Efficient Fabrication of Precise Electron Cut-outs

A time-saving method for creating accurate patient-personalized cerrobend cut-outs, utilized in electron beam therapy, is described--implemented by radiographic films taken during simulation. This technique is used frequently (but not exclusively) for the treatment of head and neck cancer, where isocentric lateral films taken for photon treatment also provide the information needed to define the posterior off-cord electron boost. The boost field is traced from the film and demagnified by xerox to the distance of the cone cut-out holder. A second simulation of the electron field is not necessary. Matching of the electron fields to the photon fields is accurate, consistent, and easy to define on the patient.