Department of Diagnostic Imaging, Hokkaido University Graduate School of Medicine, Kita 15 Nishi 7, Kita-Ku, Sapporo, Hokkaido, 060-8638, Japan.
Department of Nuclear Medicine, Hokkaido University Hospital, Kita 14 Nishi 5, Kita-Ku, Sapporo, Hokkaido, 060-8648, Japan.
Ann Nucl Med. 2024 Feb;38(2):131-138. doi: 10.1007/s12149-023-01884-3. Epub 2023 Nov 9.
Silicon photomultiplier-based positron emission tomography/computed tomography (SiPM-PET/CT) has the superior spatial resolution to conventional PET/CT (cPET/CT). This head-to-head comparison study compared the images of physiological F-fluorodeoxyglucose (FDG) accumulation in small-volume structures between SiPM-PET/CT and cPET/CT in patients scanned with both modalities, and we investigated whether the thresholds that are reported to be useful for differentiating physiological accumulations from malignant lesions can also be applied to SiPM-PET/CT.
We enrolled 21 consecutive patients with head and neck malignancies who underwent whole-body FDG-PET/CT for initial staging or a follow-up evaluation (October 2020 to March 2022). After being injected with FDG, all patients underwent PET acquisition on both Vereos PET-CT and Gemini TF64 PET-CT systems (both Philips Healthcare) in random order. For each patient, the maximum standardized uptake value (SUVmax) was measured in the pituitary gland, esophagogastric junction (EGJ), adrenal glands, lumbar enlargement of the spinal cord, and epididymis. We measured the liver SUVmean and the blood pool SUVmean to calculate the target-to-liver ratio (TLR) and the target-to-blood ratio (TBR), respectively. Between-groups differences in each variable were examined by a paired t-test. We also investigated whether there were cases of target uptake greater than the reported threshold for distinguishing pathological from physiological accumulations.
Data were available for 19 patients. Ten patients were in Group 1, i.e., the patients who underwent SiPM-PET first, and the remaining nine patients who underwent cPET first were in Group 2. In the SiPM-PET results, the SUVmax of all targets was significantly higher than that obtained by cPET in all patients, and this tendency was also observed when the patients were divided into Groups 1/2. The TLRs of all targets were significantly higher in SiPM-PET than in cPET in all patients, and SiPM-PET also showed significantly higher TBRs for all targets except the EGJ (p = 0.052).
The physiological uptake in the small structures studied herein showed high accumulation on SiPM-PET. Our results also suggest that the thresholds reported for cPET to distinguish pathological accumulations likely lead to false-positive findings in SIPM-PET evaluations.
基于硅光电倍增管的正电子发射断层扫描/计算机断层扫描（SiPM-PET/CT）的空间分辨率优于传统的正电子发射断层扫描/计算机断层扫描（cPET/CT）。本项头对头比较研究比较了两种模式下扫描的患者的小体积结构中生理 F-氟脱氧葡萄糖（FDG）积聚的图像，我们研究了用于区分生理积聚与恶性病变的报告阈值是否也可应用于 SiPM-PET/CT。
我们纳入了 21 例头颈部恶性肿瘤患者，这些患者因初始分期或随访评估（2020 年 10 月至 2022 年 3 月）而接受全身 FDG-PET/CT 检查。FDG 注射后，所有患者均以随机顺序在 Vereos PET-CT 和 Gemini TF64 PET-CT 系统（均为飞利浦医疗保健公司）上进行 PET 采集。对于每位患者，测量垂体、食管胃交界处（EGJ）、肾上腺、脊髓腰椎扩大和附睾的最大标准化摄取值（SUVmax）。我们测量肝脏 SUVmean 和血池 SUVmean，以分别计算靶肝比（TLR）和靶血比（TBR）。通过配对 t 检验检查各组之间的差异。我们还研究了是否存在目标摄取大于用于区分病理性和生理性积聚的报告阈值的情况。
19 例患者的数据可用。10 例患者为 SiPM-PET 组 1，即首先进行 SiPM-PET 的患者，其余 9 例首先进行 cPET 的患者为 cPET 组 2。在 SiPM-PET 结果中，所有患者的所有目标的 SUVmax 均明显高于 cPET 组，当患者分为 1/2 组时也观察到了这种趋势。在所有患者中，所有目标的 TLR 均明显高于 cPET，除了 EGJ（p=0.052）外，SiPM-PET 也显示出所有目标的 TBR 明显更高。
本研究中小结构的生理摄取显示 SiPM-PET 有高摄取。我们的结果还表明，用于区分病理性积聚的 cPET 报告阈值可能导致 SiPM-PET 评估中的假阳性发现。
