The effect of megavoltage field size on intrafraction cone-beam CT image quality.

To investigate the effects of scatter from a megavoltage treatment beam on intrafraction cone beam CT (CBCT) image quality. The effects of treatment beam field size and phantom geometry were investigated as well as the clinical success of IFI. Intrafraction imaging (IFI) was performed on four phantoms with four different MV field sizes using a 6 MV FFF source.