Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA.
J Appl Clin Med Phys. 2021 Sep;22(9):153-158. doi: 10.1002/acm2.13357. Epub 2021 Jul 20.
To compare the dosimetric accuracy of surface-guided radiation therapy (SGRT) and cone-beam computed tomography (CBCT) setups in proton breast treatment plans.
Data from 30 patients were retrospectively analyzed in this IRB-approved study. Patients were prescribed 4256-5040 cGy in 16-28 fractions. CBCT and AlignRT (SGRT; Vision RT Ltd.) were used for treatment setup during the first three fractions, then daily AlignRT and weekly CBCT thereafter. Each patient underwent a quality assurance CT (QA-CT) scan midway through the treatment course to assess anatomical and dosimetric changes. To emulate the SGRT and CBCT setups during treatment, the planning CT and QA-CT images were registered in two ways: (1) by registering the volume within the CTs covered by the CBCT field of view; and (2) by contouring and registering the surface surveyed by the AlignRT system. The original plan was copied onto these two datasets and the dose was recalculated. The clinical treatment volume (CTV): V ; heart: V , V , and mean dose; and ipsilateral lung: V , V , and V , were recorded. Multi and univariate analyses of variance were performed to assess the differences in dose metric values between the planning CT and the SGRT and CBCT setups.
The CTV V and lung V , V , and V dose metrics were all significantly (p < 0.01) lower on the QA-CT in both the CBCT and SGRT setup. The differences were not clinically significant and were, on average, 1.4-1.6% lower for CTV V and 1.8%-6.0% lower for the lung dose metrics. When comparing the lung and CTV V dose metrics between the CBCT and SGRT setups, no significant difference was observed. This indicates that the SGRT setup provides similar dosimetric accuracy as CBCT.
This study supports the daily use of SGRT systems for the accurate dose delivery of proton breast treatment plans.
比较表面引导放射治疗（SGRT）和锥形束 CT（CBCT）在质子乳腺治疗计划中的剂量学准确性。
本研究回顾性分析了 30 名患者的数据。患者被规定接受 4256-5040cGy 的 16-28 分次治疗。在最初的三个分次治疗中，使用 CBCT 和 AlignRT（SGRT；Vision RT Ltd.）进行治疗设置，之后每天使用 AlignRT，每周使用 CBCT。每位患者在治疗过程中进行了一次质量保证 CT（QA-CT）扫描，以评估解剖结构和剂量变化。为了在治疗过程中模拟 SGRT 和 CBCT 设置，将计划 CT 和 QA-CT 图像以两种方式进行注册：（1）通过注册 CBCT 视场覆盖的 CT 中的体积；（2）通过描绘和注册 AlignRT 系统测量的表面。将原始计划复制到这两个数据集上，并重新计算剂量。记录了临床治疗体积（CTV）：V ；心脏：V 、V 和平均剂量；以及同侧肺：V 、V 和 V 。进行了多变量和单变量方差分析，以评估计划 CT 与 SGRT 和 CBCT 设置之间剂量学值的差异。
在 CBCT 和 SGRT 设置中，QA-CT 上的 CTV V 和肺 V 、V 和 V 剂量学值均显著（p<0.01）降低。差异无临床意义，CTV V 的平均降低 1.4%-1.6%，肺剂量学值的平均降低 1.8%-6.0%。当比较 CBCT 和 SGRT 设置之间的肺和 CTV V 剂量学值时，未观察到显著差异。这表明 SGRT 设置可提供与 CBCT 相似的剂量学准确性。
本研究支持每天使用 SGRT 系统为质子乳腺治疗计划提供准确的剂量输送。
