Baran Jakub, Krzemien Wojciech, Parzych Szymon, Raczyński Lech, Bała Mateusz, Coussat Aurélien, Chug Neha, Czerwiński Eryk, Curceanu Catalina Oana, Dadgar Meysam, Dulski Kamil, Eliyan Kavya, Gajewski Jan, Gajos Aleksander, Hiesmayr Beatrix C, Kacprzak Krzysztof, Kapłon Łukasz, Klimaszewski Konrad, Korcyl Grzegorz, Kozik Tomasz, Kumar Deepak, Niedźwiecki Szymon, Panek Dominik, Perez Del Rio Elena, Ruciński Antoni, Sharma Sushil, Shopa Roman Y, Skurzok Magdalena, Stępień Ewa, Tayefiardebili Faranak, Tayefiardebili Keyvan, Wiślicki Wojciech, Moskal Paweł
Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, Kraków, Poland.
Total-Body Jagiellonian-PET Laboratory, Jagiellonian University, Kraków, Poland.
Med Phys. 2025 May;52(5):2961-2975. doi: 10.1002/mp.17627. Epub 2025 Jan 24.
Total-body (TB) Positron Emission Tomography (PET) is one of the most promising medical diagnostics modalities, opening new perspectives for personalized medicine, low-dose imaging, multi-organ dynamic imaging or kinetic modeling. The high sensitivity provided by total-body technology can be advantageous for novel tomography methods like positronium imaging, demanding the registration of triple coincidences. Currently, state-of-the-art PET scanners use inorganic scintillators. However, the high acquisition cost reduces the accessibility of TB PET technology. Several efforts are ongoing to mitigate this problem. Among the alternatives, the Jagiellonian PET (J-PET) technology, based on axially arranged plastic scintillator strips, offers a low-cost alternative solution for TB PET.
The work aimed to compare five total-body J-PET geometries with plastic scintillators suitable for multi-organ and positronium tomography as a possible next-generation J-PET scanner design.
We present comparative studies of performance characteristics of the cost-effective total-body PET scanners using J-PET technology. We investigated in silico five TB scanner geometries, varying the number of rings, scanner radii, and other parameters. Monte Carlo simulations of the anthropomorphic XCAT phantom, the extended 2-m sensitivity line source and positronium sensitivity phantoms were used to assess the performance of the geometries. Two hot spheres were placed in the lungs and in the liver of the XCAT phantom to mimic the pathological changes. We compared the sensitivity profiles and performed quantitative analysis of the reconstructed images by using quality metrics such as contrast recovery coefficient, background variability and root mean squared error. The studies are complemented by the determination of sensitivity for the positronium lifetime tomography and the relative cost analysis of the studied setups.
The analysis of the reconstructed XCAT images reveals the superiority of the seven-ring scanners over the three-ring setups. However, the three-ring scanners would be approximately 2-3 times cheaper. The peak sensitivity values for two-gamma vary from 20 to 34 cps/kBq and are dominated by the differences in geometrical acceptance of the scanners. The sensitivity curves for the positronium tomography have a similar shape to the two-gamma sensitivity profiles. The peak values are lower compared to the two-gamma cases, from about 20-28 times, with a maximum value of 1.66 cps/kBq. This can be contrasted with the 50-cm one-layer J-PET modular scanner used to perform the first in-vivo positronium imaging with a sensitivity of 0.06 cps/kBq.
The results show the feasibility of multi-organ imaging of all the systems to be considered for the next generation of TB J-PET designs. Among the scanner parameters, the most important ones are related to the axial field-of-view coverage. The two-gamma sensitivity and XCAT image reconstruction analyzes show the advantage of seven-ring scanners. However, the cost of the scintillator materials and SiPMs is more than two times higher for the longer modalities compared to the three-ring solutions. Nevertheless, the relative cost for all the scanners is about 10-4 times lower compared to the cost of the uExplorer. These properties coupled together with J-PET cost-effectiveness and triggerless acquisition mode enabling three-gamma positronium imaging, make the J-PET technology an attractive solution for broad application in clinics.
全身正电子发射断层扫描（PET）是最具前景的医学诊断方式之一，为个性化医疗、低剂量成像、多器官动态成像或动力学建模开辟了新视角。全身技术所提供的高灵敏度对于诸如正电子成像等新型断层扫描方法可能是有利的，正电子成像需要记录三重符合事件。目前，最先进的PET扫描仪使用无机闪烁体。然而，高昂的购置成本降低了全身PET技术的可及性。目前正在进行多项努力以缓解这一问题。在诸多替代方案中，基于轴向排列的塑料闪烁体条带的雅盖隆PET（J-PET）技术为全身PET提供了一种低成本的替代解决方案。
这项工作旨在比较五种配备适用于多器官和正电子断层扫描的塑料闪烁体的全身J-PET几何结构，作为下一代J-PET扫描仪设计的一种可能方案。
我们展示了使用J-PET技术的高性价比全身PET扫描仪性能特征的比较研究。我们在计算机模拟中研究了五种全身扫描仪几何结构，改变环的数量、扫描仪半径和其他参数。使用拟人化XCAT体模、扩展的2米灵敏度线源和正电子灵敏度体模的蒙特卡罗模拟来评估这些几何结构的性能。在XCAT体模的肺部和肝脏中放置两个热球以模拟病理变化。我们比较了灵敏度分布，并通过使用对比度恢复系数、背景变异性和均方根误差等质量指标对重建图像进行定量分析。通过确定正电子寿命断层扫描的灵敏度以及所研究设置的相对成本分析对这些研究进行补充。
对重建的XCAT图像的分析揭示了七环扫描仪相对于三环设置的优越性。然而，三环扫描仪的成本大约便宜2至3倍。双伽马的峰值灵敏度值在20至34 cps/kBq之间变化，主要由扫描仪几何接受度的差异主导。正电子断层扫描的灵敏度曲线形状与双伽马灵敏度分布相似。与双伽马情况相比，峰值较低，约为其20至28倍，最大值为1.66 cps/kBq。这可以与用于进行首次体内正电子成像、灵敏度为0.06 cps/kBq的50厘米单层J-PET模块化扫描仪形成对比。
结果表明，对于下一代全身J-PET设计所考虑的所有系统进行多器官成像具有可行性。在扫描仪参数中，最重要的参数与轴向视野覆盖范围有关。双伽马灵敏度和XCAT图像重建分析显示了七环扫描仪的优势。然而，与三环解决方案相比，较长模式下闪烁体材料和硅光电倍增管的成本高出两倍多。尽管如此，所有扫描仪的相对成本相比于uExplorer的成本低约10 - 4倍。这些特性与J-PET的成本效益以及实现三伽马正电子成像的无触发采集模式相结合，使J-PET技术成为临床上广泛应用的有吸引力的解决方案。
