A new radiotherapy using boron and neutrons is now available in Japan for head and neck cancer that has recurred despite all types of conventional treatment. It's being offered at a private medical facility for the first time in the world. A patient who was told removing part of his throat, including his vocal cords, was the only solution had the therapy, and his cancer disappeared a year later. We look at the therapy's mechanism and side effects and compare it with other radiotherapies.