UH researchers develop innovative technique in X-ray phase contrast imaging

Researchers at the University of Houston have unveiled a significant advancement in X-ray imaging technology that promises improvements across medical diagnostics, materials and industrial imaging, transportation security, and other fields.

Mini Das, Moores Professor at UH's College of Natural Sciences and Mathematics and Cullen College of Engineering, along with Physics graduate student Jingcheng Yuan, introduced a novel light transport model for a single-mask phase imaging system. Their work was featured on the cover of Optica, a leading journal in theoretical and applied optics and photonics. The new model enhances non-destructive deep imaging for visibility of light-element materials, including soft tissues such as cancers and background tissues like plastics and explosives.

“Older X-ray technology relies on X-ray absorption to produce an image,” Das said. “But this method struggles with materials of similar density, leading to low contrast and difficulty distinguishing between different materials, which is a challenge across medical imaging, explosive detection and other fields.”

X-ray phase contrast imaging (PCI) has garnered attention for its potential to provide enhanced contrast for soft tissues by utilizing relative phase changes as the X-rays pass through an object. Among various techniques available, the single-mask differential stands out due to its simplicity and effectiveness in yielding higher contrast images compared to other methods. It achieves this through single-shot, low-dose imaging.

“Our new light transport model enables the understanding of contrast formation and how multiple contrast features mingle in acquired data,” Das explained. “As a result, it allows the retrieval of images with two distinct types of contrast mechanisms from a single exposure, which is a significant advancement over traditional methods.”

The design employs an X-ray mask with periodic slits that enhance edge contrast by aligning with detector pixels to capture differential phase information. This setup simplifies the process by reducing the need for high-resolution detectors or complex multi-shot processes.

Das’s team has tested their model through rigorous simulations using their laboratory benchtop X-ray imaging system. The next objective is to integrate the technology into portable systems and retrofit existing setups for real-world applications such as hospitals, industrial-ray imaging, and airports.

“Our research opens up new possibilities for X-ray imaging by providing a simple, effective and low-cost method for enhancing image contrast which is a critical need for non-destructive deep imaging,” Das stated. “It makes phase contrast imaging more accessible and practical, leading to better diagnostics and improved security screening. It is a versatile solution for a wide range of imaging challenges. We are in the process of testing feasibility for several applications.”

Funding sources for Das’s research include NSF, CDMRP, NIH with recent funding from the National Institute of Biomedical Imaging and Bioengineering aimed at developing low-dose Micro-CT that utilizes multiple novel contrast mechanisms thereby reducing radiation dose and imaging time.