Biodistribution of lipiodol following hepatic arterial injection.

Lipiodol, a derivative of poppy seed oil, has been used angiographically to improve visualisation of small liver tumours. We have utilised this finding to determine whether intrahepatic arterial injection of lipiodol can be used as a vehicle to deliver selectively 131I into liver tumours. Two groups of rats were studied. Group 1 (control, no liver tumour) received 0.1 ml 131I-lipiodol (1 microCi) into the hepatic artery. Animals were killed at regular time intervals over 30 days and organs were submitted to well-counting. Over 90% of activity remained in the liver at 6 h. Eighty per cent activity was lost from the normal liver, to be excreted in the urine over 30 days. Group 2 animals received intraportal injections of 7.5 x 10(5) MC28 sarcoma cells. Multiple liver metastases were present after 14 days. Animals were similarly studied at each time interval and samples from tumour and normal liver were submitted to well-counting. Lipiodol was selectively retained within tumour and cleared from normal liver. 131I-lipiodol may prove valuable as a delivery agent for radio/chemotherapy to liver metastases.