PURPOSE Performance standards for quantitative 18F-FDG PET/CT studies are provided by the EANM Research Ltd. (EARL) to enable comparability of quantitative PET in multicentre studies. Yet, such specifications are not available for 68Ga. Therefore, our aim was to evaluate 68Ga-PET/CT quantification variability in a multicentre setting. METHODS A survey across Dutch hospitals was performed to evaluate differences in clinical 68Ga PET/CT study protocols. 68Ga and 18F phantom acquisitions were performed by 8 centres with 13 different PET/CT systems according to EARL protocol. The cylindrical phantom and NEMA image quality (IQ) phantom were used to assess image noise and to identify recovery coefficients (RCs) for quantitative analysis. Both phantoms were used to evaluate cross-calibration between the PET/CT system and local dose calibrator. RESULTS The survey across Dutch hospitals showed a large variation in clinical 68Ga PET/CT acquisition and reconstruction protocols. 68Ga PET/CT image noise was below 10%. Cross-calibration was within 10% deviation, except for one system to overestimate 18F and two systems to underestimate the 68Ga activity concentration. RC-curves for 18F and 68Ga were within and on the lower limit of current EARL standards, respectively. After correction for local 68Ga/18F cross-calibration, mean 68Ga performance was 5% below mean EARL performance specifications. CONCLUSIONS 68Ga PET/CT quantification performs on the lower limits of the current EARL RC standards for 18F. Correction for local 68Ga/18F cross-calibration mismatch is advised, while maintaining the EARL reconstruction protocol thereby avoiding multiple EARL protocols.

中文翻译：

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多中心定量68Ga PET / CT性能的统一。

目的EANM Research Ltd.（EARL）提供了定量18F-FDG PET / CT研究的性能标准，以实现定量PET在多中心研究中的可比性。但是，此类规格不适用于68Ga。因此，我们的目标是在多中心环境中评估68Ga-PET / CT的定量变异性。方法对荷兰各医院进行了一项调查，以评估临床68Ga PET / CT研究方案的差异。根据EARL协议，由13个不同的PET / CT系统的8个中心进行了68Ga和18F幻像采集。圆柱体模和NEMA图像质量（IQ）体模用于评估图像噪声并识别回收系数（RC）以进行定量分析。两个模型均用于评估PET / CT系统和局部剂量校准器之间的交叉校准。结果在荷兰各医院进行的调查显示，临床68Ga PET / CT采集和重建方案存在很大差异。68Ga PET / CT图像噪声低于10％。交叉校准偏差在10％以内，除了一个系统高估18F和两个系统低估68Ga活性浓度。18F和68Ga的RC曲线分别在当前EARL标准的上下限之内。在对本地68Ga / 18F交叉校准进行校正之后，平均68Ga性能比EARL性能指标低了5％。结论68Ga PET / CT定量在当前18F EARL RC标准的下限进行。建议在保持EARL重建协议的同时对局部68Ga / 18F交叉校准不匹配进行校正，从而避免使用多个EARL协议。