A transit portal dosimetry method for respiratory gating quality assurance with a dynamic 3D printed tumor phantom

Backgrounds: Respiratory gating is one of the motion management techniques that is used to deliver radiation dose to a tumor at a specific position under free breathing. However, due to the dynamic feedback process of this approach, regular equipment quality assurance (QA) and patient-specific QA ch...

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Main Authors: Tan, Hong Qi, Koh, Calvin Wei Yang, Tan, Lloyd Kuan Rui, Lew, Kah Seng, Chua, Clifford Ghee Ann, Ang, Khong Wei, Lee, James Cheow Lei, Park, Sung Yong
Other Authors: School of Physical and Mathematical Sciences
Format: Article
Language:English
Published: 2022
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Online Access:https://hdl.handle.net/10356/161368
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Institution: Nanyang Technological University
Language: English
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spelling sg-ntu-dr.10356-1613682023-02-28T19:59:09Z A transit portal dosimetry method for respiratory gating quality assurance with a dynamic 3D printed tumor phantom Tan, Hong Qi Koh, Calvin Wei Yang Tan, Lloyd Kuan Rui Lew, Kah Seng Chua, Clifford Ghee Ann Ang, Khong Wei Lee, James Cheow Lei Park, Sung Yong School of Physical and Mathematical Sciences National Cancer Centre, Singapore Science::Physics EPID Motion Management Backgrounds: Respiratory gating is one of the motion management techniques that is used to deliver radiation dose to a tumor at a specific position under free breathing. However, due to the dynamic feedback process of this approach, regular equipment quality assurance (QA) and patient-specific QA checks need to be performed. This work proposes a new QA methodology using electronic portal imaging detector (EPID) to determine the target localization accuracy of phase gating. Methods: QA tools comprising 3D printed spherical tumor phantoms, programmable stages, and an EPID detector are characterized and assembled. Algorithms for predicting portal dose (PD) through moving phantoms are developed and verified using gamma analysis for two spherical tumor phantoms (2 cm and 4 cm), two different 6 MV volumetric modulated arc therapy plans, and two different gating windows (30%–70% and 40%–60%). Comparison between the two gating windows is then performed using the Wilcoxon signed-rank test. An optimizer routine, which is used to determine the optimal window, based on maximal gamma passing rate (GPR), was applied to an actual breathing curve and breathing plan. This was done to ascertain if our method yielded a similar result with the actual gating window. Results: High GPRs of more than 97% and 91% were observed when comparing the predicted PD with the measured PD in moving phantom at 2 mm/2% and1 mm/1% levels, respectively. Analysis of gamma heatmaps shows an excellent agreement with the tumor phantom. The GPR of 40%–60% PD was significantly lower than that of the 30%–70%PD at the 1 mm/1% level (p=0.0064). At the 2 mm/2% level, no significant differences were observed. The optimizer routine could accurately predict the center of the gating window to within a 10% range. Conclusion: We have successfully performed and verified a new method for QA with the use of a moving phantom with EPID for phase gating with real-time position management. Published version This work was supported by SingHealth Duke-NUS Academic Medicine and National Health Innovation Centre Singapore Joint MedTech grant (AM-NHIC/JMT006/2020) and Duke-NUS Oncology Aca-demic Clinical Programme Proton Research Fund(08/FY2021/EX(SL)/92-A146, 08/FY2020/EX(SL)/76-A152) grants. 2022-08-30T01:04:37Z 2022-08-30T01:04:37Z 2022 Journal Article Tan, H. Q., Koh, C. W. Y., Tan, L. K. R., Lew, K. S., Chua, C. G. A., Ang, K. W., Lee, J. C. L. & Park, S. Y. (2022). A transit portal dosimetry method for respiratory gating quality assurance with a dynamic 3D printed tumor phantom. Journal of Applied Clinical Medical Physics, 23(5), e13560-. https://dx.doi.org/10.1002/acm2.13560 1526-9914 https://hdl.handle.net/10356/161368 10.1002/acm2.13560 35147283 2-s2.0-85124748986 5 23 e13560 en AM-NHIC/JMT006/2020 08/FY2021/EX(SL)/92-A146 08/FY2020/EX(SL)/76-A152 Journal of Applied Clinical Medical Physics © 2022 The Authors. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium,provided the original work is properly cited. application/pdf
