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Title: Dosimetry of cone-defined stereotactic radiosurgery fields with a commercial synthetic diamond detector

Abstract

Purpose: Small field x-ray beam dosimetry is difficult due to lack of lateral electronic equilibrium, source occlusion, high dose gradients, and detector volume averaging. Currently, there is no single definitive detector recommended for small field dosimetry. The objective of this work was to evaluate the performance of a new commercial synthetic diamond detector, namely, the PTW 60019 microDiamond, for the dosimetry of small x-ray fields as used in stereotactic radiosurgery (SRS). Methods: Small field sizes were defined by BrainLAB circular cones (4–30 mm diameter) on a Novalis Trilogy linear accelerator and using the 6 MV SRS x-ray beam mode for all measurements. Percentage depth doses (PDDs) were measured and compared to an IBA SFD and a PTW 60012 E diode. Cross profiles were measured and compared to an IBA SFD diode. Field factors, Ω{sub Q{sub c{sub l{sub i{sub n,Q{sub m{sub s{sub r}{sup f{sub c}{sub l}{sub i}{sub n},f{sub m}{sub s}{sub r}}}}}}}}}, were calculated by Monte Carlo methods using BEAMnrc and correction factors, k{sub Q{sub c{sub l{sub i{sub n,Q{sub m{sub s{sub r}{sup f{sub c}{sub l}{sub i}{sub n},f{sub m}{sub s}{sub r}}}}}}}}}, were derived for the PTW 60019 microDiamond detector. Results: For the small fields of 4–30 mm diameter, there were dose differences inmore » the PDDs of up to 1.5% when compared to an IBA SFD and PTW 60012 E diode detector. For the cross profile measurements the penumbra values varied, depending upon the orientation of the detector. The field factors, Ω{sub Q{sub c{sub l{sub i{sub n,Q{sub m{sub s{sub r}{sup f{sub c}{sub l}{sub i}{sub n},f{sub m}{sub s}{sub r}}}}}}}}}, were calculated for these field diameters at a depth of 1.4 cm in water and they were within 2.7% of published values for a similar linear accelerator. The corrections factors, k{sub Q{sub c{sub l{sub i{sub n,Q{sub m{sub s{sub r}{sup f{sub c}{sub l}{sub i}{sub n},f{sub m}{sub s}{sub r}}}}}}}}}, were derived for the PTW 60019 microDiamond detector. Conclusions: The authors conclude that the new PTW 60019 microDiamond detector is generally suitable for relative dosimetry in small 6 MV SRS beams for a Novalis Trilogy linear equipped with circular cones.« less

Authors:
;  [1];  [2];  [3]
  1. School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology, Level 4 O Block, Garden’s Point, Brisbane, QLD 4001 (Australia)
  2. Department of Radiation Oncology, Chris O’Brien Lifehouse, 119-143 Missenden Road, Camperdown, NSW 2050 (Australia)
  3. Department of Radiation Oncology, St Vincent’s Hospital, Victoria Street, Darlinghurst, NSW 2010 (Australia)
Publication Date:
OSTI Identifier:
22317938
Resource Type:
Journal Article
Journal Name:
Medical Physics
Additional Journal Information:
Journal Volume: 41; Journal Issue: 11; Other Information: (c) 2014 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:
07 ISOTOPES AND RADIATION SOURCES; COMPARATIVE EVALUATIONS; CONES; CORRECTIONS; DEPTH DOSE DISTRIBUTIONS; DIAMONDS; DOSIMETRY; FLUORINE IONS; IODINE IONS; LINEAR ACCELERATORS; MONTE CARLO METHOD; ORIENTATION; PERFORMANCE; RADIOTHERAPY; STRONTIUM SULFIDES; SULFUR IONS; SURGERY; X RADIATION

