External beam radiation, for example, requires about ten treatments over a 30-day period to deliver a total dose of 2,000 to 2,500 rads. Unfortunately, this dose is too small to be completely effective, but any larger amount would cause too much damage to healthy tissue. By contrast, radioactive microspheres injected into the liver safely deliver an average dose of 15,000 rads in one treatment with minimal damage to healthy surrounding tissue. Best of all, says Day, there are very few side effects. The single injection of microspheres into the bloodstream takes about one minute.
Delivery is through a catheter inserted into a major artery.
The patient is observed for a few hours after injection and, if no complications develop, can go home the same day and resume normal activity. Most patients rarely suffer side effects, though a few may have a low grade fever that lasts for 24 hours. The liver, which continues to function normally, remains radioactive for about four weeks, but the radiation is too weak to escape from the body. After the radioactivity in the microspheres disappears, they remain harmlessly in the liver. The glass microspheres are incredibly small, about one-third the diameter of a strand of hair.