A comprehensive dosimetric study of Monte Carlo and pencil-beam algorithms on intensity-modulated proton therapy for breast cancer

Xiaoying Liang, Zuofeng Li, Dandan Zheng, Julie A. Bradley, Michael Rutenberg, Nancy Mendenhall

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

PB algorithms are commonly used for proton therapy. Previously reported limitations of the PB algorithm for proton therapy are mainly focused on high-density gradients and small-field dosimetry, the effect of PB algorithms on intensity-modulated proton therapy (IMPT) for breast cancer has yet to be illuminated. In this study, we examined 20 patients with breast cancer and systematically investigated the dosimetric impact of MC and PB algorithms on IMPT. Four plans were generated for each patient: (a) a PB plan that optimized and computed the final dose using a PB algorithm; (b) a MC-recomputed plan that recomputed the final dose of the PB plan using a MC algorithm; (c) a MC-renormalized plan that renormalized the MC-recomputed plan to restore the target coverage; and (d) a MC-optimized plan that optimized and computed the final dose using a MC algorithm. The DVH on CTVs and on organ-at-risks (OARs) from each plan were studied. The Mann–Whitney U-test was used for testing the differences between any two types of plans. We found that PB algorithms significantly overestimated the target dose in breast IMPT plans. The median value of the CTV D99%, D95%, and Dmean dropped by 3.7%, 3.4%, and 2.1%, respectively, of the prescription dose in the MC-recomputed plans compared with the PB plans. The magnitude of the target dose overestimation by the PB algorithm was higher for the breast CTV than for the chest wall CTV. In the MC-renormalized plans, the target dose coverage was comparable with the original PB plans, but renormalization led to a significant increase in target hot spots as well as skin dose. The MC-optimized plans led to sufficient target dose coverage, acceptable target hot spots, and good sparing of skin and other OARs. Utilizing the MC algorithm for both plan optimization and final dose computation in breast IMPT treatment planning is therefore desirable.

Original languageEnglish (US)
Pages (from-to)128-136
Number of pages9
JournalJournal of applied clinical medical physics
Volume20
Issue number1
DOIs
StatePublished - Jan 2019

Fingerprint

Proton Therapy
pencil beams
breast
therapy
Protons
cancer
Breast Neoplasms
protons
dosage
Organs at Risk
Breast
Skin
organs
Thoracic Wall
Dosimetry
Prescriptions
chest

Keywords

  • IMPT
  • breast cancer
  • dose algorithms

ASJC Scopus subject areas

  • Radiation
  • Instrumentation
  • Radiology Nuclear Medicine and imaging

Cite this

A comprehensive dosimetric study of Monte Carlo and pencil-beam algorithms on intensity-modulated proton therapy for breast cancer. / Liang, Xiaoying; Li, Zuofeng; Zheng, Dandan; Bradley, Julie A.; Rutenberg, Michael; Mendenhall, Nancy.

In: Journal of applied clinical medical physics, Vol. 20, No. 1, 01.2019, p. 128-136.

Research output: Contribution to journalArticle

Liang, Xiaoying ; Li, Zuofeng ; Zheng, Dandan ; Bradley, Julie A. ; Rutenberg, Michael ; Mendenhall, Nancy. / A comprehensive dosimetric study of Monte Carlo and pencil-beam algorithms on intensity-modulated proton therapy for breast cancer. In: Journal of applied clinical medical physics. 2019 ; Vol. 20, No. 1. pp. 128-136.
@article{604949aaea0943cb806181d049d4a22e,
title = "A comprehensive dosimetric study of Monte Carlo and pencil-beam algorithms on intensity-modulated proton therapy for breast cancer",
abstract = "PB algorithms are commonly used for proton therapy. Previously reported limitations of the PB algorithm for proton therapy are mainly focused on high-density gradients and small-field dosimetry, the effect of PB algorithms on intensity-modulated proton therapy (IMPT) for breast cancer has yet to be illuminated. In this study, we examined 20 patients with breast cancer and systematically investigated the dosimetric impact of MC and PB algorithms on IMPT. Four plans were generated for each patient: (a) a PB plan that optimized and computed the final dose using a PB algorithm; (b) a MC-recomputed plan that recomputed the final dose of the PB plan using a MC algorithm; (c) a MC-renormalized plan that renormalized the MC-recomputed plan to restore the target coverage; and (d) a MC-optimized plan that optimized and computed the final dose using a MC algorithm. The DVH on CTVs and on organ-at-risks (OARs) from each plan were studied. The Mann–Whitney U-test was used for testing the differences between any two types of plans. We found that PB algorithms significantly overestimated the target dose in breast IMPT plans. The median value of the CTV D99{\%}, D95{\%}, and Dmean dropped by 3.7{\%}, 3.4{\%}, and 2.1{\%}, respectively, of the prescription dose in the MC-recomputed plans compared with the PB plans. The magnitude of the target dose overestimation by the PB algorithm was higher for the breast CTV than for the chest wall CTV. In the MC-renormalized plans, the target dose coverage was comparable with the original PB plans, but renormalization led to a significant increase in target hot spots as well as skin dose. The MC-optimized plans led to sufficient target dose coverage, acceptable target hot spots, and good sparing of skin and other OARs. Utilizing the MC algorithm for both plan optimization and final dose computation in breast IMPT treatment planning is therefore desirable.",
keywords = "IMPT, breast cancer, dose algorithms",
author = "Xiaoying Liang and Zuofeng Li and Dandan Zheng and Bradley, {Julie A.} and Michael Rutenberg and Nancy Mendenhall",
year = "2019",
month = "1",
doi = "10.1002/acm2.12497",
language = "English (US)",
volume = "20",
pages = "128--136",
journal = "Journal of applied clinical medical physics / American College of Medical Physics",
issn = "1526-9914",
publisher = "American Institute of Physics Publising LLC",
number = "1",

