Researchers at the University of California, Irvine (UCI) have developed a groundbreaking technology that achieves 3D imaging from a single X-ray projection. Known as X-ray–Induced Acoustic Computed Tomography (XACT), this innovation promises to transform medical diagnostics and other imaging applications by reducing radiation exposure and introducing compact, efficient imaging systems.
Computed tomography (CT) has been a cornerstone of modern imaging, providing detailed three-dimensional views of the human body and other materials. However, conventional CT relies on hundreds of X-ray projections from multiple angles, exposing patients to significant radiation and necessitating large, immobile systems. The new XACT technology, recently published in the journal Science Advances, represents a paradigm shift in imaging science.
"In XACT, the generated sound waves by X-rays change the way X-ray imaging works, converting X-rays to ultrasound. X-rays typically travel in straight lines, so one projection only provides 2D information. However, X-ray-induced acoustic signals propagate in three dimensions, allowing for 3D imaging with a single projection," explained Shawn Xiang, PhD, the study’s corresponding author and an associate professor at UCI’s Departments of Radiological Sciences and Biomedical Engineering.
The process harnesses the interaction between X-rays and tissue to produce acoustic waves, which travel at a speed of 1,500 meters per second. Ultrasound detectors capture these waves, enabling real-time 3D imaging without the need for complex mechanical systems or rotational access. "For the first time, we have proved that 3D imaging can be obtained with a single X-ray projection based on X-ray-induced acoustic detection in both phantoms and biological tissue," added Siqi Wang, PhD, the study’s first author.
A Safer, More Efficient Imaging Solution
XACT’s ability to achieve 3D imaging with just one projection marks a significant departure from traditional CT methods, which often require upwards of 600 projections. "The groundbreaking finding here is that you can make 3D X-ray imaging with just a single projection, which typically needs 600 projections or more," noted Vahid Yaghmai, MD, MS, FSAR, chair of the UCI Department of Radiological Sciences.
Among its advantages, XACT significantly reduces radiation exposure, making it a safer option for routine diagnostics such as breast cancer screening. Additionally, the compact design of XACT systems, which leverage portable X-ray sources and ultrasound detectors, offers flexibility and accessibility in settings previously beyond the reach of traditional CT systems.
Potential Beyond Medicine
While the medical applications of XACT are profound, its implications extend beyond healthcare. The technology’s ability to provide 3D imaging without rotational access makes it ideal for nondestructive testing in engineering and material science. This opens up new possibilities for imaging in constrained environments, such as industrial inspections and structural integrity assessments.
Future Developments
Despite its promise, XACT faces challenges, including resolution constraints linked to the frequency and size of ultrasound detectors. Researchers are optimistic about overcoming these hurdles through advancements in higher-frequency transducers and deep learning-powered reconstruction algorithms, which could further refine the technology’s performance.
Redefining Imaging Standards
XACT represents a leap forward in imaging technology, combining reduced radiation exposure, compact system design, and unprecedented efficiency. As the technology continues to evolve, it has the potential to redefine both medical and industrial imaging, paving the way for high-resolution, low-dose 3D imaging to become the norm.
