Normal tissue dose and second cancer risk due to megavoltage fan-beam CT, static tomotherapy and helical tomotherapy in breast radiotherapy

This study investigates the dose from the 1 mm collimator width megavoltage fan-beam CT (fine, normal and coarse pitch) available on tomotherapy as well as for whole-breast tomotherapy treatments. The BEIR VII lifetime attributable risk model was utilised to assess the significance of the imaging dose relative to the treatment dose.