Electron depth absorbed dose distribution for a 10 MeV clinical microtron.

Central axis depth absorbed dose distributions of the electron beam from a medical microtron accelerator have been measured. The measured distributions differ from those of existing betatrons and linear accelerators. A larger absorbed dose build-up and a sharper dose fall-off are obtained in close agreement with theoretical calcuations for monoenergetic electron beams. The differences from other accelerators are explained by the narrow energy spectrum, the clean geometry and the small amount of scattering material in the electron beam of the microtron.