HELIOS – Developing a HELium Imaging Oncology Scanner for Range Guided Radiotherapy (RGRT) for Non-Small Cell Lung Carcinoma (NSCLC)

肺癌放射治疗的目标是在最大限度减少肺、心脏和食道等敏感器官暴露的同时，向肿瘤提供辐射剂量。因此，治疗一直是肿瘤控制和器官毒性之间的权衡。然而，在肺部，肿瘤很多时候是由于病人的呼吸而移动的。由于运动引起的患者解剖结构的变化可以发生在从几秒(分数内)到几天甚至几周(分数间隔)的时间尺度上。碳离子治疗的益处受到部分间解剖变化和部分内运动的挑战。在运动肺肿瘤的治疗中，由于肿瘤运动和范围不确定性的影响，增加了对桨的辐射剂量，粒子治疗的好处大大减少。我们建议开发一种氦成像肿瘤学扫描仪(HELIOS)来促进射程引导放射治疗(RGRT)，以减少非小细胞肺癌(NSCLC)碳离子治疗的毒性，方法是体内监测移动的肿瘤的剂量。RGRT方法是基于碳束与混合的氦离子，导致氦离子离开患者，因为他们的距离更远，每个核子的能量相同。出射的氦离子将允许在体内以2 mm的精度实时监测患者体内的碳布拉格峰，从而减少受到辐射的健康组织的数量。这将降低患者的毒性，并允许改善肿瘤控制。为了开发HELIOS，我们申请资金购买探测器部件和研究人员，以实现在临床研究环境中使用HELIOS的硬件和软件。一名更有经验的博士后研究人员将在海德堡离子治疗中心(HIT)通过构建合适的肺模型和相应的测量来处理HELIOS原型的委托和验证。在这里，该项目可以依靠大量的前期工作来研究氦/碳的混合。一名博士生将同时为HELIOS开发RGRT治疗计划和图像处理所需的算法。这包括对4D成像数据上的剂量和射程射线照片进行蒙特卡洛模拟以及不确定性估计。博士生可以依靠DKFZ开发并在HIT验证的开源研究治疗计划工具包matRad，该工具包为软件开发和进一步在研究中的使用提供了强大的支柱。该项目的最后阶段将汇集HELIOS硬件和软件，为即将到来的基础和临床研究项目和应用场景铺平道路。重点将放在进一步将在线室内数据，特别是表面图像与剂量规划模拟和射程测量相关联，以制定使用HELIOS进行RGRT的研究方案和临床决策标准。

The goal of radiotherapy (RT) for lung cancer is to deliver radiation dose to the tumor while minimizing exposure of sensitive organs at risk (OARs) such as lung, heart and esophagus. Treatment has, therefore, always been a trade-off between tumor control and organ toxicity. However, in the lung many times the tumors are moving due to patient breathing. Changes in patient anatomy due to motion can occur at time scales ranging from seconds (intrafractional) to days or even several weeks (interfractional). The benefit of carbon ion therapy is challenged by both interfractional anatomical changes and intrafractional motion. In the treatment of moving lung tumors, the benefit of particle therapy is significantly reduced due to the impact of tumor motion and range uncertainties increasing the radiation dose to the OARs. We propose to develop an Helium Imaging Oncology Scanner (HELIOS) to facilitate range guided radiotherapy (RGRT) to reduce toxicity in carbon ion therapy of non-small cell lung carcinoma (NSCLC), by in-vivo monitoring of the delivered dose to a moving tumor. The RGRT approach is based on a carbon beam with mixed-in helium ions, resulting in helium ions exiting the patient due to their longer range at same energy per nucleon. The exiting helium ions will allow for in-vivo and real-time monitoring of the carbon Bragg peak within the patient with 2mm accuracy, reducing the amount of healthy tissue that is irradiated. This will reduce patient toxicity and allow for improved tumor control.To develop HELIOS, we apply for funding for detector components and research personnel to implement hardware & software for the use of HELIOS in a clinical research environment. A more experienced postdoctoral researcher will tackle the commissioning and validation of the HELIOS prototype at the Heidelberg Ion Therapy Center (HIT) through construction of an appropriate lung phantom and corresponding measurements. Here, the project can rely on substantial preliminary work investigating helium/carbon mixing. A PhD student will concurrently develop the algorithms necessary for RGRT treatment planning and image processing for HELIOS. This includes Monte Carlo simulation of dose and range radiographs on 4D imaging data as well as uncertainty estimates. The PhD student can rely on the open-source research treatment planning toolkit matRad developed at DKFZ and validated at HIT, which serves as powerful backbone for the software development and further use in research.The final phase of the project will bring together both HELIOS hardware and software to pave the way for upcoming basic and clinical research projects and application scenarios. Focus will lie on correlating further online in-room data, in particular surface images, to the dose planning simulations and range measurements to develop research protocols and clinical decision criteria for RGRT with HELIOS.