The ‘ultrasound-photoacoustic dual-modal imaging system’ combines molecular imaging contrast with ultrasound imaging, and it might visualize molecular and structural information contained in the body in real-time with none ionizing radiation. This advantage gives it the potential to reinforce medical diagnosis by providing diverse physiological and histological information, ensuring greater accuracy and safety for patients. Nonetheless, optical and ultrasound pathway integration all the time reduces the system’s performance in conventional ultrasound transducers. Due to this fact, a novel transducer that may achieve easy and seamless integration is crucial for practical application.
Professor Chulhong Kim (Department of Electrical Engineering, the Department of Convergence IT Engineering, the Department of Mechanical Engineering, and the School of Convergence Science and Technology), Dr. Seonghee Cho (Department of Electrical Engineering), and Ph.D. candidate Minsu Kim (Department of Convergence IT Engineering) at Pohang University of Science and Technology (POSTECH), addressed challenges inherent in conventional ultrasound-photoacoustic systems by developing a novel transparent ultrasonic transducer (TUT) showcasing high performance. Their research findings have been published within the ‘Nature Communications.’
An ultrasound transducer transmits or receives ultrasound. Conventional ultrasound transducers are typically made using multiple opaque layers to maximise acoustic performance, and they can not be seamlessly integrated into light pathways. This fundamental limitation all the time diminishes the performance of each optical and ultrasound systems. While many recent research projects actively explore the usage of transparent materials in TUTs to handle this issue, achieving transparency and best acoustic performance across all transducer layers continues to be an issue.
This research demonstrates a transparent material using a silicon dioxide (SiO2)-epoxy composite and applies it to a novel TUT. The novel TUT exhibits exceptional optical transparency (>80%) and maintains the identical bandwidth (±30% at the middle frequency) as conventional opaque ultrasound transducers.
Using the novel TUT within the ultrasound-photoacoustic dual-modal system resulted in depth-to-resolution ratios, surpassing 500 for ultrasound imaging and 370 for photoacoustic imaging. These ratios are three to 6 times higher than those of traditional photoacoustic single systems. Notably, this research breaks the traditional limit of a depth-to-resolution ratio 200 in photoacoustic research, achieving 370.
This imaging system also easily conducted intricate structural and functional imaging of live animals and humans.
POSTECH Professor Chulhong Kim expressed his optimism, stating, “The applying of this technology extends across various medical devices, encompassing tasks like using light stimulation for cell manipulation, employing laser surgery for tumor removal, and employing ultrasound for the examination of residual tissue.” He added, “Our aspiration is that this research might be helpful in diverse fields including those employing ultrasound and optical sensors akin to mobile devices and robotics.”
The research was conducted with support from the Mid-Profession Researcher Program, the Sejong Fellowship Program, the Governmental Medical Device R&D Program, the BK21, the BRIDGE project, and the Program for Key Research Institutes for Universities of the National Research Foundation of Korea.
