The new treatment uses a non-invasive mask that moulds onto the patient's face and sets hard in minutes.
The upgrade to the £1m Swedish machine, first unveiled in 2013, allows a more accurate scan of the head without the traditional need for a metal cage that is screwed directly onto the skull to keep it perfectly still during treatment.
Gamma Knife radiosurgery focuses hundreds of tiny beams of radiation on the tumour that are individually weak and therefore pass through healthy tissue but when they converge on the targeted area, deliver the required dose of radiation.
Bristol Royal Infirmary is only one of a handful of hospitals in the world to use the machine and the new non-invasive mask is proving understandably popular with patients. Alongside the benefits of being non-invasive, in some cases Gamma Knife radiosurgery also reduces associated side-effects of brain tumour treatment.