Early challenges in X-ray security inspection machine adoption—such as weak ray signal capture, electromagnetic interference (EMI), and insufficient radiation safety isolation—have been overcome by specialized PCB assembly technologies, particularly rigid-flex PCBs and high-precision surface mount technology (SMT). These innovations effectively enhance the sensitivity of analog front-ends for capturing faint X-ray imaging signals, while integrating multi-layer EMI and radiation shielding structures to eliminate interference from high-voltage ray generators and surrounding electronic equipment. Rigid-flex PCBs, in particular, balance compact form factors with reliable high-speed signal transmission, supporting the miniaturization of portable and channel-type X-ray inspection devices without compromising imaging resolution. This technological leap has enabled X-ray security inspection machine PCB assemblies to outperform traditional inspection circuits in key areas: