基于硅光电倍增管（SiPM）的正电子发射断层显像/计算机断层扫描（PET/CT）扫描仪的初步经验：采集时间对图像质量的影响。

Initial experience with a SiPM-based PET/CT scanner: influence of acquisition time on image quality.

作者信息

Sonni Ida, Baratto Lucia, Park Sonya, Hatami Negin, Srinivas Shyam, Davidzon Guido, Gambhir Sanjiv Sam, Iagaru Andrei

机构信息

Division of Nuclear Medicine and Molecular Imaging, Department of Radiology, Stanford University, 300 Pasteur Drive, Stanford, CA, 94305, USA.

Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Lab, Berkeley, CA, USA.

出版信息

EJNMMI Phys. 2018 Apr 18;5(1):9. doi: 10.1186/s40658-018-0207-x.

BACKGROUND

A newly introduced PET/CT scanner (Discovery Meaningful Insights-DMI, GE Healthcare) includes the silicon photomultiplier (SiPM) with time-of-flight (TOF) technology first used in the GE SIGNA PET/MRI. In this study, we investigated the impact of various acquisition times on image quality using this SiPM-based PET/CT.

METHODS

We reviewed data from 58 participants with cancer who were scanned using the DMI PET/CT scanner. The administered dosages ranged 295.3-429.9 MBq (mean ± SD 356.3 ± 37.4) and imaging started at 71-142 min (mean ± SD 101.41 ± 17.52) after administration of the radiopharmaceutical. The patients' BMI ranged 19.79-46.16 (mean ± SD 26.55 ± 5.53). We retrospectively reconstructed the raw TOF data at 30, 60, 90, and 120 s/bed and at the standard image acquisition time per clinical protocol (180 or 210 s/bed depending on BMI). Each reconstruction was reviewed blindly by two nuclear medicine physicians and scored 1-5 (1-poor, 5-excellent quality). The liver signal-to-noise ratio (SNR) was used as a quantitative measure of image quality.

RESULTS

The average scores ± SD of the readers were 2.61 ± 0.83, 3.70 ± 0.92, 4.36 ± 0.82, 4.82 ± 0.39, and 4.91 ± 0.91 for the 30, 60, 90, and 120 s/bed and at standard acquisition time, respectively. Inter-reader agreement on image quality assessment was good, with a weighted kappa of 0.80 (95% CI 0.72-0.81). In the evaluation of the effects of time per bed acquisition on semi-quantitative measurements, we found that the only time point significantly different from the standard time were 30 and 60 s (both with P < 0.001). The effects of dose and BMI were not statistically significant (P = 0.195 and 0.098, respectively). There was a significant positive effect of time on SNR (P < 0.001), as well as a significant negative effect of weight (P < 0.001).

CONCLUSIONS

Our results suggest that despite significant delays from injection to imaging (due to comparison with standard PET/CT) compared to standard clinical operations and even in a population with average BMI > 25, images can be acquired as fast as 90 s/bed using the SiPM PET/CT and still result in very good image quality (average score > 4).

背景

新引进的正电子发射断层显像/X射线计算机体层成像扫描仪（Discovery Meaningful Insights - DMI，通用电气医疗集团）采用了首次应用于通用电气SIGNA正电子发射断层显像/磁共振成像系统的带飞行时间（TOF）技术的硅光电倍增管（SiPM）。在本研究中，我们使用这种基于SiPM的正电子发射断层显像/X射线计算机体层成像扫描仪，研究了不同采集时间对图像质量的影响。

方法

我们回顾了58例癌症患者使用DMI正电子发射断层显像/X射线计算机体层成像扫描仪扫描的数据。给药剂量范围为295.3 - 429.9MBq（平均±标准差356.3±37.4），在注射放射性药物后71 - 142分钟（平均±标准差101.41±17.52）开始成像。患者的体重指数范围为19.79 - 46.16（平均±标准差26.55±5.53）。我们回顾性地在每床位30、60、90和120秒以及按照每个临床方案的标准图像采集时间（根据体重指数为180或210秒/床位）重建原始TOF数据。两名核医学医师对每次重建进行盲法评估，并给予1 - 5分的评分（1分 - 差，5分 - 质量优秀）。肝脏信噪比（SNR）用作图像质量的定量指标。

结果

对于每床位30、60、90和120秒以及标准采集时间，阅片者的平均评分±标准差分别为2.61±0.83、3.70±0.92、4.36±0.82、4.82±0.39和4.91±0.91。阅片者之间在图像质量评估上的一致性良好，加权kappa值为0.80（95%置信区间0.72 - 0.81）。在评估每床位采集时间对半定量测量的影响时，我们发现与标准时间有显著差异的唯一时间点是30和60秒（两者P均<0.001）。剂量和体重指数的影响无统计学意义（分别为P = 0.195和0.098）。时间对SNR有显著的正向影响（P<0.001），体重有显著的负向影响（P<0.001）。