Gwen Hilton was born on 22 September 1898, the daughter of Micaiah John Muller Hill, FRS, Professor of Pure Mathematics, University College, London, and Emeritus Professor of Mathematics at the University of London. Her mother was Minnie Grace, daughter of Marriott Ogle Tarbotton of Nottingham. There were two other children by the marriage, both sons. Gwen was educated at Roedean School, University College, London, and University College Hospital. At UCL as a student in 1920 she took the gold medal in the senior physiology class and in 1921 the BSc with first class honours. In 1924 at UCH Medical School she graduated MB, BS London. In 1925 she married Reginald Hilton who later became consultant physician to St Thomas's Hospital. Her only child, Clare (Mrs Terrell) is also a radiotherapist. She was appointed assistant radiologist to UCH in 1931 and in 1932 took the DMRE. From the first her interest lay in radiotherapy and in 1938, on the establishment of a radiotherapy department at the hospital, she became its first radiotherapist. In 1940 she was made a Fellow of the Faculty of Radiotherapists. In 1948 she was given the title of Director of the Radiotherapy Department, UCH. She retired in 1963 with the title of consulting radiotherapist to the hospital. In 1946 she was elected a Fellow of University College and in 1955 an Honorary FRCS. In 1959 her services to radiotherapy were recognised by her appointment as CBE. The radiotherapy department at UCH was very much of her own creation, not only in its professional excellence, but also in the way in which it reflected her talent for artistic decoration and her taste in pictures. It was her constant endeavour to make her patients feel the friendly welcome and confidence which she established throughout her staff which was the reflection of her own generous and sympathetic personality. In return she was rewarded by the trust and often by the personal friendship of many. Her intersts, shared with her husband, were wide and included music, languages, travel and literature and she was a keen gardener. They lived at 8 Elm Tree Road, St John's Wood, NW8. In her latter years after she retired from UCH her activity was greatly reduced by illness though she kept her interest in people and the arts and with it a valuable sense of humour. She died on 8 July 1971, aged 72. Her husband died in 1969.