Development of a quantitative analysis method for assessing patient body surface deformation using an optical surface tracking system
Development of a quantitative analysis method for assessing patient body surface deformation using an optical surface tracking system
复制标题
开发利用光学表面跟踪系统评估患者体表变形的定量分析方法
DOI：
10.1007/s12194-022-00676-0
复制
发表时间：
2022
影响因子：
1.6
通讯作者：
Iwai T
中科院分区：
文献类型：
--
作者：
Sato K;Sato R;Goto N;Kawamura T;Kanai T;Miyasaka Y;Lee SH;Souda H;Iwai T
本研究的目的是开发一种新的方法来定量分析患者在放射治疗过程中的体型变化，而无需额外的辐射暴露，使用光学表面跟踪系统。使用具有已知位移的立方体模评价该方法的准确度。利用三维打印的模拟真实的患者治疗前后头颈部形态的体模表面图像，建立变形表面积直方图。计算覆盖表面图像中2 cm 2面积的近最大变形值（Def-2cm 2）。还在治疗前体模上创建了体积调制弧治疗（VMAT）计划，并在治疗后体模上重新计算剂量分布，以比较剂量指数。对4例患者的体表图像进行分析，评价Def-2cm 2，探讨该方法是否可用于临床。使用立方体体模的实验导致平均变形误差为0.08 mm。使用头颈部体模时，Def-2cm 2值为17.5 mm，VMAT计划中覆盖95%计划靶体积的剂量减少了11.7%，表明体表变形可能影响剂量分布。尽管临床数据分析显示所有病例均无临床相关变形，但在体表观察到轻微皮肤下垂和呼吸变化。该方法可以定量、准确地评价物体表面的变形。该方法预计将用于做出有关修改治疗计划的决策。
This study aimed to develop a new method to quantitatively analyze body shape changes in patients during radiotherapy without additional radiation exposure using an optical surface tracking system. This method’s accuracy was evaluated using a cubic phantom with a known shift. Surface images of three-dimensionally printed phantoms, which simulated the head and neck shapes of real patients before and after treatment, were used to create a deformation surface area histogram. The near-maximum deformation value covering an area of 2 cm2in the surface image (Def-2cm2) was calculated. A volumetric modulated arc therapy (VMAT) plan was also created on the pre-treatment phantom, and the dose distribution was recalculated on the post-treatment phantom to compare the dose indices. Surface images of four patients were analyzed to evaluate Def-2cm2and examine whether this method can be used in clinical cases. Experiments with the cubic phantom resulted in a mean deformation error of 0.08 mm. With head and neck phantoms, the Def-2cm2value was 17.5 mm, and the dose that covered 95% of the planning target volume in the VMAT plan decreased by 11.7%, indicating that deformation of the body surface may affect the dose distribution. Although analysis of the clinical data showed no clinically relevant deformation in any of the cases, slight skin sagging and respiratory changes in the body surface were observed. The proposed method can quantitatively and accurately evaluate the deformation of a body surface. This method is expected to be used to make decisions regarding modifications to treatment plans.