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Radioembolization (Y90)

Radioembolization is a minimally invasive procedure that combines embolization and radiation therapy to treat liver cancer. Tiny glass or resin beads filled with the radioactive isotope yttrium Y-90 are placed inside the blood vessels that feed a tumor. This blocks the supply of blood to the cancer cells and delivers a high dose of radiation to the tumor while sparing normal tissue. It can help extend the lives of patients with inoperable tumors and improve their quality of life.

Your doctor will tell you how to prepare and instruct you on eating or drinking before the procedure. Tell your doctor if there's a possibility you are pregnant or breastfeeding and discuss any recent illnesses, medical conditions, allergies and medications you're taking, including herbal supplements and aspirin. You may be advised to stop taking aspirin, nonsteroidal anti-inflammatory drugs (NSAIDs) or blood thinners several days prior to your procedure. Leave jewelry at home and wear loose, comfortable clothing. You may be asked to wear a gown. Have someone drive you home afterward, and plan to have your contact with children and adults restricted for three to seven days.

What is Radioembolization?

Radioembolization is a combination of radiation therapy and a procedure called embolization to treat cancer of the liver.

Embolization is a minimally invasive treatment in which blood vessels or malformations within blood vessels are occluded, or blocked off, to prevent blood flow.

Radiation therapy is the use of a certain type of energy, called ionizing radiation, to kill cancer cells and shrink tumors. Unlike external beam therapy (EBT), in which high-energy x-ray beams generated by a machine are directed at the tumor from outside the body, radioembolization involves placing a radioactive material directly inside the body. This form of treatment is called internal radiation therapy.

In radioembolization, tiny glass or resin beads called microspheres are placed inside the blood vessels that feed a tumor in order to block the supply of blood to the cancer cells. Once these microspheres, which are filled with the radioactive isotope yttrium Y-90, become lodged at the tumor site, they deliver a high dose of radiation to the tumor and not to normal tissues.

What are some common uses of the procedure?

Radioembolization is used to treat tumors that were initially formed in the liver or have spread (or metastasized) to the liver from another part of the body. It is a palliative treatment, which means it does not provide a cure but instead helps slow down the growth of the disease and alleviate symptoms. The procedure is an option for patients who are not candidates for other treatments, including surgery or liver transplantation.

How should I prepare?

Several days before the procedure, you will have an office consultation with the interventional radiologist who will perform your procedure.

Prior to your procedure, your doctor may test your blood to check your kidney function and to determine if your blood clots normally.

You will also receive an angiogram that will produce pictures of the blood vessels feeding the tumor seven to 10 days before your procedure.

You will need to make plans for your return home following your procedure as your contact with children and adults may be restricted for three to seven days.

Tell your doctor about all the medications you take, including herbal supplements. List any allergies, especially to local anesthetic, general anesthesia, or contrast materials. Your doctor may tell you to stop taking aspirin, nonsteroidal anti-inflammatory drugs (NSAIDs) or blood thinners before your procedure.

Tell your doctor about recent illnesses or other medical conditions.

Women should always tell their doctor and technologist if they are pregnant. Doctors will not perform many tests during pregnancy to avoid exposing the fetus to radiation. If an x-ray is necessary, the doctor will take precautions to minimize radiation exposure to the baby. See the Safety in X-ray, Interventional Radiology and Nuclear Medicine Procedures page for more information about pregnancy and x-rays.

You will receive specific instructions on how to prepare, including any changes you need to make to your regular medication schedule.

You will be given a sedative prior to the procedure. You will receive specific instructions on eating and drinking before the procedure and will need to have a relative or friend accompany you and drive you home afterward.

The nurse will give you a gown to wear during the procedure.

What does the equipment look like?

X-ray equipment, a catheter and microspheres, or tiny glass beads filled with the radioisotope yttrium-90 are used in this procedure.

Radioembolization procedures are typically performed using x-ray guidance.

