A new imaging breakthrough combines ultrasound and light-based techniques to generate vivid 3D images that show both tissue structure and blood vessel activity. Developed by researchers at Caltech and USC, the system delivers detailed results quickly and without radiation or contrast dyes. It has already been used to image multiple parts of the human body. The approach could significantly improve cancer detection, nerve-damage monitoring, and brain imaging.
Standard ultrasound is fast, affordable, and widely used, but it mainly shows tissue shape in two dimensions and offers a limited viewing area. Photoacoustic imaging provides a different kind of information. It works by sending laser light into the body and detecting the sound waves produced when certain molecules absorb that light. This allows doctors and researchers to see blood vessels in optical color and observe blood flow through arteries and veins. However, photoacoustic imaging does not capture detailed tissue structure well.
Other common imaging methods, including computed tomography (CT) and magnetic resonance imaging (MRI), come with tradeoffs. These techniques may require contrast agents, expose patients to ionizing radiation, cost more, or take too long to use frequently.
Combining Ultrasound and Photoacoustic Imaging
To overcome these limitations, the research team developed RUS-PAT (rotational ultrasound tomography, RUST, combined with photoacoustic tomography, PAT).
Photoacoustic tomography was first developed more than two decades ago by Lihong Wang, the Bren Professor of Medical Engineering and Electrical Engineering and the Andrew and Peggy Cherng Medical Engineering Leadership Chair at Caltech. In PAT, tissue molecules that absorb light vibrate after being hit by short laser pulses, producing acoustic signals that can be measured and converted into detailed images.
Wang, who also serves as Caltech's executive officer for medical engineering, said the goal of the new project was to merge the strengths of ultrasound and photoacoustic imaging. "But it's not like one plus one," he explains. "We needed to find an optimal way of combining the two technologies."
This method can be used anywhere light can reach, RUS-PAT may have wide clinical applications. In breast cancer imaging, it could help doctors pinpoint a tumor's location while also revealing information about its biological activity. For patients with diabetic neuropathy, the technique could allow physicians to monitor both nerve structure and oxygen supply in a single scan. Wang also notes its potential for brain research, where scientists could study brain anatomy while simultaneously observing blood flow dynamics.
At present, the system can image tissue up to about 4 centimeters deep. Light can also be delivered using endoscopic tools, which may allow access to deeper areas of the body. Each RUS-PAT scan takes less than one minute.
Standard ultrasound is fast, affordable, and widely used, but it mainly shows tissue shape in two dimensions and offers a limited viewing area. Photoacoustic imaging provides a different kind of information. It works by sending laser light into the body and detecting the sound waves produced when certain molecules absorb that light. This allows doctors and researchers to see blood vessels in optical color and observe blood flow through arteries and veins. However, photoacoustic imaging does not capture detailed tissue structure well.
Other common imaging methods, including computed tomography (CT) and magnetic resonance imaging (MRI), come with tradeoffs. These techniques may require contrast agents, expose patients to ionizing radiation, cost more, or take too long to use frequently.
Combining Ultrasound and Photoacoustic Imaging
To overcome these limitations, the research team developed RUS-PAT (rotational ultrasound tomography, RUST, combined with photoacoustic tomography, PAT).
Photoacoustic tomography was first developed more than two decades ago by Lihong Wang, the Bren Professor of Medical Engineering and Electrical Engineering and the Andrew and Peggy Cherng Medical Engineering Leadership Chair at Caltech. In PAT, tissue molecules that absorb light vibrate after being hit by short laser pulses, producing acoustic signals that can be measured and converted into detailed images.
Wang, who also serves as Caltech's executive officer for medical engineering, said the goal of the new project was to merge the strengths of ultrasound and photoacoustic imaging. "But it's not like one plus one," he explains. "We needed to find an optimal way of combining the two technologies."
This method can be used anywhere light can reach, RUS-PAT may have wide clinical applications. In breast cancer imaging, it could help doctors pinpoint a tumor's location while also revealing information about its biological activity. For patients with diabetic neuropathy, the technique could allow physicians to monitor both nerve structure and oxygen supply in a single scan. Wang also notes its potential for brain research, where scientists could study brain anatomy while simultaneously observing blood flow dynamics.
At present, the system can image tissue up to about 4 centimeters deep. Light can also be delivered using endoscopic tools, which may allow access to deeper areas of the body. Each RUS-PAT scan takes less than one minute.
