Fibroblast activation protein (FAP), expressed in the tumor microenvironment of a variety of cancers, has become a target of novel PET tracers. The purpose of this report is to evaluate the imaging characteristics of ⁶⁸Ga-FAP-2286, present the first—to our knowledge—dosimetry analysis to date, and compare the agent with ¹⁸F-FDG and FAPI compounds. Methods: Patients were administered 219 ± 43 MBq of ⁶⁸Ga-FAP-2286 and scanned after 60 min. Uptake was measured in up to 5 lesions per patient and within the kidneys, spleen, liver, and mediastinum (blood pool). Absorbed doses were evaluated using MIM Encore and OLINDA/EXM version 1.1 using the International Commission on Radiological Protection publication 103 tissue weighting factor. Results: Forty-six patients were imaged with ⁶⁸Ga-FAP-2286 PET. The highest average uptake was seen in sarcoma, cholangiocarcinoma, and colon cancer. The lowest uptake was found in lung cancer and testicular cancer. The average SUV_max was significantly higher on ⁶⁸Ga-FAP-2286 PET than on ¹⁸F-FDG PET in cholangiocarcinoma (18.2 ± 6.4 vs. 9.1 ± 5.0, P = 0.007), breast cancer (11.1 ± 6.8 vs. 4.1 ± 2.2, P < 0.001), colon cancer (13.8 ± 2.2 vs. 7.6 ± 1.7, P = 0.001), hepatocellular carcinoma (9.3 ± 3.5 vs. 4.7 ± 1.3, P = 0.01), head and neck cancer (11.3 ± 3.5 vs. 7.6 ± 5.5, P = 0.04), and pancreatic adenocarcinoma (7.4 ± 1.8 vs. 3.7 ± 1.0, P = 0.01). The total-body effective dose was estimated at 1.16E−02 mSv/MBq, with the greatest absorbed organ dose in the urinary bladder wall (9.98E−02 mGy/MBq). Conclusion: ⁶⁸Ga-FAP-2286 biodistribution, dosimetry, and tumor uptake were similar to those of previously reported FAPI compounds. Additionally,⁶⁸Ga-FAP-2286 PET had consistently higher uptake than ¹⁸F-FDG PET. These results are especially promising in the setting of small-volume disease and differentiating tumor from inflammatory uptake.

成纤维细胞激活蛋白（FAP）在多种癌症的肿瘤微环境中表达，已成为新型 PET 示踪剂的靶点。本报告的目的是评估 ⁶⁸ Ga-FAP-2286 的成像特性，提出迄今为止我们所知的第一个剂量测定分析，并将该试剂与 ¹⁸ 进行比较F-FDG 和 FAPI 化合物。方法：向患者施用 219 ± 43 MBq ⁶⁸ Ga-FAP-2286，并在 60 分钟后进行扫描。对每位患者最多 5 个病灶以及肾脏、脾脏、肝脏和纵隔（血池）内的摄取进行测量。使用 MIM Encore 和 OLINDA/EXM 1.1 版并使用国际放射防护委员会出版物 103 组织权重因子来评估吸收剂量。结果：46 名患者使用 ⁶⁸ Ga-FAP-2286 PET 进行成像。肉瘤、胆管癌和结肠癌的平均摄取量最高。肺癌和睾丸癌的摄取量最低。在胆管癌中， ⁶⁸ Ga-FAP-2286 PET 的平均 SUV _max 显着高于 ¹⁸ F-FDG PET（18.2 ± 6.4 vs. 9.1 ± 5.0，P = 0.007）、乳腺癌（11.1 ± 6.8 vs. 4.1 ± 2.2，P < 0.001）、结肠癌（13.8 ± 2.2 vs. 7.6 ± 1.7，P = 0.001）、肝细胞癌（9.3 ± 3.5 vs. 4.7） ± 1.3，P = 0.01）、头颈癌（11.3 ± 3.5 vs. 7.6 ± 5.5，P = 0.04）和胰腺癌（7.4 ± 1.8 vs. 3.7 ± 1.0，P = 0.01）。全身有效剂量估计为 1.16E−02 mSv/MBq，其中最大吸收器官剂量在膀胱壁（9.98E−02 mGy/MBq）。结论： ⁶⁸ Ga-FAP-2286 的生物分布、剂量测定和肿瘤摄取与之前报道的 FAPI 化合物相似。 此外， ⁶⁸ Ga-FAP-2286 PET 的吸收率始终高于 ¹⁸ F-FDG PET。这些结果在小体积疾病和区分肿瘤与炎症吸收的情况下特别有希望。