在低磁场磁共振线性加速器扫描仪中使用主动和被动植入物进行空间完整性的表征
Bertrand Pouymayou1, Yoel Perez-Haas1, Florin Allemann2
1Department of Radiation Oncology, University Hospital Zurich and University of Zurich, Zurich, Switzerland.
Physics and imaging in radiation oncology
|April 22, 2024
概括
金属植入物会导致低场MR-LINAC图像中的几何扭曲,在文物附近的距离高达3毫米. 超出20mm的空间完整性得到恢复,为植入物附近的放射治疗规划提供了信息.
科学领域:
- 医学物理 医学物理
- 放射治疗成像技术的成像技术
- 生物医学工程 生物医学工程
背景情况:
- 标准的磁共振 (MR) 成像协议确保了放射治疗的空间完整性.
- 无论是被动的还是活的金属植入物,都会显著扭曲MRI图像,从而影响放射治疗的计划.
- 低场0.35 T MR线性加速器 (LINAC) 越来越多地用于放射治疗规划.
研究的目的:
- 在低场MR-LINAC规划图像中描述金属植入物引起的几何扭曲.
- 量化被动和主动植入物对图像空间完整性的影响.
- 为改善在金属植入物附近的放射治疗计划提供数据.
主要方法:
- 一个具有1276个控制点的空间完整性幻影被设计和扫描在一个水箱里.
- 图像使用临床平衡稳定状态自由前行序列 (1.5x1.5x1.5毫米分辨率) 在0.35 T MR-LINAC.上获得.
- 幻影被扫描,并没有各种部/肩部关节整形植入物和活性心脏刺激器.
- 通过测量检测到和理论控制点之间的欧几里德距离来评估空间完整性.
- 定义了第一个没有工件的平面 (FPFA),以评估超越带状工件的完整性.
主要成果:
- 被动和活跃的植入物分别引起了高达2毫米和3毫米的扭曲,距离主要带纹器件的20毫米以内.
- 超出20毫米的带纹文物,图像的空间完整性得到恢复.
- 观察到的扭曲对于精确的放射治疗规划具有重要意义.
结论:
- 描述了常见金属植入物对低场MR-LINAC规划序列的影响.
- 测量支持在风险器官轮时创建额外的边缘,并在植入物附近目标体积.
- 这项研究为提高金属植入物患者放射治疗的安全性和准确性提供了关键信息.
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