This exam typically uses a radiographic table, one or two x-ray tubes, and a video monitor. Fluoroscopy converts x-rays into video images. Doctors use it to watch and guide procedures. The x-ray machine and a detector suspended over the exam table produce the video.

A catheter is a long, thin plastic tube that is considerably smaller than a "pencil lead." It is about 1/8 inch in diameter.

Millions of glass beads, amounting to about half a teaspoon full, each of which is smaller in diameter than a human hair, deliver the ionizing radiation.

This procedure may use other equipment, including an intravenous line (IV), ultrasound machine and devices that monitor your heart beat and blood pressure.

How does the procedure work?

Using x-ray imaging and a contrast material to visualize the blood vessels, the interventional radiologist inserts a catheter through the skin into a blood vessel and advances it to the treatment site. The radiation-filled microspheres, or glass beads, are then inserted through the catheter and advanced to the blood vessels supplying the tumor with blood.

Once the microspheres lodge at the tumor site, they deliver a high dosage of radiation directly to the cancer cells. The microspheres will block the flow of blood to the tumor, depriving the diseased cells of the oxygen and nutrients needed to grow.

There are two primary blood vessels that bring blood to the liver. Normal liver tissue receives about 75 percent of its blood supply from the portal vein and about 25 percent from the hepatic artery and its branches. When a tumor grows in the liver, it receives almost all of its blood supply from the hepatic artery. Because radioactive microspheres are delivered through the hepatic artery, they reach the tumor very directly while sparing most of the healthy liver tissue.

The radiation from yttrium-90 continually decreases over a two-week period and disappears after 30 days. The tiny microspheres remain in the liver without causing any problems.

How is the procedure performed?

Image-guided, minimally invasive procedures such as radioembolization are most often performed by a specially trained interventional radiologist in an interventional radiology suite or occasionally in the operating room.

An initial arteriogram as described below is performed to visualize the upper abdominal arteries. At that time, arteries to areas of the stomach and duodenum which may have beads flow into them are closed with tiny coils of wire. At the end of the procedure, a bead with a nuclear medicine tracer on it is injected through the catheter to simulate the treatment. This will allow the interventional radiologist to calculate how much of the treatment dose can go to the lungs so that lung damage does not occur.

This procedure is often done on an outpatient basis. However, some patients may require admission following the procedure. Ask your doctor if you will need to be admitted.

Your doctor may provide medications to help prevent nausea and pain and antibiotics to help prevent infection.

The doctor or nurse will position you on your back.

The doctor or nurse may connect you to monitors that track your heart rate, blood pressure, oxygen level, and pulse.

A nurse or technologist will insert an intravenous (IV) line into a vein in your hand or arm to administer a sedative. This procedure may use moderate sedation. It does not require a breathing tube. However, some patients may require general anesthesia.

The nurse will sterilize the area of your body where the catheter is to be inserted. They will sterilize and cover this area with a surgical drape.

Your doctor will numb the area with a local anesthetic. This may briefly burn or sting before the area becomes numb.

The doctor will make a very small skin incision at the site.

Using image-guidance, the doctor inserts a catheter through the skin into the femoral artery (a large groin blood vessel) and maneuvers it to the treatment site.

Once the catheter is positioned in the branches of the hepatic artery that are feeding the tumor, the tiny glass beads or microspheres are injected through the catheter to the site. Over the next 10 to 14 days, the radiation will be released from the microspheres lodged in the blood vessels.

When the procedure is complete, the doctor will remove the catheter and apply pressure to stop any bleeding. Sometimes, your doctor may use a closure device to seal the small hole in the artery. This will allow you to move around more quickly. No stitches are visible on the skin. The nurse will cover this tiny opening in the skin with a dressing.

The doctor or nurse will remove your IV line before you go home.

This procedure is usually completed within an hour.

What will I experience during and after the procedure?

The doctor or nurse will attach devices to your body to monitor your heart rate and blood pressure.

