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Title: Water and tissue equivalence of a new PRESAGE{sup Registered-Sign} formulation for 3D proton beam dosimetry: A Monte Carlo study

Abstract

Purpose: To evaluate the water and tissue equivalence of a new PRESAGE{sup Registered-Sign} 3D dosimeter for proton therapy. Methods: The GEANT4 software toolkit was used to calculate and compare total dose delivered by a proton beam with mean energy 62 MeV in a PRESAGE{sup Registered-Sign} dosimeter, water, and soft tissue. The dose delivered by primary protons and secondary particles was calculated. Depth-dose profiles and isodose contours of deposited energy were compared for the materials of interest. Results: The proton beam range was found to be Almost-Equal-To 27 mm for PRESAGE{sup Registered-Sign }, 29.9 mm for soft tissue, and 30.5 mm for water. This can be attributed to the lower collisional stopping power of water compared to soft tissue and PRESAGE{sup Registered-Sign }. The difference between total dose delivered in PRESAGE{sup Registered-Sign} and total dose delivered in water or tissue is less than 2% across the entire water/tissue equivalent range of the proton beam. The largest difference between total dose in PRESAGE{sup Registered-Sign} and total dose in water is 1.4%, while for soft tissue it is 1.8%. In both cases, this occurs at the distal end of the beam. Nevertheless, the authors find that PRESAGE{sup Registered-Sign} dosimeter is overall more tissue-equivalentmore » than water-equivalent before the Bragg peak. After the Bragg peak, the differences in the depth doses are found to be due to differences in primary proton energy deposition; PRESAGE{sup Registered-Sign} and soft tissue stop protons more rapidly than water. The dose delivered by secondary electrons in the PRESAGE{sup Registered-Sign} differs by less than 1% from that in soft tissue and water. The contribution of secondary particles to the total dose is less than 4% for electrons and Almost-Equal-To 1% for protons in all the materials of interest. Conclusions: These results demonstrate that the new PRESAGE{sup Registered-Sign} formula may be considered both a tissue- and water-equivalent 3D dosimeter for a 62 MeV proton beam. The results further suggest that tissue-equivalent thickness may provide better dosimetric and geometric accuracy than water-equivalent thickness for 3D dosimetry of this proton beam.« less

Authors:
; ; ; ;  [1];  [2];  [3];  [4]
  1. Institute of Medical Physics, School of Physics, University of Sydney, NSW 2006 (Australia)
  2. (United Kingdom)
  3. (United States)
  4. (Australia)
Publication Date:
OSTI Identifier:
22099093
Resource Type:
Journal Article
Journal Name:
Medical Physics
Additional Journal Information:
Journal Volume: 39; Journal Issue: 11; Other Information: (c) 2012 American Association of Physicists in Medicine; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0094-2405
Country of Publication:
United States
Language:
English
Subject:
61 RADIATION PROTECTION AND DOSIMETRY; 60 APPLIED LIFE SCIENCES; ACCURACY; BRAGG CURVE; COMPUTER CODES; DEPTH DOSE DISTRIBUTIONS; DOSEMETERS; DOSIMETRY; MEV RANGE 10-100; MONTE CARLO METHOD; PROTON BEAMS; PROTONS; RADIATION DOSES; RADIOTHERAPY; STOPPING POWER; WATER

