131I-Lipiodol

131I-Lipiodol is a **radiopharmaceutical drug** that consists of Lipiodol (an ethyl ester mixture of iodinated fatty acids derived from poppy seed oil) labeled with radioactive iodine-131. It is primarily used for the **treatment of hepatocellular carcinoma (HCC)**, especially in patients with unresectable tumors, portal vein thrombosis, or unfit for transplantation. The agent selectively accumulates in HCC due to the tumor’s rich vascularity and lipophilic environment, allowing targeted internal radiation therapy. The mechanism of action is based on the **local emission of beta particles by iodine-131**, leading to cytotoxicity in the tumor while minimizing damage to surrounding healthy tissue. The drug is administered via **intra-arterial (usually hepatic artery) injection**. Originally approved under the brand name Lipiocis in 1995, it was withdrawn in 2010 due to lung toxicity concerns and has since been reintroduced (notably in India and Brazil). It is also investigated and used as adjuvant therapy post-resection in HCC.

Brand names

Lipiocis

Other names

Iodine-131 LipiodolIodine131 LipiodolIodine 131 Lipiodol131I-Ethiodized Oil