skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: TH-C-BRD-11: Robustness of Pencil Beam Scanning Proton Therapy for Pelvic Cancer Under Anatomical Changes

Abstract

Purpose: Pencil beam scanning (PBS) proton therapy provides excellent dosimetric benefits in pelvic cancer treatment, yet day-to-day anatomical variations in pelvic region tend to cause range uncertainties. This study evaluates the dosimetric robustness under anatomical changes for three PBS intensity-modulated proton therapy (IMPT), IMPT using worstcase robust optimization (thereafter ‘Robust IMPT’), and single-field uniform dose (SFUD), in cervical cancer treatment. Methods: IMPT, Robust IMPT, and SFUD plans using the same beam directions and the same prescription (Rx) were generated on computed tomography (CT) images acquired on the simulation day. The dose from each plan was then recomputed on CT images acquired in subsequent two to five weeks using the same protocol. The weekly CTs were registered to the planning CT based on bony anatomy. Target coverage was considered adequate on each weekly CT if dose to 99% of the internal target volume (D-ITV99%) reached at least 95% of the Rx dose. Statistical analysis was then performed on the 21 weekly CT images available for the 7 enrolled patients. Results: Statistically, IMPT was unable to maintain target coverage (mean D-ITV99% = 90.5% Rx, p = 0.004), and SFUD was able to maintain target coverage (mean D-ITV99% = 98.0% Rx, p =more » 0.0064), in the weeks following simulation. Robust IMPT was able to improve the robustness of IMPT significantly (p < 0.0001), though its maintenance of target coverage was not statistically significant by the 95% Rx criteria (mean D-ITV99% = 96.0%, p = 0.1677). Conclusion: During the multi-week treatment course with anatomical variations, SFUD is robust in terms of maintaining target coverage while IMPT is not. The worst-case optimized Robust IMPT, assuming ±3.5% range uncertainties, improves the robustness of IMPT under anatomical changes significantly, even though it was not designed to account for anatomical changes by mechanism.« less

Authors:
; ; ; ;  [1]
  1. University of Iowa, Iowa City, IA (United States)
Publication Date:
OSTI Identifier:
22409848
Resource Type:
Journal Article
Journal Name:
Medical Physics
Additional Journal Information:
Journal Volume: 41; Journal Issue: 6; 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:
60 APPLIED LIFE SCIENCES; ANATOMY; CAT SCANNING; NEOPLASMS; OPTIMIZATION; PATIENTS; PROTON BEAMS; RADIOTHERAPY

Citation Formats

Dinges, E, Bhatia, S, Gross, B, McGuire, S, and Wang, D. TH-C-BRD-11: Robustness of Pencil Beam Scanning Proton Therapy for Pelvic Cancer Under Anatomical Changes. United States: N. p., 2014. Web. doi:10.1118/1.4889609.
Dinges, E, Bhatia, S, Gross, B, McGuire, S, & Wang, D. TH-C-BRD-11: Robustness of Pencil Beam Scanning Proton Therapy for Pelvic Cancer Under Anatomical Changes. United States. https://doi.org/10.1118/1.4889609
Dinges, E, Bhatia, S, Gross, B, McGuire, S, and Wang, D. 2014. "TH-C-BRD-11: Robustness of Pencil Beam Scanning Proton Therapy for Pelvic Cancer Under Anatomical Changes". United States. https://doi.org/10.1118/1.4889609.
@article{osti_22409848,
title = {TH-C-BRD-11: Robustness of Pencil Beam Scanning Proton Therapy for Pelvic Cancer Under Anatomical Changes},
author = {Dinges, E and Bhatia, S and Gross, B and McGuire, S and Wang, D},
abstractNote = {Purpose: Pencil beam scanning (PBS) proton therapy provides excellent dosimetric benefits in pelvic cancer treatment, yet day-to-day anatomical variations in pelvic region tend to cause range uncertainties. This study evaluates the dosimetric robustness under anatomical changes for three PBS intensity-modulated proton therapy (IMPT), IMPT using worstcase robust optimization (thereafter ‘Robust IMPT’), and single-field uniform dose (SFUD), in cervical cancer treatment. Methods: IMPT, Robust IMPT, and SFUD plans using the same beam directions and the same prescription (Rx) were generated on computed tomography (CT) images acquired on the simulation day. The dose from each plan was then recomputed on CT images acquired in subsequent two to five weeks using the same protocol. The weekly CTs were registered to the planning CT based on bony anatomy. Target coverage was considered adequate on each weekly CT if dose to 99% of the internal target volume (D-ITV99%) reached at least 95% of the Rx dose. Statistical analysis was then performed on the 21 weekly CT images available for the 7 enrolled patients. Results: Statistically, IMPT was unable to maintain target coverage (mean D-ITV99% = 90.5% Rx, p = 0.004), and SFUD was able to maintain target coverage (mean D-ITV99% = 98.0% Rx, p = 0.0064), in the weeks following simulation. Robust IMPT was able to improve the robustness of IMPT significantly (p < 0.0001), though its maintenance of target coverage was not statistically significant by the 95% Rx criteria (mean D-ITV99% = 96.0%, p = 0.1677). Conclusion: During the multi-week treatment course with anatomical variations, SFUD is robust in terms of maintaining target coverage while IMPT is not. The worst-case optimized Robust IMPT, assuming ±3.5% range uncertainties, improves the robustness of IMPT under anatomical changes significantly, even though it was not designed to account for anatomical changes by mechanism.},
doi = {10.1118/1.4889609},
url = {https://www.osti.gov/biblio/22409848}, journal = {Medical Physics},
issn = {0094-2405},
number = 6,
volume = 41,
place = {United States},
year = {Sun Jun 15 00:00:00 EDT 2014},
month = {Sun Jun 15 00:00:00 EDT 2014}
}