Ian began his career as a Medical Physicist in 1989, working at the Hammersmith hospital, London.

Since 1998 he has worked almost exclusively with the Gamma Knife, being responsible for over 6,000 patient treatments and has helped start up over 100 Gamma Knife centres worldwide. He is considered a world authority on treatment plan metrics, having formulated the Paddick Conformity Index and the Gradient Index.

In 2003, Ian became a freelance physicist and set up Medical Physics Limited; a group of physicists providing expert radiosurgery physics services to Gamma Knife centres in the UK, Europe and the USA, as well as the manufacturers of the Gamma Knife; Elekta Instruments.

Ian is currently on the faculty of five Gamma Knife centres; Queen Square, London, Cromwell Hospital, London, Barts and the Royal London, Thornbury Radiosurgery Centre, Sheffield and St. Elisabeth Hospital, Tilburg, Netherlands.

He was the first physicist to serve as President of the International Stereotactic Radiosurgery Society (ISRS) and this year has received Fabrikant Award for his contribution to SRS.