Monte Carlo simulation analysis of backscatter factor for low-energy X-ray

Abstract

The method for obtaining the patient skin dose by measuring the air kerma in the patient skin surface is being recommended. Backscatter factors (BSFs) which correspond to the radiation field in the patient skin surface and the quality of the X-ray are necessary in that time. Though it has been well used the backscattering coefficient published by Supplement 17 of Brit. J. Radiol., there are some problems and man inspections are necessary. Because it is difficult that it is measured BSF included the each structure of the human internal organs and the body tissues for the patient skin dose. Then the backscattering coefficient was obtained using the Monte Carlo calculation code, and the usefulness was examined by comparing with the measured value of the TLD element. The results with EGS4 Monte Carlo code were similar to the results measured by using TLDs, so that it is considered that it is effective in the x-ray equipment and under the experimental condition, which were used for this method. However, the present results became the low values of 4-7 percent than those of Supplement 17, IPSM and AAPM. It is necessary to examine them including the characteristics of x-ray generators such as the x-ray spectrum.