title: Anisotropy function for 192Ir low-dose-rate brachytherapy sources: an EGS4 Monte Carlo study.
abstract: The anisotropy function of low-dose-rate 192Ir interstitial brachytherapy sources was studied. Absolute dose rates around 192Ir seeds with stainless steel or platinum cladding and a platinum covered wire have been estimated using the EGS4 Monte Carlo simulation system with a very well tested user code. Our results were compared with available experimental data. Excellent agreement between calculated and measured anisotropy function was found for stainless steel clad 192Ir sources, except along the longitudinal axis of the sources. Dosimetry data for the platinum covered seed and 3 mm long wire with platinum cladding as well as for the stainless steel clad 192Ir source are presented in TG43 format. The influence of phantom dimensions on the anisotropy function was found to be non-negligible over 7 cm, enhancing the anisotropy function by 1-2%. Our results have estimated statistical uncertainties below 1% at 1 sigma level up to 10 cm excluding the longitudinal axis where statistical uncertainties below 3% up to 10 cm are observed.
authors.affiliation: Departamento de Física, Centro de Estudios Aplicados al Desarrollo Nuclear Miramar, La Habana, Cuba. rcapotenoy@yahoo.com
authors.forename: R
authors.initials: R
authors.lastname: Capote
authors.forename: E
authors.initials: E
authors.lastname: Mainegra
authors.forename: E
authors.initials: E
authors.lastname: López
mesh_terms: D016880:Anisotropy; D001918:Brachytherapy / Q000379:methods*; D006801:Humans; D007496:Iridium Radioisotopes / Q000627:therapeutic use*; D009010:Monte Carlo Method; D019047:Phantoms, Imaging; D010984:Platinum; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted; D013193:Stainless Steel
chemical_list: D007496:Iridium Radioisotopes; D013193:Stainless Steel; D010984:Platinum