Doctors in Britain say a radical new treatment for Parkinson's could improve the lives of millions who suffer from the disease.

Sheila Roy says she can finally enjoy life at her countryside home in Cambridge, England. She has lived with Parkinson's disease for 17 years, but a team of Oxford scientists developed a treatment that changed her life.

“I can see a glimmer of a person I use to be now, which is really exciting,” she said.

Roy was one of only 15 people in the world to take part in a gene therapy experiment that was previously tested on lab animals. Scientists create and inject a virus into the brain. It jumpstarts the production of dopamine, a chemical that fights Parkinson's. Without dopamine, patients suffer tremors and uncontrolled movements.

“In principle, it should give patients a better quality of life through their day because of less ups and downs during the day,” said Dr. Philip Buttery, of the Cambridge Center for Brain Repair.

Doctors say more studies involving hundreds of patients will be needed to prove the treatment is safe and works long term. Other gene therapy experiments are happening in the U.S., but the British experiment is the first treatment in the world that generates dopamine in a patient's brain.

Roy said she knows it’s not a cure, but says she feels 10 years younger.

“If you can treat the symptoms and control in some way the deterioration in what you can do, it has to be better for you, and it is,” she said.