Neurosurgeon Kate Drummond is an expert on brain cancers, how they grow and how to get rid of them. It's hard to imagine anything quite as invasive as brain surgery and increasingly, Kate's patients want to know if their brain tumour is the result of using a mobile phone. But not all neurosurgeons agree. After nearly twenty years in use, mobile phones are now so common that if they were dangerous, you'd expect severe health impacts to be widespread. The latest science says there's a possible link between mobile phone use and brain cancer, but what do we really need to know to answer that question once and for all?