Researchers use ultra-low-light ghost imaging to produce high-resolution images with less than 1% of the standard radiation dose.
Researchers have developed a computational imaging method that produces clear, high-resolution X-ray images using a fraction of the radiation required by traditional methods. The approach could eventually make medical diagnostics safer for sensitive populations, including children and pregnant patients.
The study, published in Optica, demonstrates that 2-megapixel resolution is achievable using only 0.48% of the X-ray photons typically required for standard X-ray imaging. This proof-of-concept suggests that comparable image quality may be possible with significantly lower radiation doses than are used in current clinical practice.
“While traditional X-ray imaging relies on enough X-ray photons reaching a detector to form a clear image, our approach uses computational techniques to reconstruct an image from fewer photons,” says Tiqiao Xiao, research team leader at the Shanghai Advanced Research Institute, Chinese Academy of Sciences, in a release. “We were able to show the low-dose potential of this approach by achieving megapixel radiology with ultra-low-light.”
Advancing Ghost Imaging Technology
The method utilizes ghost imaging, a computational approach that correlates two X-ray beams. One beam encodes a random pattern as a reference and does not probe the sample, while the second beam passes through the object. By correlating the two, researchers can reconstruct an image while exposing the object to very little X-ray power.
To overcome previous limitations in resolution and dose efficiency, the team reengineered the imaging system. They split the X-ray beam into a weak beam for the sample and a stronger reference beam, allowing for more information to be gathered from every photon. The system also uses two specialized detectors: one to capture faint signals and another to record fine spatial details.
The researchers also utilized a synthetic-aperture imaging approach. This uses an algorithm to reconstruct a high-resolution image from dozens of measurements, which is fewer than required by previous ghost imaging methods.
“Together, these advances balance three key performance indicators simultaneously: a large field of view, ultra-low photon consumption, and high imaging resolution,” says Xiao, in a release. “This provides a more practical and effective solution for X-ray ghost imaging.”
Experimental Results and Clinical Potential
The research team tested the method at the Shanghai Synchrotron Radiation Facility. In a controlled experiment, they compared the new method against conventional direct X-ray radiology under identical ultra-low-photon conditions.
The results showed that the new technique produced images measuring 1992 × 944 pixels with the same contrast-to-noise ratio as conventional radiology while using only 0.48% of the photons. Additionally, the method achieved the maximum contrast-to-noise ratio possible with conventional radiology while using 100 times fewer photons.
While the technology could eventually be integrated into hospital equipment such as chest X-rays and computed tomography scans, the researchers note that further development is required for clinical use. The team plans to improve image quality and demonstrate the method using laboratory X-ray sources, such as X-ray tubes, to move the technology toward real-world medical applications.
“Our technology could be combined with routine hospital imaging equipment such as chest X-rays and CT scans,” says Xiao, in a release. “It would make medical X-ray imaging safer, which is especially important for children, pregnant patients, and people needing frequent scans.”
Photo caption: Researchers have shown that it’s possible to take clear, high-resolution X-ray images using very little radiation. An image acquired using the new method (a) is compared with conventional radiology (b) under identical photon counts.
Photo credit: Tiqiao Xiao, Shanghai Advanced Research Institute, Chinese Academy of Sciences
