Ryan Scott, 23, became the first NHS patient to be treated at a new state-of-the-art centre with proton beam therapy.
The keen motocross rider and football fan was diagnosed with a brain tumour a year ago after suffering headaches and severe neck pain.
In PBT treatment protons are fired at cancers at up to 100,000 miles a second but stop when they reach the tumour – minimising damage to healthy tissue.
And Ryan said: “Without this treatment there was a risk of my eyesight being significantly affected.
“I truly feel as though I’ve been given my freedom back. I am so grateful.”
Ryan told his story as the Rutherford Cancer Centre in Newport, South Wales, was officially opened yesterday.
He met Welsh Health Minister Vaughan Gething, who toured the facility and spoke to staff including lead radiographer Kate Leaver and her deputy Kerry Owen.
Before Ryan was referred to the Rutherford, he had endured three gruelling ops in the UK.
Doctors thought he would have to travel to Florida for further surgery, at a cost of £120,000 to the NHS.
The treatment at the new private clinic in Wales cost half that amount.
Ryan said: “I was worried about my future, annoyed that seizures had lost me my driving licence and cost me my motocross hobby.
“Twelve months ago I struggled to lift my head off the pillow. Now I’m looking forward to getting back on the bike again.”
Ryan was an ideal candidate for PBT, which targets cancers very precisely, because his tumour was perilously close to the optic nerve.
Describing his treatment, which started on World Cancer Day on February 4 as “a walk in the park”, he said: “When I first saw the machine I thought it was something out of science fiction. I was scared after three lots of surgery but it was painless with no side-effects.”
Ryan lay on a couch to receive two beams lasting 90 seconds each.
He said he felt “great” at the end of 30 short treatments spanning six weeks.
The Cardiff City fan from Llechryd, Ceredigion, is now eager to return to work in the family timber frame manufacturing business.
Radiographer Kerry, who looked after him throughout his treatment, said: “Ryan is a brave young man who has benefited from this revolutionary process.
“When I became a radiographer 11 years ago I wouldn’t have believed this possible.”
The NHS has one dedicated PBT centre at The Christie hospital in Manchester, with a second due to open in London in the summer of 2020.