With this technique, interventional radiologists pass special plastic tubes (called catheters) into the arteries of the liver, directly seeding particles delivering radiation into tumor. The catheters are usually passed up to the liver through one of the main arteries in the groin or wrist. This technique is excellent for killing several small tumors in the same area or tumors that cannot be treated effectively by any other method. One advantage of this technique is that liver tumors get almost all their blood supply from arteries, but healthy areas of the liver get most of their blood from veins.

The technique is sometimes used immediately before a liver transplant, in an attempt to kill all the tumor cells so that they do not move into the new liver. This procedure is done under sedation.