Correction of scattered radiation for cone-beam computed tomography at high X-ray energies

Cone-beam computed tomography (CT) using X-ray tubes of high energy (450 keV) faces the problem of strong artifacts and a significant contrast degradation in reconstructed images. System components of cone-beam CT scanners operating at high X-ray energies have to be optimized to reduce the amount of scattered photons hitting the detector. In addition it is mandatory to apply scatter correction algorithms. A prototype of a cone-beam CT system equipped with a 450 kV industrial X-ray tube has been developed within the framework of a European research project. The influences of scattered radiation generated by the object have been extensively evaluated using Monte Carlo (MC) simulations. Furthermore scattering reduction and correction methods have been developed. A key task was the implementation of a new hybrid method for the fast and accurate calculation of the scattering intensity distribution in X-ray projections for industrial cone-beam CT.