Skip to content
The National Physical Laboratory The National Physical Laboratory
Accessibility and language tools

Russell Thomas

Russell Thomas

NPL Fellow

Russell Thomas is an NPL Fellow in Dosimetry and Science Area Leader in Radiotherapy and Radiation Dosimetry.

Russell joined NPL in 1994 after studying Physics with Medical Applications at King’s College London. Since then, he has played a central role in developing primary standards for absorbed dose, helping to ensure accurate and safe radiotherapy treatment for patients. A major part of Russell’s career has focused on improving proton therapy dosimetry. In 2003, he and his colleagues began developing a new type of primary standard calorimeter that could be used directly in clinical proton beams. Despite the technical challenges involved, this approach is now being adopted and further developed by National Metrology Institutes around the world. This work led to a new Institute of Physics and Engineering in Medicine (IPEM) code of practice, which significantly reduces uncertainty in reference dosimetry for proton radiotherapy. Russell and his team are now supporting UK centres to adopt this new method, which has also attracted strong interest from international facilities.

Russell has also contributed to several other dosimetry codes of practice that improve safety and consistency in radiotherapy. In 2020, he led the first measurements of absolute dose using the NPL proton primary standard graphite calorimeter in ultra-high-dose-rate proton beams at Cincinnati Children’s Hospital in the USA. These measurements helped the clinical team secure US Food and Drug Administration (FDA) approval to conduct the world’s first human clinical trials of this type of treatment.

Russell has undertaken secondments to the International Bureau of Weights and Measures (BIPM) in Paris and completed a two-year placement in the Radiotherapy Department at the Royal Surrey County Hospital. This led to him gaining State Registration as a Clinical Scientist. He is an IPEM Fellow and a Visiting Professor at the University of Surrey.

In the 2025 King’s Birthday Honours, Russell received an Officer of the Order of the British Empire (OBE) for ‘services to radiotherapy and cancer treatment’.

Areas of interest

  • Radiotherapy dosimetry and measurement standards
  • Proton therapy dosimetry
  • Primary standards and codes of practice
  • MRI-Linac and advanced radiotherapy platforms
  • Monte Carlo modelling and computer simulation
  • Clinical quality assurance and audit
  • Treatment delivery and patient positioning
  • Artificial Intelligence and its use and validation in healthcare