Citation Formats

Gorjiara, Tina, Kuncic, Zdenka, Doran, Simon, Adamovics, John, Baldock, Clive, CRUK-EPSRC Cancer Imaging Centre, Institute of Cancer Research, Sutton Surrey SM2 5NG, Department of Chemistry and Biology, Rider University, Lawrenceville, New Jersey, 08648, and Institute of Medical Physics, School of Physics, University of Sydney, NSW 2006, Australia and Faculty of Science, Macquarie University, NSW 2109. Water and tissue equivalence of a new PRESAGE{sup Registered-Sign} formulation for 3D proton beam dosimetry: A Monte Carlo study. United States: N. p., 2012. Web. doi:10.1118/1.4757922.
Gorjiara, Tina, Kuncic, Zdenka, Doran, Simon, Adamovics, John, Baldock, Clive, CRUK-EPSRC Cancer Imaging Centre, Institute of Cancer Research, Sutton Surrey SM2 5NG, Department of Chemistry and Biology, Rider University, Lawrenceville, New Jersey, 08648, & Institute of Medical Physics, School of Physics, University of Sydney, NSW 2006, Australia and Faculty of Science, Macquarie University, NSW 2109. Water and tissue equivalence of a new PRESAGE{sup Registered-Sign} formulation for 3D proton beam dosimetry: A Monte Carlo study. United States. doi:10.1118/1.4757922.
Gorjiara, Tina, Kuncic, Zdenka, Doran, Simon, Adamovics, John, Baldock, Clive, CRUK-EPSRC Cancer Imaging Centre, Institute of Cancer Research, Sutton Surrey SM2 5NG, Department of Chemistry and Biology, Rider University, Lawrenceville, New Jersey, 08648, and Institute of Medical Physics, School of Physics, University of Sydney, NSW 2006, Australia and Faculty of Science, Macquarie University, NSW 2109. Thu . "Water and tissue equivalence of a new PRESAGE{sup Registered-Sign} formulation for 3D proton beam dosimetry: A Monte Carlo study". United States. doi:10.1118/1.4757922.
@article{osti_22099093,
title = {Water and tissue equivalence of a new PRESAGE{sup Registered-Sign} formulation for 3D proton beam dosimetry: A Monte Carlo study},
author = {Gorjiara, Tina and Kuncic, Zdenka and Doran, Simon and Adamovics, John and Baldock, Clive and CRUK-EPSRC Cancer Imaging Centre, Institute of Cancer Research, Sutton Surrey SM2 5NG and Department of Chemistry and Biology, Rider University, Lawrenceville, New Jersey, 08648 and Institute of Medical Physics, School of Physics, University of Sydney, NSW 2006, Australia and Faculty of Science, Macquarie University, NSW 2109},
abstractNote = {Purpose: To evaluate the water and tissue equivalence of a new PRESAGE{sup Registered-Sign} 3D dosimeter for proton therapy. Methods: The GEANT4 software toolkit was used to calculate and compare total dose delivered by a proton beam with mean energy 62 MeV in a PRESAGE{sup Registered-Sign} dosimeter, water, and soft tissue. The dose delivered by primary protons and secondary particles was calculated. Depth-dose profiles and isodose contours of deposited energy were compared for the materials of interest. Results: The proton beam range was found to be Almost-Equal-To 27 mm for PRESAGE{sup Registered-Sign }, 29.9 mm for soft tissue, and 30.5 mm for water. This can be attributed to the lower collisional stopping power of water compared to soft tissue and PRESAGE{sup Registered-Sign }. The difference between total dose delivered in PRESAGE{sup Registered-Sign} and total dose delivered in water or tissue is less than 2% across the entire water/tissue equivalent range of the proton beam. The largest difference between total dose in PRESAGE{sup Registered-Sign} and total dose in water is 1.4%, while for soft tissue it is 1.8%. In both cases, this occurs at the distal end of the beam. Nevertheless, the authors find that PRESAGE{sup Registered-Sign} dosimeter is overall more tissue-equivalent than water-equivalent before the Bragg peak. After the Bragg peak, the differences in the depth doses are found to be due to differences in primary proton energy deposition; PRESAGE{sup Registered-Sign} and soft tissue stop protons more rapidly than water. The dose delivered by secondary electrons in the PRESAGE{sup Registered-Sign} differs by less than 1% from that in soft tissue and water. The contribution of secondary particles to the total dose is less than 4% for electrons and Almost-Equal-To 1% for protons in all the materials of interest. Conclusions: These results demonstrate that the new PRESAGE{sup Registered-Sign} formula may be considered both a tissue- and water-equivalent 3D dosimeter for a 62 MeV proton beam. The results further suggest that tissue-equivalent thickness may provide better dosimetric and geometric accuracy than water-equivalent thickness for 3D dosimetry of this proton beam.},
doi = {10.1118/1.4757922},
journal = {Medical Physics},
issn = {0094-2405},
number = 11,
volume = 39,
place = {United States},
year = {2012},
month = {11}
}