An examination of differences in absorbed dose profile between measurement and calculation in x-ray computed tomography

Multidetector X-ray computed tomography technology is developing rapidly. As the number of detectors increases, the spread of the X-ray beam width along the rotation axis increases. In our previous measurement and calculation using the Electron Gamma Shower ver. 5 Monte Carlo simulation, the maximum absorbed dose position shifted from the surface to a deeper region in a cylindrical poly(methyl methacrylate) phantom as the X-ray beam width spread. However, there were some differences between the measurement and the calculation. In this study, we focus on the X-ray tube angle and examine these differences. The results indicate that the form of the absorbed dose profile varied greatly and the maximum dose position changed if the initial irradiation angle of the X-ray tube changed.