Ultrasonically modulated X-ray phase contrast imaging

We show that the radiation pressure exerted by a beam of ultrasound can be used for contrast enhancement in high resolution X-ray imaging of tissue. Interfacial features of objects are highlighted as a result of both the displacement introduced by the ultrasound and the inherent sensitivity of X-ray phase contrast imaging to density variations. The potential of the method is demonstrated by imaging various tumor phantoms and tumors from mice. The directionality of the acoustic radiation force and its localization in space permits the imaging of ultrasound-selected tissue volumes. The results suggest that the method may permit the detection of tumors in soft tissue in their early stages of development.