title: Study of the formalism used to determine the absorbed dose for low-energy x-ray beams.
abstract: We have studied the procedure commonly recommended by dosimetry protocols for the determination of the absorbed dose in water for low-energy x-rays beams, generated with potentials up to 150 kVp. X-ray beams with different spectra obtained with the XCOMP5R code were transported using the Monte Carlo code PENELOPE in order to calculate backscatter factors and mass-energy absorption coefficients. We have analyzed the uncertainty in the absorbed doses, calculated using the half-value layer to characterize the x-ray beams, due to the uncertainties in both backscatter factors and mass-energy absorption coefficients. We have found that this uncertainty is larger than 5% and can reach values above 11% for some HVL(1) values. The characterization of these doses with the homogeneity coefficient or the generating potential, in addition to the half-value layer is also studied. Using HVL(1) and the kVp, the absorbed dose to water can be reproduced to within 3% for all spectra.
authors.affiliation: Departamento de Física Atómica, Molecular y Nuclear, Universidad de Granada, E-18071 Granada, Spain. ur1ch2@correo.ugr.es
authors.forename: U
authors.initials: U
authors.lastname: Chica
authors.forename: M
authors.initials: M
authors.lastname: Anguiano
authors.forename: A M
authors.initials: AM
authors.lastname: Lallena
mesh_terms: D000042:Absorption; D000388:Air; D001834:Body Water / Q000528:radiation effects; D004307:Dose-Response Relationship, Radiation; D009010:Monte Carlo Method; D011829:Radiation Dosage; D011874:Radiometry / Q000379:methods*; D012542:Scattering, Radiation; D012984:Software; D035501:Uncertainty; D014867:Water / Q000737:chemistry; D014965:X-Rays
chemical_list: D014867:Water