This page was reviewed under our medical and editorial policy by

Maurie Markman, MD, President, Medicine & Science at CTCA.

This page was updated on May 20, 2022.

Doctors may recommend that those diagnosed with liver cancer undergo a type of radiation therapy called radioembolization. This treatment slows the growth of liver cancer and reduces its symptoms.

The majority of patients with the most common form of liver cancer, hepatocellular carcinoma, aren’t diagnosed until the disease has reached an advanced stage—past the point when surgical removal of tumors and other treatments may be recommended. For some patients, radioembolization shrinks tumors to the point where a liver transplant becomes a possibility.

Oncologists also use this procedure to treat other types of cancer that have spread or metastasized to the liver. Secondary cancer—one that has spread from another organ, including the colon and the breast—causes more liver tumors than cancer that originates in the liver. Sometimes, radioembolization is used in combination with chemotherapy.

How does it work?

The procedure combines embolization—the process of blocking blood flow—with radiation therapy. Instead of standard radiation therapy in which a machine beams X-rays at the tumor, a surgeon injects radioactive beads into blood vessels feeding the tumor. Specifically, these microscopic glass or resin beads, called microspheres, are filled with the isotope yttrium-90, or Y-90 for short. They emit ionizing radiation designed to kill cancer cells. They stay in the area of the tumor, sparing surrounding healthy tissue, and also serve to block the tumor’s blood supply, starving the cancer of oxygen and nutrients.

The radiation’s effects may start to decrease in the days that follow and stop completely two weeks after that. The harmless beads remain in the body.

Before the procedure

Ahead of the procedure, you may undergo blood tests to measure your blood clotting and kidney functions. You may be asked about current medications and advised to avoid taking blood thinning drugs, including aspirin and some herbal supplements.

The arteries in your upper abdomen are mapped using a diagnostic test called an angiogram. This helps doctors visualize the blood vessels connected to the tumor. Locating the branches of the artery feeding the tumor and injecting them with the radioactive beads is designed to reduce damage to healthy liver tissue.

During this pre-procedure angiogram, a dye is injected into the bloodstream and shows up on X-rays that outline your blood vessels. You may feel some discomfort if a local anesthetic is injected at the incision site for the catheter. The injection of the contrast dye may cause a warm feeling.

During the procedure

On the day of the procedure, you may be given medication to prevent pain and nausea or a possible infection. You may feel slight discomfort when an intravenous (IV) line for sedation is placed into a vein.

The procedure starts with another angiogram, which serves as a roadmap for the radiologist. This involves making a small incision in the area of the upper hip and groin to place a needle into the femoral artery. To prevent the radioactive beads used in radioembolization from flowing into the tissues of the stomach and duodenum (the first section of the small intestine), tiny metal coils may be used to block blood vessels from the liver to those areas. A special bead may be injected and traced by X-ray imaging to calculate how much of the radioactive material could possibly end up in the lungs.

For the radioembolization, a thin catheter, about an eighth of an inch in diameter, is inserted and threaded up to the tumor site. Once the catheter reaches the tumor, the microbeads are injected. The dose amounts to about a half teaspoon. The catheter is removed and the incision closed.

After the procedure

Radioembolization generally is performed on an outpatient basis, so most patients go home the same day. To reduce exposing other people to radiation, you may be asked to avoid contact as much as possible for a few days, especially with pregnant women and children. For about a week afterward, you’ll need to sleep alone and not sit next to anyone for more than two hours.

Side effects and risks

All forms of embolization may block blood flow to nearby healthy tissue, with the possibility of causing damage. The chances rise with the size of the artery blocked. For that reason, liver function may suffer as a result, and the procedure may not be suitable for you if you have a liver heavily damaged by hepatitis or cirrhosis.

Still, radioembolization is considered minimally invasive and fairly painless, and it’s designed to spare healthy liver tissue. It causes fewer side effects than standard radiation therapy.

Common side effects after the procedure include:

  • Fatigue
  • Nausea
  • Pain
  • Low-grade fever, usually lasting a week or two

Less common but serious complications range from fluid buildup in the abdomen (ascites) to the microbeads flowing to the stomach or duodenum and causing an ulcer to the rare possibility of developing an inflamed pancreas or a liver abscess.

Expect some bruising at the insertion site for the catheter that’s used during the angiogram and radioembolization. Infection remains a risk, though very small, as with any surgical procedure.

Although an angiogram is considered low risk, an allergic reaction to the contrast dye may lead to kidney failure.


After the procedure, your care team may schedule a follow-up visit including blood tests and further imaging.

Radioembolization improves the health of 70 to 95 percent of patients with all types of liver cancer, according to the Radiological Society of North America and the American College of Radiology. As many as 95 percent of patients with colorectal cancer that spread to the liver and 97 percent of patients with neuroendocrine tumors have shown benefits from this therapy.

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