目的 探讨131I-BDI-1在荷人膀胱癌裸鼠模型中的体内生物分布和对肿瘤的靶向定位性能以及其生物安全性，并由此估算131I-BDI-1在人体内主要脏器的内照射吸收剂量和人体有效剂量。方法 通过氯胺-T法用131I溶液直接标记抗人膀胱癌单克隆抗体BDI-1，制备131I-BDI-1,荷人膀胱癌EJ细胞裸鼠尾静脉注射222kBq 131I-BDI-1后，于不同时刻处死动物，取感兴趣器官和组织，称重并测量放射性计数，计算131I-BDI-1在荷瘤裸鼠中的标准摄取值和靶/非靶组织比值。利用标准的MIRD数据表计算人体的%ID/g,通过 MIRDOSE3.1 软件估算131I-BDI-1对人体各个器官的辐射吸收剂量及有效剂量。 结果 生物分布数据示131I-BDI-1血液清除缓慢，肿瘤部位放射性明显持续滞留，除血液外，具有较高的靶/非靶组织比值。131I-BDI-1人体内照射的有效剂量为1.46×10−2mGy/MBq。结论 131I-BDI-1对肿瘤有良好的靶向性，有望成为一种新型的针对人膀胱癌肿瘤的诊治药物，其辐射吸收剂量较低，作为肿瘤治疗药物是安全的。

Objective To explore the biodistribution of 131I-BDI-1 in nude mice model bearing human bladder cancer, and to evaluate the medical internal radiation dose (MIRD) in major tissues and organs of human body. Methods Antihuman bladder carcinoma monoclonal antibodies BDI-1 was labeled with 131I directly by chloramine-T method to prepare 131I-BDI-1. Nude mice bearing human bladder cancer were injected 222 kBq of 131I-BDI-1 via tail vein. Then the mice were sacrificed at different time. Organs and tissues of interest were taken, weighed and radioactive counts were measured. Standard uptake value and ratio of target to non target tissues of 131I-BDI-1 in nude mice bearing tumor were calculated. Standard uptake value by the MIRD of 131I-BDI-1 in human body was calculated by software to estimate the effective dose of 131I-BDI-1 in standard human model. Results The biodistribution data showed that the blood clearance of 131I-BDI-1 was slow, and tumor radioactivity retention was long. The uptake ratio of target to non target tissues was high except tumor to blood. The effective dose of 131I-BDI-1 in standard human model was 1.46×10−2mGy/MBq. Conclusion 131I-BDI-1, can target human bladder cancer EJ and remains in the tumor for long time. The MIRD is reasonable .The result suggests radioiodine labeled BDI-1 may be a suitable agent for bladder tumor imaging and therapy.