Selective Internal Radiation Therapy (SIRT)

Radioembolization is a minimally-invasive treatment used to treat primary or metastatic liver cancer. It may also be called intra-arterial brachytherapy or Selective Internal Radiation Therapy (SIRT) and it uses microspheres withYttrium-90, which are radioactive beads, to treat the cancer. These tiny beads, or microspheres, are very small at 20-30 micrometers (approximately one 25 thousandth of an inch) in diameter, and are placed directly into the tumor. The beads emit high radiation for approximately 10-12 days from the inside of the tumor to shrink it.

If your doctor feels you might be a candidate for this type of treatment he or she will refer you to the Vascular Interventional Radiology group. This group is made up of Interventional Radiologists, registered nurses, and a physicist who will all work with you to evaluate, plan, and carry out your treatment. This treatment is a palliative, not a curative treatment and can be used to treat liver cancer that can not be removed with surgery, has the potential to shrink your tumors or downstage them so you are eligible for other treatments, surgery, or a liver transplant. In some cases, this treatment has been shown to extend patients lives while improving quality of life for patients living with cancer.


Your doctor will discuss all your treatment options with you in the Interventional Radiology Clinic before scheduling you for a treatment. Here you will meet the Interventional Radiologist who will perform your procedure and the nurse that will follow you before and after your treatment. They will be reviewing your history, current list of medications, labs, CT, MRI, or PET scans.

It is possible you will not be a candidate for radioembolization treatment because of abnormal liver function, abnormal or no arteries near your liver tumors, a very large portion of your liver is covered by tumors, or your bilirubin, albumin, or other lab values are out of normal range. If you are not a candidate your doctor will work with your medical oncologist to help you choose the best options for you.

If you are a candidate for this procedure you will undergo a planning arteriogram to evaluate the blood supply to your liver. Liver/lung shunt evaluation will be performed with injection of Technetium 99m labeled MAA into the hepatic artery. This in essence simulates the actual deliver of the yttrium-90 microspheres and allows us to evaluate the expected distribution of the microspheres within the liver and to make sure that too many spheres don't end up outside of the liver in the gut or within the lungs. During this procedure, certain arteries may need to be embolized (blocked off) to prevent the radioactive beads from reaching other organs. If the hepatic arterial anatomy is appropriate and there is no evidence of significant shunt of spheres to the lungs or intestine we will schedule a date for the actual implantation of the yttrium labeled microspheres.


  • Because the radiation destroys the tumor cells from within the tumor there is minimal injury to the surrounding healthy liver tissue. This also lessens the side effects you feel from the radiation.
  • Once you have received the radioactive microspheres, the external radiation exposure to other individuals is very low and highly unlikely to cause harm. To be cautious for 3 days following therapy minimize contact (within a yard) with children under the age of 10 and pregnant women.
  • Radioembolization is the only treatment approved in the United States to treat primary liver cancer in patients with portal vein thrombosis (PVT).
  • Short recovery period.


  • After the procedure some patients may have the following:
    • Fatigue (usually lasts 10-12 days)
    • Mild abdominal discomfort /bloating
    • Nausea/vomiting may be present 1-2 days post procedure due to sedation medications given during the procedure
    • Fever (10% of patients)
  • Even after safety screening, there is a very small risk (less than 1%) that radiation could be delivered to your lungs and/or digestive tract, resulting in:
    • Lung damage, which could include swelling, scarring or shortness of breath.
    • Irritation of the gastrointestinal tract, which could result in chronic pain, nausea, vomiting, ulcers, bleeding, or pancreatitis.
  • Any procedure where the skin is penetrated carries a risk of infection.
  • Any procedure that requires placement of a catheter (small tube) inside the blood vessel can cause damage to the vessel, bruising or bleeding at the puncture site.
  • Because of the contrast material used to view your vessels with x-ray there is a chance of allergic reaction to the contrast. There is also a risk for kidney damage for those with diabetes or pre-existing kidney disease.

These effects vary for every patient. Medicines are given to help prevent or relieve most of these side effects. Also, steps can be taken to prevent allergic reactions to contrast and lessen the chance of kidney damage for those at risk. If you have any questions on these risks discuss them with your doctor.

Yttrium 90 microsphere treatment of the liver:

Once it has been determined that you are an appropriate candidate for the therapy, a dose will be ordered and will take 1-2 weeks to arrive. You will undergo a second angiogram (very much similar to the planning angiogram) during which the spheres will be instilled into the affected portion of your liver. Once the treatment is complete the catheters will be removed and you will be observed in the hospital. If you do well, you will be discharged same day, making this an outpatient procedure. If you have any complications like fever, vomiting or pain then you will stay in the hospital until these have resolved. Most patients tolerate the procedure quite well and are discharged as outpatients.

What happens after the procedure?

Since conscious sedation medicine was administered and the femoral artery was punctured, you will be required to stay to recover for 4-6 hours after the end of the procedure. While in recovery, you are monitored closely for signs of bleeding from the artery in the groin and ensure that the effects of the sedation have worn off. Patients must have a responsible adult available to drive/escort you home from the hospital.

Since the artery is a high pressure system, patients should refrain from lifting more than 10 lbs, refrain from strenuous activity or anything which causes abdominal distension for the following 48-72 hours. Any straining such as vomiting, coughing, forced bowel movements could dislodge the clot that forms to seal the artery and cause bleeding. If you note any signs of bleeding, such as bulging under the skin the size of a golf ball, put direct pressure to the area, call your doctor, and go to the nearest emergency room or call 911 for assistance.

Do not take a tub bath, go in a hot tub or submerge in water for 5 days. Leave the sterile dressing on for 24 hours, then shower and clean the area daily.  Place a clean Band-Aid over the site each day for 5 days. Report any signs of infection (redness, swelling, discharge and fever) to your doctor.Take prescribed medicines as directed. For some this may include:

  • Medicine to help protect stomach upset
  • An antibiotic

Be sure to call the Interventional Radiology Office immediately at 802-847-8359 if you notice any of the following:

  • Swelling or bleeding at the puncture site
  • Fever higher than 101 F
  • Redness at the puncture site, or increasing tenderness or discharge at the puncture site.

Is there any follow-up needed?

In 1 week, an Interventional Radiology staff member will call to see how you are feeling. At 4 weeks, all patients have blood tests repeated. Repeat CT/MRI and/or PET scans are done at Fletcher Allen Health Care Hospital.You then will have a one-month office visit with the radiologist in the Interventional Radiology clinic to review your scans and blood work. At that time, it will be decided if a second radioembolization treatment is needed. To provide safe care, we are able to treat only one lobe of the liver at a time with radioembolization. Therefore, if you have tumors in both lobes of your liver, you may need a second treatment.


If you have any questions or need to reschedule an appointment please feel free to contact the Interventional Radiology Office at 802- 847-8359. Our business hours are Monday – Friday 8:30 a.m. to 5 p.m. Someone is available to take your call after hours for emergencies.

This information is provided by the Fletcher Allen Health Care, Department of Radiology, Division of Interventional Radiology and is not intended to replace the medical advice of your doctor or health care provider. Please consult your health care provider for advice about a specific medical condition. For additional health information, please contact your health care provider.