UC Irvine researchers reveal a revolutionary new approach for 3D CT imaging from a single X-ray projection
December 17, 2024
Traditional CT (left) vs. XACT (right): XACT eliminates the need for gantry rotation to reconstruct a 3D image, offering a more portable and faster imaging solution.
Orange, Calif. — Computed tomography (CT) has long been a cornerstone of modern imaging, providing detailed 3D insights into the human body and other materials. However, conventional CT requires hundreds of X-ray projections from multiple angles, exposing patients to significant radiation doses and relying on large, immobile systems.
To address this issue, researchers from the UC Irvine School of Medicine Departments of Radiological Sciences and the Department of Biomedical Engineering recently published a study in the journal Science Advances in which they introduce a groundbreaking technology that achieves 3D imaging with a single X-ray projection called X-ray–Induced Acoustic Computed Tomography (XACT).
"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," says Dr. Vahid Yaghmai, who leads UCI Health Radiology Services and serves as chair of the UC Irvine Department of Radiological Sciences. He was not directly involved in the study.
A new paradigm in imaging
"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," said Shawn Xiang, PhD, the study’s corresponding author and an associate professor in the radiological sciences and biomedical engineering departments.
XACT leverages the interaction between X-rays and tissue to produce acoustic waves, which travel at a speed of 1,500 meters per second. These waves are captured by ultrasound detectors, enabling real-time, three-dimensional imaging without the need for mechanical scanning or complex gantry systems.
"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," said Siqi Wang, PhD, the study’s first author. Wang completed his PhD at UC Irvine in Xiang’s lab and is now a postdoctoral research scholar at Stanford University.
Benefits beyond traditional CT
One of XACT’s most significant advantages is its efficiency and reduced radiation exposure. This makes XACT a safer and more accessible alternative, particularly for applications like routine diagnostics and breast cancer screening. Furthermore, with portable X-ray sources and ultrasound detectors, XACT systems promise compact, gantry-free designs, enabling imaging in settings previously inaccessible to traditional CT systems.
Challenges and future directions
While the potential of XACT is immense, current limitations include resolution constraints tied to the frequency and size of the ultrasound detectors. Future improvements, such as higher-frequency transducers and advanced reconstruction algorithms powered by deep learning, could further enhance its performance.
Redefining imaging across fields
The ability to achieve 3D imaging from a single X-ray projection positions XACT as a transformative tool not only for medical diagnostics but also for nondestructive testing in engineering and material science. Its innovative approach eliminates the need for rotational access, opening new possibilities for imaging in constrained environments.
XACT also represents a leap forward in imaging technology, combining reduced radiation exposure, compact system design and unprecedented efficiency. As this technology continues to evolve, it has the potential to redefine medical and industrial imaging, bringing us closer to a future where high-resolution, low-dose 3D imaging is the norm in healthcare and beyond.
Related stories
About UCI Health
UCI Health, one of California’s largest academic health systems, is the clinical enterprise of the University of California, Irvine. The 1,317-bed system comprises its main campus UCI Medical Center, a 459-bed, acute care hospital in Orange, Calif., the UCI Health — Irvine medical campus, four hospitals and affiliated physicians of the UCI Health Community Network in Orange and Los Angeles counties and ambulatory care centers across the region. Recognized as a Top Hospital by The Leapfrog Group, UCI Medical Center provides tertiary and quaternary care and is home to Orange County’s only National Cancer Institute-designated comprehensive cancer center, high-risk perinatal/neonatal program and American College of Surgeons-verified Level I adult and Level II pediatric trauma center, gold level 1 geriatric emergency department and regional burn center. UCI Health serves a region of nearly 4 million people in Orange County, western Riverside County and southeast Los Angeles County. Follow us on Facebook, Instagram, LinkedIn and Twitter.
About the UC Irvine School of Medicine
Each year, the UC Irvine School of Medicine educates more than 400 medical students and nearly 150 PhD and MS students. More than 700 residents and fellows are trained at UCI Medical Center in Orange and affiliated institutions. Multiple MD, PhD and MS degrees are offered. Students are encouraged to pursue an expansive range of interests and options. For medical students, there are numerous concurrent dual degree programs, including an MD/MBA, MD/MPH, or an MD/MS degree through one of three mission-based programs: the Health Education to Advance Leaders in Integrative Medicine (HEAL-IM), the Program in Medical Education for Leadership Education to Advance Diversity-African, Black and Caribbean (PRIME LEAD-ABC), and the Program in Medical Education for the Latino Community (PRIME-LC). The UC Irvine School of Medicine is accredited by the Liaison Committee on Medical Accreditation and ranks among the top 50 nationwide for research. For more information, visit medschool.uci.edu.
