i first met Selwyn Lucas a week before his surgery, at Charing Cross hospital, when he attended his final assessment.
His right hand does not shake when it is at rest, but begins to vibrate uncontrollably when he goes to use it.
Each time he tried to do something with his hand it began to shake.
He was asked to draw a spiral shape and as soon as he put pen to paper his right hand began juddering.
This is typical of the condition known as "essential tremor", which affects one in 25 adults over the age of 40.
It contrasts with the tremors in Parkinson's disease, which occur when the patient's hand or other affected limb is at rest.
Mr Lucas, who is a painter and decorator, said the tremors began nearly 20 years ago and have got progressively worse.
"I have to use my left hand when painting to do all the edging, otherwise I would end up with wiggly lines between the walls and ceiling," he said.
"My concern is that it might spread to my left hand."
Close shave
On the morning of surgery, Mr Lucas arrived at St Mary's Hospital with a shaved head - necessary because hair could trap heat from the ultrasound and cause a burn.
After another shave, to remove any remaining follicles, a metal frame was bolted to his scalp to ensure that his head remained completely still during treatment.
He was then led to the MRI suite and his head inserted in the ultrasound machine.