the positions of the two different radiation sources were accurately represented. The study findings can offer guidance for optimizing detectors with similar structures, thereby enhancing their performance in various field applications.

Hyounggun Lee a, Seonghee Choi b d, Sangwoo Han b d, Wonho Lee c d

a
Medical Accelerator Research Team, Korea Institute of Radiological and Medical Sciences, Nowon-ro 75, Seoul, 01812, Republic of Korea
b
Health and Safety Convergence Science, College of Health Science, Korea University, Anam-ro 145, Seoul, 02841, Republic of Korea
c
School of Health and Environmental Science, College of Health Science, Korea University, Anam-ro 145, Seoul, 02841, Republic of Korea
d
Transdisciplinary Major in Learning Health Systems, Graduate School, Korea University, Anam-ro 145, Seoul, 02841, Republic of Korea