A new handheld photoacoustic tomography (PAT) scanner developed by researchers at University College London (UCL) promises to revolutionize medical imaging by generating high-resolution 3D images in seconds. This advancement addresses the limitations of existing PAT technology, which has been hindered by slow processing speeds and susceptibility to motion artifacts. The scanner could significantly improve the early detection and monitoring of diseases such as cancer, diabetes, and arthritis.
The device utilizes laser-generated ultrasound waves to visualize subtle changes in veins and arteries at a sub-millimeter scale, up to 15mm deep within tissues. Existing PAT scanners often require several minutes to capture a single image, making them impractical for clinical use due to patient movement. The UCL team's innovation reduces image acquisition time by 100 to 1,000 times, enabling real-time imaging of dynamic physiological events.
Technical Advancements
The new scanner incorporates two key improvements: a novel design that detects ultrasound waves at multiple points simultaneously, and the application of mathematical principles similar to those used in digital image compression. This allows high-quality images to be reconstructed from fewer measurements, drastically reducing acquisition time.
"We’ve come a long way with photoacoustic imaging in recent years, but there were still barriers to using it in the clinic. The breakthrough in this study is the acceleration in the time it takes to acquire images," said Professor Paul Beard, UCL Medical Physics and Biomedical Engineering.
Clinical Applications
In pre-clinical tests, the handheld scanner was used on patients with type-2 diabetes, rheumatoid arthritis, and breast cancer, as well as healthy volunteers. The scanner successfully produced detailed 3D images of microvasculature in the feet of diabetic patients, revealing deformities and structural changes indicative of peripheral vascular disease (PVD). In breast cancer patients, the scanner visualized skin inflammation associated with the disease.
"In one of our patients, we could see smooth, uniform vessels in the left foot and deformed, squiggly vessels in the same region of the right foot, indicative of problems that may lead to tissue damage in future. Photoacoustic imaging could give us much more detailed information to facilitate early diagnosis, as well as better understand disease progression more generally," said Andrew Plumb, Associate Professor of Medical Imaging at UCL.
Future Directions
The researchers are currently focusing on applications in peripheral vascular disease, oncology, head and neck cancer, arthritis, diabetes, and skin inflammation. They plan to conduct more extensive testing on larger patient cohorts and refine the scanner for use by untrained personnel. The team anticipates seeking FDA approval within the next three to five years.
"In the future, photoacoustic imaging could be used to detect a cancerous tumour and monitor it relatively easily. It could also be used to help cancer surgeons better distinguish tumour tissue from normal tissue by visualising the blood vessels in the tumour, helping to ensure all of the tumour is removed during surgery and minimising the risk of recurrence. I can envisage lots of ways it will be useful," said Dr. Huynh.