}

TY - JOUR

T1 - A comprehensive dosimetric study of Monte Carlo and pencil-beam algorithms on intensity-modulated proton therapy for breast cancer

AU - Liang, Xiaoying

AU - Li, Zuofeng

AU - Zheng, Dandan

AU - Bradley, Julie A.

AU - Rutenberg, Michael

AU - Mendenhall, Nancy

PY - 2019/1

Y1 - 2019/1

N2 - PB algorithms are commonly used for proton therapy. Previously reported limitations of the PB algorithm for proton therapy are mainly focused on high-density gradients and small-field dosimetry, the effect of PB algorithms on intensity-modulated proton therapy (IMPT) for breast cancer has yet to be illuminated. In this study, we examined 20 patients with breast cancer and systematically investigated the dosimetric impact of MC and PB algorithms on IMPT. Four plans were generated for each patient: (a) a PB plan that optimized and computed the final dose using a PB algorithm; (b) a MC-recomputed plan that recomputed the final dose of the PB plan using a MC algorithm; (c) a MC-renormalized plan that renormalized the MC-recomputed plan to restore the target coverage; and (d) a MC-optimized plan that optimized and computed the final dose using a MC algorithm. The DVH on CTVs and on organ-at-risks (OARs) from each plan were studied. The Mann–Whitney U-test was used for testing the differences between any two types of plans. We found that PB algorithms significantly overestimated the target dose in breast IMPT plans. The median value of the CTV D99%, D95%, and Dmean dropped by 3.7%, 3.4%, and 2.1%, respectively, of the prescription dose in the MC-recomputed plans compared with the PB plans. The magnitude of the target dose overestimation by the PB algorithm was higher for the breast CTV than for the chest wall CTV. In the MC-renormalized plans, the target dose coverage was comparable with the original PB plans, but renormalization led to a significant increase in target hot spots as well as skin dose. The MC-optimized plans led to sufficient target dose coverage, acceptable target hot spots, and good sparing of skin and other OARs. Utilizing the MC algorithm for both plan optimization and final dose computation in breast IMPT treatment planning is therefore desirable.

AB - PB algorithms are commonly used for proton therapy. Previously reported limitations of the PB algorithm for proton therapy are mainly focused on high-density gradients and small-field dosimetry, the effect of PB algorithms on intensity-modulated proton therapy (IMPT) for breast cancer has yet to be illuminated. In this study, we examined 20 patients with breast cancer and systematically investigated the dosimetric impact of MC and PB algorithms on IMPT. Four plans were generated for each patient: (a) a PB plan that optimized and computed the final dose using a PB algorithm; (b) a MC-recomputed plan that recomputed the final dose of the PB plan using a MC algorithm; (c) a MC-renormalized plan that renormalized the MC-recomputed plan to restore the target coverage; and (d) a MC-optimized plan that optimized and computed the final dose using a MC algorithm. The DVH on CTVs and on organ-at-risks (OARs) from each plan were studied. The Mann–Whitney U-test was used for testing the differences between any two types of plans. We found that PB algorithms significantly overestimated the target dose in breast IMPT plans. The median value of the CTV D99%, D95%, and Dmean dropped by 3.7%, 3.4%, and 2.1%, respectively, of the prescription dose in the MC-recomputed plans compared with the PB plans. The magnitude of the target dose overestimation by the PB algorithm was higher for the breast CTV than for the chest wall CTV. In the MC-renormalized plans, the target dose coverage was comparable with the original PB plans, but renormalization led to a significant increase in target hot spots as well as skin dose. The MC-optimized plans led to sufficient target dose coverage, acceptable target hot spots, and good sparing of skin and other OARs. Utilizing the MC algorithm for both plan optimization and final dose computation in breast IMPT treatment planning is therefore desirable.

KW - IMPT

KW - breast cancer

KW - dose algorithms

UR - http://www.scopus.com/inward/record.url?scp=85057818965&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85057818965&partnerID=8YFLogxK

U2 - 10.1002/acm2.12497

DO - 10.1002/acm2.12497

M3 - Article

C2 - 30488548

AN - SCOPUS:85057818965

VL - 20

SP - 128

EP - 136

JO - Journal of applied clinical medical physics / American College of Medical Physics

JF - Journal of applied clinical medical physics / American College of Medical Physics

SN - 1526-9914

IS - 1

ER -