我们的目的是研究 [68Ga]Ga-FAPI-04 PET/CT 作为替代诊断和治疗诊断工具的潜力，用于治疗 [177Lu]Lu-DOTATATE 治疗难治的高分化 NET。接受至少两个周期 [177Lu] 治疗的患者]Lu-DOTATATE 治疗转移性 NET 和治疗中进展的情况均包括在内。所有患者均在3周内进行了[68Ga]Ga-DOTATATE和[68Ga]Ga-FAPI-04 PET/CT检查。记录了与 NET 和肿瘤部位相关的 PET 阳性病变的数量。 Mann-Whitney U 和卡方检验用于比较示踪剂的 SUVmax 水平和检测到的转移数量。研究纳入了符合资格标准的 12 名患者（7 名男性，5 名女性）。 10 名患者患有不同来源的 1-2 级 NET，两名患者患有副神经节瘤和嗜铬细胞瘤。 230 个病变中的 198 个 (86%) 为 SSTR 阳性，中位 SUVmax 为 16.6 (2.2-76.5)，230 个病变中的 88 个 (38.2%) 为 [68Ga]Ga-FAPI-04 阳性，中位 SUVmax 5.1 (2.3-21)。 [68Ga]Ga-DOTATATE PET/CT 中的中位 SUVmax 水平和检测到的肿瘤数量显着更高 (p=<0.001)。 5 名患者 (42%) 的 [68Ga]Ga-FAPI-04 PET/CT 完全 (n:2) 或几乎完全 (n:3) 阴性。两名 (17%) 患者的肿瘤中 SSTR/FAPI 摄取发生翻转。在 4 名患者 (33%) 中，[68Ga]Ga-FAPI-04 PET/CT 的肿瘤摄取或 PET 阳性病灶数量较差。只有一名患者 (8%) 在 [68Ga]Ga-FAPI-04 PET/CT 中肿瘤摄取较高。对FAPI为主的患者进行低剂量[177Lu]Lu-FAPI-46剂量测定；肾脏、肝脏、脾脏和全身每 GBq 吸收的辐射剂量分别为 1.26 Gy、0.36 Gy、0.32 Gy 和 0.2 Gy。每 GBq 的平均吸收剂量对于肝脏质量为 0.33 Gy，对于转移淋巴结为 0.41 Gy。我们的初步结果表明，[68Ga]Ga-FAPI-04 PET/CT 主要失败于对 [177Lu]Lu- 难治的分化良好的 NET。 DOTATATE 疗法作为替代诊断或治疗诊断剂的作用有限。需要对更多患者群体进行进一步研究，以确定 [68Ga]Ga-FAPI-04 PET/CT 对 NET 的影响。© 2023。作者获得 Springer-Verlag GmbH（德国 Springer 旗下公司）的独家许可自然。

We aimed to investigate the potential of [68Ga]Ga-FAPI-04 PET/CT as an alternative diagnostic and theranostic tool in well-differentiated NETs refractory to [177Lu]Lu-DOTATATE therapy.Patients who received at least two cycles of [177Lu]Lu-DOTATATE therapy for metastatic NETs and progressed under treatment were included. All patients had performed [68Ga]Ga-DOTATATE and [68Ga]Ga-FAPI-04 PET/CT within 3 weeks. The number of PET-positive lesions related to NETs and tumor sites was documented. Mann-Whitney U and chi-square tests were used to compare SUVmax levels of tracers and the number of detected metastases.Twelve patients (7 male, 5 female) who met the eligibility criteria were included in the study. Ten patients had grade 1-2 NET of various origins, and two had paraganglioma and pheochromocytoma. One hundred ninety-eight of 230 lesions (86%) were SSTR positive with a median SUVmax of 16.6 (2.2-76.5), and 88 of 230 lesions (38.2%) were [68Ga]Ga-FAPI-04 positive with a median SUVmax of 5.1 (2.3-21). Median SUVmax level and detected number of tumors were significantly higher in [68Ga]Ga-DOTATATE PET/CT (p=<0.001). [68Ga]Ga-FAPI-04 PET/CT was completely (n:2) or almost completely (n:3) negative in 5 (42%) patients. Two (17%) patients had flip-flop SSTR/FAPI uptake in tumors. In four patients (33%), tumor uptake or the number of PET-positive lesions was inferior in [68Ga]Ga-FAPI-04 PET/CT. In only one patient (8%), tumor uptakes were higher in [68Ga]Ga-FAPI-04 PET/CT. Low-dose [177Lu]Lu-FAPI-46 dosimetry was performed on the FAPI-dominant patient; absorbed radiation doses per GBq were 1.26 Gy, 0.36 Gy, 0.32 Gy, and 0.2 Gy for kidneys, liver, spleen, and total body, respectively. The mean absorbed dose per GBq was 0.33 Gy for liver mass and 0.41 Gy for metastatic lymph nodes.Our preliminary results demonstrated that [68Ga]Ga-FAPI-04 PET/CT mainly failed in well-differentiated NETs refractory to [177Lu]Lu-DOTATATE therapy and had a limited role as an alternative diagnostic or theranostic agent. Further investigations with a larger patient population are required to determine the impact of [68Ga]Ga-FAPI-04 PET/CT on NETs.© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.