institution Nanyang Technological University
building NTU Library
continent Asia
country Singapore
Singapore
content_provider NTU Library
collection DR-NTU
language English
topic Science::Physics
EPID
Motion Management
spellingShingle Science::Physics
EPID
Motion Management
Tan, Hong Qi
Koh, Calvin Wei Yang
Tan, Lloyd Kuan Rui
Lew, Kah Seng
Chua, Clifford Ghee Ann
Ang, Khong Wei
Lee, James Cheow Lei
Park, Sung Yong
A transit portal dosimetry method for respiratory gating quality assurance with a dynamic 3D printed tumor phantom
description Backgrounds: Respiratory gating is one of the motion management techniques that is used to deliver radiation dose to a tumor at a specific position under free breathing. However, due to the dynamic feedback process of this approach, regular equipment quality assurance (QA) and patient-specific QA checks need to be performed. This work proposes a new QA methodology using electronic portal imaging detector (EPID) to determine the target localization accuracy of phase gating. Methods: QA tools comprising 3D printed spherical tumor phantoms, programmable stages, and an EPID detector are characterized and assembled. Algorithms for predicting portal dose (PD) through moving phantoms are developed and verified using gamma analysis for two spherical tumor phantoms (2 cm and 4 cm), two different 6 MV volumetric modulated arc therapy plans, and two different gating windows (30%–70% and 40%–60%). Comparison between the two gating windows is then performed using the Wilcoxon signed-rank test. An optimizer routine, which is used to determine the optimal window, based on maximal gamma passing rate (GPR), was applied to an actual breathing curve and breathing plan. This was done to ascertain if our method yielded a similar result with the actual gating window. Results: High GPRs of more than 97% and 91% were observed when comparing the predicted PD with the measured PD in moving phantom at 2 mm/2% and1 mm/1% levels, respectively. Analysis of gamma heatmaps shows an excellent agreement with the tumor phantom. The GPR of 40%–60% PD was significantly lower than that of the 30%–70%PD at the 1 mm/1% level (p=0.0064). At the 2 mm/2% level, no significant differences were observed. The optimizer routine could accurately predict the center of the gating window to within a 10% range. Conclusion: We have successfully performed and verified a new method for QA with the use of a moving phantom with EPID for phase gating with real-time position management.
author2 School of Physical and Mathematical Sciences
author_facet School of Physical and Mathematical Sciences
Tan, Hong Qi
Koh, Calvin Wei Yang
Tan, Lloyd Kuan Rui
Lew, Kah Seng
Chua, Clifford Ghee Ann
Ang, Khong Wei
Lee, James Cheow Lei
Park, Sung Yong
format Article
author Tan, Hong Qi
Koh, Calvin Wei Yang
Tan, Lloyd Kuan Rui
Lew, Kah Seng
Chua, Clifford Ghee Ann
Ang, Khong Wei
Lee, James Cheow Lei
Park, Sung Yong
author_sort Tan, Hong Qi
title A transit portal dosimetry method for respiratory gating quality assurance with a dynamic 3D printed tumor phantom
title_short A transit portal dosimetry method for respiratory gating quality assurance with a dynamic 3D printed tumor phantom
title_full A transit portal dosimetry method for respiratory gating quality assurance with a dynamic 3D printed tumor phantom
title_fullStr A transit portal dosimetry method for respiratory gating quality assurance with a dynamic 3D printed tumor phantom
title_full_unstemmed A transit portal dosimetry method for respiratory gating quality assurance with a dynamic 3D printed tumor phantom
title_sort transit portal dosimetry method for respiratory gating quality assurance with a dynamic 3d printed tumor phantom
publishDate 2022
url https://hdl.handle.net/10356/161368
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