College of Physics, Key Laboratory of Radiation Physics and Technology, Ministry of Education, Sichuan University, Chengdu, 610064, China.
College of Physics, Key Laboratory of Radiation Physics and Technology, Ministry of Education, Sichuan University, Chengdu, 610064, China.
Appl Radiat Isot. 2021 Apr;170:109592. doi: 10.1016/j.apradiso.2021.109592. Epub 2021 Jan 13.
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.
伽马射线成像技术得到了发展，并广泛应用于几个核工程领域。具体而言，与传统的逐点辐射探测器相比，编码孔径伽马相机具有视场宽、角分辨率高、效率高等优点。已经评估和开发了几种用于表征图像质量的方法，包括质量因数 (FOM) 方法和对比度噪声比 (CNR) 方法。这些方法根据情况各有其缺点。FOM 在表现背景噪声波动对真实图像纯度的影响方面缺乏可靠性。CNR 在用沿 X 和 Y 方向移动的源来表征图像质量时具有不一致的灵敏度。因此，提出了一种新的 CNR 方法，以在真实成像中实现更好的性能和更大的一致性。使用我们在实验室中开发的编码孔径成像系统，我们在 MATLAB 和 Geant4 平台内进行了模拟，并进行了真实成像实验，以分析和比较图像以及这三种表征方法的结果。结果表明，新的 CNR 方法在真实成像性能方面是可靠和实用的。
