Optical imaging methods generally do not allow a high penetration or imaging depth due to light scattering in the tissue. Ultrasound-based imaging methods can penetrate deeper into the tissue, but have low contrast in acoustically homogeneous tissue types. Ultrasound is preferred because it has no side effects, is painless and, unlike X-rays, is completely risk-free.

Optoacoustic imaging combines the advantages of both techniques. The absorbing structures in the tissue (e.g. the smallest vessels) are heated locally by the ultrashort light pulses, which leads to a temporary minimal expansion of the tissue at certain points (thermoelastic expansion). This creates measurable pressure waves in the ultrasound range, which are detected by sensors. The cell structures are not damaged, the procedure is painless and risk-free. For imaging, there is an advantageous combination of light absorption contrasting and the improved ratio of resolution to increased ultrasound-induced penetration depth. Artificial intelligence is used for further processing and improved evaluation of the data.