Department of Radiology & Nuclear Medicine, Amsterdam University Medical Centers, location VUmc, De Boelelaan 1117, 1081 HV, Amsterdam, The Netherlands.
Department of Medical Technology, North Estonia Medical Centre Foundation, Tallinn, Estonia.
Eur J Nucl Med Mol Imaging. 2021 Aug;48(9):2856-2870. doi: 10.1007/s00259-021-05201-w. Epub 2021 Jan 31.
In order to achieve comparability of image quality, harmonisation of PET system performance is imperative. In this study, prototype harmonisation criteria for PET brain studies were developed.
Twelve clinical PET/CT systems (4 GE, 4 Philips, 4 Siemens, including SiPM-based "digital" systems) were used to acquire 30-min PET scans of a Hoffman 3D Brain phantom filled with ~ 33 kBq·mL [F]FDG. Scan data were reconstructed using various reconstruction settings. The images were rigidly coregistered to a template (voxel size 1.17 × 1.17 × 2.00 mm) onto which several volumes of interest (VOIs) were defined. Recovery coefficients (RC) and grey matter to white matter ratios (GMWMr) were derived for eroded (denoted in the text by subscript e) and non-eroded grey (GM) and white (WM) matter VOIs as well as a mid-phantom cold spot (VOI) and VOIs from the Hammers atlas. In addition, left-right hemisphere differences and voxel-by-voxel differences compared to a reference image were assessed.
Systematic differences were observed for reconstructions with and without point-spread-function modelling (PSF and PSF, respectively). Normalising to image-derived activity, upper and lower limits ensuring image comparability were as follows: for PSF, RC = [0.97-1.01] and GMWMr = [3.51-3.91] for eroded VOI and RC = [0.78-0.83] and GMWMr = [1.77-2.06] for non-eroded VOI, and for PSF, RC = [0.92-0.99] and GMWMr = [3.14-3.68] for eroded VOI and RC = [0.75-0.81] and GMWMr = [1.72-1.95] for non-eroded VOI.
To achieve inter-scanner comparability, we propose selecting reconstruction settings based on RC and GMWMr as specified in "Results". These proposed standards should be tested prospectively to validate and/or refine the harmonisation criteria.
为了实现图像质量的可比性，有必要对 PET 系统性能进行协调。本研究制定了用于 PET 脑研究的原型协调标准。
使用 12 台临床 PET/CT 系统（4 台 GE、4 台飞利浦、4 台西门子，包括基于 SiPM 的“数字”系统）采集充满~33 kBq·mL[F]FDG 的 Hoffman 3D 脑体模的 30 分钟 PET 扫描。使用各种重建设置重建扫描数据。将图像刚性地配准到模板上（体素大小为 1.17×1.17×2.00mm），并在其上定义了几个感兴趣区（VOI）。从侵蚀（在文本中用下标 e 表示）和非侵蚀灰质（GM）和白质（WM）VOI 以及体模中的一个冷点（VOI）和来自 Hammers 图谱的 VOI 中得出了恢复系数（RC）和灰质与白质比（GMWMr）。此外，还评估了左右半球差异和与参考图像的体素差异。
对于有和没有点扩散函数建模（PSF 和 PSF）的重建，观察到系统差异。归一化到图像衍生的活性，确保图像可比性的上限和下限如下：对于 PSF，RC=[0.97-1.01]和 GMWMr=[3.51-3.91]用于侵蚀 VOI，RC=[0.78-0.83]和 GMWMr=[1.77-2.06]用于非侵蚀 VOI，对于 PSF，RC=[0.92-0.99]和 GMWMr=[3.14-3.68]用于侵蚀 VOI，RC=[0.75-0.81]和 GMWMr=[1.72-1.95]用于非侵蚀 VOI。
为了实现扫描仪间的可比性，我们建议根据“结果”中指定的 RC 和 GMWMr 选择重建设置。应前瞻性地测试这些建议的标准，以验证和/或完善协调标准。
