标题： 粒子诱导的瞬发伽马成像的新方法 显示英文标题

标题： New approaches to particle induced prompt gamma imaging

摘要： 质子在靶材中相互作用引起的瞬发伽马辐射的分布携带了关于质子射程和靶材组成的相关信息。 为了对瞬发伽马进行成像，我们提出了不同的方法。 第一种方法是利用刀刃准直器与紧凑型PET探测器相结合，通过测量由康普顿散射事件产生的瞬发伽马深度分布来验证质子射程。 第二种方法旨在通过在患者体内引入一种生物相容性标记物，从而明确识别感兴趣区域内是否存在质子，并测量该标记物的特征瞬发伽马与背景材料的对比。 第三种方法展示了一种新型的位置敏感伽马成像设计，具有毫米级可调的位置分辨率和高探测效率，这是向三维瞬发伽马成像迈出的一步，有助于更好地理解靶材组成。 使用GATE/Geant4蒙特卡罗框架对这些设计进行了模拟。 在INER和长庚纪念医院的质子设施上对标记物进行了实验测试。 使用刀刃PET方法，在肿瘤区域附近1 cm范围内的位移可以实现0.7 mm的射程验证，而在4 cm窗口内的位移可以达到4 mm。 对于标记物方法，我们确定984 keV为占主导地位的瞬发伽马，并显示在50%相对PG强度下，R80位置位于3 mm厚的48Ti标记物内。 使用位置敏感伽马成像方法，我们提出了一种可行的设计，在6.1 MeV下实现2.6 mm的空间分辨率和5.4E-6的探测效率，并且在一次运行中最多可实现八个深度位置。 讨论了这些方法的相对优势以及实施中的挑战。 显示英文摘要

摘要： The distribution of the prompt gamma emissions induced by proton interactions in a target material carries information concerning the proton range and target composition. In order to image prompt gamma we present different approaches. The first approach is based on knife-edge collimator utilized in tandem with a compact PET type detector in order to verify proton range by measuring the depth distribution of prompt gamma relying on Compton scattered events. A second approach aims at unambiguously identifying the presence of protons in a region of interest by introducing a bio-compatible fiducial marker in the patient and measuring the characteristic prompt gamma of the marker against background material. A third approach illustrates a novel design for position sensitive gamma imaging with a millimeter level adjustable position resolution with a high detection efficiency which is a step towards 3D prompt gamma imaging, useful to better understand the target composition. Simulations of the designs were performed using GATE/Geant4 Monte Carlo framework. Experimental tests on fiducial marker were conducted at the proton facilities in INER and Chang Gung Memorial hospital. Using the knife-edge PET approach a range verification of 0.7 mm can be achieved for shifts within 1 cm near the tumor region and up to 4 mm for shifts within a 4 cm window. For the fiducial marker approach we identify 984 keV as the dominant prompt gamma and show that for the 50% relative PG intensity, the R80 position falls within a 3 mm thick 48Ti marker. Using the position sensitive gamma imaging approach we present a feasible design to achieve spatial resolution values of 2.6 mm with a detection efficiency of 5.4E-6 at 6.1 MeV and up to eight depth positions in a single run. The relative advantage of these methods and the challenges in the implementation are discussed.