Positronium Lifetime Image Reconstruction for TOF PET.
Positronium Lifetime Image Reconstruction for TOF PET.
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DOI：
10.1109/tmi.2022.3174561
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发表时间：
2022-10
影响因子：
10.6
通讯作者：
中科院分区：
文献类型：
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正电子发射断层扫描（Positron emission tomography，PET）在临床和临床前应用中广泛使用。正电子素寿命携带正电子发射处组织微环境的相关信息，但由于两个技术挑战，此类信息一直未被获取。一个挑战是探测三重符合事件的灵敏度较低。随着轴向视野长（1 - 2米）的PET扫描仪的近期发展，这个问题已得到缓解。另一个挑战是现有方法所形成的正电子素寿命图像的空间分辨率较低，这是由现有PET扫描仪的飞行时间（TOF）分辨率（200 - 500皮秒）所决定的。本文通过开发一种新的图像重建方法解决了第二个挑战，该方法利用现有的飞行时间PET生成高分辨率的正电子素寿命图像。模拟研究表明，所提出的方法能够以比PET扫描仪飞行时间分辨率所设定的极限好得多的空间分辨率重建正电子素寿命图像。所提出的方法为使用现有的飞行时间PET扫描仪进行正电子素寿命成像提供了可能性。寿命信息可用于了解体内组织微环境，这有助于疾病机制的研究和合适治疗方法的选择。
Positron emission tomography is widely used in clinical and preclinical applications. Positronium lifetime carries information about the tissue microenvironment where positrons are emitted, but such information has not been captured because of two technical challenges. One challenge is the low sensitivity in detecting triple coincidence events. This problem has been mitigated by the recent developments of PET scanners with long (1–2 m) axial field of view. The other challenge is the low spatial resolution of the positronium lifetime images formed by existing methods that is determined by the time-of-flight (TOF) resolution (200–500 ps) of existing PET scanners. This paper solves the second challenge by developing a new image reconstruction method to generate high-resolution positronium lifetime images using existing TOF PET. Simulation studies demonstrate that the proposed method can reconstruct positronium lifetime images at much better spatial resolution than the limit set by the TOF resolution of the PET scanner. The proposed method opens up the possibility of performing positronium lifetime imaging using existing TOF PET scanners. The lifetime information can be used to understand the tissue microenvironment in vivo which could facilitate the study of disease mechanism and selection of proper treatments.