Quantitative imaging biomarkers are becoming usual in oncology for assessing therapy response. The harmonization of image quantitation reporting has become of utmost importance due to the multi-center trials increase. The NEMA image quality test is often considered for the evaluation of quantitation and is more accurate with a radioactive solid phantom that reduces variability. The goal of this project is to determine the level of variability among imaging centers if acquisition and imaging protocol parameters are left to the center’s preference while all other parameters are fixed including the scanner type. A NEMA-IQ phantom filled with radioactive 68Ge solid resin was imaged in five clinical sites throughout Europe. Sites reconstructed data with OSEM and BSREM algorithms applying the sites’ clinical parameters. Images were analyzed according with the NEMA-NU2-2012 standard using the manufacturer-provided NEMA tools to calculate contrast recovery (CR) and background variability (BV) for each sphere and the lung error (LE) estimation. In addition, a 18F-filled NEMA-IQ phantom was also evaluated to obtain a gauge for variability among centers when the sites were provided with identical specific instructions for acquisition and reconstruction protocol (the aggregate of data from 12 additional sites is presented). The data using the 68Ge solid phantom showed no statistical differences among different sites, proving a very good reproducibility among the PET center models even if dispersion of data is higher with OSEM compared to BSREM. Furthermore, BSREM shows better CR and comparable BV, while LE is slightly reduced. Two centers exhibit significant differences in CR and BV values for the 18F NEMA NU2-2012 experiments; these outlier results are explained. The same PET system type from the various sites produced similar quantitative results, despite allowing each site to choose their clinical protocols with no restriction on data acquisition and reconstruction parameters. BSREM leads to lower dispersion of quantitative data among different sites. A solid radioactive phantom may be recommended to qualify the sites to perform quantitative imaging.

中文翻译：

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通过NEMA图像质量测试评估多个发现IQ PET / CT系统之间的PET定量准确性。

定量成像生物标志物正在肿瘤学中用于评估治疗反应。由于多中心试验的增加，图像定量报告的统一变得极为重要。通常考虑使用NEMA图像质量测试来评估定量，并且使用减少变差的放射性固体体模更为准确。该项目的目的是确定采集中心和成像协议参数是否由中心优先选择，而所有其他参数（包括扫描仪类型）是否固定，则确定成像中心之间的差异程度。在整个欧洲的五个临床地点对装有放射性68Ge固体树脂的NEMA-IQ幻像进行了成像。使用OSEM和BSREM算法根据站点的临床参数重建站点的数据。使用制造商提供的NEMA工具根据NEMA-NU2-2012标准对图像进行分析，以计算每个球体的对比度恢复（CR）和背景变异性（BV）以及肺部误差（LE）估计值。此外，当为站点提供采集和重建方案的相同特定指令时，还评估了填充18F的NEMA-IQ幻象，以获取中心之间的变异性量表（显示了来自其他12个站点的数据汇总）。使用68Ge实体模型的数据在不同位置之间没有统计差异，即使PET中心模型的数据分散性高于BSREM，也证明了PET中心模型之间具有很好的可重复性。此外，BSREM显示出更好的CR和可比的BV，而LE则略有下降。对于18F NEMA NU2-2012实验，两个中心的CR和BV值存在显着差异；这些异常结果将得到解释。尽管允许每个站点选择其临床方案，而对数据采集和重建参数没有限制，但来自各个站点的相同PET系统类型产生了相似的定量结果。BSREM导致定量数据在不同站点之间的分散性降低。可以建议使用坚固的放射性体模来对部位进行鉴定，以进行定量成像。BSREM导致定量数据在不同站点之间的分散性降低。可以建议使用坚固的放射性体模来对部位进行鉴定，以进行定量成像。BSREM导致定量数据在不同站点之间的分散性降低。可以建议使用坚固的放射性体模来对部位进行鉴定，以进行定量成像。