Hotta Masatoshi, Horikawa Daisuke, Kurihara Keiichi, Ohashi Shuhei, Saito Kaori, Inagaki Fuyuki
Department of Nuclear Medicine, National Center for Global Health and Medicine, Shinjuku, Tokyo, Japan.
Department of Surgery, National Center for Global Health and Medicine, Shinjuku, Tokyo, Japan.
Ann Nucl Med. 2025 Apr 14. doi: 10.1007/s12149-025-02050-7.
In-pentetreotide imaging remains used for pre-treatment screening in peptide receptor radionuclide therapy (PRRT) in regions where somatostatin receptor (SSTR)-PET tracers are clinically unavailable. Post-treatment Lu-DOTATATE imaging at the first PRRT cycle serves as a baseline for response assessment on subsequent post-treatment imaging, paralleling the role of pre-treatment In-pentetreotide imaging. However, differences between these SSTR scans have not been reported. This study aims to compare In-pentetreotide and Lu-DOTATATE imaging, focusing on lesion uptake and numbers.
This retrospective, single-center study included patients with neuroendocrine tumors (NETs) who underwent PRRT at our hospital. Planar and SPECT/CT of pre-treatment In-pentetreotide and post-treatment Lu-DOTATATE imaging at the first PRRT cycle were analyzed. For visual analysis, the number of SSTR-positive (Krenning score ≥ 2) lesions was counted for each tracer. For quantitative analysis, up to three representative SSTR-positive lesions per patient were selected, and the maximum standardized uptake value (SUVmax) and tumor-to-background (T/B) ratio were measured. Wilcoxon signed-rank test was used to compare lesion counts and uptake parameters.
A total of 10 patients and 28 lesions were included. The median interval between In-pentetreotide and Lu-DOTATATE imaging was 43 days. Lu-DOTATATE imaging detected significantly more lesions than In-pentetreotide on both planar (median 10 vs. 6.5 lesions, p = 0.009) and SPECT/CT (median 13.5 vs. 8 lesions, p = 0.014). Lesion uptake was higher with Lu-DOTATATE, with SUVmax (median 4.5 vs. 2.9, p < 0.001) and T/B ratios (median 13.9 vs. 4.7, p < 0.001). Sub-centimeter lesions accounted for most of the additional detections on Lu-DOTATATE SPECT/CT.
Baseline Lu-DOTATATE imaging demonstrated higher lesion uptake and detected more lesions compared to pre-treatment In-pentetreotide imaging. Careful interpretation of baseline Lu-DOTATATE imaging is essential to avoid misinterpreting the increased number of detected lesions as disease progression. Screening with In-pentetreotide imaging may underestimate treatable lesions by PRRT, particularly when planar imaging alone is used, highlighting the need for SSTR PET in pre-treatment evaluation.
在生长抑素受体（SSTR）-PET示踪剂临床上无法获得的地区，铟-喷替肽显像仍用于肽受体放射性核素治疗（PRRT）的预处理筛查。在第一个PRRT周期进行的治疗后镥-奥曲肽显像作为后续治疗后显像反应评估的基线，与预处理铟-喷替肽显像的作用相似。然而，这些SSTR扫描之间的差异尚未见报道。本研究旨在比较铟-喷替肽和镥-奥曲肽显像，重点关注病灶摄取和数量。
这项回顾性单中心研究纳入了在我院接受PRRT的神经内分泌肿瘤（NETs）患者。分析了预处理铟-喷替肽和第一个PRRT周期治疗后镥-奥曲肽显像的平面及SPECT/CT图像。对于视觉分析，计算每种示踪剂的SSTR阳性（克伦宁评分≥2）病灶数量。对于定量分析，每位患者最多选择三个代表性的SSTR阳性病灶，测量最大标准化摄取值（SUVmax）和肿瘤与本底（T/B）比值。采用Wilcoxon符号秩检验比较病灶数量和摄取参数。
共纳入10例患者和28个病灶。铟-喷替肽和镥-奥曲肽显像的中位间隔时间为43天。在平面显像（中位值10个病灶对6.5个病灶，p = 0.009）和SPECT/CT显像（中位值13.5个病灶对8个病灶，p = 0.014）上，镥-奥曲肽显像检测到的病灶均明显多于铟-喷替肽显像。镥-奥曲肽的病灶摄取更高，SUVmax（中位值4.5对2.9，p < 0.001）和T/B比值（中位值13.9对4.7，p < 0.001）。亚厘米级病灶占镥-奥曲肽SPECT/CT上额外检测到的病灶的大部分。
与预处理铟-喷替肽显像相比，基线镥-奥曲肽显像显示出更高的病灶摄取且检测到更多病灶。仔细解读基线镥-奥曲肽显像对于避免将检测到的病灶数量增加误解为疾病进展至关重要。用铟-喷替肽显像进行筛查可能会低估PRRT可治疗的病灶，尤其是仅使用平面显像时，这突出了在预处理评估中使用SSTR PET的必要性。
