Purpose: X-ray grating interferometry (XGI) provides substantially increased contrast over conventional absorption-based imaging methods and therefore shows great potential for future biomedical applications. In this work, we propose a single-shot phase retrieval method for synchrotron-based high-energy x-ray grating interferometry. Contrary to existing retrieval methods, the presented novel approach enables direct retrieval of the object's phase map quantitatively from a single projection image, thus significantly simplifying the experimental procedure and reducing data acquisition times.
Methods: The phase retrieval method is analytically derived, based on the phase-attenuation duality of soft tissues when being imaged with high-energy x rays. The sensitivity of the retrieved phase map, quantified by the standard deviation, is evaluated as a function of the photon number. Numerical experiments are performed to validate the proposed method and provide some quantitative insight.
Results: The numerical results show that the method can provide high-quality phase images, where the well-known streak artifacts are significantly suppressed. Moreover, the retrieved phase maps confirm that the method is highly stable with respect to statistical noise.
Conclusions: Thanks to simplified experimental procedure and reduced acquisition time and dose deposition to the sample, we believe that this new method can find its potential in biomedical imaging and in vivo studies. Future work will focus on the adaptation of the method to polychromatic x ray from tube source and to computed tomography.
Keywords: grating interferometry; phase retrieval; phase-attenuation duality; x-ray imaging.
© 2019 American Association of Physicists in Medicine.