John Mallard (14 January 1927-25 February 2021) was an English physicist who played a crucial role in the development of two of the world’s most important medical technologies at present: Magnetic Resonance Imaging (MRI) and Positron Emission Tomography (PET). He also played a key role in the international development of medical physics.

Mallard was born in Kingsthorpe, Northampton, England. He completed his PhD research into magnetic properties of uranium at University College, Nottingham (at that time part of the University of London) under Professor Leslie Fleetwood Bates in 1947.

Mallard worked as an Assistant Physicist with the Liverpool Radium Institute, where he completed his training in hospital physics. In 1953, he joined Hammersmith Hospital and Post Graduate Medical School. In 1959, Mallard developed the first whole-body isotope scanner in the UK with C. J. Peachey, which was used for detecting a brain tumour.

Mallard published his theories on electron spin resonance and its potential medical use in Nature, a prestigious journal, in 1964, but they went largely unnoticed for a long time. The following year, he was appointed the University’s first Professor of Medical Physics at Aberdeen. In his inaugural lecture shortly after joining the University, Professor Mallard predicted PET would become one of the most powerful tools for studying human diseases.

Mallard brought to Scotland its first PET scanner, leading a national fundraising campaign. The scanner was located at the Woodend Hospital, which has been since replaced by the John Mallard PET Centre at the Aberdeen Royal Infirmary.

In the 1970s, Mallard set up a team of specialists led by Dr. Jim Hutchinson to build a unique MRI scanner (0.04 Tesla). They applied it to imaging of laboratory animals.  The team also built the first full-body MRI scanner, which was used with a patient for the first time on April 26, 1980.

During the 1980s, his team discovered “spin warp imaging”, a technique that could produce three-dimensional images unaffected by the movement of patients. Later in the 1980s, Mallard’s team had originally developed the images in colour, but had to go back to greyscale given that radiologists were not used to colour images.

In 1992, Mallard retired from the University of Averdeen, UK. He remained very active in the international development of medical physics and biomedical engineering. He was founding president of the International Union of Physical and Engineering Sciences in Medicine (IUPESM) as well as president of the International Organization for Medical Physics (IOMP).  In this position, he made de first steps towards the recognition of the medical physics and biomedical engineering scientific fields by the International Council of Scientific Unions.

In 1992, Mallard was appointed Officer of the Order of the British Empire, the IUPESM awarded him their first Fellowship for International Leadership, and in 2016, IOMP established an international award – The John Mallard Award which honours a medical physicist who has developed an innovation of high scientific quality and who has applied this innovation in clinical practice. The American Association of Physicists in Medicine awarded him the Landau Memorial Plaque.

Mallard is regarded as one of the scientists who most contributed to the establishment and development of medical physics as an academic discipline.

Author:
Dr. Luis Humberto Ros