MODEL RELEASED. Gamma knife radiotherapy. Patient having a head frame fitted in preparation for gamma knife radiotherapy. This is usually used to treat brain tumours. The patient receives a mild anaesthetic before a frame is pinned to his head. The head must be held firm during gamma radiotherapy as this technique involves the targetting of gamma radiation on a specific region of the brain. Photographed at the Gamma Knife Centre, Erasme Hospital, Brussels, Belgium.