Comparison of measured backscatter factors with Monte Carlo simulations for low energy X-ray

Experimentally determined values of X-ray backscatter factors (BSFs) are presented and compared with Monte Carlo simulation results. Measurements were made using X-rays generated at voltages between 50 and 100 kVp and various phantoms that differed in shape and size. To study the influence of irradiation geometry on BSFs, measurements were performed for different photon beam field diameters at the phantom front face. The phantoms were placed on the irradiation bench of an X-ray unit at a fixed distance of 100 cm from the focal spot. In this paper, BSFs were determined experimentally by using a measuring technique that utilized an ionization chamber of volume 1 cm3. The generalized particle transport program MCNPX code was used for Monte Carlo simulations. Measured results are analyzed and discussed in comparison with simulated values and we acquired phantom images using a 512 channel linear array photodetector.