Department of Medical Imaging, Henan Provincial People's Hospital, Henan, China.
UIH America Inc., Houston, Texas; and.
J Nucl Med. 2022 Apr;63(4):622-628. doi: 10.2967/jnumed.120.261651. Epub 2021 Aug 12.
Parametric imaging of the net influx rate ( ) in F-FDG PET has been shown to provide improved quantification and specificity for cancer detection compared with SUV imaging. Current methods of generating parametric images usually require a long dynamic scanning time. With the recently developed uEXPLORER scanner, a dramatic increase in sensitivity has reduced the noise in dynamic imaging, making it more robust to use a nonlinear estimation method and flexible protocols. In this work, we explored 2 new possible protocols besides the standard 60-min one for the possibility of reducing scanning time for imaging. The gold standard protocol (protocol 1) was conventional dynamic scanning with a 60-min scanning time. The first proposed protocol (protocol 2) included 2 scanning periods: 0-4 min and 54-60 min after injection. The second proposed protocol (protocol 3) consisted of a single scanning period from 50 to 60 min after injection, with a second injection applied at 56 min. The 2 new protocols were simulated from the 60-min standard scans. A hybrid input function combining the population-based input function and the image-derived input function (IDIF) was used. The results were also compared with the IDIF acquired from protocol 1. A previously developed maximum-likelihood approach was used to estimate the images. In total, 7 cancer patients imaged using the uEXPLORER scanner were enrolled in this study. Lesions were identified from the patient data, and the lesion values were compared among the different protocols. The acquired hybrid input function was comparable in shape to the IDIF for each patient. The average difference in area under the curve was about 3%, suggesting good quantitative accuracy. The visual difference between the images generated using IDIF and those generated using the hybrid input function was also minimal. The acquired images using different protocols were visually comparable. The average difference in the lesions was 2.8% ± 2.1% for protocol 2 and 1% ± 2.2% for protocol 3. The results suggest that it is possible to acquire images using the nonlinear estimation approach with a much-reduced scanning time. Between the 2 new protocols, the protocol with dual injection shows the greatest promise in terms of practicality.
正电子发射断层扫描（PET）的净流入率（）参数成像已被证明在癌症检测的定量和特异性方面优于 SUV 成像。目前生成参数图像的方法通常需要较长的动态扫描时间。使用最近开发的 uEXPLORER 扫描仪，灵敏度的大幅提高降低了动态成像中的噪声，使其更适合使用非线性估计方法和灵活的方案。在这项工作中，我们探索了除标准 60 分钟方案外的 2 种新的可能方案，以减少成像的扫描时间。金标准方案（方案 1）是传统的动态扫描，扫描时间为 60 分钟。第一个提出的方案（方案 2）包括 2 个扫描期：注射后 0-4 分钟和 54-60 分钟。第二个提出的方案（方案 3）由注射后 50-60 分钟的单个扫描期组成，在 56 分钟时应用第二次注射。这 2 个新方案是从标准 60 分钟扫描中模拟出来的。使用了一种混合输入函数，结合了基于人群的输入函数和图像衍生的输入函数（IDIF）。结果也与方案 1 中获得的 IDIF 进行了比较。以前开发的最大似然方法用于估计图像。总共纳入了使用 uEXPLORER 扫描仪成像的 7 名癌症患者。从患者数据中识别出病变，并比较了不同方案之间的病变值。获得的混合输入函数在形状上与每位患者的 IDIF 相似。曲线下面积的平均差异约为 3%，表明定量精度良好。使用 IDIF 和混合输入函数生成的图像之间的视觉差异也最小。使用不同方案获得的图像在视觉上是可比的。对于方案 2，病变的平均差异为 2.8%±2.1%，对于方案 3，为 1%±2.2%。结果表明，使用大大减少的扫描时间，使用非线性估计方法获得图像是可能的。在这 2 个新方案中，双注射方案在实用性方面最有希望。
