Prostate-specific membrane antigen (PSMA) and gastrin-releasing peptide receptors are both overexpressed in prostate cancer (PC) but may provide complementary information.⁶⁸Ga-PSMA-R2 and ⁶⁸Ga-NeoB (DOTA-p-aminomethylaniline-diglycolic acid-DPhe-Gln-Trp-Ala-Val-Gly-His-NH-CH[CH₂-CH(CH₃)₂]₂) are novel PET radiopharmaceuticals that were developed for theranostic use. In this phase II imaging study, we assessed the feasibility, safety, and diagnostic performance of ⁶⁸Ga-NeoB and ⁶⁸Ga-PSMA-R2 PET/MRI for detection of biochemically recurrent PC. Methods: We prospectively enrolled 27 men with suspected biochemically recurrent PC after initial treatment but noncontributory conventional imaging results (negative or equivocal findings on MRI, CT, and/or bone scan). Participants underwent ⁶⁸Ga-NeoB and ⁶⁸Ga-PSMA-R2 PET/MRI within 2 wk in noncontrolled order. The SUV_max of putative PC lesions was measured and compared with a composite reference standard (histopathology, follow-up imaging, prostate-specific antigen change). The SUV_max and SUV_mean of background organs were measured. Vital signs were recorded before injection of the radiopharmaceuticals and after the scans. Adverse events were recorded up to 72 h after each scan. Results: The prostate-specific antigen level at enrollment was 3.5 ± 3.9 ng/mL (range, 0.3–13.5 ng/mL). ⁶⁸Ga-NeoB PET/MRI detected 31 lesions in 18 patients (66.7%), whereas ⁶⁸Ga-PSMA-R2 identified 20 lesions in 15 participants (55.6%). ⁶⁸Ga-NeoB PET/MRI showed higher sensitivity (85.7% vs. 71.4%), accuracy (88.9% vs. 77.8%), and negative predictive value (66.7% vs. 50.0%) than ⁶⁸Ga-PSMA-R2, whereas specificity and positive predictive value were equally high (100.0% for both). In 6 patients, ⁶⁸Ga-NeoB PET/MRI identified 14 lesions that were false-negative on ⁶⁸Ga-PSMA-R2 PET/MRI. The mean lesion SUV_max was 6.6 ± 3.2 (range, 2.9–13.2) for ⁶⁸Ga-NeoB and 4.4 ± 1.5 (range, 2.6–8.8) for ⁶⁸Ga-PSMA-R2 (P = 0.019). Overall lower uptake was noted in tumors and background organs for ⁶⁸Ga-PSMA-R2. There were no significant changes in vital signs before and after the scans. No adverse events were reported in the 72-h period after scans. Conclusion: ⁶⁸Ga-NeoB and ⁶⁸Ga-PSMA-R2 are safe for diagnostic imaging. ⁶⁸Ga-NeoB PET/MRI showed better diagnostic performance than ⁶⁸Ga-PSMA-R2. ⁶⁸Ga-PSMA-R2 showed overall lower uptake, equally in background organs and tumors, and might therefore not be an ideal theranostic compound. Further evaluation in larger cohorts is needed to confirm our preliminary data.

前列腺特异性膜抗原 (PSMA) 和胃泌素释放肽受体在前列腺癌 (PC) 中均过度表达，但可能提供补充信息。 ⁶⁸ Ga-PSMA-R2 和 ⁶⁸ Ga-NeoB (DOTA-对氨基甲基苯胺-二甘醇酸-DPhe-Gln-Trp-Ala-Val-Gly-His-NH-CH [CH ₂ -CH(CH ₃ ) ₂ ] ₂ ) 是为治疗诊断用途而开发的新型 PET 放射性药物。在这项 II 期成像研究中，我们评估了 ⁶⁸ Ga-NeoB 和 ⁶⁸ Ga-PSMA-R2 PET/MRI 用于检测生化复发 PC 的可行性、安全性和诊断性能。方法：我们前瞻性地招募了 27 名在初步治疗后疑似生化复发性 PC 但常规影像学结果无贡献的男性（MRI、CT 和/或骨扫描结果阴性或模棱两可）。参与者在 2 周内以非对照顺序接受 ⁶⁸ Ga-NeoB 和 ⁶⁸ Ga-PSMA-R2 PET/MRI。测量假定 PC 病变的 SUV _max 并与综合参考标准（组织病理学、随访成像、前列腺特异性抗原变化）进行比较。测量背景器官的SUV _max 和SUV _mean 。在注射放射性药物之前和扫描之后记录生命体征。每次扫描后 72 小时内记录不良事件。结果：入组时前列腺特异性抗原水平为 3.5 ± 3.9 ng/mL（范围，0.3–13.5 ng/mL）。 ⁶⁸ Ga-NeoB PET/MRI 在 18 名患者 (66.7%) 中检测到 31 个病变，而 ⁶⁸ Ga-PSMA-R2 在 15 名参与者 (55.6%) 中检测到 20 个病变。 ⁶⁸ Ga-NeoB PET/MRI 显示出更高的灵敏度（85.7% vs. 71.4%）、准确度（88.9% vs. 77.8%）和阴性预测值（66.7% vs. 50.8%）。0%）高于 ⁶⁸ Ga-PSMA-R2，而特异性和阳性预测值同样高（均为 100.0%）。在 6 名患者中， ⁶⁸ Ga-NeoB PET/MRI 识别出 14 个在 ⁶⁸ Ga-PSMA-R2 PET/MRI 上呈假阴性的病变。 ⁶⁸ Ga-NeoB 的平均损伤 SUV _max 为 6.6 ± 3.2（范围，2.9–13.2）， ⁶⁸ 的平均损伤 SUV _max 为 4.4 ± 1.5（范围，2.6–8.8）。 b21> Ga-PSMA-R2 (P = 0.019)。肿瘤和背景器官中对 ⁶⁸ Ga-PSMA-R2 的总体摄取量较低。扫描前后生命体征没有明显变化。扫描后 72 小时内未报告不良事件。结论： ⁶⁸ Ga-NeoB和 ⁶⁸ Ga-PSMA-R2对于诊断成像是安全的。 ⁶⁸ Ga-NeoB PET/MRI 显示出比 ⁶⁸ Ga-PSMA-R2 更好的诊断性能。 ⁶⁸ Ga-PSMA-R2 在背景器官和肿瘤中表现出整体较低的摄取，因此可能不是理想的治疗诊断化合物。需要对更大的队列进行进一步评估以确认我们的初步数据。