前列腺特异性膜抗原 (PSMA) 靶向放射配体治疗 (RLT) 正在彻底改变转移性去势抵抗性前列腺癌 (mCRPC) 患者的治疗格局。本研究旨在针对伊朗 mCRPC 患者建立 [177Lu]Lu-PSMA-617 RLT 的患者特异性辐射剂量测定。12 名活检证实的前列腺癌患者（年龄 68.73 ± 5.26 年）接受了 6.62 ± 0.36 GBq [177Lu]Lu- PSMA-617 RLT。大约在给药后 4、48 和 72 小时采集治疗后全身平面扫描，并在 48 小时左右使用西门子 Symbia T2 进行单次 SPECT/CT 以获得累积活动。成像方案和剂量测定方法旨在平衡治疗后剂量测定的时间效率和准确性。使用准确的活动校准，通过将 SPECT/CT 图像作为源/几何图形导入层析成像发射 (GATE) 蒙特卡罗 (MC) 工具包的 Geant4 应用程序来计算 S 值。遵循医学内部辐射剂量 (MIRD) 方案，使用剂量因子和累积活动来计算危险器官 (OAR) 和肿瘤病变的后续吸收剂量 (AD)，以进行精确的剂量估计。使用 MC 方法，平均 AD 为肝、脾、左右肾、肿瘤病灶分别为0.11±0.04Gy/GBq、0.08±0.03Gy/GBq、0.34±0.09Gy/GBq、0.34±0.10Gy/GBq、0.8 3 ± 0.54 Gy/GBq,分别。值得注意的是，肿瘤病灶表现出显着较高的 AD，表明恶性细胞对放射性药物的摄取增强。本研究表明，mCRPC 患者中 [177Lu]Lu-PSMA-617 RLT 的 OAR 和肿瘤病灶的 AD 与现有文献一致。剂量测定结果表明，增加 [177Lu]Lu-PSMA-617 RLT 的给药活性是可行的，并且不会对 OAR 造成显着的不利影响风险，正如我们的数据所支持的。然而，为了验证更高剂量的安全性和有效性，建议进行进一步的临床随访研究。

Prostate-specific membrane antigen (PSMA)-targeted radioligand therapy (RLT) is revolutionizing the treatment landscape for metastatic castration-resistant prostate cancer (mCRPC) patients. This study aimed to establish patient-specific radiation dosimetry for [177Lu]Lu-PSMA-617 RLT in Iranian patients with mCRPC.Twelve biopsy-proven prostate cancer patients (aged 68.73 ± 5.26 yr) underwent 6.62 ± 0.36 GBq [177Lu]Lu-PSMA-617 RLT. Post-therapy whole-body planar scans were acquired approximately at 4, 48, and 72 h post-administration, alongside a single SPECT/CT around 48 h using Siemens Symbia T2 to obtain cumulated activity. An imaging protocol and dosimetry approach were designed to balance between time efficacy and accuracy in post-therapeutic dosimetry. Using accurate activity calibration, S-values were calculated by importing SPECT/CT images as the source/geometry into the Geant4 application for the tomographic emission (GATE) Monte Carlo (MC) toolkit. The Medical Internal Radiation Dose (MIRD) scheme was followed for subsequent absorbed dose (AD) calculations in organs at risk (OAR) and tumoral lesions using the dose actor and accumulated activities for precise dose estimations.Using the MC approach, the mean ADs to the liver, spleen, right and left kidneys, and tumor lesions were 0.11 ± 0.04 Gy/GBq, 0.08 ± 0.03 Gy/GBq, 0.34 ± 0.09 Gy/GBq, 0.34 ± 0.10 Gy/GBq, and 0.83 ± 0.54 Gy/GBq, respectively. Notably, tumoral lesions demonstrated significantly higher ADs, indicating enhanced uptake of radiopharmaceuticals by malignant cells.This study indicates that the ADs of OARs and tumoral lesions from [177Lu]Lu-PSMA-617 RLT in patients with mCRPC are consistent with existing literature. The dosimetry findings suggest that increasing the administered activity of [177Lu]Lu-PSMA-617 RLT is feasible and does not pose a significant risk of adverse effects on OARs, as supported by our data. However, to validate the safety and efficacy of higher doses, further clinical follow-up studies are recommended.