Low-dose x-ray phase contrast tomography: Experimental setup, image reconstruction and applications in biomedicine

An unmet demand for high resolution tomographic imaging modalities providing enhanced soft tissue contrast exists in a number of biomedical disciplines. X-ray phase contrast imaging (XPCi) methods can provide a solution: contrast is driven by phase (refraction) effects rather than attenuation effects, the formers being much larger than the latters for weakly attenuating materials and energies typically used for biomedical imaging. However, the majority of the existing XPCi methods suffer from drawbacks affecting their implementation outside specialized facilities such as synchrotrons and therefore their applicability to biomedical research. The Edge Illumination (EI) XPCi method has the potential to overcome or at least mitigate most of these drawbacks. Its major strengths are its simple setup, compatibility with commercially available x-ray tubes and potential for low-dose imaging. EI XPCi has recently been implemented as a tomographic modality, and it was demonstrated that the method can provide quantitatively accurate volumetric images acquired with low entrance doses. This paper explains the experimental requirements for tomographic EI XPCi, outlines the image reconstruction process and discusses potential applications in biomedicine. As an example, first experimental images of an atherosclerotic plaque specimen are presented.