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（RT）的目标是向肿瘤提供辐射剂量，同时尽量减少暴露于敏感危险器官（OARs），如肺、心脏和食道。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，很多时候肿瘤是由于患者的呼吸而移动的。由于运动引起的患者解剖结构的变化可以在时间尺度上发生，从几秒钟（分数内）到几天甚至几周（分数间）。碳离子治疗的益处受到分数间解剖变化和分数内运动的挑战。在移动性肺肿瘤的治疗中，由于肿瘤运动和范围不确定性的影响，粒子治疗的益处显著降低，增加了对桨叶的辐射剂量。我们建议开发一种氦成像肿瘤扫描仪（HELIOS），以促进范围引导放疗（RGRT），以减少碳离子治疗非小细胞肺癌（NSCLC）的毒性，通过体内监测给药剂量的移动肿瘤。RGRT方法是基于混合氦离子的碳束，导致氦离子在每个核子相同能量下的射程更远而离开患者。排出的氦离子将允许在体内实时监测患者体内的碳布拉格峰，精度为2mm，减少健康组织的辐照量。这将减少病人的毒性，并允许改善肿瘤控制。为了开发HELIOS，我们申请资助检测器组件和研究人员，以实现在临床研究环境中使用HELIOS的硬件和软件。一位更有经验的博士后研究员将在海德堡离子治疗中心（HIT）通过构建合适的肺模体和相应的测量来解决HELIOS原型的调试和验证问题。在这里，该项目可以依赖于对氦/碳混合的大量初步研究工作。博士生将同时开发RGRT治疗计划和HELIOS图像处理所需的算法。这包括对4D成像数据的剂量和范围x线片的蒙特卡罗模拟以及不确定性估计。博士生可以依靠由DKFZ开发并在哈工大验证的开源研究治疗计划工具包matRad，作为软件开发和进一步研究使用的强大支柱。项目的最后阶段将整合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，与剂量计划模拟和范围测量相关联，以制定使用HELIOS的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.