基于MRI的非小细胞肺癌多维放疗技术

Respiration and tumor heterogeneity are the important factors to affect the outcome of non-small cell lung cancer (NSCLC) treated with radiotherapy. To overcome the problems, firstly, we intend to improve the respiratory signal recording system to search skin motion law through multiple points with stereo vision. To utilize the non-ionizing characteristics of MR, the four dimensional MR (4D MR) acquisition method will be developed and the personal motion relationship model of respiration and lung cancer be established. 4D radiotherapy planning optimization algorithm based on probabilistic model of different respiratory state distribution will be studied. Secondly, MR imaging automatic segment and deformation registration algorithms, and MRI-based individual lung cancer motion analysis technology would be established. According to the personal model, MLC-based real-time tracking strategy combining with the probabilistic model-based 4D radiotherapy planning, the gated radiotherapy and real-time tracking radiation technique will be found. Finally, to fully use the functional MR information, the relationship between the characteristics (parameters) of functional MR imaging, biological markers and radio-sensitivity will be studied. To combine precise radiotherapy and functional MR imaging, the CT-MR-functional MR fusion method will be optimized. The multiple dimensional radiotherapy technique will ultimately fulfilled integrating 4D and MRI functional imaging for NSCLC.

吸运动和肿瘤异质性是影响非小细胞肺癌放疗疗效的重要因素。为此，拟完善立体视觉技术提取体表多点运动规律的呼吸信号提取系统，发挥MR无电离辐射特点，开发基于呼吸状态的4DMR获取方法，建立呼吸信号与肺肿瘤之间的个体化运动关系模型；统计不同呼吸状态的概率分布，研究基于概率模型的4D放疗计划。其次，开发MRI自动勾画和形变配准算法，建立基于MRI的肺癌个体化运动分析技术；根据个体化运动关系模型，探索基于电动MLC的实时跟踪策略，结合基于概率模型的4D放疗计划，建立门控放疗和实时跟踪放疗技术。最后，充分挖掘MR功能影像信息，研究其影像特征、参数及相关生物学指标与放疗敏感性之间的关系，探索相关的机制。开发CT、MR影像与MR功能影像的融合技术，使MR功能影像与精确放疗技术有机融合。最终实现运动控制与MR功能影像相结合的非小细胞肺癌多维放疗技术。

呼吸运动和肿瘤异质性是影响非小细胞肺癌放疗疗效的重要因素。本项目优化了呼吸引导模式，建立呼吸信号提取系统。在已经建立的基于CT的呼吸信号提取系统的基础上，建立体表三点定位和快速MR序列扫描相结合的多信号提取技术，建立呼吸信号模型，使之可以应用于多种设备。建立皮肤表面与肺部肿瘤之间的个体化运动关系模型。在MR快速扫描的同时采集呼吸信号，利用同一时刻采集的多标记点回顾性的建立呼吸信号状态，建立呼吸状态的概率分布模型，实现对异常呼吸状态的优化处理。建立基于4D MR的呼吸运动控制技术平台。建立器官边界自动提取和靶区自动勾画技术，优化筛选不同的形变配准算法，实现4DMRI数据的高效处理。应用MRI功能影像与呼吸运动控制技术平台相结合，开发MRI功能影像与4DMR影像融合技术。研究灌注影像与肿瘤血管形成、微血管密度、乏氧及放射敏感性之间的关系；研究了扩散加权成像在预测放疗敏感性和疗效之间的能力。