New light transport model improves X-ray phase contrast imaging

Researchers at the University of Houston have unveiled a breakthrough in X-ray imaging technology that could bring significant improvements in medical diagnostics, materials and industrial imaging, transportation safety and other applications.

In an article featured on the cover of OpticalMini Das, Moores Professor in the UH College of Natural Sciences and Mathematics and Cullen College of Engineering, and Jingcheng Yuan, a UH physics graduate student, present a new light transport model for a single-mask phase imaging system that improves nondestructive deep imaging for the visibility of light-element materials, including soft tissues such as cancers and background tissues such as plastics and explosives.

“Old X-ray technology relies on the absorption of X-rays to produce an image,” Das says. “But this method is difficult to use with materials of similar density, resulting in low contrast and difficulty distinguishing between different materials, which is a challenge for medical imaging, explosives detection and other fields.”

X-ray phase contrast imaging, or PCI, has gained considerable attention in recent years because of its potential to provide enhanced contrast for soft tissues by utilizing the relative phase changes as X-rays pass through an object. Among the many techniques available, single-mask differential imaging stands out for its simplicity and effectiveness in translating into practical applications and producing higher-contrast images than other methods. And it does so in a much simpler and more efficient manner with low-dose imaging in a single shot.

“Our new light transport model provides insight into contrast formation and how multiple contrast features mix in the acquired data,” Das said. “It thus enables the recovery of images with two distinct types of contrast mechanisms from a single exposure, which is a significant advancement over traditional methods.”

The design uses an X-ray mask with periodic slits, creating a compact configuration that improves edge contrast.

“This mask aligns with the detector pixels, allowing us to capture differential phase information that more clearly shows variations between materials. The main advantage of this solution is that it simplifies setup and reduces the need for high-resolution detectors or complex multi-shot processes,” Das added.

Das’s team has already tested its model through rigorous simulations and on its own laboratory X-ray imaging system. The next goal, she says, is to integrate the technology into portable systems and retrofit existing imaging setups to test it in real-world environments, such as hospitals, industrial X-ray imaging and airports.

“Our research opens up new possibilities for X-ray imaging by providing a simple, efficient and inexpensive method to enhance image contrast, which is a critical need for non-destructive deep imaging,” says Das.

“This makes phase contrast imaging more accessible and convenient, leading to better diagnostics and improved safety monitoring. It is a versatile solution for a wide range of imaging challenges. We are currently testing the feasibility of a number of applications.”