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

Title: Robust optimization methods for cardiac sparing in tangential breast IMRT

Abstract

Purpose: In left-sided tangential breast intensity modulated radiation therapy (IMRT), the heart may enter the radiation field and receive excessive radiation while the patient is breathing. The patient’s breathing pattern is often irregular and unpredictable. We verify the clinical applicability of a heart-sparing robust optimization approach for breast IMRT. We compare robust optimized plans with clinical plans at free-breathing and clinical plans at deep inspiration breath-hold (DIBH) using active breathing control (ABC). Methods: Eight patients were included in the study with each patient simulated using 4D-CT. The 4D-CT image acquisition generated ten breathing phase datasets. An average scan was constructed using all the phase datasets. Two of the eight patients were also imaged at breath-hold using ABC. The 4D-CT datasets were used to calculate the accumulated dose for robust optimized and clinical plans based on deformable registration. We generated a set of simulated breathing probability mass functions, which represent the fraction of time patients spend in different breathing phases. The robust optimization method was applied to each patient using a set of dose-influence matrices extracted from the 4D-CT data and a model of the breathing motion uncertainty. The goal of the optimization models was to minimize the dose to themore » heart while ensuring dose constraints on the target were achieved under breathing motion uncertainty. Results: Robust optimized plans were improved or equivalent to the clinical plans in terms of heart sparing for all patients studied. The robust method reduced the accumulated heart dose (D10cc) by up to 801 cGy compared to the clinical method while also improving the coverage of the accumulated whole breast target volume. On average, the robust method reduced the heart dose (D10cc) by 364 cGy and improved the optBreast dose (D99%) by 477 cGy. In addition, the robust method had smaller deviations from the planned dose to the accumulated dose. The deviation of the accumulated dose from the planned dose for the optBreast (D99%) was 12 cGy for robust versus 445 cGy for clinical. The deviation for the heart (D10cc) was 41 cGy for robust and 320 cGy for clinical. Conclusions: The robust optimization approach can reduce heart dose compared to the clinical method at free-breathing and can potentially reduce the need for breath-hold techniques.« less

Authors:
 [1];  [2];  [3];  [2]
  1. Mechanical and Industrial Engineering Department, University of Toronto, Toronto, Ontario M5S 3G8 (Canada)
  2. Radiation Medicine Program, UHN Princess Margaret Cancer Centre, Toronto, Ontario M5G 2M9 (Canada)
  3. Mechanical and Industrial Engineering Department, University of Toronto, Toronto, Ontario M5S 3G8, Canada and Techna Institute for the Advancement of Technology for Health, Toronto, Ontario M5G 1P5 (Canada)
Publication Date:
OSTI Identifier:
22413543
Resource Type:
Journal Article
Journal Name:
Medical Physics
Additional Journal Information:
Journal Volume: 42; Journal Issue: 5; Other Information: (c) 2015 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; CAT SCANNING; HEART; MAMMARY GLANDS; OPTIMIZATION; PATIENTS; RADIATION DOSES; RADIOTHERAPY; RESPIRATION

Citation Formats

Mahmoudzadeh, Houra, Lee, Jenny, Chan, Timothy C. Y., Purdie, Thomas G., Department of Radiation Oncology, University of Toronto, Toronto, Ontario M5S 3S2, and Techna Institute for the Advancement of Technology for Health, Toronto, Ontario M5G 1P5. Robust optimization methods for cardiac sparing in tangential breast IMRT. United States: N. p., 2015. Web. doi:10.1118/1.4916092.
Mahmoudzadeh, Houra, Lee, Jenny, Chan, Timothy C. Y., Purdie, Thomas G., Department of Radiation Oncology, University of Toronto, Toronto, Ontario M5S 3S2, & Techna Institute for the Advancement of Technology for Health, Toronto, Ontario M5G 1P5. Robust optimization methods for cardiac sparing in tangential breast IMRT. United States. https://doi.org/10.1118/1.4916092
Mahmoudzadeh, Houra, Lee, Jenny, Chan, Timothy C. Y., Purdie, Thomas G., Department of Radiation Oncology, University of Toronto, Toronto, Ontario M5S 3S2, and Techna Institute for the Advancement of Technology for Health, Toronto, Ontario M5G 1P5. 2015. "Robust optimization methods for cardiac sparing in tangential breast IMRT". United States. https://doi.org/10.1118/1.4916092.
@article{osti_22413543,
title = {Robust optimization methods for cardiac sparing in tangential breast IMRT},
author = {Mahmoudzadeh, Houra and Lee, Jenny and Chan, Timothy C. Y. and Purdie, Thomas G. and Department of Radiation Oncology, University of Toronto, Toronto, Ontario M5S 3S2 and Techna Institute for the Advancement of Technology for Health, Toronto, Ontario M5G 1P5},
abstractNote = {Purpose: In left-sided tangential breast intensity modulated radiation therapy (IMRT), the heart may enter the radiation field and receive excessive radiation while the patient is breathing. The patient’s breathing pattern is often irregular and unpredictable. We verify the clinical applicability of a heart-sparing robust optimization approach for breast IMRT. We compare robust optimized plans with clinical plans at free-breathing and clinical plans at deep inspiration breath-hold (DIBH) using active breathing control (ABC). Methods: Eight patients were included in the study with each patient simulated using 4D-CT. The 4D-CT image acquisition generated ten breathing phase datasets. An average scan was constructed using all the phase datasets. Two of the eight patients were also imaged at breath-hold using ABC. The 4D-CT datasets were used to calculate the accumulated dose for robust optimized and clinical plans based on deformable registration. We generated a set of simulated breathing probability mass functions, which represent the fraction of time patients spend in different breathing phases. The robust optimization method was applied to each patient using a set of dose-influence matrices extracted from the 4D-CT data and a model of the breathing motion uncertainty. The goal of the optimization models was to minimize the dose to the heart while ensuring dose constraints on the target were achieved under breathing motion uncertainty. Results: Robust optimized plans were improved or equivalent to the clinical plans in terms of heart sparing for all patients studied. The robust method reduced the accumulated heart dose (D10cc) by up to 801 cGy compared to the clinical method while also improving the coverage of the accumulated whole breast target volume. On average, the robust method reduced the heart dose (D10cc) by 364 cGy and improved the optBreast dose (D99%) by 477 cGy. In addition, the robust method had smaller deviations from the planned dose to the accumulated dose. The deviation of the accumulated dose from the planned dose for the optBreast (D99%) was 12 cGy for robust versus 445 cGy for clinical. The deviation for the heart (D10cc) was 41 cGy for robust and 320 cGy for clinical. Conclusions: The robust optimization approach can reduce heart dose compared to the clinical method at free-breathing and can potentially reduce the need for breath-hold techniques.},
doi = {10.1118/1.4916092},
url = {https://www.osti.gov/biblio/22413543}, journal = {Medical Physics},
issn = {0094-2405},
number = 5,
volume = 42,
place = {United States},
year = {Fri May 15 00:00:00 EDT 2015},
month = {Fri May 15 00:00:00 EDT 2015}
}