A research team at Pohang University of Science and Technology POSTECH has developed a pen-sized microscope that can observe blood vessels and organs at ultra-high resolution. Solving the three challenges of portability, fast imaging speed, and clear image quality, the achievement was published in the international journal Nature Communications in Dec. last year.
When a camera gets smaller, its lens also gets smaller, making it harder to maintain image quality. The same goes for medical imaging equipment. To obtain precise images, the equipment inevitably becomes larger. For a long time, researchers have aimed to create a device that can be carried by hand in operating rooms or emergency settings while providing clear images.
Photoacoustic microscopy (PAM), which uses both light and sound, has drawn attention as a technology that can overcome these limits. Just as thunder follows lightning, when a laser is fired at tissue, ultrasound is generated momentarily; by analyzing this, blood vessels and microstructures can be rendered in three-dimensional images. While it has the advantage of not requiring a contrast agent, most systems are large and stationary, making them difficult to move.
The research team led by Professor Kim Cheolhong at Pohang University of Science and Technology POSTECH developed hPAM-TUT (handheld PhotoAcoustic Microscopy with Transparent Ultrasound Transducer), a photoacoustic microscope that drastically simplifies the structure while maintaining image quality. By using a transparent ultrasound transducer that transmits light, they aligned the paths of the laser and ultrasound, and instead of complex mirrors, they applied a method that scans light by vibrating a slender optical fiber itself.
The completed hPAM-TUT measures 17 mm in diameter and weighs only 11 g. It achieves a resolution of 7 μm (micrometers), about one-tenth the thickness of a human hair, and acquires a single three-dimensional volumetric image from a 2.6 mm field of view in 1.5 seconds.
The research team validated its performance through animal experiments. Imaging the stomach and small intestine of mice, they clearly identified complex vascular networks, and after administering epinephrine, used in emergency treatment, they observed in real time the process in which the microvessels in the ear constricted and then recovered. They clearly visualized the abnormal vascular structures that form around tumors in the early stages of metastasis. Quantitative analysis showed that tumor regions had significantly higher vessel density and structural complexity than normal tissue.
The research team said, "There is strong potential for clinical use, such as checking lesions in real time during surgery or rapidly detecting early cancers when combined with endoscopy," and noted, "We expect it to expand as a foundational technology that improves the accuracy of diagnosis and treatment across various fields, including dermatology, oncology, laparoscopic surgery, and intraoperative image-guided diagnosis."
References
Nature Communications (2025), DOI: https://doi.org/10.1038/s41467-025-68148-8