重离子治癌在束 TOF-PET全数字化电子学系统关键技术研究

In-Beam TOF-PET (Time of Flight Positron Emission Tomography) as the only noninvasive method for monitoring of beam position and irradiation dose in heavy ion tumor therapy, it can solve the problem of monitoring the distribution of irradiation dose and the position of heavy ion beam with the imaging methods in the treatment of the heavy ion tumor radiotherapy. However, the electronic system for In-Beam TOF-PET needs to be explored urgently. With the development of beam image monitoring technology, this project is focus on designing an all-digital electronic system used for the In-Beam TOF-PET, and also studying corresponding key technologies. The pulse digitization technology based on the switched capacitor array is adopted. Meanwhile, The FPGA will be used to realize digital signal processing algorithms such as TDC (Time-to-Digital Converter) and coincidence algorithm, etc., which can replace many complicated traditional analog circuits. The electronic system will meet the requirements of In-Beam TOF-PET with high performance, such as high count rate, high time resolution and high precision of particle energy measurement. It also can greatly ease the system data transmission pressure, simplify software design, and improve real-time response. . This project is significant in methodology. The new techniques and methods with the project research are important and meaningful for tracking international frontier and developing new medical nuclear electronics and data acquisition devices. The research results can promote the localization of key devices for tumor radiotherapy, there are application requirements for that not only in heavy ion therapy, but also there are wide application value and prospect in other particle beam radiation therapy system.

在束TOF-PET作为唯一非侵入性检测的方法，可以解决重离子治瘤时对入射束流定位及剂量的快速、准确影像监测的难题。而与之配套的新型读出电子学系统亟待深入研究。本项目依托在束影像监测技术的发展，拟开展在束TOF-PET全数字化电子学系统的设计和关键技术研究；采用基于开关电容阵列的脉冲数字化技术，并在FPGA中实现时间测量和实时符合判选等数字信号处理算法取代大量传统电路的技术路线；解决在束TOF-PET探测器系统高计数率、高时间分辨率和高精度粒子能量测量的问题，同时将极大地缓解整个系统数据带宽压力，简化软件设计，提高实时性。 .本课题具有方法学上的研究意义，其涉及的技术与方法对跟踪国际前沿和发展高性能医用核电子学、数据获取技术有着十分重要的意义。其研究成果可以促进肿瘤放射治疗关键设备的国产化，它不仅在重离子治癌装置中有着重要的应用需求，而且在其它粒子束放射治疗系统中也有广泛的应用价值和前景。

在束TOF-PET作为唯一非侵入性检测的方法，可以解决重离子治瘤时对入射束流定位及剂量的快速、准确影像监测的难题。本项目依托在束影像监测技术的发展，开展在束TOF-PET全数字化电子学系统的设计和关键技术研究，成功研制了一套全数字化电子学系统，包括脉冲数字化电路、符合处理电路、时钟同步电路和获取软件。主要完成以下研究内容：1）基于开关电容阵列芯片和自研滤波成型芯片分别研制脉冲数字化电路实现单光子事件测量，研究基于FPGA延迟链TDC时间测量，并在FPGA对时间、能量和位置信息进行实时处理；2）研制符合处理电路，开发了基于全数字化信息的TOF PET信息处理框架，研究了基于时间戳的实时符合判选算法和高速数据传输方法，使得系统事件率达到1000000 events/s；3）研制时钟同步电路，解决系统的高精度、低抖动的系统时钟和同步问题；4）TOF-PET样机系统进行联调，并在国产碳离子治疗装置终端进行束流验证测试。通过项目的研究，建立一整套全数字化信息实时处理方法，为实现重离子治癌时入射束流定位及剂量分布的实时、快速、准确的影像监测技术积累经验和奠定基础。其研究成果可以促进肿瘤放射治疗关键设备的国产化，它不仅在重离子治癌装置中有着重要的应用需求，而且在其它粒子束放射治疗系统中也有广泛的应用价值和前景。在本项目的研究资助下，共发表学术论文11篇，获得授权发明专利5项；培养博士学位研究生3名，硕士学位研究生3名；参加国内外学术交流会议4次。