Towards multimodal melanoma depth determination with Optoacoustics and Optical Coherence Tomography

The depth of a melanoma lesion is one of the most important factors in determining the tumor stage. Currently a depth measurement is only possible by analyzing the histology after surgical excision. Optical Coherence Tomography (OCT) and Optoacoustics (OA) are well suited techniques for research on biological tissue and can provide depth information of tissue substructures depending on their respective contrast mechanism. OCT shows the distribution of scattering structures. Within the first millimeter, it provides tomograms with a resolution of a few microns. Complementary, OA measures the distribution of absorbers within a depth of up to several centimeters. To facilitate the combination of the two modalities, we developed an OA detector which is transparent in the wavelength range used by our OCT. This way, the two modalities can measure simultaneously at the same position without affecting one another. While the customized OCT system detects changes in the scattering properties, the self-build OA system measures the pressure waves resulting from the absorption profile. Here, we present our multimodal OA-OCT measurements of layered samples.