Radiosurgery

What is Radiosurgery?

Radiosurgery is a medical procedure used for brain tumour treatment, as well as treatment for other forms of cancer. It uses non-invasive, highly precise radiation beams, usually in one single session, to destroy painlessly or shrink tumours that could otherwise be inaccessible for open surgery.

It is also known as stereotactic radiosurgery (SRS) when used to target brain tumours.

Radiosurgery is effective on discrete, well encapsulated and quite small brain tumours (less then 3 to 4 cm in diameter). Super skinny beams of x-rays or gamma rays are directed at the tumour from different angles. For this procedure, you wear a rigid head frame. The therapy may be given during a single visit (stereotactic radiosurgery) or over several visits. You may also hear these being referred to as Gamma Knife and Cyberknife. These are the commercial names, like Hoover is for vacuum cleaners.

There are some differences between the two.

The Cyberknife is a low energy linear accelerator and does not require you to be placed in a frame fixed to the skull. It is frameless SRS.

The Gamma Knife is good for particularly small targets and is given after a radiation source helmet is placed on your head. There is also Novalis Tx Radiosurgery.

These all offer a similar (but not identical) minimally invasive approach to brain tumour treatment, and are available privately and through the NHS.

Don’t be misled by the words surgery and knife. There is no invasive surgery, so no knife. In this type of treatment though the beams converge on a single point – the tumour. There is no margin added.

In addition to cancer, radiosurgery is also shown to be beneficial for the treatment of non-cancerous conditions, including disorders such as arteriovenous malformations (AVMs) which are an abnormal connection between veins and arteries that can be dangerous when occurring in the brain. Radiosurgery is an established medical procedure and was first developed in 1951.

 

What is the difference between radiosurgery and radiotherapy?

Radiotherapy also uses non-invasive radiation beams to treat cancer cells and shrink tumours. But unlike radiosurgery, radiotherapy is normally given as a series of short, daily treatments called fractions and not a single session with a higher dose of radiation. How many fractions or daily treatments will depend on the tumour type and fitness of the patient.

 

How does radiosurgery and radiotherapy treat cancer?

Radiosurgery and radiotherapy use high-energy radiation beams to deliver the prescribed radiation dose directly to tumour cells, causing them to shrink or die. Treatment results, which are visible on follow-up scans, include shrinkage of the tumour or no further tumour growth. Because cell destruction is a lengthy process, it can often take up to six months before the effect of treatment can be determined by doctors. 

 

What type of patient can radiosurgery benefit?

Due to its power and accuracy radiosurgery can give clinicians the ability to treat patients with cancers once considered untreatable and those for whom surgery is not an option, such as tumours deep in the brain.

Of the 120+ different types of brain tumour that people can contract, you are most likely to have radiosurgery if you have an acoustic neuroma that is less than 3cm across. Radiosurgery can also be used for other brain tumours, including small secondary brain tumours, small pituitary adenomas and for people who can't have brain surgery due to other medical conditions. It is also used for Haemangioblastomas that couldn't be removed, were only partially removed, or came back after surgery.

Specialists don't recommend radiosurgery for larger brain tumours. It isn't possible to get the same dose of radiotherapy throughout the treatment area with a large brain tumour.

Radiosurgery may also not be suitable if there are certain nerves running through the treatment area. The nerves could be given too much radiation. This could cause problems such as hearing loss, depending on the role of the affected nerves.

 

Information courtesy of brainstrust