Simulation study of an X-ray diffraction beamlet array for dark-field chest CT.

Abstract

We introduce diffraction beamlet arrays (DBAs), a technique that overcomes the limitations of conventional X-ray grating interferometry, especially when combined with computed tomography (CT) applications. Traditional interferometry systems face significant design challenges when dealing with high energies, large fields of view, and short lengths, such as those required for full-body CT scans. DBAs offer a solution to these issues by generating intensity fringes through the superposition of diffracted and transmitted beamlets, rather than relying on interference. This innovative approach allows for independent variation of the diffraction angle and fringe period, decoupling the fringe formation distance from the design energy. As a result, it is possible to construct imaging systems comparable to Talbot-Lau interferometers with a more flexible parameter space. This flexibility enables shorter system designs, interchangeable design energies, and larger source grating pitches. The advantages of DBAs are demonstrated with a simulation study for the design of a chest X-ray dark-field CT, where traditional Talbot-Lau systems would require grating parameters that are currently impractical to manufacture.