There is a postcode lottery for an essential surgical treatment for Parkinson's depending on which side of Scotland you live, a charity has said.
Parkinson's UK said people in the east of Scotland had to travel to England for Deep Brain Stimulation (DBS).
But those in the west get it in Scotland.
A proposal to create a Scotland-wide service at the new Queen Elizabeth University Hospital in Glasgow will be considered by NHS Scotland next month.
DBS involves inserting electrodes in the brain to reduce physical shaking.
It is often the last option for people who have very serious symptoms which cannot be controlled through medication alone.
It is offered to people with Parkinson's, "essential tremor" and dystonia, which is a rarer neurological disorder affecting movement.
While DBS is available in Glasgow, only patients who live in the west of Scotland are offered it.
Those in the east are offered appointments in England, and Parkinson's UK said these patients often struggle to get follow-up care.
It has called for equal access to the surgical treatment.
Katherine Crawford, the charity's director in Scotland, said: "Around 30 people with Parkinson's in Scotland would be likely to benefit from DBS surgery each year.
"The creation of a sustainable National Service in Glasgow would significantly improve access to the treatment for every suitable candidate in Scotland and provide a specialist centre that delivers improved outcomes for people with Parkinson's."
Les Macleod, 59, from Arran, said having DBS six years ago had given him his life back.
He added: "To put it very briefly, I was a goner - I'd lost lots of weight, I was practically housebound, and could barely make it out of my bed because of my Parkinson's.
"It's not a cure, but I can do so much more now. I'm so glad that my two daughters have been able to see me almost back to normal after years of being so unwell. I feel like I have been given a second chance at life."
Consultant neurologist Dr Ed Newman, who is a specialist in Parkinson's at the Queen Elizabeth Hospital, said: "Deep Brain Stimulation can be a life changing procedure. Over the last 25 years, many thousands of people worldwide have had this surgery, and it is now established as an essential treatment option for selected patients with advanced Parkinson's disease or dystonia.
"The establishment of a single National Service in Scotland, run on similar lines to the 13 NHS DBS centres in England, would be a huge step forward in the care of patients with advanced Parkinson's disease and dystonia across Scotland."
The Scottish Tremor Society says the problem is that many of Scotland's neurosurgeons have retired and have been difficult to replace.
'Safe and sustainable'
"We need to get people interested in neurosurgery," said Mary Ramsay.
"We need to get them to take the place of the people who have retired. Then there wouldn't be a postcode lottery. It's frustrating."
Mrs Ramsay, who lives in Inverness, has had Deep Brain Stimulation herself but still has to travel to Newcastle for appointments with a neurosurgeon.
A spokesman for the Scottish government said everyone in Scotland who is considered clinically appropriate for DBS treatment is able to access it.
He added: "DBS is a highly specialised, low volume treatment and so we need to ensure any services established are safe and sustainable.
"That is why the National Specialist Services Committee is in the process of considering an application to set up a comprehensive national Deep Brain Stimulation service for Scotland at the Institute of Neurological Sciences in Glasgow.
"The committee is due to make recommendations to the Scottish government within the next few months."