Physical Sciences Inc. and Dartmouth imager shows nerves by fluorescence under normal operating-room light
A prototype fluorescence imager separates weak nerve signals from bright room light, so the lights need not be dimmed. It has been tested on animal models, excised human nerves and amputated human limbs.
Researchers from Physical Sciences Inc. and Dartmouth College have developed an intraoperative fluorescence imager that visualizes labeled nerves under standard operating-room lighting. The work by J. Park et al. was published in Journal of Biomedical Optics in 2026 spiedigitallibrary.org
Journal of Biomedical Opticsspiedigitallibrary.orgOpen source ↗. The system uses spatio-temporal modulation (STM) to suppress interference from strong room lights. It was tested on live animal models, excised human nerve specimens and perfused amputated human limbs.
Why room lighting is a problem
Fluorescence-guided surgery relies on agents that label nerve tissue. It could improve nerve identification in orthopedic, craniofacial and otolaryngological operations, where nerve structures are complex and delicate. The fluorescence signal is weak, especially at visible wavelengths, and strong ambient light interferes with it.
Currently the operating-room lights are dimmed or turned off during fluorescence imaging. According to the authors, this substantially disrupts the surgical workflow and reduces the chance of clinical adoption. Light from surgical lamps reaches the camera together with the fluorescence and lowers contrast. Instead of simply blocking it, the researchers gave the fluorescence signal a recognizable spatial and temporal pattern.
How spatio-temporal modulation works
The imager uses a line-scan scheme that collects signal from a narrow region at a time. This encodes the fluorescence into a distinctive spatial frequency within a narrow time window spiedigitallibrary.org
Journal of Biomedical Opticsspiedigitallibrary.orgOpen source ↗. Spatial-frequency demodulation and time-gating then extract the matching signal. Background light that is constant in time and uniform in space is rejected.
Test results
Preliminary studies showed that the imager detected nerve structures despite strong ambient illumination. The evaluation was then extended from live animal models to excised human nerve specimens and perfused amputated human limbs. In these experiments the system produced high-contrast fluorescence images of nerve tissue under normal operating-room lighting.
The authors describe the result as a significant step toward practical clinical implementation of fluorescence-guided nerve identification. Its performance during human surgical procedures has not yet been evaluated, and further clinical evaluation will be needed.
