"Grating-based x-ray differential phase-contrast CT is compatible with a polychromatic x-ray source, and can produce radiographic and tomographic images with higher contrast in soft tissues compared to the conventional attenuation-based x-ray imaging," lead investigator Yi Yang, PhD, told AuntMinnie.com. It therefore has great potential in a variety of applications, including medical diagnosis, biological study, and material sciences, he said.
In their study, the researchers employed a phase-stepping procedure to extract the phase signal for x-ray differential phase-contrast CT.
"Because of the possible fabrication imperfection in absorption grating and the mismatch between the phase grating and x-ray spectrum, the experimental determined phase-stepping curve exhibits a phenomenon of twin peaks that differ remarkably in their heights," Yang said.
The group's theoretical analysis and experiments show that this large differential in the twin peaks offers an opportunity to obtain more information about the phase contrast and dark-field contrast of the object, followed by dewrapping of the retrieved phase signal, according to Yang.
"This means the imperfection in the absorption grating can actually be turned into a benefit in the phase retrieval process," he said.
