[¹⁷⁷Lu]Lu-DOTATATE has been approved for progressive and inoperable gastroenteropancreatic neuroendocrine tumors (GEP-NETs) that overexpress somatostatin receptors. The absorbed doses by limiting organs and tumors can be quantified by serial postinfusion scintigraphy measurements of the -emissions from ¹⁷⁷Lu. The objective of this work was to explore how postinfusion [¹⁷⁷Lu]Lu-DOTATATE dosimetry could influence clinical management by predicting treatment efficacy (tumor shrinkage and survival) and toxicity. Methods: Patients with GEP-NETs treated with [¹⁷⁷Lu]Lu-DOTATATE between 2016 and 2022 and who underwent dosimetry were included. Absorbed doses were calculated for healthy organs (liver, kidneys, bone marrow, and spleen) and tumors using PLANET Dose and the local energy deposition method based on serial posttreatment SPECT/CT. Up to 5 lesions per site were selected and measured on images collected at baseline and 3 mo after treatment end (measurement masked to the somatostatin receptor imaging uptake). For toxicity assessment, laboratory parameters were regularly monitored. Clinical data, including time to death or progression, were collected from the patients’ health records. Correlations between absorbed doses by organs and toxicity and between absorbed doses by lesions and tumor volume variation were studied using regression models. Results: In total, 35 dosimetric studies were performed in patients with mostly grade 2 (77%) tumors and metastases in liver (89%), lymph nodes (77%), and bone (34%), and 146 lesions were analyzed: 1–9 lesions per patient, mostly liver metastases (65%) and lymph nodes (25%). The median total absorbed dose by tumors was 94.4 Gy. The absorbed doses by tumors significantly decreased between cycles. The absorbed dose by tumors was significantly associated with tumor volume variation (P < 0.001) 3 mo after treatment end, and it was a significant prognostic factor for survival. Toxicity analysis showed a correlation between the decrease of hematologic parameters such as lymphocytes or platelet concentrations and the absorbed doses by the spleen or bone marrow. The mean absorbed dose by the kidneys was not correlated with nephrotoxicity during the studied period. Conclusion: In patients treated with [¹⁷⁷Lu]Lu-DOTATATE for GEP-NETs, tumor and healthy organ dosimetry can predict survival and toxicities, thus influencing clinical management.

[ ¹⁷⁷ Lu]Lu-DOTATATE 已被批准用于治疗过度表达生长抑素受体的进行性且无法手术的胃肠胰神经内分泌肿瘤 (GEP-NET)。限制器官和肿瘤吸收的剂量可以通过对 ¹⁷⁷ Lu 的发射进行连续输注后闪烁扫描测量来量化。这项工作的目的是探讨输注后 [ ¹⁷⁷ Lu]Lu-DOTATATE 剂量测定如何通过预测治疗效果（肿瘤缩小和存活）和毒性来影响临床管理。方法：纳入 2016 年至 2022 年间接受 [ ¹⁷⁷ Lu]Lu-DOTATATE 治疗并接受剂量测定的 GEP-NET 患者。使用 PLANET Dose 和基于连续治疗后 SPECT/CT 的局部能量沉积方法计算健康器官（肝脏、肾脏、骨髓和脾脏）和肿瘤的吸收剂量。每个部位最多选择 5 个病灶，并根据基线和治疗结束后 3 个月收集的图像进行测量（测量掩盖了生长抑素受体成像摄取）。为了进行毒性评估，定期监测实验室参数。从患者的健康记录中收集临床数据，包括死亡时间或进展时间。使用回归模型研究了器官吸收剂量与毒性之间以及病变吸收剂量与肿瘤体积变化之间的相关性。结果：总共对大多数 2 级 (77%) 肿瘤和肝转移 (89%)、淋巴结转移 (77%) 和骨转移 (34%) 的患者进行了 35 项剂量测定研究，并对 146 个病灶进行了分析：每名患者有 1-9 个病灶，主要是肝转移 (65%) 和淋巴结转移 (25%)。肿瘤的中位总吸收剂量为 94.4 Gy。肿瘤吸收的剂量在周期之间显着减少。 肿瘤吸收剂量与治疗结束后3个月肿瘤体积变化显着相关（P < 0.001），并且是生存的重要预后因素。毒性分析显示血液学参数（例如淋巴细胞或血小板浓度）的降低与脾脏或骨髓吸收的剂量之间存在相关性。在研究期间，肾脏的平均吸收剂量与肾毒性不相关。结论：在接受 [ ¹⁷⁷ Lu]Lu-DOTATATE GEP-NET 治疗的患者中，肿瘤和健康器官剂量测定可以预测生存和毒性，从而影响临床管理。