A cancer treatment at the centre of an NHS controversy in 2014 causes fewer side effects in children than conventional radiotherapy, according to new research.
The study, published in The Lancet Oncology, suggests proton beam therapy is as effective as other treatments.
Researchers looked at 59 patients aged between three and 21 from 2003 to 2009.
In 2014 the parents of Ashya King took him out of hospital in Hampshire to get the treatment abroad.
Their actions led to a police operation to find them.
Ashya, who was five at the time of his treatment, is now cancer free, his family said last year.
All the patients who took part in the study, led by Dr Torunn Yock from the Massachusetts General Hospital in the US, had the most common kind of malignant brain tumour in children, known as medulloblastoma.