MAGNETIC RESONANCE GUIDED ENHANCED RADIOTHERAPY

磁共振引导增强放射治疗

基本信息

批准号：
6394697
负责人：
BRUCE E HAMMER
金额：
$ 11.14万
依托单位：
UNIVERSITY OF MINNESOTA
依托单位国家：
美国
项目类别：
财政年份：
2000
资助国家：
美国
起止时间：
2000-09-30 至 2004-06-30
项目状态：
已结题

项目摘要

The proposed research will integrate a state-of-the-art linear accelerator with a 1.5 T MRI system to yield a first generation diagnostic-therapeutic modality. Combining a magnetic resonance scanner with a radiation therapy unit yields a synergy and forms the foundation for Magnetic Resonance Guided Enhanced Radiation Therapy (MR-GERT). MR-GERT has the capability of imaging a turr and surrounding tissue while simultaneously visualizing the path of an ionizing particulate radiation beam, e.g., electron, proton, heavy ion. The proposed research is highly innovative in that it will create a new methodology that combines radiation treatment with diagnostic imaging in the same physical space. The NMR relaxation properties of tissue will alter in the presence of an intense particulate ionizing radiation beam. This occurs for the following reasons: (1) ionizing radiation such as e-beams, p+beams, etc., generate charged particles in matter through which they pass. In aqueous systems, free radicals form during exposure to ionizing radiation. This creates susceptibility differences along the radiation path that will affect regional magnetic field homogeneity. T2 (i.e. apparent spin-spin relaxation due to magnetic field non-uniformity) should be affected and measurable; (2) Unpaired electrons from free radicals, especially the hydrated electron, interact with neighboring proton spins of water and will reduce T1 (spin- lattice) and T2 (spin-spin) relaxation times; (3) The electron beam will create a small pertubation of the local magnetic field resulting in a phase shift or loss of phase coherence of the NMR signal. Visualization of a radiation beam during radiation treatment should be possible by obtaining T1, T2 and T2* weighted MR images. This allows accurate determination of radiation dose to tumor and healthy tissue in-situ. No modality exists that can do this. Real time imaging of the radiation field opens the way to dynamic tumor targeting in regions of the body where organ displacement is a problem.

拟议的研究将将最先进的线性加速器与1.5 T MRI系统整合在一起，以产生第一代诊断性治疗方式。将磁共振扫描仪与放射治疗单元相结合可产生协同作用，并为引导增强的辐射疗法（MR-GERT）构成基础。 MR-GERT具有成像turr和周围组织的能力，同时可视化电离颗粒辐射束的路径，例如电子，质子，重离子。拟议的研究具有很高的创新性，因为它将创建一种新方法，将辐射处理与在同一物理空间中的诊断成像结合在一起。组织的NMR弛豫特性将在存在强烈的颗粒电离辐射束的情况下改变。出于以下原因而发生这种情况：（1）电离辐射（例如电子束，p+梁等）在它们通过的物质中产生带电的颗粒。在水性系统中，在暴露于电离辐射期间形成自由基。这会沿着辐射路径产生敏感性差异，这将影响区域磁场同质性。 T2（即由于磁场不均匀而引起的明显的自旋旋转松弛）应受到影响和可测量；（2）来自自由基的未配对电子，尤其是水合电子，与相邻的水自旋相互作用，并将减少T1（Spin-Lattice）和T2（Spin-Spin）松弛时间；（3）电子束将产生对局部磁场的小渗透，从而导致NMR信号的相位移位或相干性丧失。通过获得T1，T2和T2*加权MR图像，应在辐射处理过程中的辐射束可视化。这允许准确确定对肿瘤和健康组织的辐射剂量。不存在可以做到这一点的方式。辐射场的实时成像为在器官位移是一个问题的身体区域的动态肿瘤靶向开辟了道路。