Patients receiving tangential breast irradiation represent a significant proportion of the workload in a radiotherapy department. This paper describes the optimisation of an existing technique for tangential breast irradiation. Simulator sessions have been made more efficient by adopting a systematic approach to the simulation process, and set up times on treatment have been reduced and accuracy increased by improving the reliability of the patient set-up. There has been an overall reduction in both the problems and the time taken to both simulate and treat patients.

Patient position variation has been minimised by the use of vac-fix bags and the choice of reference tattoo placement on the patient's skin. The single simulation session for planning treatment has been organised into three parts: definition of target volume, calculation of treatment and field parameters and simulation of treatment fields. The improvement in patient set-up on treatment has been confirmed by a reduction in the variability of FSDs measured during treatment.