title: In vivo dosimetry in the urethra using alanine/ESR during (192)Ir HDR brachytherapy of prostate cancer--a phantom study.
abstract: A phantom study for dosimetry in the urethra using alanine/ESR during (192)Ir HDR brachytherapy of prostate cancer is presented. The measurement method of the secondary standard of the Physikalisch-Technische Bundesanstalt had to be slightly modified in order to be able to measure inside a Foley catheter. The absorbed dose to water response of the alanine dosimetry system to (192)Ir was determined with a reproducibility of 1.8% relative to (60)Co. The resulting uncertainty for measurements inside the urethra was estimated to be 3.6%, excluding the uncertainty of the dose rate constant Lambda. The applied dose calculated by a treatment planning system is compared to the measured dose for a small series of (192)Ir HDR irradiations in a gel phantom. The differences between the measured and applied dose are well within the limits of uncertainty. Therefore, the method is considered to be suitable for measurements in vivo.
authors.affiliation: Physikalisch-Technische Bundesanstalt, Braunschweig, Germany. mathias.anton@ptb.de
authors.forename: Mathias
authors.initials: M
authors.lastname: Anton
authors.forename: Daniela
authors.initials: D
authors.lastname: Wagner
authors.forename: Hans-Joachim
authors.initials: HJ
authors.lastname: Selbach
authors.forename: Thomas
authors.initials: T
authors.lastname: Hackel
authors.forename: Robert Michael
authors.initials: RM
authors.lastname: Hermann
authors.forename: Clemens Friedrich
authors.initials: CF
authors.lastname: Hess
authors.forename: Hilke
authors.initials: H
authors.lastname: Vorwerk
mesh_terms: D000409:Alanine; D001918:Brachytherapy; D004578:Electron Spin Resonance Spectroscopy; D006801:Humans; D007496:Iridium Radioisotopes / Q000627:therapeutic use*; D008297:Male; D019047:Phantoms, Imaging; D011471:Prostatic Neoplasms / Q000532:radiotherapy*; D011829:Radiation Dosage; D011874:Radiometry / Q000295:instrumentation*; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted; D035501:Uncertainty; D014521:Urethra / Q000528:radiation effects*
chemical_list: D007496:Iridium Radioisotopes; D000409:Alanine