Citation Formats

Morales, Johnny E., E-mail: johnny.morales@lh.org.au, Crowe, Scott B., Trapp, J. V., Hill, Robin, and Freeman, Nigel. Dosimetry of cone-defined stereotactic radiosurgery fields with a commercial synthetic diamond detector. United States: N. p., 2014. Web. doi:10.1118/1.4895827.
Morales, Johnny E., E-mail: johnny.morales@lh.org.au, Crowe, Scott B., Trapp, J. V., Hill, Robin, & Freeman, Nigel. Dosimetry of cone-defined stereotactic radiosurgery fields with a commercial synthetic diamond detector. United States. https://doi.org/10.1118/1.4895827
Morales, Johnny E., E-mail: johnny.morales@lh.org.au, Crowe, Scott B., Trapp, J. V., Hill, Robin, and Freeman, Nigel. Sat . "Dosimetry of cone-defined stereotactic radiosurgery fields with a commercial synthetic diamond detector". United States. https://doi.org/10.1118/1.4895827.
@article{osti_22317938,
title = {Dosimetry of cone-defined stereotactic radiosurgery fields with a commercial synthetic diamond detector},
author = {Morales, Johnny E., E-mail: johnny.morales@lh.org.au and Crowe, Scott B. and Trapp, J. V. and Hill, Robin and Freeman, Nigel},
abstractNote = {Purpose: Small field x-ray beam dosimetry is difficult due to lack of lateral electronic equilibrium, source occlusion, high dose gradients, and detector volume averaging. Currently, there is no single definitive detector recommended for small field dosimetry. The objective of this work was to evaluate the performance of a new commercial synthetic diamond detector, namely, the PTW 60019 microDiamond, for the dosimetry of small x-ray fields as used in stereotactic radiosurgery (SRS). Methods: Small field sizes were defined by BrainLAB circular cones (4–30 mm diameter) on a Novalis Trilogy linear accelerator and using the 6 MV SRS x-ray beam mode for all measurements. Percentage depth doses (PDDs) were measured and compared to an IBA SFD and a PTW 60012 E diode. Cross profiles were measured and compared to an IBA SFD diode. Field factors, Ω{sub Q{sub c{sub l{sub i{sub n,Q{sub m{sub s{sub r}{sup f{sub c}{sub l}{sub i}{sub n},f{sub m}{sub s}{sub r}}}}}}}}}, were calculated by Monte Carlo methods using BEAMnrc and correction factors, k{sub Q{sub c{sub l{sub i{sub n,Q{sub m{sub s{sub r}{sup f{sub c}{sub l}{sub i}{sub n},f{sub m}{sub s}{sub r}}}}}}}}}, were derived for the PTW 60019 microDiamond detector. Results: For the small fields of 4–30 mm diameter, there were dose differences in the PDDs of up to 1.5% when compared to an IBA SFD and PTW 60012 E diode detector. For the cross profile measurements the penumbra values varied, depending upon the orientation of the detector. The field factors, Ω{sub Q{sub c{sub l{sub i{sub n,Q{sub m{sub s{sub r}{sup f{sub c}{sub l}{sub i}{sub n},f{sub m}{sub s}{sub r}}}}}}}}}, were calculated for these field diameters at a depth of 1.4 cm in water and they were within 2.7% of published values for a similar linear accelerator. The corrections factors, k{sub Q{sub c{sub l{sub i{sub n,Q{sub m{sub s{sub r}{sup f{sub c}{sub l}{sub i}{sub n},f{sub m}{sub s}{sub r}}}}}}}}}, were derived for the PTW 60019 microDiamond detector. Conclusions: The authors conclude that the new PTW 60019 microDiamond detector is generally suitable for relative dosimetry in small 6 MV SRS beams for a Novalis Trilogy linear equipped with circular cones.},
doi = {10.1118/1.4895827},
url = {https://www.osti.gov/biblio/22317938}, journal = {Medical Physics},
issn = {0094-2405},
number = 11,
volume = 41,
place = {United States},
year = {2014},
month = {11}
}