Impact of correcting beam hardening and detector response function in photon-counting X-ray imaging when using anti-coincidence mode

X-ray imaging using photon-counting detectors (PCDs) allows for the calculation of quantitative images such as the effective atomic number ( 𝑍 e f f ). However, physical phenomena such as characteristic X-ray emission and charge sharing can cause incomplete total absorption events during signal generation, which reduces the accuracy of X-ray penetration analysis. To solve the problem, an anti-coincidence mode (ACM) has been developed, but complete correction has not been established. We aimed to investigate the accuracy of 𝑍 e f f image when the proposed software-based corrections, namely beam hardening and response function corrections, are added to the hardware-based correction of the ACM. The response function was calculated using the Monte-Carlo simulation code. In a simulation study, we analyzed a phantom composed of virtual materials with 𝑍 e f f values of 4–16. While sufficient accuracy cannot be achieved by applying only the ACM, it was demonstrated that low-noise 𝑍 e f f images can be obtained by applying our correction. Furthermore, it was demonstrated that 𝑍 e f f images of food samples can be generated by using actual non-destructive testing equipment with a 10 m/min transportation speed. In conclusion, our correction procedure can maximize the performance of PCDs, and our findings are essential for promoting imaging techniques concerning quantitative images.