Breast intraoperative electron radiotherapy: Image-based setup verification and in-vivo dosimetry
Breast intraoperative electron radiotherapy: Image-based setup verification and in-vivo dosimetry
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DOI：
10.1016/j.ejmp.2019.03.017
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发表时间：
2019-04-01
影响因子：
3.4
通讯作者：
Akbari, Mohammad Esmail
中科院分区：
文献类型：
--
作者：
Baghani, Hamid Reza;Robatjazi, Mostafa;Akbari, Mohammad Esmail
简介：术中放疗的单次分割性质高度要求质量保证程序，以鉴定射束设置和治疗输送。本研究的目的是评估乳腺术中电子放射治疗（IOERT）和体内剂量递送verified.Materials和方法的治疗设置：25例乳腺癌患者入选，并设置验证为每例使用C形臂成像。用EBT 2胶片测量靶面和远端的受照剂量。获得的剂量测定结果和预测的差异的显着性水平进行了评估，通过T统计test.Results：在两个不同的斜视图中采集的C形臂图像显示任何不对准的施加器和屏蔽盘之间。测量的表面剂量和预期剂量之间的平均差异为1.8% +/- 1.2（p = 0.983），而测量的远端剂量和预期剂量之间的差异很大，为11.1% +/- 1.5（p < 0.001）。这种差异主要与屏蔽盘的后向散射效应有关。目标深度的不均匀性也可以有助于这种显着的difference.Conclusion：采用术中成像IOERT设置验证可以大大提高治疗质量。因此，建议将此成像程序作为治疗质量保证的一部分。预测的和测量的表面剂量之间的有利协议证明了剂量输送验证的EBT 2膜的适用性。在体剂量测量结果表明，屏蔽盘的电子背散射可影响瘤床远端的受照剂量。
Introduction: Single fraction nature of intraoperative radiotherapy highly demands a quality assurance procedure to qualify both beam setup and treatment delivery. The aim of this study is to evaluate the treatment setup during breast intraoperative electron radiotherapy (IOERT) and in-vivo dose delivery verification.Materials and methods: Twenty-five breast cancer patients were enrolled and setup verification for each case was performed using C-arm imaging. The received dose by surface and distal end of target was measured by EBT2 film. The significance level of difference between obtained dosimetry results and predicted ones was evaluated by the T statistical test.Results: Acquired C-arm images in two different oblique views revealed any misalignment between the applicator and shielding disk. The mean difference between the measured surface dose and expected one was 1.8% +/- 1.2 (p = 0.983) while a great disagreement, 11.1% +/- 1.5 (p < 0.001), was observed between the measured distal end dose and expected one. This discrepancy is mainly correlated to the backscattering effect from the shielding disk. Target depth nonuniformities can also contribute to this remarkable difference.Conclusion: Employing the intraoperative imaging for IOERT setup verification can considerably improve the treatment quality. Therefore, it is suggested to implement this imaging procedure as a part of treatment quality assurance. Favorable agreement between the predicted and measured surface doses demonstrates the applicability of EBT2 film for dose delivery verification. The results of in-vivo dosimetry showed that the electron backscattering from employed shielding disk can affect the received dose by the distal end of tumor bed.