Evaluating the Potential of 188Re-ECD/Lipiodol as a Therapeutic Radiopharmaceutical by Intratumoral Injection for Hepatoma Treatment

Abstract Background/Objectives: Intratumoral injection of a radiopharmaceutical is a potential modality to treat liver tumors. Rhenium-188 (188Re) was used to chelate with ethyl cysteinate dimer (ECD) in lipiodol solution to form 188Re-ECD/lipiodol, which was then evaluated for its therapeutic potential in a rodent hepatoma model. Materials and Methods: Male Sprague-Dawley rats were implanted with N1-S1 hepatoma cells orthotopically and randomly divided into two groups. Group 1 (n = 29) and group 2 (n = 10) received 188Re-ECD/lipiodol (30.4 ± 21.8 MBq/0.1 mL) and 0.1 mL of normal saline by intratumoral injection, respectively. Three rats in group 1 were imaged by micro–single-photon emission computed tomography/computed tomography scan to evaluate the biodistribution pattern. All rats were monitored for change of tumor size and survival rate after 2 months. Results: The in vitro stability test showed that 188Re-ECD was well-retained in the lipiodol phase for 48 hours. The biodistribution image revealed th...