Enhancing ultrasound imaging: KRISS develops detachable acoustic lens for precise focus adjustment
KRISS unveils a detachable acoustic lens that allows easy focus adjustment in ultrasound devices
image: Researchers Who Developed the Detachable Aspheric Acoustic Lens
(Back row, from left clockwise: Dr. Doh Il, Head of the Medical Metrology Group; Dr. Baik Kyung Min; Dr. Kim Yong Tae)
Credit: Korea Research Institute of Standards and Science (KRISS)
The Korea Research Institute of Standards and Science (KRISS, President Lee Ho Seong) has developed a detachable acoustic lens that allows for easy adjustment of the focal length in ultrasonic inspection equipment. Much like swapping lenses on a DSLR camera to improve image quality, this technology enables users to optimize the resolution of ultrasonic imaging systems for specific inspection tasks. The innovation is expected to significantly enhance accuracy in both medical diagnostics and industrial safety inspections.
Ultrasonic imaging technology works by transmitting sound waves into an object or the human body and capturing the reflected signals to visualize internal structures. Among these technologies, the C-scan method is known for its ability to generate high-resolution images. It is widely used in diagnostic medical equipment for tasks such as cancer detection, as well as in nondestructive testing (NDT) systems to assess defects in aircraft components and industrial pipelines.
To produce high-resolution ultrasound images, it is essential to increase the intensity of the transmitted and reflected ultrasound waves and precisely control the focal length. For this purpose, focused ultrasound transducers are commonly used in C-scan ultrasound inspection systems. These devices concentrate the broadly dispersed ultrasound energy directly onto the target area, thereby enhancing image quality.
However, a major limitation is that each focused ultrasound transducer has a fixed focal length. This means that multiple transducers with different focal lengths must be purchased, leading to high costs. Moreover, it is difficult to fine-tune the focus to match the position, size, or shape of the object being examined, making it challenging to achieve optimal resolution in ultrasound imaging.
To overcome this limitation, the Acoustics, Ultrasound and Vibration Metrology Group at KRISS has developed ‘a detachable acoustic lens design technology’. By attaching the newly developed lens to a focused ultrasound transducer with a fixed focal length, users can adjust the focal distance to suit the inspection target—without needing to replace the equipment. This enables optimized image resolution tailored to the specific object being examined.
Notably, the acoustic lens developed by the KRISS research team is designed with an aspheric shape, offering clearer focus and higher resolution compared to conventional spherical lenses. Traditional acoustic lenses are typically spherical, which leads to spherical aberration—blurring at the edges of the image due to the lens shape. To address this, the team also devised a foldable design that allows the lens size to be flexibly adjusted to match the attachment area.
When the KRISS-designed acoustic lens is attached to a flat ultrasound transducer with low resolution, it can deliver performance comparable to that of a focused ultrasound transducer. The team developed both convex acoustic lenses for focused transducers and flat-form acoustic lens designs.
When the newly developed acoustic lens was attached to a C-scan ultrasound imaging device and used to analyze a phantom model simulating the human body, the system successfully visualized fine structures as small as 25 micrometers (μm, one millionth of a meter). This represents a resolution approximately 1.5 times higher than that of a device without the lens at the same focal distance.
Dr. Kim Yong Tae, Principal Research Scientist of the Acoustics, Ultrasound and Vibration Metrology Group at KRISS, stated, “We plan to expand the application of this lens design technology beyond C-scan systems to various types of ultrasound imaging.”
This research was supported by the Korea Medical Device Development Fund, funded by the Korean government (the Ministry of Science and ICT, the Ministry of Trade, Industry and Energy, the Ministry of Health & Welfare, and the Ministry of Food and Drug Safety). It was published in January in Measurement Science and Technology (Impact Factor: 2.4).
* Note: This research was supported by the Korea Medical Device Development Fund (NTIS Project Number: 9991007024, KMDF Project Number: KMDF_PR_202011B03-04).