x-ray spectra calculation for different target-filter of mammograms using mcnp code

abstractbackground: an electron beam generated x-ray spectrum consists of characteristic x-ray and continuous bermsstrahlung. the aim of this research is calculating and comparing x-ray spectra for different target filter of mammograms. materials and methods: monte carlo is a very powerful tool to simulate a series of different target-filter assembly in order to calculate the x-ray spectra. mcnp version 4c has been used for simulation set up to calculate x-ray spectra for different target-filter combination of mammograms. results: the spectra of different and the most commonly used target– filter in mammography equipments (mo-mo, mo-rh, rh-rh, w-rh, mo-al and rh-al) have been calculated.  conclusion: the computational results can be used to select a suitable x-ray spectrum for mammography as well as for computing the absorbed dose. also, the monte carlo result of mo-mo is in good agreement with the published results.