X-RAY TARGET ASSEMBLY AND RADIATION THERAPY SYSTEMS AND METHODS

A multi-region target that is configured to selectively generate two different energy distributions when exposed to an excitation electron beam is described. The multi-region target includes multiple regions with different x-ray generating characteristics. Thus, the interaction between an excitation electron beam and the target generates an x-ray beam with an energy distribution that depends upon which target region is exposed to the excitation electron beam. The different x-ray spectra may be used to produce an enhanced contrast x-ray image. A method of detecting the rotational position of the multi-region target based upon the contrast level of the resulting images also is described.