Ashya King: What is proton beam therapy?
31 August 2014 Last updated at 22:48 BST
The parents of a boy with a brain tumour who took him out of a hospital treating him in Southampton say they want him to receive a special treatment for his tumour.
The treatment, known as proton beam therapy, is currently only available in the UK to treat eye cancers, but patients with other forms of cancer can apply for NHS funding for therapy abroad.
Jon Brain reports.