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This study aimed to evaluate the safety and efficacy of multiple cycles of 177Lu-DOTA-Evans blue (EB)-TATE peptide receptor radionuclide therapy (PRRT) at escalating doses in neuroendocrine tumors (NETs). Methods: Thirty-two NET patients were randomly divided into 3 groups and treated with escalating doses. Group A received 1.17 ± 0.09 GBq/cycle; group B, 1.89 ± 0.53 GBq/cycle; and group C, 3.97 ± 0.84 GBq/cycle. The treatment was planned for up to 3 cycles. Treatment-related adverse events were graded according to the National Cancer Institute Common Terminology Criteria for Adverse Events (CTCAE), version 5.0. Treatment response was evaluated according to the European Organisation for Research and Treatment of Cancer criteria and modified PERCIST. Results: Administration of PRRT was well tolerated, without life-threatening adverse events (CTCAE grade 4). CTCAE grade 3 hematotoxicity was recorded in 1 patient (16.6%) in group B (thrombocytopenia) and 3 patients (21.4%) in group C (thrombocytopenia in 3, anemia in 1). CTCAE grade 3 hepatotoxicity (elevated aspartate aminotransferase) was recorded in 1 patient in group A (8.3%) and 1 patient in group C (7.1%). No nephrotoxicity was observed. According to the criteria of the European Organisation for Research and Treatment of Cancer, the overall disease response rates were similar in groups A, B, and C (50.0%, 50.0%, and 42.9%, respectively), and the overall disease control rates were higher in groups B (83.3%) and C (71.5%) than in group A (66.7%). According to modified PERCIST, a lower disease response rate but a similar disease control rate were found. When a comparable baseline SUVmax ranging from 15 to 40 was selected, the percentage change in SUVmax increased slightly in group A (2.1% ± 40.8%) but decreased significantly in groups B and C (-38.7% ± 10.0% and -14.7% ± 20.0%, respectively) after the first PRRT (P = 0.001) and decreased in all 3 groups after the third PRRT (groups A, B, and C: -6.9% ± 42.3%, -49.2% ± 30.9%, -11.9% ± 37.9%, respectively; P = 0.044). Conclusion: Dose escalations of up to 3.97 GBq/cycle seem to be well tolerated for 177Lu-DOTA-EB-TATE. 177Lu-DOTA-EB-TATE doses of 1.89 and 3.97 GBq/cycle were effective in tumor control and more effective than 1.17 GBq/cycle.

(68)Ga-DOTA-JR11 is a somatostatin receptor subtype 2–specific antagonist used for PET/CT imaging. The purpose of this study was to compare (68)Ga-DOTA-JR11 and (68)Ga-DOTATATE PET/CT in patients with metastatic, well-differentiated neuroendocrine tumors. Methods: Patients with histologically proven, metastatic or unresectable, well-differentiated neuroendocrine tumors were prospectively recruited to this study. Each patient received an intravenous injection of (68)Ga-DOTATATE (155 ± 52 MBq) on the first day and (68)Ga-DOTA-JR11 (148 ± 52 MBq) on the second day. Whole-body PET/CT scans were performed at 40–60 min after injection on the same scanner. Physiologic normal-organ uptake, lesion numbers, and lesion uptake were compared. Results: Thirty-one patients were prospectively enrolled in the study. The SUV(max) of the spleen, renal cortex, adrenal glands, pituitary glands, stomach wall, normal liver parenchyma, small intestine, pancreas, and bone marrow was significantly lower on (68)Ga-DOTA-JR11 than on (68)Ga-DOTATATE PET/CT (P < 0.001). (68)Ga-DOTA-JR11 detected significantly more liver lesions (552 vs. 365, P = 0.001) but fewer bone lesions (158 vs. 388, P = 0.016) than (68)Ga-DOTATATE. The target-to-background ratio of liver lesions was significantly higher on (68)Ga-DOTA-JR11 (7.7 ± 5.4 vs. 3.4 ± 2.0, P < 0.001). (68)Ga-DOTA-JR11 and (68)Ga-DOTATATE PET/CT showed comparable results for primary tumors and lymph node metastases on both patient-based and lesion-based comparisons. Conclusion: (68)Ga-DOTA-JR11 performs better in detecting liver metastases, with a better tumor-to-background ratio, whereas (68)Ga-DOTATATE may outperform (68)Ga-DOTA-JR11 in the detection of bone metastases. However, the lower somatostatin receptor subtype 2 affinity of (68)Ga-DOTA-JR11 than of (177)Lu-DOTA-JR11 may limit its role as a diagnostic pair for the theranostic approach with (177)Lu-DOTA-JR11.