PRIMO, C.O.ANGELOCCI, L.V.KARAM JUNIOR, D.ZEITUNI, C.A.ROSTELATO, M.E.C.M.2021-08-032021-08-032021PRIMO, C.O.; ANGELOCCI, L.V.; KARAM JUNIOR, D.; ZEITUNI, C.A.; ROSTELATO, M.E.C.M. Dose-rate constant and air-kerma strength evaluation of a new 125I brachytherapy source using Monte-Carlo. <b>Brazilian Journal of Radiation Sciences</b>, v. 9, n. 1A, p. 1-11, 2021. DOI: <a href="https://dx.doi.org/10.15392/bjrs.v9i1A.1441">10.15392/bjrs.v9i1A.1441</a>. Disponível em: http://repositorio.ipen.br/handle/123456789/32116.2319-0612http://repositorio.ipen.br/handle/123456789/32116Brachytherapy is a modality of radiotherapy which treats tumors using ionizing radiation with sources located close to the tumor. The sources can be produced from several radionuclides in various formats, such as Iodine-125 seeds and Iridium-192 wires. In order to produce a new Iodine-125 seed in IPEN/CNEN and ensure its quality, it is essential to describe the seed dosimetry, so when applied in a treatment the lowest possible dose to neighboring healthy tissues can be reached. The report by the AAPM’s Task Group 43 U1 is a document that indicates the dosimetry procedures in brachytherapy based on physical and geometrical parameters. In this study, dose-rate constant and air-kerma strength parameters were simulated using the Monte Carlo radiation transport code MCNP4C. The air-kerma strength is obtained from an ideal modeled seed, since its actual value should be measured for seeds individually in a specialized lab with a Wide-Angle Free-Air Chamber (WAFAC). Dose-rate constant and air-kerma strength are parameters that depends on intrinsic characteristics of the source, i.e. geometry, radionuclide, encapsulation, and together they define the dose-rate to the reference point. Radial dose function describes the dose fall-off with distance from the source. This study presents the values found for these parameters with associated statistical uncertainty, and is part of a larger project that aims the full dosimetry of this new seed model, including experimental measures.1-11openAccessbrachytherapycomputerized simulationdose ratesdosimetryiodine 125kermamonte carlo methodArtigo de periódico1A910.15392/bjrs.v9i1A.14410000-0003-2943-60970000-0002-7303-6720https://orcid.org/0000-0003-2943-6097https://orcid.org/0000-0002-7303-6720Sem Percentil