Domestic researchers have unveiled a new ultrasound technology that opens a new chapter in cancer early diagnosis. This technology is expected to overcome the limitations of existing endoscopic ultrasound and dramatically improve the accuracy of cancer diagnosis.
Professor Kim Cheol-hong of Pohang University of Science and Technology's Department of Electrical and Electronic Engineering, Department of IT Convergence Engineering, Department of Mechanical Engineering, and Graduate School of Convergence; Professor Kim Hyung-ham from the same departments; Ph.D. student Kim Jae-woo from the Department of IT Convergence Engineering; and integrated student researcher Heo Da-som announced on the 16th that they developed the world's first high-performance photoacoustic endoscope based on a transparent ultrasound transducer in collaboration with Professor Kim Hee-man from Yonsei University Severance Hospital. A transducer refers to a device that converts energy from one form to another.
Endoscopic ultrasound is widely used in gastroenterology for cancer diagnosis. However, it has the disadvantage of low contrast in soft tissues and only provides structural information about tissues, resulting in decreased sensitivity. To overcome this, many studies aimed to improve the early diagnosis rate of cancer by providing additional vascular information through the combination of photoacoustic technology with endoscopic ultrasound. However, it was difficult to simultaneously obtain high-quality photoacoustic and ultrasound images within a microscale probe.
This is because to obtain high-resolution images, light and ultrasound need to be aligned in the same direction, but previously, there were limitations in achieving this alignment. As a result, it was necessary to either drill holes in the ultrasound transducer to secure the light path or tilt the optical system to match the two paths, which meant sacrificing the quality of either the ultrasound or photoacoustic images.
The researchers developed a microscale (1 mm² level) transparent ultrasound transducer capable of simultaneously implementing high-resolution ultrasound and photoacoustic images. This transducer is made of transparent materials such as indium-tin oxide electrodes and polyurethane sound-absorbing layers, allowing for the maintenance of the transducer's shape while securing the light path, thus providing high-resolution ultrasound and photoacoustic images. The researchers succeeded in integrating the optical and acoustic systems within this microscale probe and aligning the two paths.
To evaluate this technology, the researchers inserted it into a commercial endoscope channel and captured images of a pig's esophagus. As a result, they successfully visualized all layers from the esophageal mucosa to the muscle layer, and the ultrasound performance was outstanding, comparable to that of commercial endoscopes. Additionally, they were able to obtain high-resolution photoacoustic images over long distances, demonstrating the high clinical applicability of photoacoustic-ultrasound endoscopes.
Professor Kim Cheol-hong noted, "We expect to overcome the limitations of existing photoacoustic-ultrasound and dramatically enhance diagnostic accuracy." Professor Kim Hee-man stated, "The transparent ultrasound transducer-based photoacoustic-ultrasound endoscopy technology and the successful experimental results will be an important first step in the development and localization of innovative diagnostic medical devices."
This research was published in the international journal Science Advances on the 22nd.
Reference materials
Science Advances (2024), DOI: https://doi.org/10.1126/sciadv.adq9960