A monte carlo simulation based on measured tube current modulation data in x-ray computed tomography

In recent times, almost all X-ray computed tomography (CT) scanners use a tube current modulation (TCM) technique. Hence, examining the effects of TCM on the organ doses of patients is very important. To examine the effects of TCM in detail, we have estimated the organ doses in the TCM CT examination using an anthropomorphic phantom and Electron Gamma Shower ver. 5 (EGS5) Monte Carlo simulation. There are some differences between the measurement and simulation results, especially in dosimeters that were inserted near the surface of the phantom. In this study, therefore, we aimed at revealing the reason for differences between measurement and simulations. In the results of this study, it was revealed that the internal dose profile of the patient varies at every scan in helical scanning. In addition, the variance of internal dose profiles increase as the techniques of CT scanning becomes more complicated.