Domestic researchers have succeeded for the first time in the world in implementing a clear 3D image of the internal body by combining laser and ultrasound principles without directly touching the skin with the device.
Professor Lee Byung-ha from the Gwangju Institute of Science and Technology (GIST) Department of Electrical and Computer Engineering noted on the 13th that he developed optical-based non-contact photoacoustic tomography (PAT) technology in collaboration with Professor Choi Won-sik from Korea University Department of Physics. The research results were published online in the international journal 'Photoacoustics' on the 25th of last month.
Photoacoustic tomography is a technology that detects ultrasound (photoacoustic waves) generated in tissues that absorb the energy of a laser shot at them for a short time, reconstructing the internal structure in three dimensions. By combining the high selectivity of light and the deep penetration capability of ultrasound, it is useful in various fields such as tumor detection and blood vessel observation.
However, existing photoacoustic tomography required ultrasound sensors to be closely adhered to the skin to receive signals, which limited its application depending on the size or shape of the sensors and degraded sensitivity and resolution. Moreover, it was difficult to use in sensitive areas such as the eye or burned areas.
The research team implemented a non-contact photoacoustic imaging system that generates and detects ultrasound signals using only lasers and optical sensors without any ultrasound sensors. After generating photoacoustic waves in tissues with a laser, the subtle ultrasound waves spreading on the biomaterial surface were converted into digital images and recorded at a video level, analyzing this to restore the internal vascular structure in three dimensions with precision.
Additionally, a new algorithm was added to send information back to the position where the wave began. High-resolution 3D images were implemented at depths of up to 5 mm, with widths of 158 μm (micrometers; 1 μm is one millionth of a meter) and heights of 92 μm. 3D images of a 10 mm by 10 mm area were processed in less than one second, achieving an imaging speed more than 10 times faster than before.
Using the developed technology, the research team vividly captured the thigh blood vessels of mice and the vascular structure of chicken embryos in three dimensions, comparing them to actual anatomical images and confirming a high degree of consistency. Blood vessels beneath opaque layers, such as adipose tissue, were also clearly identified. This is particularly expected to lead to innovation in the field of medical imaging diagnosis as it allows for observing internal biological tissues in high-resolution 3D images without the need to closely adhere ultrasound sensors to the skin.
Professor Lee Byung-ha said, "With this research, we have implemented technology that can quickly measure ultrasound signals generated internally in the body over a wide area using only light without the need for physical contact," and he added, "It can be broadly used not only in medical imaging, such as diagnosis of cerebrovascular diseases and tumors but also in non-destructive testing across various industries like semiconductor wafers and nuclear facilities."
References
Photoacoustics (2025), DOI: https://doi.org/10.1016/j.pacs.2025.100753