de la Pinta C, Sevillano D, Colmenares R, Barrio S, Olavarria A, Palomera A, Romera R, Cobos J, Muriel A, Fernández E, Perna L C, Albillos A, Sancho S
Radiation Oncology Department. IRYCIS. Ramón y Cajal Hospital. Crta Colmenar Viejo Km 9,100. 28034, Madrid, Spain.
Medical Physics Department. Ramón y Cajal Hospital. IRYCIS, Crta Colmenar Viejo Km 9,100 28034, Madrid, Spain.
Tech Innov Patient Support Radiat Oncol. 2023 Jun 20;27:100215. doi: 10.1016/j.tipsro.2023.100215. eCollection 2023 Sep.
Liver stereotactic body radiotherapy (SBRT) is increasingly being used to treat tumours. The purpose of this study was to compare the differences in patient positioning when using implanted fiducials as surrogates compared to alternative methods based on liver contour or bone registration.
Eighteen patients treated with SBRT who underwent a fiducial placement procedure were included. Fiducial guidance was our gold standard to guide treatment in this study. After recording the displacements, when fusing the planning CT and CBCT performed in the treatment unit using fiducials, liver contour and bone reference, the differences between fiducials and liver contour and bone reference were calculated. Data from 88 CBCT were analyzed. The correlation between the displacements found with fiducials and those performed based on the liver contour and the nearest bone structure as references was determined. The mean, median, variance, range and standard deviation of the displacements with each of the fusion methods were obtained. μ, Ʃ, and σ values and margins were obtained.
Lateral displacements of less than 3 mm with respect to the gold standard in 92% vs. 62.5% of cases using liver contour and bone references, respectively, with 93.2% vs. 65.9% in the AP axis and SI movement in 69.3% vs. 51.1%. The errors μ, σ and Ʃ of the fusions with hepatic contour and bone reference in SI were 0.26 mm, 4 mm and 3 mm, and 0.8 mm, 5 mm and 3 mm respectively.
Our study showed that displacements were smaller with the use of hepatic contour compared to bone reference and comparable to those obtained with the use of fiducials in the lateral, AP and SI motion axes. This would justify that hepatic contouring can be a guide in the treatment of patients in the absence of fiducials.
肝脏立体定向体部放疗（SBRT）越来越多地用于治疗肿瘤。本研究的目的是比较使用植入基准标记作为替代物与基于肝脏轮廓或骨配准的其他方法时患者定位的差异。
纳入18例接受SBRT治疗且进行了基准标记放置程序的患者。在本研究中，基准标记引导是指导治疗的金标准。记录位移后，在使用基准标记、肝脏轮廓和骨参考融合治疗单元中进行的计划CT和CBCT时，计算基准标记与肝脏轮廓和骨参考之间的差异。分析了88次CBCT的数据。确定了使用基准标记发现的位移与基于肝脏轮廓和最近骨结构作为参考的位移之间的相关性。获得了每种融合方法位移的均值、中位数、方差、范围和标准差。获得了μ、Ʃ和σ值以及边界。
相对于金标准，在使用肝脏轮廓和骨参考的情况下，分别有92%和62.5%的病例横向位移小于3mm，在前后轴上分别为93.2%和65.9%，在头脚方向移动上分别为69.3%和51.1%。使用肝脏轮廓和骨参考在头脚方向融合的误差μ、σ和Ʃ分别为0.26mm、4mm和3mm，以及0.8mm、5mm和3mm。
我们的研究表明，与骨参考相比，使用肝脏轮廓时的位移较小，并且在横向、前后和头脚运动轴上与使用基准标记时获得的位移相当。这将证明在没有基准标记的情况下，肝脏轮廓勾画可作为患者治疗的指导。
