This study assesses the usefulness of intra-arterial injection of iodized oil (Lipiodol) as a tool for evaluating the therapeutic choice in a series of 72 consecutive patients with hepatocellular carcinoma (HCC). In 52 of these patients a scintigraphic study of the biodistribution of iodized oil was done, using 131I-iodized oil injection. A single tumor was detected in only 17 cases; 18 patients had a tumor involving only 1 lobe; in 7 cases CT scan disclosed a minute nodule in the opposite lobe of the main tumor. Eighteen patients had a portal thrombosis; in 12 of these cases CT scan showed iodized oil in the tumor emboli. The degree of intratumoral retention of iodized oil depended on the size of tumors and on the presence of arterioportal shunts. Our study demonstrates that only a few patients (4%) with HCC might benefit from curative surgery. The therapeutic benefit of methods using iodized oil injection might be estimated by means of its biodistribution variables (CT and/or scintigraphic data).