Professor Christopher R Hill FlnstP (1929-2024)

Professor and honorary doctor, Christopher R Hill, also known as ‘Kit’ Hill, played a key part in developing early ultrasound scanners and in developing the use of ultrasound in cancer diagnosis and treatment. As a physicist working in medicine and biology, he spanned almost 50 years of technical change.

Kit was born in Carshalton, Surrey. He attended the University of Oxford (St Edmund Hall) to study physics BSc (hons) in 1951, before completing two years’ national service with the Royal Electrical and Mechanical Engineers.

As a PhD student at the Institute of Cancer Research and Royal Cancer Hospital (later to become the Royal Marsden Hospital), in 1958, he explored the levels of nuclear isotopes from hydrogen bomb (H-bomb) testing in the late 1950s that were deposited on grass and entered the food chain.

He established there was more naturally occurring polonium in the grass on Snowdon than plutonium originating from H-bombs or power station accidents. He subsequently explored the relative levels of key radionuclides in the organs of people eating diets heavy in reindeer meat (feeding on slow-growing lichens) by comparison with those of populations in South London, and built what was likely the largest pulse ionisation scanner (a spectrometer) from basic materials available at the time.

Between 1958-1994, Kit worked as a research scientist before becoming head of department at the combined research physics department of the Royal Marsden Hospital and the Institute of Cancer Research. His key focus was on the use of ultrasound in medicine and biology and over the next decades he worked with a growing team of colleagues, both medical and technical, to develop the capabilities, and safety, of ultrasound in diagnosis and in treatment. Part of this involved working out how to measure the energy intensity of ultrasound waves and establish dosimetry.

The work of the department extended across the wider range of physics in medicine, including in cancer diagnosis and treatment, and in his capacity as head of department he brought one of the first MRI scanners into the UK, for research into the usefulness of the technique in cancer management.

Kit worked with the Radiation Protection Committee of the British Institute of Radiology, the International Commission on Radiological Protection, the International Society for Therapeutic Ultrasound, and European and World Federations of Ultrasound in Medicine, among others, in committees, and writing for their journals and other books.

As a professor, he saw it as his job to teach, as well as guide and support his research team. He travelled to conferences and taught radiographers and sonographers in India and Egypt, including supporting their development of ultrasound departments.

Approaching retirement, Kit was active at British and international levels as a committee member, Secretary and Treasurer for Pugwash Conferences on Science and World Affairs. As a member of the Pugwash committee, he joined physicist, Sir Joseph Rotblat, in travelling to Oslo to receive the 1995 Nobel Peace Prize for their efforts “to diminish the part played by nuclear arms in international politics and, in the longer run, to eliminate such arms”.

Kit died in Sheffield on 15 April 2024. He is survived by daughters Frances and Catherine, sons Mark and David, six grandchildren and six great grandchildren.