Using computer guidance, many beams of radiation (X-rays and gamma rays) are accurately focused onto a target in the brain. In this way, inaccessible or inoperable lesions can be treated avoiding an operation. The accuracy of the system makes sure important brain structures next to the target receive a much lower dose, and hence there is less risk to the patient.
What can be treated ?
Radiosurgery is very good for small tumours that are localised and can be clearly seen on MRI scans. These include small meningiomas, metastases (cancer from elsewhere in the body), and acoustic neuromas. It is also commonly used to obliterate small arterio-venous malformations (AVM’s) that bleed into the brain. This treatment can also be used for trigeminal neuralgia (unilateral facial pain).
How is it done ?
A frame is placed on the patient’s head using small pins that are inserted under local anaesthesia. The patient then has an MRI brain scan. The data from this scan is transferred to a planning computer where Dr Hong and a radiotherapist will decide on a treatment plan, before starting treatment. The treatment itself is not noticed by the patient who lies on the treatment couch and often falls asleep. It can take several hours with multiple adjustments of the frame. When the treatment has ended, the frame is removed and most of the time, the patient returns home or to his hotel.
What are the side effects ?
The planning is tailored to the patient’s brain to minimise side effects on the surrounding normal brain tissue. Large lesions are less suitable for radiosurgery because of the swelling that can result after the radiosurgery treatment, but smaller lesions can also swell a little so that the brain next to it is affected. Sometimes, steroids are prescribed to decrease the swelling. Radiosurgery can also damage the brain several years after the treatment so neurosurgical follow-up is required.