Harnessing Nonlinearity in Optoacoustic Imaging for Enhanced Tissue Visualization
Helmholtz Munich researchers have introduced a new imaging method that exploits light, sound, and temperature-induced material changes. This approach uncovers a novel contrast mechanism in optoacoustic imaging, driven by tiny temperature-based shifts in electromagnetic properties. It boosts sensitivity and resolution, allowing for more precise tissue visualization. With significant potential to enhance diagnostics, this advancement could transform biomedical applications, particularly in tissue characterization and disease monitoring.
Optoacoustic imaging is a powerful tool for high-resolution visualization of biological tissues. A recent study in Light: Science & Applications explored nonlinear changes in optoacoustic tomography at low light fluence. Researchers at the Institute for Biological and Medical Imaging found that thermally induced changes in electromagnetic permittivity contribute to signal nonlinearity. Using theoretical models and experiments, they showed that these effects are most prominent in high-frequency signals and can serve as a new contrast mechanism.
The researchers reconstructed the first images based on this contrast in phantoms and live mouse tissues. This method could enhance disease monitoring in organs like the kidney and liver. “While further studies are required to corroborate our postulation on the sources of non-linearity, the new method can be widely employed in basic research and clinical translation applications,” says Vasilis Ntziachristos, Director of the Institute for Biological and Medical Imaging at Helmholtz Munich.
Original Publication
Malekzadeh-Najafabadi et al., 2025: Nonlinearity of optoacoustic signals and a new contrast mechanism for imaging. Light: Science & Applications. DOI: 10.1038/s41377-025-01772-7
