Radiation dose enhancement at tissue-tungsten interfaces in HDR brachytherapy

Han, Z; Safavi-Naeini, M; Alnaghy, S; Cutajar, DL; Guatelli, S; Petasecca, M; Franklin, DR; Malaroda, A; Carrara, M; Bucci, J; Zaider, M; Lerch, MLF; Rosenfeld, AB

Radiation dose enhancement at tissue-tungsten interfaces in HDR brachytherapy

Han, Z Safavi-Naeini, M Alnaghy, S Cutajar, DL Guatelli, S Petasecca, M Franklin, DR

Malaroda, A Carrara, M Bucci, J Zaider, M Lerch, MLF Rosenfeld, AB

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Publication Type:: Journal Article
Citation:: Physics in Medicine and Biology, 2014, 59 (21), pp. 6659 - 6671
Issue Date:: 2014-11-07

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Field	Value	Language
dc.contributor.author	Han, Z	en_US
dc.contributor.author	Safavi-Naeini, M	en_US
dc.contributor.author	Alnaghy, S	en_US
dc.contributor.author	Cutajar, DL	en_US
dc.contributor.author	Guatelli, S	en_US
dc.contributor.author	Petasecca, M	en_US
dc.contributor.author	Franklin, DR https://orcid.org/0000-0002-9563-5943	en_US
dc.contributor.author	Malaroda, A	en_US
dc.contributor.author	Carrara, M	en_US
dc.contributor.author	Bucci, J	en_US
dc.contributor.author	Zaider, M	en_US
dc.contributor.author	Lerch, MLF	en_US
dc.contributor.author	Rosenfeld, AB	en_US
dc.date.issued	2014-11-07	en_US
dc.identifier.citation	Physics in Medicine and Biology, 2014, 59 (21), pp. 6659 - 6671	en_US
dc.identifier.issn	0031-9155	en_US
dc.identifier.uri	http://hdl.handle.net/10453/38373
dc.description.abstract	© 2014 Institute of Physics and Engineering in Medicine. HDR BrachyView is a novel in-body dosimetric imaging system for real-time monitoring and verification of the source position in high dose rate (HDR) prostate brachytherapy treatment. It is based on a high-resolution pixelated detector array with a semi-cylindrical multi-pinhole tungsten collimator and is designed to fit inside a compact rectal probe, and is able to resolve the 3D position of the source with a maximum error of 1.5 mm. This paper presents an evaluation of the additional dose that will be delivered to the patient as a result of backscatter radiation from the collimator. Monte Carlo simulations of planar and cylindrical collimators embedded in a tissue-equivalent phantom were performed using Geant4, with an 192Ir source placed at two different source-collimator distances. The planar configuration was replicated experimentally to validate the simulations, with a MOSkin dosimetry probe used to measure dose at three distances from the collimator. For the cylindrical collimator simulation, backscatter dose enhancement was calculated as a function of axial and azimuthal displacement, and dose distribution maps were generated at three distances from the collimator surface. Although significant backscatter dose enhancement was observed for both geometries immediately adjacent to the collimator, simulations and experiments indicate that backscatter dose is negligible at distances beyond 1 mm from the collimator. Since HDR BrachyView is enclosed within a 1 mm thick tissue-equivalent plastic shell, all backscatter radiation resulting from its use will therefore be absorbed before reaching the rectal wall or other tissues. dosimetry, brachytherapy, HDR	en_US
dc.relation.ispartof	Physics in Medicine and Biology	en_US
dc.relation.isbasedon	10.1088/0022-3727/59/21/6659	en_US
dc.subject.classification	Nuclear Medicine & Medical Imaging	en_US
dc.subject.mesh	Humans	en_US
dc.subject.mesh	Prostatic Neoplasms	en_US
dc.subject.mesh	Tungsten	en_US
dc.subject.mesh	Brachytherapy	en_US
dc.subject.mesh	Radiotherapy Dosage	en_US
dc.subject.mesh	Monte Carlo Method	en_US
dc.subject.mesh	Phantoms, Imaging	en_US
dc.subject.mesh	Scattering, Radiation	en_US
dc.subject.mesh	Computer Simulation	en_US
dc.subject.mesh	Image Processing, Computer-Assisted	en_US
dc.subject.mesh	Software	en_US
dc.subject.mesh	Male	en_US
dc.subject.mesh	Radiotherapy, Image-Guided	en_US
dc.title	Radiation dose enhancement at tissue-tungsten interfaces in HDR brachytherapy	en_US
dc.type	Journal Article
utslib.citation.volume	21	en_US
utslib.citation.volume	59	en_US
utslib.for	1117 Public Health and Health Services	en_US
utslib.for	0299 Other Physical Sciences	en_US
utslib.for	0903 Biomedical Engineering	en_US
utslib.for	1103 Clinical Sciences	en_US
pubs.embargo.period	Not known	en_US
pubs.organisational-group	/University of Technology Sydney
pubs.organisational-group	/University of Technology Sydney/Faculty of Engineering and Information Technology
pubs.organisational-group	/University of Technology Sydney/Faculty of Engineering and Information Technology/School of Electrical and Data Engineering
pubs.organisational-group	/University of Technology Sydney/Strength - CRIN - Realtime Information Networks
utslib.copyright.status	open_access
pubs.issue	21	en_US
pubs.publication-status	Published	en_US
pubs.volume	59	en_US

Abstract:

© 2014 Institute of Physics and Engineering in Medicine. HDR BrachyView is a novel in-body dosimetric imaging system for real-time monitoring and verification of the source position in high dose rate (HDR) prostate brachytherapy treatment. It is based on a high-resolution pixelated detector array with a semi-cylindrical multi-pinhole tungsten collimator and is designed to fit inside a compact rectal probe, and is able to resolve the 3D position of the source with a maximum error of 1.5 mm. This paper presents an evaluation of the additional dose that will be delivered to the patient as a result of backscatter radiation from the collimator. Monte Carlo simulations of planar and cylindrical collimators embedded in a tissue-equivalent phantom were performed using Geant4, with an 192Ir source placed at two different source-collimator distances. The planar configuration was replicated experimentally to validate the simulations, with a MOSkin dosimetry probe used to measure dose at three distances from the collimator. For the cylindrical collimator simulation, backscatter dose enhancement was calculated as a function of axial and azimuthal displacement, and dose distribution maps were generated at three distances from the collimator surface. Although significant backscatter dose enhancement was observed for both geometries immediately adjacent to the collimator, simulations and experiments indicate that backscatter dose is negligible at distances beyond 1 mm from the collimator. Since HDR BrachyView is enclosed within a 1 mm thick tissue-equivalent plastic shell, all backscatter radiation resulting from its use will therefore be absorbed before reaching the rectal wall or other tissues. dosimetry, brachytherapy, HDR

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http://hdl.handle.net/10453/38373