A new contrast-to-noise ratio for image quality characterization of a coded-aperture γ camera

Balin Zhu; Zhonghai Wang; Tai Gao; Qi Chen; Qichang Huang; Xiaoqin Mao; Chaoyang Zhao; Mingrui Tao; Peiwen Qi; Qianru Zhao; Yulong Li; Rong Zhou; Chaowen Yang

doi:10.1016/j.apradiso.2021.109592

A new contrast-to-noise ratio for image quality characterization of a coded-aperture γ camera

Appl Radiat Isot. 2021 Apr:170:109592. doi: 10.1016/j.apradiso.2021.109592. Epub 2021 Jan 13.

Authors

Balin Zhu¹, Zhonghai Wang², Tai Gao¹, Qi Chen¹, Qichang Huang³, Xiaoqin Mao¹, Chaoyang Zhao¹, Mingrui Tao¹, Peiwen Qi¹, Qianru Zhao¹, Yulong Li¹, Rong Zhou¹, Chaowen Yang¹

Affiliations

¹ College of Physics, Key Laboratory of Radiation Physics and Technology, Ministry of Education, Sichuan University, Chengdu, 610064, China.
² College of Physics, Key Laboratory of Radiation Physics and Technology, Ministry of Education, Sichuan University, Chengdu, 610064, China. Electronic address: zhonghaiwang@scu.edu.cn.
³ Science and Technology on Reactor System Design Technology Laboratory, Nuclear Power Institute of China, Chengdu, 610213, China.

PMID: 33497919
DOI: 10.1016/j.apradiso.2021.109592

Abstract

The gamma-ray imaging technique was developed and is widely used in several nuclear engineering fields. Specifically, compared with the traditional point-by-point radiation detector, the coded-aperture gamma camera has advantages of a wide field of view, high angular resolution, and high efficiency. Several methods for characterizing image quality, including the figure of merit (FOM) method and the contrast-to-noise ratio (CNR) method, were assessed and developed. These methods have their respective drawbacks depending on the circumstances. The FOM lacks reliability in exhibiting the impact of background noise fluctuation on the purity of a real image. The CNR characterizes image quality with inconsistent sensitivity while the source moves along the X and Y directions. Therefore, a new CNR method was proposed to achieve better performance and greater consistency in real imaging. With our coded-aperture imaging system developed in the laboratory, we performed simulations within the MATLAB and Geant4 platforms and real imaging experiments to analyze and compare images and the results of these three characterization methods. The results show that the new CNR method is reliable and practical in regard to real imaging performance.

Keywords: Characterization method; Coded aperture; Gamma imaging; Image quality.