Development of magnetic resonance image guided radiotherapy

放射治疗（RT）仍然是原发性和转移性癌症的有效治疗方法。现代治疗在图像引导下提供辐射。这使得能够更好地控制剂量放置，允许对肿瘤的剂量递增，同时减少附近有风险器官的副作用。目前的护理标准是一组计划扫描，然后是几周的RT。在放射肿瘤学中，磁共振成像（MRI）用于获得软组织的精细非侵入性图像。然而，计划和治疗之间的基本不确定性、治疗过程中的运动以及几周内肿瘤大小的不可避免的变化最终限制了RT的精确度和准确性。正常组织的潜在过度治疗或肿瘤剂量不足是可能的，这可能会损害患者的生活质量和生存期。该提案描述了一个广泛的研究计划，我们将开发新的MRI技术，以指导和适应RT交付。我们的目标是使用最近开发的称为MRI-LINAC的先进图像引导RT平台来实现这一目标，该平台将外部束线性加速器与诊断1.5T MRI扫描仪集成在一起。这两种技术的结合是协同作用的：治疗期间的成像（称为“光束”）可以实现自适应肿瘤跟踪，治疗和成像功能的能力使医生能够快速评估对治疗的反应。我们的短期目标是：（1）开发用于自适应RT的实时射束成像，（2）优化仅MR治疗模拟，（3）推进基于MR的体内剂量测定，以及（4）整合分子成像用于治疗反应监测。这些流的组合旨在提高MRI在放射肿瘤学中的价值，在规划，交付和反应评估的不同领域。从长远来看，可视化肿瘤及其反应的能力将彻底改变RT在临床上的使用方式，但使其成为现实的技术进步尚未得到发展。这项工作的目的是开发的基础技术，在MR引导RT最终的临床应用。这些技术涵盖了从脉冲序列到硬件的整个MR技术范围，预计不仅在肿瘤学领域，而且在诊断和介入放射学领域都将产生广泛的影响。我们还预计我们计划的硬件开发方面将产生巨大的商业潜力。**

Radiotherapy (RT) remains an effective treatment for both primary and metastatic cancers. Modern treatments deliver radiation under image guidance. This enables better control on dose placement, allowing dose escalation to tumours whilst reducing side effects in nearby organs at risk. The current standard of care is a single set of planning scans, followed by several weeks of RT.***In radiation oncology, magnetic resonance imaging (MRI) is used to obtain exquisite non-invasive images of soft tissues. However, fundamental uncertainties inaccuracies between planning and treatment, motion during the treatment itself, and inevitable changes in tumour size over several weeks ultimately limit RT precision and accuracy. Potential overtreatment of normal tissue or under-dosing of tumour are possible, which can harm patient quality of life and survival.***This proposal describes a broad research program in which we will develop the novel MRI technologies necessary to guide and adapt RT delivery. We aim to do this using a recently developed advanced image-guided RT platform called the MRI-LINAC, which integrates an external beam linear accelerator with a diagnostic 1.5T MRI scanner. The combination of these two technologies is synergistic: imaging during treatment (referred to as “beam-on”) enables adaptive tumour tracking, and the ability to treat and then image function allows the doctor to quickly assess response to treatment.***Our short term objectives are (1) development of real-time beam-on imaging for adaptive RT, (2) optimization of MR-only treatment simulation, (3) advances for in vivo, MR-based dosimetry, and (4) integration of molecular imaging for treatment response monitoring. The combination of these streams aims to improve the value of MRI in radiation oncology, in the diverse areas of planning, delivery, and response assessment. In the long run, the ability to visualize tumours and their response will revolutionize the way in which RT is clinically used, but the technical advances to make this a reality have not yet been developed.***The aim of this work is to develop the fundamental techniques in MR-guided RT which underlie eventual clinical applications. These techniques span the entire range of MR technology from pulse sequences to hardware, and are anticipated to have wide-ranging implications not only within oncology, but also within both diagnostic as well as interventional radiology. We also anticipate significant commercial potential arising from hardware development aspects of our program.**