en Radiation Biology Radiation Biology تحقيق بديع Original Research <p align="center"><strong> ABSTRACT</strong></p><p><strong>Background:</strong> 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.</p><p> <strong>Materials and Methods:</strong> 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.</p><p> <strong>Results:</strong> 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. </p><p> <strong>Conclusion: </strong>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.</p> ,Monte Carlo simulation,mammography,, target- filter combination,X-ray spectra,MCNP code 129 133 http://ijrr.com/browse.php?a_code=A-10-1-160&slc_lang=en&sid=1 A.A. Mowlavi amowlavi@sttu.ac.ir 79003194753284600416 79003194753284600416 Yes