EPID-guided 3D dose verification of lung SBRT
EPID-guided 3D dose verification of lung SBRT
复制标题
DOI：
10.1118/1.3532821
复制
发表时间：
2011-01-01
期刊：
影响因子：
3.8
通讯作者：
Berbeco, R. I.
中科院分区：
文献类型：
--
作者：
Aristophanous, M.;Rottmann, J.;Berbeco, R. I.
目的：探讨利用电子门静脉成像设备（EPID）在治疗过程中拍摄的肿瘤轨迹来验证给药剂量的可行性。方法：该方法利用每个场的计划影响度和肿瘤运动轨迹计算传递影响度。设计了一项模拟研究来评估该方法的可行性。CIRS动态胸腔假体与真实的软树脂肿瘤一起使用，模拟真实的患者肿瘤。用所提出的方法计算的剂量与在肿瘤模型的小裂缝中插入15个金属氧化物半导体场效应晶体管（mosfet）的直接测量结果进行了比较。幻影以不同的运动范围和设置误差照射肿瘤静止和移动。在所有分娩过程中记录EPID图像，并使用内部开发的软件跟踪治疗后的肿瘤模型。将每个场的计划能量与肿瘤运动轨迹进行卷积以获得传递的能量。利用每个电场的输送通量，计算输送剂量。将估计的释放剂量与用mosfet直接测量的剂量进行比较。提出的方法的可行性也证明了一个真实的肺癌患者，治疗立体定向放射治疗。结果：用传递通量法计算的传递剂量与MOSFET的测量结果吻合良好，根据剂量梯度的接近程度，平均差异在0.8% ~ 8.3%之间。对于患者治疗，比较了计划和交付的剂量体积直方图，验证了目标体积的总体良好覆盖率。结论：该方法成功地应用于幻体和临床资料，并对其准确性进行了评价。验证每个治疗部分可以启用在治疗过程中应用的校正策略，以确保所需的剂量覆盖。(C) 2011年美国医学物理学家协会。(DOI: 10.1118/1.3532821)
Purpose: To investigate the feasibility of utilizing tumor tracks from electronic portal imaging device (EPID) images taken during treatment to verify the delivered dose.Methods: The proposed method is based on a computation of the delivered fluence by utilizing the planned fluence and the tumor motion track for each field. A phantom study was designed to assess the feasibility of the method. The CIRS dynamic thorax phantom was utilized with a realistic soft resin tumor, modeled after a real patient tumor. The dose calculated with the proposed method was compared to direct measurements taken with 15 metal oxide semiconductor field effect transistors (MOSFETs) inserted in small fissures made in the tumor model. The phantom was irradiated with the tumor static and moved with different range of motions and setup errors. EPID images were recorded throughout all deliveries and the tumor model was tracked post-treatment with in-house developed software. The planned fluence for each field was convolved with the tumor motion tracks to obtain the delivered fluence. Utilizing the delivered fluence from each field, the delivered dose was calculated. The estimated delivered dose was compared to the dose directly measured with the MOSFETs. The feasibility of the proposed method was also demonstrated on a real lung cancer patient, treated with stereotactic body radiotherapy.Results: The calculation of delivered dose with the delivered fluence method was in good agreement with the MOSFET measurements, with average differences ranging from 0.8% to 8.3% depending on the proximity of a dose gradient. For the patient treatment, the planned and delivered dose volume histograms were compared and verified the overall good coverage of the target volume.Conclusions: The delivered fluence method was applied successfully on phantom and clinical data and its accuracy was evaluated. Verifying each treatment fraction may enable correction strategies that can be applied during the course of treatment to ensure the desired dose coverage. (C) 2011 American Association of Physicists in Medicine. [DOI: 10.1118/1.3532821]