Careggi University Hospital, Medical Physic Unit, Florence, Italy.
Elekta AB, Stockholm, Sweden.
J Appl Clin Med Phys. 2020 Jun;21(6):114-120. doi: 10.1002/acm2.12872. Epub 2020 Apr 10.
To develop and validate a robust template for VMAT SBRT of lung lesions, using the multicriterial optimization (MCO) of a commercial treatment planning system.
The template was established and refined on 10 lung SBRT patients planned for 55 Gy/5 fr. To improve gradient and conformity a ring structure around the planning target volume (PTV) was set in the list of objectives. Ideal fluence optimization was conducted giving priority to organs at risk (OARs) and using the MCO, which further pushes OARs doses. Segmentation was conducted giving priority to PTV coverage. Two different templates were produced with different degrees of modulation, by setting the Fluence Smoothing parameter to Medium (MFS) and High (HFS). Each template was applied on 20 further patients. Automatic and manual plans were compared in terms of dosimetric parameters, delivery time, and complexity. Statistical significance of differences was evaluated using paired two-sided Wilcoxon signed-rank test.
No statistically significant differences in PTV coverage and maximum dose were observed, while an improvement was observed in gradient and conformity. A general improvement in dose to OARs was seen, which resulted to be significant for chest wall V , total lung V , and spinal cord D . MFS plans are characterized by a higher modulation and longer delivery time than manual plans. HFS plans have a modulation and a delivery time comparable to manual plans, but still present an advantage in terms of gradient.
The automation of the planning process for lung SBRT using robust templates and MCO was demonstrated to be feasible and more efficient.
使用商业治疗计划系统的多标准优化（MCO），开发和验证用于肺部病变 VMAT-SBRT 的稳健模板。
该模板是在 10 名计划接受 55Gy/5 次分割的肺部 SBRT 患者中建立和完善的。为了提高梯度和适形性，在计划靶区（PTV）列表中设置了一个围绕 PTV 的环形结构。进行了理想的通量优化，优先考虑危及器官（OARs），并使用 MCO，这进一步推高了 OARs 剂量。分割优先考虑 PTV 覆盖。通过将通量平滑参数设置为中（MFS）和高（HFS），生成了两个具有不同调制程度的不同模板。每个模板都应用于另外 20 名患者。在剂量学参数、治疗时间和复杂性方面比较了自动和手动计划。使用配对双边 Wilcoxon 符号秩检验评估差异的统计学意义。
在 PTV 覆盖和最大剂量方面没有观察到统计学上的显著差异，而在梯度和适形性方面观察到了改善。OARs 的剂量普遍改善，结果对于胸壁 V、全肺 V 和脊髓 D 具有统计学意义。MFS 计划的调制程度更高，治疗时间比手动计划长。HFS 计划的调制和治疗时间与手动计划相当，但在梯度方面仍具有优势。
使用稳健模板和 MCO 自动化肺部 SBRT 的规划过程是可行且更高效的。
