The Barbie-sized unit was the brainchild of St James' paediatric radiotherapist Lucy Hume, who said the aim is to 'educate children who are coming for radiotherapy treatment.'
The machine moves in the same way as a real £1.6m linear accelerator, and the hospital received £5,000 of funding from the Yorkshire Cancer Centre Appeal to make it.
"We want to try and prevent the stress and the upset," Lucy said, explaining that previously they had tried to show children the linear accelerator chambers of real machines before their treatment, but that it hadn't always been possible.
"We wanted to make it look like a real machine," Lucy continued. "The couch moves up and down, the floor spins around and the machine moves around."
The hospital hopes that the doll-sized model will give reassurance to children and cut down the number who need a general anaesthetic to have radiotherapy.
One mum whose six-year-old son has had radiotherapy for a brain tumour and who is now having chemo said it was a 'fantastic' idea.
"Some are really scared when they come in and see the machines, but after playing with this, they won't be," Tracey Mitchell told the Yorkshire Evening Post.
Radiotherapy clinical technologist Wayne Sykes who operates the doll machine as well as the full-sized version said the 'look on the kids' faces was absolutely fantastic'.
"Anything you can do to make life a bit easier for them is worth it," he added.
What an fantastic idea!
More on Parentdish: Mattel to create a bald Barbie for child cancer sufferers