Sir: The Cromwell Hospital gamma unit is not the first to be installed in Britain exclusively for clinical use ("The dawn of bloodless surgery", 8 September). Stereotactic radiosurgery was introduced to the UK when the Leksell unit in Sheffield (unconnected to the University) became operational 13 years ago. Since then, over 2,200 vascular malformations, more than 800 benign and malignant tumours as well as a number of pain and other functional disorders such as epilepsy, have been treated with Sheffield gamma knife.
DAVID M C FOSTER
Director, National Centre for Stereotactic Radiosurgery