Imaging apparatus comprises a radiation source arranged to generate a divergent imaging beam and an associated radiation detector mounted on a C-arm which can rotate. A first drive is arranged to move the radiation source and the detector relative to a subject in a scanning direction to generate output signals from the detector, thereby performing a scan generating image data containing distortion in a direction transverse to the scanning direction. A second drive is arranged to rotate the C-arm, to change the orientation of the radiation source in a direction transverse to the scanning direction incrementally between repeated scans, thereby to generate a plurality of sets of image data. A processor, which can be a PC or a dedicated processor, is provided for processing each set of image data to obtain equivalent parallel imaging beam data therefrom, corresponding to a given angle in the divergent imaging beam, and for combining a plurality of said equivalent parallel imaging beam data to generate a synthesized parallel imaging beam image. The apparatus includes a display for generating a visual display of the synthesized parallel imaging beam image. The resulting synthesized image has the distortion removed and measurements can be made from the image. The invention extends to a method carried out with the apparatus.