You will feel a slight pinch when the nurse inserts the needle into your vein for the IV line and when they inject the local anesthetic. Most of the sensation is at the skin incision site. The doctor will numb this area using local anesthetic. You may feel pressure when the doctor inserts the catheter into the vein or artery. However, you will not feel serious discomfort.

If the procedure uses sedation, you will feel relaxed, sleepy, and comfortable. You may or may not remain awake, depending on how deeply you are sedated.

You may feel slight pressure when the doctor inserts the catheter, but no serious discomfort.

As the contrast material passes through your body, you may feel warm. This will quickly pass.

Radioembolization is generally painless; however, some patients may experience brief pain when the microspheres are injected. Pain that continues for more than six to eight hours usually means an ulcer has developed in the patient's stomach or duodenum. These ulcers would be treated as any other ulcer.

You will remain in the recovery room until you are completely awake and ready to return home.

Few patients experience some side effects called post-embolization syndrome, including nausea, vomiting and fever. Pain is the most common side effect that occurs because the blood supply to the treated area is cut off. It can readily be controlled by medications given by mouth or your IV.

These side effects usually subside within three to five days and may be alleviated with medication. You should tell your doctor if these symptoms last more than seven to 10 days.

You may also experience a low grade fever, lethargy and fatigue that usually last about one week.

You should be able to resume normal activities within a day or two following the procedure.

During the week following your radioembolization, you will need to limit contact with others while the radiation in your body diminishes. You should not do the following for at least seven days after the procedure:

  • sleep in the same bed as your partner.
  • use public transportation that requires you to sit next to another person for more than two hours.
  • come in close contact with children or pregnant women.

Radioembolization may be performed in two separate treatments if there are tumors on both sides of the liver. CT scans or MRI may be performed every three months following the treatment to determine the size of the treated tumor.

Who interprets the results and how do I get them?

After the procedure is complete, the interventional radiologist will tell you whether the procedure was a success.

Your interventional radiologist may recommend a follow-up visit.

This visit may include a physical check-up, imaging exam(s), and blood tests. During your follow-up visit, tell your doctor if you have noticed any side effects or changes.

What are the benefits vs. risks?


  • For patients with inoperable tumors, radioembolization can extend lives from months to years and improve quality of life. In some cases, it may allow for more curative options such as surgery or liver transplantation.
  • Radioembolization produces fewer side effects compared to standard radiation therapy.
  • No surgical incision is necessary—only a small nick in the skin that does not need stitches.
  • A higher dose of radiation to the tumor is given during radioembolization than with standard external beam therapy.


  • Any procedure that penetrates the skin carries a risk of infection. The chance of infection requiring antibiotic treatment appears to be less than one in 1,000.
  • There is a very slight risk of an allergic reaction if the procedure uses an injection of contrast material.
  • Any procedure that places a catheter inside a blood vessel carries certain risks. These risks include damage to the blood vessel, bruising or bleeding at the puncture site, and infection. The doctor will take precautions to mitigate these risks.
  • There is a risk that the microspheres may lodge in the wrong place, putting the patient at risk for an ulcer in the stomach or duodenum. This happens in approximately two percent of patients.
  • There is a risk of infection after radioembolization, even if an antibiotic has been given.
  • Because angiography is part of the procedure, there is a risk of an allergic reaction to the contrast material.

What are the limitations of Radioembolization?

Radioembolization is not recommended in cases of severe liver or kidney dysfunction, abnormal blood clotting or a blockage of the bile ducts. In some cases—despite liver dysfunction—radioembolization may be done in small amounts and in several procedures to try and minimize the effect on the normal liver.

Radioembolization is a treatment, not a cure. Approximately 70 to 95 percent of the patients will see improvement in the liver and, depending on the type of liver cancer, it may improve survival rates. Multiple studies show that up to 95 percent of patients with colorectal metastases (tumors that have spread) and up to 97 percent of patients with neuroendocrine tumors benefit from radioembolization.

This page was reviewed on January, 30, 2019


Radiologist and patient consultation. View full size with caption

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