Calculation of average conversion coefficients for air kerma to effective dose for diagnostic X-ray beams

This work aims to calculate the average conversion coefficients from air kerma to ambient dose equivalent, H*(10)/Kair, and effective dose, E/Kair, for 50 kVp, 100 kVp and 150 kVp X ray beams used for medical diagnostic, after transmission through barriers of lead. The X ray qualities used were those recommended by the Birch and Marshall for primary diagnostic X rays. Several lead layers were irradiated with 50cm X 50cm primary beam spectra. The transmitted spectra were calculated to obtain the conversion coefficients for beams found in radiodiagnostic services. The calculations were done using the MCNPX code and voxel model FAX. The values obtained were compared with data derived from the literature. In addition, conversion coefficients for X ray qualities after penetration of lead layers were studied to get data which might be of interest in shielding of diagnostic rooms. (author)