A Computerized Tomography (CT) scan combines a series of X-ray images obtained from different angles to create the patient’s cross-sectional images of body parts. It can be used especially for bones, blood vessels and soft tissues. As a comparison between two devices, the obtained information by using CT scan on the patient is more significant than the information obtained by a normal plain X-ray device. Since CT uses various doses of X-rays for the imaging of the body, radiation protection became a major topic of investigation. One of the fundamental principles of radiation protection is the distance factor. In CT facilities, the maximum dose occurs near the gantry and the dose rate decreases by distance. In order to know the rate of the reduction of the amount of dose, that distance is very important for the radiation protection procedure, especially for applying the criteria of the International Commission on Radiological Protection (ICRP) on radiation protection. The aim of this study was the validation of the Monte Carlo method for such backscattering studies. In this study, we measured the backscattered dose rates with small distances from the gantry to the exit door and compared them with the Monte Carlo (MC) results. In order to calculate the Monte Carlo results, we also modeled a simulation input for the CT facility by using MCNP-X (version 2.4.0) Monte Carlo code. We obtained the backscattered dose rate changes that depend on the distance factor by using the Monte Carlo method. We achieved a good agreement between MCNP-X results and clinical experimental results. It can be concluded that Monte Carlo (MC) is a strong tool for radiation protection calculations in CT facilities.

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