title: Calculation of conversion coefficients for clinical photon spectra using the MCNP code.
abstract: In this work, the MCNP4B code has been employed to calculate conversion coefficients from air kerma to the ambient dose equivalent, H*(10)/Ka, for monoenergetic photon energies from 10 keV to 50 MeV, assuming the kerma approximation. Also estimated are the H*(10)/Ka for photon beams produced by linear accelerators, such as Clinac-4 and Clinac-2500, after transmission through primary barriers of radiotherapy treatment rooms. The results for the conversion coefficients for monoenergetic photon energies, with statistical uncertainty <2%, are compared with those in ICRP publication 74 and good agreements were obtained. The conversion coefficients calculated for real clinic spectra transmitted through walls of concrete of 1, 1.5 and 2 m thick, are in the range of 1.06-1.12 Sv Gy(-1).
authors.affiliation: PEN/COPPE/CT/UFRJ, Universidade Federal do Rio de Janeiro, 21945-970-Ilha do Fundão, Caixa Postal 68509, Rio de Janeiro, RJ, Brazil.
authors.forename: M A F
authors.initials: MA
authors.lastname: Lima
authors.forename: A X
authors.initials: AX
authors.lastname: Silva
authors.forename: V R
authors.initials: VR
authors.lastname: Crispim
mesh_terms: D003198:Computer Simulation; D003252:Construction Materials; D008962:Models, Theoretical; D009010:Monte Carlo Method; D010315:Particle Accelerators; D019047:Phantoms, Imaging; D017785:Photons; D011829:Radiation Dosage; D011835:Radiation Protection / Q000295:instrumentation; D011874:Radiometry / Q000706:statistics & numerical data*; D011879:Radiotherapy Dosage; D012984:Software; D013053:Spectrophotometry / Q000706:statistics & numerical data*; D014965:X-Rays