Rogé Maximilien, Henni Ahmed Hadj, Neggaz Yasmine Adda, Mallet Romain, Hanzen Chantal, Dubray Bernard, Colard Elyse, Gensanne David, Thureau Sébastien
Départment of Radiation Oncology, Centre Henri Becquerel, Rouen, France.
QuantIF-LITIS EA4108, University of Rouen, Rouen, France.
Front Oncol. 2022 May 12;12:827195. doi: 10.3389/fonc.2022.827195. eCollection 2022.
Stereotactic body radiotherapy (SBRT) is a treatment option for spine metastases. The International Spine Radiosurgery Consortium (ISRC) has published consensus guidelines for target delineation in spine SBRT. A new software called Elements™ Spine SRS by Brainlab that includes the module Elements SmartBrush Spine (v3.0, Munich, Germany) has been developed specifically for SBRT treatment of spine metastases, and the latter provides the ability to perform semiautomatic clinical target volume (CTV) generation based on gross tumor volume (GTV) localization and guidelines. The aims of our study were to evaluate this software by studying differences in volumes between semiautomatic CTV contours compared to manual contouring performed by an expert radiation oncologist and to determine the dosimetric impact of these differences on treatment plans.
A total of 35 volumes ("Expert GTV" and "Expert CTV") from 30 patients were defined by a single expert. A semiautomatic definition of these 35 CTVs based on the location of "Expert GTV" and following ISRC guidelines was also performed in Elements SmartBrush Spine ("Brainlab CTV"). The spatial overlap between "Brainlab" and "Expert" CTVs was calculated using the Dice similarity coefficient (DSC). We considered a threshold of 0.80 or above to indicate that Elements SmartBrush Spine performed very well with adequate contours for clinical use. Two dosimetric treatment plans, each corresponding to a specific planning target volume (PTV; Expert PTV, Brainlab PTV), were created for 11 patients.
We showed that "Brainlab CTV" and "Expert CTV" mean volumes were 29.8 ± 16.1 and 28.7 ± 15.7 cm, respectively (p = 0.23). We also showed that the mean DSC for semiautomatic contouring relative to expert manual contouring was 0.85 ± 0.08 and less than 0.80 in five cases. For metastases involving the vertebral body only (n = 13,37%), the mean DSC was 0.90 ± 0.03, and for ones involving other or several vertebral regions (n = 22.63%), the mean DSC was 0.81 ± 0.08 (p < 0.001). The comparison of dosimetric treatment plans was performed for equivalent PTV coverage. There were no differences between doses received by organs at risk (spinal cord and esophagus) for Expert and Brainlab PTVs, respectively.
The results showed that the semiautomatic method had quite good accuracy and can be used in clinical routine even for complex lesions.
立体定向体部放疗（SBRT）是脊柱转移瘤的一种治疗选择。国际脊柱放射外科联盟（ISRC）已发布脊柱SBRT靶区勾画的共识指南。Brainlab公司开发了一款名为Elements™ Spine SRS的新软件，其中包括Elements SmartBrush Spine模块（版本3.0，德国慕尼黑），该软件专门用于脊柱转移瘤的SBRT治疗，后者能够根据大体肿瘤体积（GTV）定位和指南半自动生成临床靶区体积（CTV）。我们研究的目的是通过比较半自动CTV轮廓与放射肿瘤学专家手动勾画轮廓之间的体积差异来评估该软件，并确定这些差异对治疗计划的剂量学影响。
由一位专家确定了30例患者的35个体积（“专家GTV”和“专家CTV”）。还在Elements SmartBrush Spine（“Brainlab CTV”）中基于“专家GTV”的位置并遵循ISRC指南对这35个CTV进行了半自动定义。使用Dice相似系数（DSC）计算“Brainlab”和“专家”CTV之间的空间重叠。我们将0.80或更高的阈值视为表明Elements SmartBrush Spine表现良好，轮廓足以用于临床。为11例患者创建了两个剂量学治疗计划，每个计划对应一个特定的计划靶区体积（PTV；专家PTV，Brainlab PTV）。
我们发现“Brainlab CTV”和“专家CTV”的平均体积分别为29.8±16.1和28.7±15.7 cm³（p = 0.23）。我们还发现半自动轮廓相对于专家手动轮廓的平均DSC为0.85±0.08，有5例低于0.80。对于仅累及椎体的转移瘤（n = 13,37%），平均DSC为0.90±0.03，对于累及其他或多个椎体区域的转移瘤（n = 22,63%），平均DSC为0.81±0.08（p < 0.001）。对剂量学治疗计划进行了等效PTV覆盖的比较。专家PTV和Brainlab PTV分别对危及器官（脊髓和食管）的受量没有差异。
结果表明，半自动方法具有相当高的准确性，即使对于复杂病变也可用于临床常规。
