Obituary: Professor J. E. Roberts

ERIC ROBERTS'S first contact with a problem of physics applied to medicine was early in 1932 when Huddersfield Royal Infirmary asked the Leeds University Physics Department for help in finding some lost radium.

Roberts went to Huddersfield armed with a gold leaf electroscope from the first-year labs, together with a Bakelite rod and catskin with which to charge it. A two-day survey of the theatres and drains yielded many false alarms due to moisture on the sulphur insulation plug of the electroscope, but no radium was found. At that time there were possibly three or four "Hospital Physicists" in the United Kingdom and it appeared to Roberts that he might be able to make a scientific contribution to this developing area.

He was born in the West Riding of Yorkshire in 1907, and was educated at Normanton Grammar School and Leeds University. He graduated in 1928 and remained in the Physics Department until 1932, first on a University Fellowship to obtain his PhD in just two years and then as a Research Assistant.

On 1 September 1932 he moved from Yorkshire for the first time in his life to go to London to take up a post as Physicist at the Cancer Hospital (Free) in the Fulham Road (later the Royal Marsden Hospital). At Fulham Road Roberts worked with the late Val Mayneord, and the pair made a large number of scientific contributions to research in the newly developing fields of cancer treatment and diagnosis.

At the time of his arrival in Fulham Road a 400kV X-ray machine had been installed in the Physics Department. This was the first machine of its type in Europe. There were major problems with radiation dosimetry since radiotherapists prescribed treatment in terms of "erythema dose" which was the quantity of radiation likely to produce a faint redness of the skin on the average patient.

Roberts was a pioneer of scientific dosimetry and was one of the people to define treatment rontgens and relate them to the esoteric unit of "erythema dose". He and Val Mayneord developed measuring apparatus and later with Frank Farmer the ionising chamber system which has developed into the universally known Farmer dosemeter.

The only source of high-energy gamma rays between the wars was radium which was used in what was called the "radium bomb". This contained about one gramme of radium packed into the lead body of the machine. Roberts recalled that the radium in the "bomb" was also used in the hospital theatres and it was his duty on a daily basis, to pack and unpack the "bomb" to suit the requirements for implants. This duty was performed on a bench of lead.

In 1937 Roberts moved to the Middlesex Hospital Medical School where, after the Second World War, he was appointed the Joel Professor of Physics Applied to Medicine, at London University, a post he held until his retirement in 1970.

He was a founder member of the Hospital Physicists' Association, becoming its President in 1950. Two years later, he became President of the British Institute of Radiology. From 1960 until 1971 he was the first Consultant Adviser in Physics to the DHSS, and Chairman of its Radiotherapy Apparatus Safety Panel. He was a member of the Radioactive Substances Advisory Committee and the first editor of the medical physics journal Physics in Medicine and Biology. At the same time, he became editor of the British Journal of Radiology.

His world-wide commitments included the International Atomic Energy Authority Regional Adviser to the Middle East in the 1960s and adviser to the governments of Malaysia, Libya and Syria. He travelled widely in the execution of his duties.

When he retired in 1970 he moved to Norfolk, where he was able to continue his work as a Methodist local preacher, an occupation with which he had been involved since the 1930s. He wrote two theological books, the last of these 10 years ago, but he firmly believed that one should retire from preaching at the age of 70.

In the 1980s he and his wife moved to Tewkesbury to be near their daughter. He continued his lively interest in medical physics and joined enthusiastically in the scientific meetings of the local Gloucestershire Medical Physics Department. Last year, members of this department arranged a symposium to celebrate his 90th birthday, when seven of his colleagues and former students presented papers on aspects of Roberts's contributions to Medical Physics. This was held at Frenchay Hospital, Bristol, in conjunction with an exhibition of the history of medical radiation.

Eric Roberts married in 1932. Although he was engaged when he moved to London he had not intended to marry so soon. But he said that he found himself so lonely in the big city that he needed a companion. His wife died two years ago. He is survived by two daughters, five granddaughters and six great- grandchildren. He was proud of the fact that two of his granddaughters became scientists - one has an Electrical Engineering degree and the other a degree in Mathematics.

John Eric Roberts, medical physicist: born Leeds 5 September 1907; Research Assistant in Physics, Leeds University 1930-32; Assistant Physicist, Royal Cancer Hospital 1932-37; Senior Assistant Physicist, Middlesex Hospital 1937-46; Joel Professor of Physics Applied to Medicine, London University 1946-69 (Emeritus); Physicist to Middlesex Hospital 1946-70; married 1932 Sarah Raybould (died 1996; two daughters); died Badgeworth, Gloucestershire 14 October 1998.