open access

Vol 25, No 3 (2020)
Original research articles
Published online: 2020-05-01
Submitted: 2019-06-09
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Characterization of robust optimization for VMAT plan for liver cancer

Hideharu Miura, Shuichi Ozawa, Hayate Kusaba, Yoshiko Doi, Masahiko Kenjo, Kiyoshi Yamada, Yasushi Nagata
DOI: 10.1016/j.rpor.2020.03.012
·
Rep Pract Oncol Radiother 2020;25(3):376-381.

open access

Vol 25, No 3 (2020)
Original research articles
Published online: 2020-05-01
Submitted: 2019-06-09

Abstract

Purpose

We investigated the feasibility of robust optimization for volumetric modulated arc therapy (VMAT) stereotactic body radiation therapy (SBRT) for liver cancer in comparison with planning target volume (PTV)-based optimized plans. Treatment plan quality, robustness, complexity, and accuracy of dose delivery were assessed.

Methods

Ten liver cancer patients were selected for this study. PTV-based optimized plans with an 8-mm PTV margin and robust optimized plans with an 8-mm setup uncertainty were generated. Plan perturbed doses were evaluated using a setup error of 8mm in all directions from the isocenter. The dosimetric comparison parameters were clinical target volume (CTV) doses (D98%, D50%, and D2%), liver doses, and monitor unit (MU). Plan complexity was evaluated using the modulation complexity score for VMAT (MCSv).

Results

There was no significant difference between the two optimizations with respect to CTV doses and MUs. Robust optimized plans had a higher liver dose than did PTV-based optimized plans. Plan perturbed dose evaluations showed that doses to the CTV for the robust optimized plans had small variations. Robust optimized plans were less complex than PTV-based optimized plans. Robust optimized plans had statistically significant fewer leaf position errors than did PTV-based optimized plans.

Conclusions

Comparison of treatment plan quality, robustness, and plan complexity of both optimizations showed that robust optimization could be feasibile for VMAT of liver cancer.

Abstract

Purpose

We investigated the feasibility of robust optimization for volumetric modulated arc therapy (VMAT) stereotactic body radiation therapy (SBRT) for liver cancer in comparison with planning target volume (PTV)-based optimized plans. Treatment plan quality, robustness, complexity, and accuracy of dose delivery were assessed.

Methods

Ten liver cancer patients were selected for this study. PTV-based optimized plans with an 8-mm PTV margin and robust optimized plans with an 8-mm setup uncertainty were generated. Plan perturbed doses were evaluated using a setup error of 8mm in all directions from the isocenter. The dosimetric comparison parameters were clinical target volume (CTV) doses (D98%, D50%, and D2%), liver doses, and monitor unit (MU). Plan complexity was evaluated using the modulation complexity score for VMAT (MCSv).

Results

There was no significant difference between the two optimizations with respect to CTV doses and MUs. Robust optimized plans had a higher liver dose than did PTV-based optimized plans. Plan perturbed dose evaluations showed that doses to the CTV for the robust optimized plans had small variations. Robust optimized plans were less complex than PTV-based optimized plans. Robust optimized plans had statistically significant fewer leaf position errors than did PTV-based optimized plans.

Conclusions

Comparison of treatment plan quality, robustness, and plan complexity of both optimizations showed that robust optimization could be feasibile for VMAT of liver cancer.

Get Citation

Keywords

Robust optimization; Liver; Dosimetry comparison; Plan complexity; VMAT

About this article
Title

Characterization of robust optimization for VMAT plan for liver cancer

Journal

Reports of Practical Oncology and Radiotherapy

Issue

Vol 25, No 3 (2020)

Pages

376-381

Published online

2020-05-01

DOI

10.1016/j.rpor.2020.03.012

Bibliographic record

Rep Pract Oncol Radiother 2020;25(3):376-381.

Keywords

Robust optimization
Liver
Dosimetry comparison
Plan complexity
VMAT

Authors

Hideharu Miura
Shuichi Ozawa
Hayate Kusaba
Yoshiko Doi
Masahiko Kenjo
Kiyoshi Yamada
Yasushi Nagata

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