发表机构
National Centre for Nuclear Research; INSA-Lyon; Université Claude Bernard Lyon 1; CNRS; Inserm; IT:U Interdisciplinary Transformation University; University of Vienna（国家核研究中心; 里昂国立应用科学学院; 里昂第一大学（克洛德·贝尔纳大学）; 法国国家科学研究中心; 法国国家健康与医学研究院; IT:U跨学科转型大学; 维也纳大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
该研究提出TRIO算法，构建三光子事件的贝叶斯图像重建框架，基于QED先验，兼容标准放射性核素，模拟显示定位误差优于传统方法，可适配现有TOF-PET扫描仪。
AI 中文摘要
PET（正电子发射断层成像）依靠正电子-电子湮灭产生的双光子符合来提供功能图像。在人体组织中，约40%的湮灭过程会先形成正电子素（Ps），其中正电子素的正交态（o-Ps）部分衰变为三个光子，其余则通过拾取或自旋交换过程以双光子形式湮灭。这一三光子通道携带了周围微环境的额外信息，其中三光子与双光子的产额比可作为潜在的诊断标志物。我们提出了TRIO算法，这是一种新型的逐事件三光子图像重建算法，被构建为贝叶斯最大后验概率推断问题。TRIO在单一概率框架内统一了基于时间的三边定位、基于能量的重建，以及首次从正电子素衰变的量子电动力学（QED）描述中推导得出的物理信息先验。与需要 prompt 光子、因此仅适用于特定放射性核素的正电子素寿命成像不同，TRIO仅依赖三个光子，完全兼容如18F这类标准放射性核素。以西门子Biograph Quadra扫描仪为原型的蒙特卡罗模拟显示，其平均位置误差为1.62厘米，相比基于时间的三边定位（3.05厘米）误差约减半，相比仅基于能量的重建（18厘米）误差约降低一个数量级。更重要的是，所提出的贝叶斯方法兼容现有可记录三光子湮灭符合的TOF-PET扫描仪。
英文摘要
PET provides functional images relying on two-photon coincidences from positron-electron annihilation. In human tissue, about 40\% of annihilations are preceded by Ps formation, of which o-Ps component partially decays into three photons, with the remainder annihilating via pick-off or spin-exchange into two photons. This three-photon channel carries additional information about the surrounding micro-environment, including the three-to-two-photon yield ratio as a potential diagnostic marker. We propose the TRIO algorithm, a novel three-photon event-by-event image reconstruction algorithm formulated as a Bayesian maximum a posteriori inference problem. TRIO unifies time-based trilateration, energy-based reconstruction and, for the first time, a physics-informed prior derived from the QED description of Ps decay within a single probabilistic framework. In contrast to positronium lifetime imaging, which requires a prompt photon and is therefore restricted to specific radionuclides, TRIO relies solely on the three photons and is fully compatible with standard radionuclides such as 18F. Monte Carlo simulation modelled after the Siemens Biograph Quadra scanner demonstrates a mean position error of 1.62~cm, improving by approximately a factor of two over the time-based trilateration (3.05 cm) and by about an order of magnitude over energy-based reconstruction alone (18 cm). More importantly, the proposed Bayesian approach is compatible with existing TOF-PET scanners that can register three-photon annihilation coincidences.
Comments17 pages, 4 figures
