John Mallard

John Rowland Mallard OBE FRSE FREng (14 January 1927 – 25 February 2021) was an English physicist and professor of Medical Physics at the University of Aberdeen from 1965 until his retirement in 1992. He was known for setting up and leading the team that developed the first magnetic resonance imaging (MRI) full body scanner and, in particular, positron emission tomography (PET). He was born in Kingsthorpe, Northampton, England.

Career Mallard completed his PhD research into magnetic properties of uranium at University College, Nottingham under Professor Leslie Fleetwood Bates in 1947. He joined Hammersmith Hospital and Post Graduate Medical School in 1953, and in 1959 Mallard developed the first whole-body isotope scanner (homemade) in the UK, used for detecting a brain tumour, with C. J. Peachey. Mallard published his theories on electron spin resonance and cancer in the journal Nature in 1964 but they went largely unnoticed. to build the first MRI full body scanner. The scanner was first used on 28 August 1980, During the 1980s, Mallard discovered "spin warp imaging", a technique that could produce three-dimensional images unaffected by the movement of patients. During the 1980s, there was a discussion on where MRI scanners should be based because radiologists were used to images not numbers, Mallard was quoted as saying:

"The human body is extremely complex. When, in addition, we first attempt to image a new property such as proton magnetic resonance, there is bound to be difficulty in interpreting the results... With this in mind, we have carried out a biological back-up program of T1 measurement on normal and pathological tissues to ease the problem of image interpretation and to find pointers toward the most fruitful fields for the application of NMR imaging"

Later in the 1980s, when imaging became standard on scanners, Mallard's team had originally developed the images in colour but had to transfer them into greyscale as radiologists were not used to colour.

Honours and awards In 1972 he was elected a Fellow of the Royal Society of Edinburgh and a Fellow of the Royal Academy of Engineering in 1993. In 1998, the John Mallard Scottish PET Centre was opened in Aberdeen Royal Infirmary by the Minister for Health, Sam Galbraith. He was honoured with the Freedom of the City of Aberdeen in 2004. In 2004 the Institute of Physics and Engineering in Medicine established a lecture in his name, to be given annually at the United Kingdom Radiological Congress. Mallard honours also include the Royal Society Wellcome Prize and gold medal, the George von Hevesy Memorial Lecture Medal, the Royal Medal of the Royal Society of Edinburgh, the Landau Memorial Plaque of the American Association of Physicists in Medicine, and the Academic Enterprise Competition Prize of the British Technology Group.

Death Mallard died, at the age of 94, on 25 February 2021.