SIRT – known as selective internal radiation therapy is a relatively new procedure in the medical world from what we know and has just gone through a very in depth and successful trial in England that spanned over a number of years. This data all needs to be collected and evaluated and within the next few years decided wether it will be available on the NHS.
What is it though? Well it is a specific way of giving radiotherapy directly to the liver, be that tumours from primary liver cancer or secondary tumours (from the bowel in my case). It is a specific targeted radiotherapy for tumours that cannot be removed by surgery. It uses microscopic radioactive beads that are fed through your hepatic artery (main blood vessel leading to the liver). Each bead is smaller than the width of a human hair, yes TINY!!!
It works by this tiny but potent microspheres gathering around the tumour through the blood vessels, therefore blocking the blood supply to the tumours and whilst there, radiating in order to break down the tumours. the radiation only goes as far as a few millimetres so therefore preventing damage to healthy tissue.
So what happens? Well it is a procedure that runs over a series of weeks and requires a number of sessions. The two main sessions which are the prep/planning procedure and then the actual SIRT (which can be broken down into a few smaller procedures).
Planning or prep procedure – involves an angiogram which looks at the blood supply to the liver. The doctor (interventional radiologist) blocks off tiny blood vessels that lead to other areas of the body like the stomach or lungs. This stops the SIRT microspheres from travelling to other areas of the body and damaging healthy tissue. Doctor goes in through a small incision in the groin (usually) where a catheter joins the femoral artery. Using x-rays, the doctor guides the catheter into your liver. They then inject a dye to show up the blood vessels. The doctor can see if there are blood vessels that lead to other areas of the body and will block these off preventing the dye (at this stage) and the micro-beads (later stage) getting to other organs. This procedure also involves a lung shunting scan, at the end of the planning angiogram a radioactive dye (similar to micro-beads) is inserted through the catheter. You then have a scan that picks up the radioactive dye this is called a lung shunting scan. This takes about an hour. It shows where the micro-beads will go when having the treatment. This scan determines wether it is safe to go ahead.
SIRT – This normally happens 1 or 2 weeks after the planning or prep procedure. To have SIRT another angiogram is performed when the catheter is in the right place, the doctor slowly injects the micro-beads into the liver. The whole process takes about an hour. After the treatment need to lie flat for a few hours to allow the wound to heal properly. Most people need to stay in hospital overnight.