Detachable Acoustic Lens Boosts Ultrasound Imaging Versatility and Resolution
Researchers at the Korea Research Institute of Standards and Science (KRISS) have created a detachable acoustic lens that allows users to easily adjust the focal length of ultrasonic inspection equipment. Similar to switching lenses on a DSLR camera to enhance image quality, this advancement enables tailored optimization of ultrasonic imaging resolution, promising improved performance in both medical diagnostics and industrial inspections.
Ultrasonic imaging sends sound waves into the body or objects and captures the returning echoes to visualize internal structures. One high-resolution method, known as C-scan, is frequently used in medical diagnostics—such as detecting cancer—and in nondestructive testing (NDT) of aircraft parts and pipelines.
To generate sharp ultrasound images, it’s critical to intensify the ultrasound signal and precisely control the focal point. Focused ultrasound transducers are widely used in C-scan systems for this reason—they channel the dispersed ultrasound energy directly toward a specific area, enhancing image clarity.
However, each focused transducer comes with a fixed focal length, which requires users to purchase multiple transducers to inspect targets at varying depths. This setup is costly and inflexible, making it hard to adapt the focus to the object’s specific position or shape, and limiting the ability to fine-tune image resolution.
To solve this problem, KRISS's Acoustics, Ultrasound and Vibration Metrology Group developed a detachable acoustic lens system. The lens can be attached to an ultrasound transducer with a fixed focal length, allowing users to dynamically adjust the focus without replacing the device. This innovation enables custom image resolution tailored to the inspection target.
The new lens features an aspheric shape that improves image clarity over traditional spherical lenses, which suffer from spherical aberration—blurring at image edges. Additionally, the team designed the lens to be foldable, allowing it to adapt in size to the transducer's attachment surface.
When used with a flat ultrasound transducer, which typically produces low-resolution images, the KRISS-designed lens can elevate performance to that of a focused transducer. The researchers developed both convex and flat-form lens types to accommodate different transducer designs.
In testing, the lens was attached to a C-scan ultrasound system and used to scan a phantom model that mimics human tissue. The system successfully resolved internal features as small as 25 micrometers—achieving 1.5 times the resolution of the same device without the lens at an identical focal length.
“We plan to expand the application of this lens design technology beyond C-scan systems to various types of ultrasound imaging,” said Dr. Kim Yong Tae, Principal Research Scientist at KRISS.
The research, funded by the Korea Medical Device Development Fund and supported by several government ministries, was published in January in Measurement Science and Technology (Impact Factor: 2.4).