title: Eigenspectra optoacoustic tomography achieves quantitative blood oxygenation imaging deep in tissues.
abstract: Light propagating in tissue attains a spectrum that varies with location due to wavelength-dependent fluence attenuation, an effect that causes spectral corruption. Spectral corruption has limited the quantification accuracy of optical and optoacoustic spectroscopic methods, and impeded the goal of imaging blood oxygen saturation (sO2) deep in tissues; a critical goal for the assessment of oxygenation in physiological processes and disease. Here we describe light fluence in the spectral domain and introduce eigenspectra multispectral optoacoustic tomography (eMSOT) to account for wavelength-dependent light attenuation, and estimate blood sO2 within deep tissue. We validate eMSOT in simulations, phantoms and animal measurements and spatially resolve sO2 in muscle and tumours, validating our measurements with histology data. eMSOT shows substantial sO2 accuracy enhancement over previous optoacoustic methods, potentially serving as a valuable tool for imaging tissue pathophysiology.
authors.affiliation: Institute of Biological and Medical Imaging (IBMI), Helmholtz Zentrum München, Ingolstädter Landstrasse 1, Neuherberg 85764, Germany.|Chair for Biological Imaging, Technische Universität München, Trogerstr. 9, München 81675, Germany.
authors.forename: Stratis
authors.initials: S
authors.lastname: Tzoumas
authors.affiliation: Institute of Biological and Medical Imaging (IBMI), Helmholtz Zentrum München, Ingolstädter Landstrasse 1, Neuherberg 85764, Germany.
authors.forename: Antonio
authors.initials: A
authors.lastname: Nunes
authors.affiliation: Institute of Biological and Medical Imaging (IBMI), Helmholtz Zentrum München, Ingolstädter Landstrasse 1, Neuherberg 85764, Germany.
authors.forename: Ivan
authors.initials: I
authors.lastname: Olefir
authors.affiliation: Department of Radiation Oncology, Klinikum rechts der Isar, Technische Universität München, Ismaninger Str. 22, München 81675, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Stangl
authors.affiliation: Institute of Biological and Medical Imaging (IBMI), Helmholtz Zentrum München, Ingolstädter Landstrasse 1, Neuherberg 85764, Germany.|Chair for Biological Imaging, Technische Universität München, Trogerstr. 9, München 81675, Germany.
authors.forename: Panagiotis
authors.identifier: 0000-0002-1396-3426
authors.initials: P
authors.lastname: Symvoulidis
authors.affiliation: Institute of Biological and Medical Imaging (IBMI), Helmholtz Zentrum München, Ingolstädter Landstrasse 1, Neuherberg 85764, Germany.|Chair for Biological Imaging, Technische Universität München, Trogerstr. 9, München 81675, Germany.
authors.forename: Sarah
authors.initials: S
authors.lastname: Glasl
authors.affiliation: Department of Radiation Oncology, Klinikum rechts der Isar, Technische Universität München, Ismaninger Str. 22, München 81675, Germany.
authors.forename: Christine
authors.initials: C
authors.lastname: Bayer
authors.affiliation: Department of Radiation Oncology, Klinikum rechts der Isar, Technische Universität München, Ismaninger Str. 22, München 81675, Germany.|CCG-Innate immunity in Tumor Biology, Helmholtz Zentrum München, Ingolstädter Landstrasse 1, Neuherberg 85764, Germany.
authors.forename: Gabriele
authors.initials: G
authors.lastname: Multhoff
authors.affiliation: Institute of Biological and Medical Imaging (IBMI), Helmholtz Zentrum München, Ingolstädter Landstrasse 1, Neuherberg 85764, Germany.|Chair for Biological Imaging, Technische Universität München, Trogerstr. 9, München 81675, Germany.
authors.forename: Vasilis
authors.initials: V
authors.lastname: Ntziachristos
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D005260:Female; D008325:Mammary Neoplasms, Experimental / Q000000981:diagnostic imaging*; D008819:Mice, Nude; D018482:Muscle, Skeletal / Q000000981:diagnostic imaging; D010100:Oxygen / Q000097:blood*; D061088:Photoacoustic Techniques; D014054:Tomography / Q000379:methods*
chemical_list: D010100:Oxygen