Evaluation of a radiotherapy electron contamination deflecting system

The combination of a clinically useable neodymium iron boron rare earth magnetic deflector with a clinically viable thin walled helium bag which could be placed over a patients skin has shown that it could be very effective in reducing unwanted skin dose to radiotherapy patients by the removal of unwanted lepton contamination from the entry beam while not affecting dose at depth or beam symmetry. Results have shown that up to 70% of existing dose applied to the patients skin which causes damage could be removed by the tested devices. The magnetic deflectors characteristics for interference with linear accelerator electronic components and field strengths that a patient would be exposed to are also tested.