In 2007, the U.S. Congress mandated the implementation of the “Security and Accountability For Every Port Act of 2006,” which requires complete scanning of 100% of U.S.-bound shipping containers. To address this requirement, we developed a container inspection method that enables continuous high-speed screening, with considerable performance improvement. In this study, we developed a fixed-type high-precision container inspection system using dual-angle X-ray beams from a 9 MV linear accelerator (LINAC). We first calculated the X-ray irradiation angle-dependent changes in the contrast-to-noise ratio (CNR) of the images via Monte Carlo simulation. Using the calculated CNRs, the primary and secondary angles of the X-ray beam were set to 0 and 2.8, respectively. A system based on the proposed dual-angle X-ray imaging technology was installed and evaluated by scanning a real cargo container truck. For the evaluation, we designed test equipment based on the ANSI N42.46 report and examined the beam penetration power, contrast sensitivity, spatial resolution, and wire detectability of the developed system. The maximum penetration thicknesses for the primary and secondary angle beams were found to be 410 and 400 mm, respectively. At the primary beam angle, the contrast sensitivities were 1.52% and 0.49% when the thicknesses of the steel plate were 80% and 50% of the maximum penetration thickness, respectively. At the secondary angle, the sensitivities were 1.88% at 80% maximum penetration thickness, and 0.5% at 50%. A line pattern formed by individual slits of 4.6 mm width could be easily recognized in an acquired image. In addition, the developed system could clearly identify a 1.6 mm diameter copper wire. Further, when a steel plate was added, the change in the wire-recognition ability of the imaging system was found to be similar at both beam angles. These results indicate that the developed system is suitable for container screening using a 9 MV LINAC. Shapes that could not be identified from one beam irradiation angle could more accurately be analyzed using images from two different angles.

2007 年，美国国会授权实施“2006 年每个港口的安全和责任法案”，该法案要求对 100% 的美国海运集装箱进行全面扫描。为满足这一要求，我们开发了一种容器检测方法，可实现连续高速筛选，并显着提高性能。在这项研究中，我们使用来自 9 MV 直线加速器 (LINAC) 的双角度 X 射线束开发了一种固定式高精度集装箱检查系统。我们首先通过蒙特卡罗模拟计算了图像对比度噪声比 (CNR) 中 X 射线照射角度相关的变化。使用计算的 CNR，X 射线束的主角和副角分别设置为 0 和 2.8。通过扫描真实的货运集装箱卡车，安装并评估了基于所提出的双角度 X 射线成像技术的系统。为了进行评估，我们根据 ANSI N42.46 报告设计了测试设备，并检查了所开发系统的光束穿透能力、对比敏感度、空间分辨率和电线可检测性。主要和次要角梁的最大穿透厚度分别为 410 和 400 毫米。在主光束角，当钢板厚度为最大穿透厚度的80%和50%时，对比敏感度分别为1.52%和0.49%。在第二角度，最大穿透厚度为 80% 时的灵敏度为 1.88%，最大穿透厚度为 0.5% 时为 0.5%。由 4 个单独狭缝形成的线条图案。在获取的图像中可以轻松识别 6 毫米的宽度。此外，开发的系统可以清楚地识别直径为 1.6 毫米的铜线。此外，当添加钢板时，发现成像系统的线识别能力的变化在两个光束角上相似。这些结果表明开发的系统适用于使用 9 MV LINAC 的容器筛选。使用来自两个不同角度的图像可以更准确地分析从一个光束照射角度无法识别的形状。这些结果表明开发的系统适用于使用 9 MV LINAC 的容器筛选。使用两个不同角度的图像可以更准确地分析从一个光束照射角度无法识别的形状。这些结果表明开发的系统适用于使用 9 MV LINAC 的容器筛选。使用来自两个不同角度的图像可以更准确地分析从一个光束照射角度无法识别的形状。