Hepel Jaroslaw T, Evans Suzanne B, Hiatt Jessica R, Price Lori Lyn, DiPetrillo Thomas, Wazer David E, MacAusland Stephanie G
Department of Radiation Oncology, Tufts University, Tufts Medical Center, Boston, MA, USA.
Int J Radiat Oncol Biol Phys. 2009 Jun 1;74(2):458-63. doi: 10.1016/j.ijrobp.2008.08.051. Epub 2008 Dec 10.
To evaluate the accuracy of two clinical techniques for electron boost planning compared with computed tomography (CT)-based planning. Additionally, we evaluated the tumor bed characteristics at whole breast planning and boost planning.
A total of 30 women underwent tumor bed boost planning within 2 weeks of completing whole breast radiotherapy using three planning techniques: scar-based planning, palpation/clinical-based planning, and CT-based planning. The plans were analyzed for dosimetric coverage of the CT-delineated tumor bed. The cavity visualization score was used to define the CT-delineated tumor bed as well or poorly defined.
Scar-based planning resulted in inferior tumor bed coverage compared with CT-based planning, with the minimal dose received by 90% of the target volume >90% in 53% and a geographic miss in 53%. The results of palpation/clinical-based planning were significantly better: 87% and 10% for the minimal dose received by 90% of the target volume >90% and geographic miss, respectively. Of the 30 tumor beds, 16 were poorly defined by the cavity visualization score. Of these 16, 8 were well demarcated by the surgical clips. The evaluation of the 22 well-defined tumor beds revealed similar results. A comparison of the tumor bed volume from the initial planning CT scan to the boost planning CT scan revealed a decrease in size in 77% of cases. The mean decrease in volume was 52%.
The results of our study have shown that CT-based planning allows for optimal tumor bed coverage compared with clinical and scar-based approaches. However, in the setting of a poorly visualized cavity on CT without surgical clips, palpation/clinical-based planning can help delineate the appropriate target volumes and is superior to scar-based planning. CT simulation at boost planning could allow for a reduction in the boost volumes.
评估与基于计算机断层扫描（CT）的计划相比，两种用于电子束加量计划的临床技术的准确性。此外，我们评估了全乳计划和加量计划时瘤床的特征。
共有30名女性在完成全乳放疗后2周内，使用三种计划技术进行瘤床加量计划：基于瘢痕的计划、触诊/临床为基础的计划和基于CT的计划。分析这些计划对CT勾画的瘤床的剂量覆盖情况。使用腔可视化评分来定义CT勾画的瘤床界定良好或不佳。
与基于CT的计划相比，基于瘢痕的计划导致瘤床覆盖较差，90%的靶体积所接受的最小剂量>90%的情况占53%，且有53%存在几何遗漏。触诊/临床为基础的计划结果明显更好：90%的靶体积所接受的最小剂量>90%和几何遗漏的情况分别为87%和10%。在30个瘤床中，16个通过腔可视化评分界定不佳。在这16个中，8个通过手术夹清晰界定。对22个界定良好的瘤床的评估显示了相似的结果。对初始计划CT扫描到加量计划CT扫描的瘤床体积进行比较，发现77%的病例体积减小。体积平均减小52%。
我们的研究结果表明，与临床和基于瘢痕的方法相比，基于CT的计划能实现最佳的瘤床覆盖。然而，在CT上腔可视化不佳且没有手术夹的情况下，触诊/临床为基础的计划有助于勾画合适的靶体积，且优于基于瘢痕的计划。加量计划时的CT模拟可使加量体积减小。
