Monte Carlo Simulation of X-Ray Spectra Produced by Diagnostic X-Ray Machine by MCNP-4Cand Investigation of Different Variable Effects

For more than eight decades researchers have tried to predict diagnostic X-ray spectra. Image quality, patient's dose and ionization chamber read out are some of the quantities affected by energy spectra. In this study MCNP-4C has been employed to simulate the diagnostic X-ray spectra of a common X-ray tube. The effects of various targets, filters, tube voltages ripples, anode angles on the energy spectrum have been investigated. The input file of MCNP-4C consists of geometry and data cards. In order to simulate x-ray energy spectra an input file was created. In this file individual cards for geometry of the x-ray tube, electron source, energy ranges,. .. were defined. To simulate electron transport in the surrounding media, electron production, photon production and full bremsstrahlung angular distribution have been studied. Photon interactions with matter and the corresponding phenomenon such as electron production and coherent scattering have been considered. Simulated diagnostic x-ray spectrum acquired for tube voltages of 60, 70, 80 and 90 kVp (when 1.2 mm Al and 0.5 mm Be filters were applied), x-ray spectrum were also obtained for tube voltage of 100, 110, 120, 130 and 140 (when 2.5 mm Al and 1.2 mm Be filters were applied). The aforementioned simulations were performed for anode angles of 9, 12, 15, 18 and 21 degrees. To assess the effect of voltage ripple, x-ray spectrum were calculated for no ripple and 3, 5, 10, 15, 20, 25, 30, 50 and 100% ripples.Discussion and Individual spectra acquired by MCNP-4C simulation was compared with the corresponding one reported by IPEM report number 78. Every two sets of data were statistically examined by pair T-test. Very good agreements were achieved. Therefore this study confirms that simulation of x-ray spectra of common x-ray tubes can be preformed by MCNP-4C with good accuracy. The effects of target material, tube voltage, and voltage ripple and anode angle on an individual spectra are discussed.