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In water calibration of PDR 192Ir brachytherapy sources with an NE2571 ionization chamber

Nick Reynaert, Frans Verhaegen and Hubert Thierens UGent (1998) PHYSICS IN MEDICINE AND BIOLOGY. 43(8). p.2095-2107
abstract
An ionometric calibration procedure for Ir-192 PDR brachytherapy sources in terms of dose rate to water is presented. The calibration of the source is performed directly in a water phantom at short distances (1.0, 2.5 and 5.0 cm) using an NE2571 Farmer type ion chamber. To convert the measured air-kerma rate in water to dose rate to water a conversion factor (CF) was calculated by adapting the medium-energy, x-ray dosimetry protocol for a point source geometry (diverging beam). The obtained CF was verified using two different methods. Firstly, the CF was calculated by Monte Carlo simulations, where the source-ionization chamber geometry was modelled accurately. In a second method, a combination of Monte Carlo simulations and measurements of the air-kerma rate in water (at 1.0, 2.5 and 5.0 cm distance) and in air (1 m distance) was used to determine the CF. The obtained CFs were also compared with conversion factors calculated with the adapted dosimetry protocol for high-energy photons introduced by Tolli. All calculations were done for a Gammamed PDR Ir-192 source-NE2571 chamber geometry. The conversion factors obtained with the four different methods agree to within 1% at the three distances of interest. We obtained the following values (medium-energy x-ray protocol): CF(1 cm) = 1.458; CF(2.5 cm) = 1.162; CF(5.0 cm) = 1.112 (1 sigma = 0.7% for the three distances of interest). The obtained results were checked with TLD measurements. The values of the specific dose rate constant and the radial dose function calculated in this work are in accordance with the literature data.
Please use this url to cite or link to this publication:
author
organization
alternative title
In water calibration of PDR Ir-192 brachytherapy sources with an NE2571 ionization chamber
year
type
journalArticle (original)
publication status
published
subject
keyword
DOSIMETRY, MONTE-CARLO, BEAMS
journal title
PHYSICS IN MEDICINE AND BIOLOGY
Phys. Med. Biol.
volume
43
issue
8
pages
2095 - 2107
Web of Science type
Article
Web of Science id
000075324400008
ISSN
0031-9155
DOI
10.1088/0031-9155/43/8/008
language
English
UGent publication?
yes
classification
A1
copyright statement
I have transferred the copyright for this publication to the publisher
id
276541
handle
http://hdl.handle.net/1854/LU-276541
date created
2004-05-24 13:33:00
date last changed
2016-12-19 15:41:42
@article{276541,
  abstract     = {An ionometric calibration procedure for Ir-192 PDR brachytherapy sources in terms of dose rate to water is presented. The calibration of the source is performed directly in a water phantom at short distances (1.0, 2.5 and 5.0 cm) using an NE2571 Farmer type ion chamber. To convert the measured air-kerma rate in water to dose rate to water a conversion factor (CF) was calculated by adapting the medium-energy, x-ray dosimetry protocol for a point source geometry (diverging beam). The obtained CF was verified using two different methods. Firstly, the CF was calculated by Monte Carlo simulations, where the source-ionization chamber geometry was modelled accurately. In a second method, a combination of Monte Carlo simulations and measurements of the air-kerma rate in water (at 1.0, 2.5 and 5.0 cm distance) and in air (1 m distance) was used to determine the CF. The obtained CFs were also compared with conversion factors calculated with the adapted dosimetry protocol for high-energy photons introduced by Tolli. All calculations were done for a Gammamed PDR Ir-192 source-NE2571 chamber geometry. The conversion factors obtained with the four different methods agree to within 1\% at the three distances of interest. We obtained the following values (medium-energy x-ray protocol): CF(1 cm) = 1.458; CF(2.5 cm) = 1.162; CF(5.0 cm) = 1.112 (1 sigma = 0.7\% for the three distances of interest).
The obtained results were checked with TLD measurements. The values of the specific dose rate constant and the radial dose function calculated in this work are in accordance with the literature data.},
  author       = {Reynaert, Nick and Verhaegen, Frans and Thierens, Hubert},
  issn         = {0031-9155},
  journal      = {PHYSICS IN MEDICINE AND BIOLOGY},
  keyword      = {DOSIMETRY,MONTE-CARLO,BEAMS},
  language     = {eng},
  number       = {8},
  pages        = {2095--2107},
  title        = {In water calibration of PDR 192Ir brachytherapy sources with an NE2571 ionization chamber},
  url          = {http://dx.doi.org/10.1088/0031-9155/43/8/008},
  volume       = {43},
  year         = {1998},
}

Chicago
Reynaert, Nick, Frans Verhaegen, and Hubert Thierens. 1998. “In Water Calibration of PDR 192Ir Brachytherapy Sources with an NE2571 Ionization Chamber.” Physics in Medicine and Biology 43 (8): 2095–2107.
APA
Reynaert, N., Verhaegen, F., & Thierens, H. (1998). In water calibration of PDR 192Ir brachytherapy sources with an NE2571 ionization chamber. PHYSICS IN MEDICINE AND BIOLOGY, 43(8), 2095–2107.
Vancouver
1.
Reynaert N, Verhaegen F, Thierens H. In water calibration of PDR 192Ir brachytherapy sources with an NE2571 ionization chamber. PHYSICS IN MEDICINE AND BIOLOGY. 1998;43(8):2095–107.
MLA
Reynaert, Nick, Frans Verhaegen, and Hubert Thierens. “In Water Calibration of PDR 192Ir Brachytherapy Sources with an NE2571 Ionization Chamber.” PHYSICS IN MEDICINE AND BIOLOGY 43.8 (1998): 2095–2107. Print.