Department of Radiological Sciences, School of Health Science, International University of Health and Welfare, Tochigi, Japan.
Research Team for Neuroimaging, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan.
Phys Med. 2018 Aug;52:98-103. doi: 10.1016/j.ejmp.2018.07.001. Epub 2018 Jul 7.
The present study aimed to define the errors in SUV and demonstrate the feasibility of SUV harmonization among contemporary PET/CT scanners using a novel National Institute of Standards and Technology (NIST)-traceable Ge/Ga source as the reference standard.
We used Ge/Ga dose calibrator and PET sources made with same batch of Ge/Ga embedded in epoxy that is traceable to the NIST standard. Bias in the amount of radioactivity and the radioactive concentrations measured by the dose calibrators and PET/CT scanners, respectively, was determined at five Japanese sites. We adjusted optimal dial setting of the dose calibrators and PET reconstruction parameters to close the actual amount of radioactivity and the radioactive concentration, respectively, of the NIST-traceable Ge/Ga sources to harmonize SUV. Errors in SUV before and after harmonization were then calculated at each site.
The average bias in the amount of radioactivity and the radioactive concentrations measured by dose calibrator and PET scanner was -4.94% and -12.22%, respectively, before, and -0.14% and -4.81%, respectively, after harmonization. Corresponding averaged errors in SUV measured under clinical conditions were underestimated by 7.66%, but improved by -4.70% under optimal conditions.
Our proposed method using an NIST-traceable Ge/Ga source identified bias in values obtained using dose calibrators and PET scanners, and reduced SUV variability to within 5% across different models of PET scanners at five sites. Our protocol using a standard source has considerable potential for harmonizing the SUV when contemporary PET scanners are involved in multicenter studies.
本研究旨在定义 SUV 中的误差，并使用新型可溯源至美国国家标准与技术研究院（NIST）的锗/镓（Ge/Ga）源作为参考标准，证明当代 PET/CT 扫描仪之间 SUV 可调和的可行性。
我们使用 Ge/Ga 剂量校准器和使用相同批次的 Ge/Ga 制成的 PET 源，这些 Ge/Ga 嵌入环氧树脂中，可溯源至 NIST 标准。在五个日本站点，分别测定剂量校准器和 PET/CT 扫描仪所测量的放射性活度和放射性浓度的偏差。我们调整剂量校准器的最佳刻度设置和 PET 重建参数，以使 NIST 可溯源的 Ge/Ga 源的实际放射性活度和放射性浓度分别接近协调 SUV。然后，在每个站点计算 SUV 调和前后的误差。
剂量校准器和 PET 扫描仪所测量的放射性活度和放射性浓度的平均偏差分别为-4.94%和-12.22%，调和后分别为-0.14%和-4.81%。在临床条件下测量的 SUV 平均误差低估了 7.66%，但在最佳条件下改善了-4.70%。
我们使用可溯源至 NIST 的 Ge/Ga 源的方法确定了剂量校准器和 PET 扫描仪获得的数值偏差，并将五个站点不同型号的 PET 扫描仪的 SUV 变异性降低到 5%以内。我们使用标准源的方案在涉及多中心研究时，对当代 PET 扫描仪的 SUV 具有相当大的调和潜力。
