Multispectral large-area X-ray imaging enabled by stacked multilayer scintillators

Conventional energy-integration black-white X-ray imaging lacks spectral information of X-ray photons. Although X-ray spectra (energy) can be distinguished by photon-counting technique typically with CdZnTe detectors, it is very challenging to be applied to large-area flat-panel X-ray imaging (FPXI). Herein, we design multi-layer stacked scintillators of different X-ray absorption capabilities and scintillation spectrums, in this scenario, the X-ray energy can be discriminated by detecting the emission spectra of each scintillator, therefore the multispectral X-ray imaging can be easily obtained by color or multispectral visible-light camera in one single shot of X-ray. To verify this idea, stacked multilayer scintillators based on several emerging metal halides were fabricated in the cost-effective and scalable solution process, and proof-of-concept multi-energy FPXI were experimentally demonstrated. The dual-energy X-ray image of a bone-muscle model clearly showed the details that were invisible in conventional energy-integration FPXI. By stacking four layers of specifically designed multilayer scintillators with appropriate thicknesses, a prototype FPXI with four energy channels was realized, proving its extendibility to multispectral or even hyperspectral X-ray imaging. This study provides a facile and effective strategy to realize energy-resolved flat-panel X-ray imaging.