title: Beta dosimetry with microMOSFETs for endovascular brachytherapy.
abstract: The aim of this study was to investigate if microMOSFETs are suitable for the dosimetry and quality assurance of beta sources. The microMOSFET dosimeters have been tested for their angular dependence in a 6 MeV electron beam. The dose rate dependence was measured with an iridium-192 afterloading source. By varying the source-to-surface distance (SSD) in a 12 MeV electron beam the dose rate dependence in an electron beam was also investigated. To measure a depth dose curve the dose rate at 2, 5, 8 and 12 mm distance from the beta source train axis was determined with the OPTIDOS and the microMOSFET detector. A comparison between the two detector types shows that the microMOSFET is suitable for quality assurance of beta sources for endovascular brachytherapy (EVBT). The homogeneity of the source is checked by measurements at five points (for the 60 mm source at 10, 20, 30, 40 and 50 mm) along the source train. The microMOSFET was then used to evaluate the influence of a common stent type (single layer stainless steel) on the dose distribution in water. The stent led to a dose inhomogeneity of +/-8.5%. Additionally the percentage depth dose curves with and without a stent were compared. The depth dose curves show good agreement which means that the stent does not change the beta spectrum significantly.
authors.affiliation: Department of Radiotherapy and Radio-oncology, Center for Diagnostic Imaging and Image Guided Therapy, University Medical Center Hamburg-Eppendorf, Germany. e.drud@uke.uni-hamburg.de
authors.forename: Eva
authors.initials: E
authors.lastname: Drud
authors.forename: Manuel
authors.initials: M
authors.lastname: Todorovic
authors.forename: Thies
authors.initials: T
authors.lastname: Schönborn
authors.forename: Rainer
authors.initials: R
authors.lastname: Schmidt
mesh_terms: D055592:Biophysical Phenomena; D001703:Biophysics; D001918:Brachytherapy / Q000379:methods* / Q000592:standards / Q000706:statistics & numerical data; D005720:Gamma Rays / Q000627:therapeutic use; D006801:Humans; D011785:Quality Assurance, Health Care; D011874:Radiometry / Q000295:instrumentation; D011880:Radiotherapy Planning, Computer-Assisted; D011882:Radiotherapy, High-Energy; D015607:Stents; D013326:Strontium Radioisotopes / Q000627:therapeutic use; D014652:Vascular Diseases / Q000532:radiotherapy*; D015021:Yttrium Radioisotopes / Q000627:therapeutic use
chemical_list: D013326:Strontium Radioisotopes; D015021:Yttrium Radioisotopes