Kikuchi Asuka, Watanuki Shoichi, Watabe Hiroshi, Tashiro Manabu
Nuclear Medicine Laboratory, Division of Short-lived Radioisotope Research, Research Center for Accelerator and Radioisotope Science, Tohoku University, 6-3 Aoba, Aramaki, Aoba-ku, Sendai, Miyagi, 980-8578, Japan.
Radiation Protection & Safety Control Laboratory, Division of Radiation Protection and Nuclear Safety, Research Center for Accelerator and Radioisotope Science, Tohoku University, 6-3 Aoba, Aramaki, Aoba-ku, Sendai, Miyagi, 980-8578, Japan.
Radiol Phys Technol. 2025 Mar;18(1):268-274. doi: 10.1007/s12194-025-00882-6. Epub 2025 Feb 5.
Age-related deterioration in positron emission tomography (PET) systems can be monitored using cross-calibration scans for scanner calibration. This study aimed to evaluate changes in the sensitivity of a PET system over time using routinely collected cross-calibration factor (CCF) measurement data and NEMA sensitivity measurement data acquired at our facility. We used CCF measurement data acquired over eight years, from 2016 to 2023. The count rates were calculated from raw data. The NEMA sensitivity measurements were also performed in 2017 and 2024 to compare with the sensitivities obtained from the CCF measurements. The PET images were reconstructed using the CCF data. A region of interest (ROI) was placed at the center of the PET images and count rates from the PET images were obtained. The sensitivity changes in the CCF data showed a linear decrease in sensitivity over eight years, with a mean annual reduction rate of approximately 2.0%. A comparison of the NEMA sensitivity measurements indicated a decrease in sensitivity, with a 12% reduction over eight eight years. The sensitivity was higher at the center of the axial field of view than at the edges. The ROI data also showed a linear decrease in sensitivity. This is consistent with the CCF data. Additionally, the coefficient of variation increased towards the edge of the slice. By utilizing the CCF measurement data, we obtained age-related changes in the PET system, suggesting that the PET system used in our facility may experience an annual sensitivity deterioration of approximately 2.0%.
正电子发射断层扫描（PET）系统中与年龄相关的性能退化可以通过用于扫描仪校准的交叉校准扫描进行监测。本研究旨在利用在我们机构常规收集的交叉校准因子（CCF）测量数据和NEMA灵敏度测量数据，评估PET系统灵敏度随时间的变化。我们使用了2016年至2023年八年间获取的CCF测量数据。计数率从原始数据中计算得出。2017年和2024年也进行了NEMA灵敏度测量，以与从CCF测量中获得的灵敏度进行比较。使用CCF数据重建PET图像。在PET图像中心放置感兴趣区域（ROI），并获取PET图像的计数率。CCF数据中的灵敏度变化显示，八年间灵敏度呈线性下降，平均年下降率约为2.0%。NEMA灵敏度测量的比较表明灵敏度有所下降，八年间下降了12%。轴向视野中心的灵敏度高于边缘。ROI数据也显示灵敏度呈线性下降。这与CCF数据一致。此外，变异系数向切片边缘增加。通过利用CCF测量数据，我们获得了PET系统中与年龄相关的变化，表明我们机构使用的PET系统可能每年灵敏度下降约2.0%。
