It has been said that such was his renown, especially for bringing in the use of the radiological unit the rad, that the SI unit may well have been called the mayneord instead of the gray (2). It was during a meeting in 1946 with a young Harold Elford Johns, inventor of the cobalt-60 teletherapy unit, that Johns was prompted to go into medical physics. His department subsequently developed one of the world's first radioisotope scanners.