Pommranz Christian M, Elmoujarkach Ezzat A, Lan Wenhong, Cabello Jorge, Linder Pia M, Vo Hong Phuc, Mannheim Julia G, Santangelo Andrea, Conti Maurizio, la Fougère Christian, Rafecas Magdalena, Schmidt Fabian P
Department of Preclinical Imaging and Radiopharmacy, Werner Siemens Imaging Center, Eberhard Karls University Tuebingen, Roentgenweg 13, 72076, Tuebingen, Germany.
Institute for Astronomy and Astrophysics, Eberhard Karls University Tuebingen, Sand 1, 72076, Tuebingen, Germany.
EJNMMI Phys. 2025 Mar 31;12(1):31. doi: 10.1186/s40658-025-00738-3.
The high sensitivity and axial coverage of large axial field of view (LAFOV) PET scanners have an unmet potential for total-body PET research. Despite these technological advances, inherent challenges to PET scans such as patient motion persist. To provide simulation-derived ground truth information, we developed a digital replica of the Biograph Vision Quadra LAFOV PET/CT scanner closely mimicking real event processing and image reconstruction.
The framework uses a GATE model in combination with vendor-specific software prototypes for event processing and image reconstruction (e7 tools, Siemens Healthineers). The framework was validated against experimental measurements following the NEMA NU-2 2018 standard. In addition, patient-like simulations were performed with the XCAT phantom, including respiratory motion and modeled lesions of 5, 10, 20 mm size, to assess the impact of motion artefacts on PET images using a motion-free reference.
The simulation framework demonstrated high accuracy in replicating scanner performance in terms of image quality, contrast recovery (37 mm sphere: 86.5% and 85.5%; 28 mm: 82.6% and 82.4%; 22 mm: 78.8% and 77.7%; 17 mm: 74.9% and 74.6%; 13 mm: 67.0% and 67.9%; 10 mm: 55.5% and 64.3%), image noise (CV of 7.5% and 7.7%) and sensitivity (174.6 cps/kBq and 175.3 cps/kBq) for the simulation and experimental data, respectively. High agreement was found for the spatial resolution with a difference of 0.4 ± 0.3 mm and the NECR aligned well with a maximum deviation of 9%, particularly in the clinical activity range below 10 kBq/mL. Motion induced artefacts resulted in a quantification error at lesion level between - 12.3% and - 45.1%.
The experimentally validated digital twin of the Biograph Vision Quadra facilitates detailed studies of realistic patient scenarios while offering unprecedented opportunities for motion correction, dosimetry, AI training, and imaging protocol optimization.
大轴向视野（LAFOV）PET扫描仪的高灵敏度和轴向覆盖范围在全身PET研究方面具有尚未得到满足的潜力。尽管有这些技术进步，但PET扫描中诸如患者运动等固有挑战仍然存在。为了提供模拟得出的真实信息，我们开发了一款Biograph Vision Quadra LAFOV PET/CT扫描仪的数字复制品，它能紧密模拟真实事件处理和图像重建过程。
该框架使用GATE模型，并结合特定供应商的软件原型进行事件处理和图像重建（e7工具，西门子医疗）。该框架根据NEMA NU-2 2018标准进行的实验测量进行了验证。此外，使用XCAT体模进行了类似患者的模拟，包括呼吸运动以及尺寸为5、10、20毫米的模拟病变，以使用无运动参考来评估运动伪影对PET图像的影响。
模拟框架在复制扫描仪性能方面表现出高精度，在图像质量、对比度恢复（37毫米球体：86.5%和85.5%；28毫米：82.6%和82.4%；22毫米：78.8%和77.7%；17毫米：74.9%和74.6%；1,3毫米：67.0%和67.9%；10毫米：55.5%和64.3%）、图像噪声（CV为7.5%和7.7%）以及灵敏度（模拟数据和实验数据分别为174.6 cps/kBq和175.3 cps/kBq）方面。在空间分辨率上发现高度一致性，差异为0.4±0.3毫米，并且NECR对齐良好，最大偏差为9%，特别是在低于10 kBq/mL的临床活度范围内。运动引起的伪影在病变水平导致了-12.3%至-45.1%的定量误差。
经过实验验证的Biograph Vision Quadra数字孪生体有助于对真实患者情况进行详细研究，同时为运动校正、剂量测定、人工智能训练和成像协议优化提供了前所未有的机会。
