In vivo dosimetry in the urethra using alanine/ESR during (192)Ir HDR brachytherapy of prostate cancer--a phantom study.
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.
Anton
Mathias
M
Physikalisch-Technische Bundesanstalt, Braunschweig, Germany. mathias.anton@ptb.de
Wagner
Daniela
D
Selbach
Hans-Joachim
HJ
Hackel
Thomas
T
Hermann
Robert Michael
RM
Hess
Clemens Friedrich
CF
Vorwerk
Hilke
H
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*
D007496:Iridium Radioisotopes; D000409:Alanine