Dosimetric effects of quality assurance-related setup errors in passive proton therapy for prostate cancer with and without a hydrogel spacer

Yuta Omi, Keisuke Yasui, Akira Shimomura, Rie Muramatsu, Hiromitsu Iwata, Hiroyuki Ogino, Akari Furukawa, Naoki Hayashi

研究成果: Article査読

抄録

The purpose of this study was to evaluate the effect of quality assurance (QA)-related setup errors in passive proton therapy for prostate cancer with and without a hydrogel spacer. We used 20 typical computed tomography (CT) images of prostate cancer: 10 patients with and 10 patients without spacers. The following 12 model errors were assumed: output error ± 2%, range error ± 1 mm, setup error ± 1 mm for three directions, and multileaf collimator (MLC) position error ± 1 mm. We created verification plans with model errors and compared the prostate-rectal (PR) distance and dose indices with and without the spacer. The mean PR distance at the isocenter was 1.1 ± 1.3 mm without the spacer and 12.9 ± 2.9 mm with the spacer (P < 0.001). The mean rectum V53.5 GyE, V50 GyE, and V34.5 GyE in the original plan were 2.3%, 4.1%, and 12.1% without the spacer and 0.1%, 0.4%, and 3.3% with the spacer (P = 0.0011, < 0.001, and < 0.001). The effects of the range and lateral setup errors were small; however, the effects of the vertical/long setup and MLC error were significant in the cases without the spacer. The means of the maximum absolute change from original plans across all scenarios in the rectum V53.5 GyE, V50 GyE, and V34.5 GyE were 1.3%, 1.5%, and 2.3% without the spacer, and 0.2%, 0.4%, and 1.3% with the spacer (P < 0.001, < 0.001, and = 0.0019). This study indicated that spacer injections were also effective in reducing the change in the rectal dose due to setup errors.

本文言語English
ページ(範囲)328-335
ページ数8
ジャーナルRadiological Physics and Technology
14
3
DOI
出版ステータスPublished - 09-2021

All Science Journal Classification (ASJC) codes

  • 放射線
  • 理学療法、スポーツ療法とリハビリテーション
  • 放射線学、核医学およびイメージング

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