title: Multiple irradiation sensing of the optical effective attenuation coefficient for spectral correction in handheld OA imaging.
abstract: Spectral optoacoustic (OA) imaging enables spatially-resolved measurement of blood oxygenation levels, based on the distinct optical absorption spectra of oxygenated and de-oxygenated blood. Wavelength-dependent optical attenuation in the bulk tissue, however, distorts the acquired OA spectrum and thus makes quantitative oxygenation measurements challenging. We demonstrate a correction for this spectral distortion without requiringa prioriknowledge of the tissue optical properties, using the concept of multiple irradiation sensing: recording the OA signal amplitude of an absorbing structure (e.g.blood vessel), which serves as an intrinsic fluence detector, as function of irradiation position. This permits the reconstruction of the bulk effective optical attenuation coefficientμeff,λ. If performed at various irradiation wavelengths, a correction for the wavelength-dependent fluence attenuation is achieved, revealing accurate spectral information on the absorbing structures. Phantom studies were performed to show the potential of this technique for handheld clinical combined OA and ultrasound imaging.
authors.affiliation: University of Bern, Biomedical Photonics Group, Institute of Applied Physics, Sidlerstrasse 5, 3012 Bern, Switzerland.
authors.forename: K Gerrit
authors.initials: KG
authors.lastname: Held
authors.affiliation: University of Bern, Biomedical Photonics Group, Institute of Applied Physics, Sidlerstrasse 5, 3012 Bern, Switzerland.
authors.forename: Michael
authors.initials: M
authors.lastname: Jaeger
authors.affiliation: University of Bern, Biomedical Photonics Group, Institute of Applied Physics, Sidlerstrasse 5, 3012 Bern, Switzerland.
authors.forename: Jaro
authors.initials: J
authors.lastname: Rička
authors.affiliation: University of Bern, Biomedical Photonics Group, Institute of Applied Physics, Sidlerstrasse 5, 3012 Bern, Switzerland.
authors.forename: Martin
authors.initials: M
authors.lastname: Frenz
authors.affiliation: University of Bern, Biomedical Photonics Group, Institute of Applied Physics, Sidlerstrasse 5, 3012 Bern, Switzerland.
authors.forename: H Günhan
authors.initials: HG
authors.lastname: Akarçay
keywords: Blood oxygenation saturation; Fluence compensation; Light diffusion; Multiple irradiation sensing; Optoacoustic; Quantitative optoacoustic imaging; Spectral correction