Patent ID: 7545915

Claim:
A controller for an X-ray system comprising an x-ray generator for providing a tube voltage to an X-ray tube for generating X-radiation and means for detecting the intensity distribution of the X-radiation that has been transmitted through a subject to be imaged, said controller comprising: means for measuring a dose rate of said X-radiation, storage means for storing predetermined values of optimal dose rate per tube current as a function of tube voltage, means for measuring a tube current supplied to said X-ray tube by said X-ray generator, a multiplier for multiplying the tube current by a value of optimal dose rate per tube current selected from said predetermined values of optimal dose rate per tube current to determine an optimal dose rate for said subject, a comparator for comparing the measured dose rate with the optimal dose rate dependent on the thickness of said subject, and a control for adjusting the dose rate to substantially correspond with the optimal dose rate.