Importance Neuroendocrine tumors (NETs) express somatostatin receptors, which can be targeted with radiolabeled peptides. In a variety of solid tumors, radioguided surgery (RGS) has been used to guide surgical resection. Gallium 68 (⁶⁸Ga) dota peptides have been shown to be more accurate than other radioisotopes for detecting NETs. A pilot study previously demonstrated the feasibility and safety of ⁶⁸Ga-dotatate RGS for patients with NETs.

Objective To evaluate what intraoperative techniques and thresholds define positive lesions that warrant resection during ⁶⁸Ga-dotatate RGS.

Design, Setting, and Participants This prospective cohort study, conducted between October 23, 2013, and February 14, 2018, included 44 patients with NETs who underwent ⁶⁸Ga-dotatate RGS.

Intervention Gallium 68–dotatate RGS.

Main Outcomes and Measures The in vivo and ex vivo tumor to background ratio (TBR) was assessed for resected lesions and correlated with the histopathologic findings.

Results Forty-four patients (22 women and 22 men; mean [SD] age, 51.0 [13.7] years) had 133 lesions detected on preoperative imaging scans, with a diagnosis of a pancreatic NET (19 of 44 [43%]), gastrointestinal NET (22 of 44 [50%]), and pheochromocytoma or paraganglioma (3 of 44 [7%]). The TBR was obtained by normalizing to the omentum (106 of 133 [79.7%]) or other solid organs (27 of 133 [20.3%]). The omentum had a significantly lower mean (SD) count than other solid organs for background count activity 3 hours after injection (22.1 [17.0] vs 34.5 [39.0]; P < .001). The lesions containing NETs had a higher TBR than those that did not contain NETs (18.9 vs 4.4; P < .001). On a receiver operating characteristic curve analysis, a TBR of 2.5 had a sensitivity of 90% and a specificity of 25%, and a TBR of 16 had a sensitivity of 54% and a specificity of 81%.

Conclusions and Relevance A TBR of 2.5 or greater is a highly sensitive threshold for indicating a lesion to be consistent with a NET on histologic findings and thus warranting surgical resection. The omentum should be used as the background count activity for ⁶⁸Ga-dotatate RGS for patients with abdominal NETs.

重要性 神经内分泌肿瘤（NETs）表达生长抑素受体，可以用放射性标记的肽靶向。在各种实体瘤中，放射引导手术（RGS）已用于指导手术切除。镓68（⁶⁸ Ga）dota肽已被证明比其他放射性同位素更准确地检测NET。先前的一项先导研究证明了⁶⁸ Ga-dottate RGS对NET患者的可行性和安全性。

目的 评估哪些术中技术和阈值定义了在⁶⁸ Ga-点状RGS期间需要切除的阳性病变。

设计，设置和参与者 这项前瞻性队列研究于2013年10月23日至2018年2月14日之间进行，纳入了44例接受⁶⁸ Ga-dotat RGS治疗的NET患者。

干预 镓68-点状RGS。

主要结果和措施评估 体内和离体肿瘤与背景之比（TBR）切除的病变，并与组织病理学发现相关。

结果 44例患者（22名女性和22名男性；平均[SD]年龄为51.0 [13.7]岁）在术前影像学检查中发现133处病变，并诊断出胰腺网（19例，占44例[43％]），胃肠网（44个中的22个[50％]）和嗜铬细胞瘤或副神经节瘤（44个中的3个[7％]）。通过将网膜（133个中的106个[79.7％]）或其他实体器官（133个中的27个[20.3％]）标准化来获得TBR。大网膜注射后3小时的背景计数活动的平均（SD）计数显着低于其他实体器官（22.1 [17.0]对34.5 [39.0]；P  <.001）。包含NETs的病变的TBR比不包含NETs的病变高（18.9 vs 4.4; P <.001）。在接收器工作特性曲线分析中，TBR为2.5，灵敏度为90％，特异性为25％，TBR为16，灵敏度为54％，特异性为81％。

结论与相关性 TBR为2.5或更高是一个高度敏感的阈值，表明病变与组织学检查结果与NET一致，因此需要手术切除。大网膜应该用作腹网患者⁶⁸ Ga-dottate RGS的本底计数活动。