ABSTRACT
Monte Carlo method is a very accurate method to optimize medical diagnostic radiology spectra and simulation of radiation transportation. Using MCNP code, radiology and mammography attenuated x-rayspectraweresimulated.The IPEM report number 78 was used as a reference to compare with the GEANT4 and MCNP simulations because of its popularity and wide availability. The results of GEANT4 in 40keV showed a good homogeneity with IPEM report in terms of intensity, whilst the MCNP code in tube voltage 150kVp showed a very good agreement. Whereas theGEANT4outputintensityinallcases was less than the IPEM report, MCNP code showed higher characteristic peak intensity. The MCNP results were obtained with a less error percentage in comparison with IPEM reportexceptatlowenergies. The comparison shows a good agreement between these two codes. MCNP shows a very goodagreement in high tube voltage whereas GEANT4 showsvery goodagreement in low tube voltage