An x-ray imaging system uses particular emission lines that are optimized for imaging specific metallic structures in a semiconductor integrated circuit structures and optimized for the use with specific optical elements and scintillator materials. Such a system is distinguished from currently-existing x-ray imaging systems that primarily use the integral of all emission lines and the broad Bremstralung radiation. The disclosed system provides favorable imaging characteristics such as ability to enhance the contrast of certain materials in a sample, to use different contrast mechanisms in a single imaging system, and to increase the throughput of the system.