title: Quality assurance in brachytherapy: principles for ionization chamber measurement of absorbed dose close to brachytherapy sources.
abstract: At present there exists no standardized procedure for absorbed dose determination with ionization chambers in the vicinity of brachytherapy sources. In this paper, a modification of the IAEA formalism for external photon beams is proposed in order to make it applicable at a reference point 20 mm from brachytherapy sources as well. A non-uniformity correction factor is introduced to correct for the effects of the steep absorbed dose gradient, and it is concluded that reasonable accuracy is possible when the Bragg-Gray principle is assumed to be valid.
authors.affiliation: Department of Radiation Physics, University of Göteborg, Sahlgren Hospital, Sweden.
authors.forename: H
authors.initials: H
authors.lastname: Tölli
authors.forename: K A
authors.initials: KA
authors.lastname: Johansson
mesh_terms: D001918:Brachytherapy / Q000592:standards*; D006801:Humans; D011785:Quality Assurance, Health Care; D011874:Radiometry / Q000295:instrumentation / Q000379:methods*