Selective Internal Radiation Therapy (SIRT)

Selective Internal Radiation Therapy (SIRT) is a treatment for liver cancer that cannot be removed by surgery. It delivers radiation to the liver tumours via tiny radioactive beads that are injected into your bloodstream.

The treatment has two stages, separated by one to two weeks. In both stages, an angiogram is done. An Angiogram is a type of X-ray used to check blood vessels. This is followed by a radioactive injection, and then a gamma camera scan. The complete procedure is explained in detail below. 

 

How does it work?

SIRT therapy consists of two stages, usually carried out one or two weeks apart. Both stages require you to have an angiogram followed by a radioactive injection and then a gamma camera scan.

During the first stage the doctor will assess your liver’s blood supply, blocking off vessels that are not directly feeding the tumour through a process called embolization. Next, a radioactive tracer mimicking the treatment is injected. You will then have a Nuclear Medicine scan to show where this tracer has gone to within your body. This will help us to determine the next step of your treatment.

For the second stage, tiny beads, known as microspheres, are injected into the blood vessels that supply the tumour. These are injected through a small tube called a catheter. The microspheres have a diameter less than the width of a human hair and contain yttrium-90 (Y-90) which makes them radioactive. These spheres lodge in the small blood vessels of the tumour and then deliver radiation over a short distance to kill surrounding tumour cells. The short range of this radiation helps damage the cancerous tumour cells while protecting the nearby healthy tissue.