The most common metastases (secondary tumours) originate from carcinoma of the bronchus, breast and kidney, occasionally they occur from thyroid and melanomas too. In addition, there are a variety of other primary tumours that occasionally metastasise to the brain. Good results, after the use of Gamma Knife radiosurgery, have been reported in all these categories.
This is the most common indication for treatment in most Gamma Knife centres. Sheffield takes on patients who fulfil a very strict set of criteria: they have to have a firm diagnosis, good general function, a total tumour volume of less than 20 cc (i.e. all individual tumors added together) and that none of the individual tumours has a diameter greater than 3cc.