Advanced Radiation Oncology Department, Sacro Cuore Don Calabria Hospital, IRCCS Ospedale Sacro Cuore Don Calabria, Via Don A.Sempreboni 5, 37124, Negrar Di Valpolicella, VR, Italy.
University of Brescia, Brescia, Italy.
Radiat Oncol. 2021 Oct 9;16(1):197. doi: 10.1186/s13014-021-01924-0.
Approximately one third of cancer patients will develop spinal metastases, that can be associated with back pain, neurological symptoms and deterioration in performance status. Stereotactic radiosurgery (SRS) and stereotactic body radiotherapy (SBRT) have been offered in clinical practice mainly for the management of oligometastatic and oligoprogressive patients, allowing the prescription of high total dose delivered in one or few sessions to small target volumes, minimizing the dose exposure of normal tissues. Due to the high delivered doses and the proximity of critical organs at risk (OAR) such as the spinal cord, the correct definition of the treatment volume becomes even more important in SBRT treatment, thus making it necessary to standardize the method of target definition and contouring, through the adoption of specific guidelines and specific automatic contouring tools. An automatic target contouring system for spine SBRT is useful to reduce inter-observer differences in target definition. In this study, an automatic contouring tool was evaluated.
Simulation CT scans and MRI data of 20 patients with spinal metastases were evaluated. To evaluate the advantage of the automatic target contouring tool (Elements SmartBrush Spine), which uses the identification of different densities within the target vertebra, we evaluated the agreement of the contours of 20 spinal target (2 cervical, 9 dorsal and 9 lumbar column), outlined by three independent observers using the automatic tool compared to the contours obtained manually, and measured by DICE similarity coefficient.
The agreement of GTV contours outlined by independent operators was superior with the use of the automatic contour tool compared to manually outlined contours (mean DICE coefficient 0.75 vs 0.57, p = 0.048).
The dedicated contouring tool allows greater precision and reduction of inter-observer differences in the delineation of the target in SBRT spines. Thus, the evaluated system could be useful in the setting of spinal SBRT to reduce uncertainties of contouring increasing the level of precision on target delivered doses.
约三分之一的癌症患者会发生脊柱转移，可伴有背痛、神经症状和功能状态恶化。立体定向放射外科（SRS）和立体定向体部放射治疗（SBRT）已在临床实践中主要用于治疗寡转移和寡进展患者，允许在一个或少数几个疗程内对小靶区给予高总剂量，使正常组织的剂量暴露最小化。由于高剂量的应用以及脊髓等关键危及器官（OAR）的接近，在 SBRT 治疗中，靶区定义的准确性变得更加重要，因此有必要通过采用特定的指南和特定的自动勾画工具来标准化靶区定义和勾画方法。脊柱 SBRT 的自动靶区勾画系统有助于减少靶区定义的观察者间差异。在这项研究中，评估了一种自动勾画工具。
评估了 20 例脊柱转移患者的模拟 CT 扫描和 MRI 数据。为了评估自动靶区勾画工具（Elements SmartBrush Spine）的优势，该工具利用目标椎体内不同密度的识别，我们评估了三位独立观察者使用自动工具勾画的 20 个脊柱靶区（2 个颈椎、9 个胸椎和 9 个腰椎）轮廓与手动勾画轮廓的一致性，并通过 DICE 相似系数进行测量。
与手动勾画轮廓相比，使用自动勾画工具时，GTV 轮廓的一致性更好（平均 DICE 系数为 0.75 比 0.57，p=0.048）。
专用勾画工具可提高 SBRT 脊柱靶区勾画的精度，并减少观察者间差异。因此，在脊柱 SBRT 中，评估的系统有助于减少勾画不确定性，提高靶区剂量的精确度。
