title: Absolute depth-dose-rate measurements for an 192Ir HDR brachytherapy source in water using MOSFET detectors.
abstract: Reported MOSFET measurements concern mostly external radiotherapy and in vivo dosimetry. In this paper, we apply the technique for absolute dosimetry in the context of HDR brachytherapy using an 192Ir source. Measured radial dose rate distributions in water for different planes perpendicular to the source axis are presented and special attention is paid to the calibration of the R and K type detectors, and to the determination of appropriate correction factors for the sensitivity variation with the increase of the threshold voltage and the energy dependence. The experimental results are compared with Monte Carlo simulated dose rate distributions. The experimental results show a good agreement with the Monte Carlo simulations: the discrepancy between experimental and Monte Carlo results being within 5% for 82% of the points and within 10% for 95% of the points. Moreover, all points except two are found to lie within the experimental uncertainties, confirming thereby the quality of the results obtained.
authors.affiliation: Ecole Polytechnique Fédérale de Lausanne (EPFL), Laboratoire de Physique des Réacteurs et de Comportement des Systèmes, CH-1015, Lausanne, Switzerland.
authors.forename: Valéry Olivier
authors.initials: VO
authors.lastname: Zilio
authors.forename: Om Parkash
authors.initials: OP
authors.lastname: Joneja
authors.forename: Youri
authors.initials: Y
authors.lastname: Popowski
authors.forename: Anatoly
authors.initials: A
authors.lastname: Rosenfeld
authors.forename: Rakesh
authors.initials: R
authors.lastname: Chawla
mesh_terms: D001918:Brachytherapy / Q000295:instrumentation / Q000379:methods*; D002138:Calibration; D006801:Humans; D007496:Iridium Radioisotopes / Q000008:administration & dosage / Q000627:therapeutic use; D009010:Monte Carlo Method; D011874:Radiometry / Q000295:instrumentation / Q000379:methods*; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000295:instrumentation / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014867:Water / Q000737:chemistry*
chemical_list: D007496:Iridium Radioisotopes; D014867:Water