Evaluation of pharmacokinetics of 188Re-MN-16ET lipiodol and 90Y-microspheres for selective internal radiation therapy in a hepatocellular carcinoma rat model

1491 Objectives Lipiodol, an ethyl ester of poppy seed oil fatty acids, is widely used in both diagnosis and localized targeting treatment via transhepatic arterial embolization (TAE). This study conducted the pharmacokinetic study of 188Re-MN-16ET lipiodol and compared with that of clinically used 90Y-SIR-Spheres® in a N1S1 hepatoma-bearing SD rat model. Methods The 111In-microsphere (111In-MS) was prepared as a surrogate for 90Y-SIR-Spheres®. After injection of 111In-MS via the tail vein of normal SD rats, the in vivo stability was examined by quantitative analysis of ROIs derived from the planar imaging. After TAE of 188Re-MN-16ET lipiodol and 111In-MS into hepatoma-bearing rats, the biodistribution study and SPECT imaging at designated time points are performed to evaluate the pharmacokinetics. The radiation-absorbed doses of tumor and critical organs were estimated using OLINDA/EXM program based on the biodistribution data. Results A lung activity of 88% derived from planar imaging of N1S1 hepatoma-bearing SD rats at 48 h postinjection indicated good in vivo stability of 111In-MS. MicroSPECT imaging and biodistribution study revealed that both radiopharmaceuticals can accumulate in tumor after TAE. The tumor radioactivity at 48 h after TAE of 111In-MS and 111Re-MN-16ET/lipiodol was 10.93±2.15 and 9.40±5.69 %ID/g, respectively. The estimated effective liver dose was 5.13 mSv/MBq for 90Y-SIR-Spheres® and 1.14 mSv/MBq for 188Re-MN-16ET/lipiodol, while the tumor dose was 17.2 mGy/MBq and 3.65 mGy/MBq, respectively. Conclusions The results of our study suggested that 188Re-MN-16ET lipiodol, as well as 90Y-SIR-Spheres®, may be a potential therapeutic agent for hepatocellular carcinoma.