Margaret Dorothy Snelling was a consultant radiotherapist at Middlesex Hospital and the first female President of the European Association of Radiology. She was born on 20 September 1914, and educated at Wimbledon High School for Girls. She went on to study at the Royal Free Hospital School of Medicine for Women, where she qualified in 1938. She held house appointments at the Royal Free and Chelmsford. In 1940 she was associate radiotherapist at the Middlesex Hospital and took her DMR and MRCP. With the men away at war, she became a surgeon at Chase Farm Emergency Hospital, in general and neurosurgery, and gained her FRCS. She was general and orthopaedic surgeon at Haymeads Emergency Hospital from 1944 to 1946, and assistant neurosurgeon in Sheffield. She returned to the Meyerstein Institute of Radiotherapy at the Middlesex in 1947, as assistant radiotherapist and deputy director to Sir Brian Windeyer, and was also consultant to the Marie Curie and Bedford General Hospitals. She was director of the Meyerstein Institute from 1969 to 1979. She was a pioneer in the use of computers, this being the subject of her presidential address to the British Institute of Radiology in 1967. She was internationally famous for teaching overseas postgraduate students, and after retirement she visited India, Egypt and the Sudan, to promote - in collaboration with the International Atomic Energy Authority - schemes for treatment of cervical cancer in the developing world, where it is very prevalent. When her sister-in-law died, she became a dedicated aunt to her children, and was stimulated to undertake a study of ovarian cancer. Her work was always characterised by dedication and kindness, and consideration for her patients. She was gregarious and sociable, tenacious and tough, and had a good sense of humour. Despite having an untreated congenital heart abnormality, she was a keen tennis player and fenced for London University. She died on 24 April 1997.