Joseph Stanley Mitchell, CBE, FRS, FRCP (22 July 1909 – 22 February 1987) was a British radiotherapist and academic. He was Regius Professor of Physic at the University of Cambridge from 1957 to 1975. Early life Mitchel was born on 22 July 1909 in Birmingham, England. He was only son and the eldest child born to Joseph Brown Mitchell and his wife Ethel Maud Mary Mitchell (née Arnold). He was educated at Marlborough Road School and at King Edward's School, Birmingham, a boys school. He had been awarded an open scholarship to attend King Edward's School. In 1926, he won a state scholarship to the University of Birmingham. Having undertaken preclinical studies at Birmingham, in 1928 he won a scholarship to St John's College, Cambridge. At Cambridge he studied the Natural Science Tripos, and was awarded first class honours in Part I in 1930 and Part II in 1931, graduating with a Bachelor of Arts (BA) degree. Having specialised in physics in Part II, he was advised by Lord Rutherford to return to Birmingham to undertake his clinical training. He did so and graduated Bachelor of Medicine, Bachelor of Surgery (MB BChir) from the University of Cambridge in 1934. Career Mitchell began his medical career as a house officer at Birmingham General Hospital. He returned to the University of Cambridge as a postgraduate studying under Sir Eric Rideal. During this time, he held the Elmore research studentship and then the Beit Memorial Fellowship for Medical Research. He was elected a fellow of St John's College, Cambridge in 1936. In 1937, he completed his Doctor of Philosophy (PhD) degree on 'the irradiation of thin protein films'. From 1937 to 1938, he worked as a radiological officer at the Christie Hospital, a centre that specialised in the treatment of cancer, based in Manchester. In 1938, he returned to the University of Cambridge where he joined the Department of Medicine as an assistant to J. A. Ryle, the then Regius Professor of Physic. In 1939, with the outbreak of World War II, he became radiotherapist with the Emergency Medical Service in Cambridge. In 1943, he joined the newly opened Radiotherapeutic Centre at Addenbrooke's Hospital. In 1944, he joined the Chalk River Laboratories, Canada, as head of medical investigations for the joint British-Canadian atomic energy project. He ensured the safety of the workers and undertook research into the biological effects of radiation. During this