The dosimetry team ensure the machines within the department are working safely and within defined limits.

They work closely with the engineering team who are on hand to perform QC as well as provide rapid fixes to problems which arise and ensure machine clinical time is maintained.

The team look after Linacs, CT scanners, Orthovoltage units and all the associated dosimetry equipment.


The department currently has 6 Varian Truebeams and one Varian Clinic and all are capable of online MV and kV imaging as well as delivering photon (flattened and FFF) and electron treatments.

In March 2020 the Clinac is being replaced with Varians newest and most technologically advanced machine, the ETHOS, which is essentially a Halcyon which is capable for adaptive therapy.

This will provide the means to deliver truly online adaptive treatments.


Varian Ethos™ therapy is an artificial intelligence (AI)-driven holistic solution designed to increase the capability, flexibility and efficiency of radiotherapy

The team monitors the machines performance through performance of QC testing and results are recorded electronically on the QATrack+ system which runs across both the main Guildford site and the Satellite Centre at East Surrey Hospital, Redhill.


There is a Gulmay unit which delivers superficial treatments (primary skin treatments) in the energy range 80kV-250kV.

Future developments

  • Development of online adaptive planning workflow
  • Use of Monte Carlo treatmetn algorithms for electron treatment planning
  • Use of the ETHOS for routine treatments.