Nonlinear optoacoustic readings from diffusive media at near-infrared wavelengths

Jaber Malekzadeh-Najafabadi; Jaya Prakash; Vasilis Ntziachristos

doi:10.1002/jbio.201600310

Nonlinear optoacoustic readings from diffusive media at near-infrared wavelengths

J Biophotonics. 2018 Jan;11(1). doi: 10.1002/jbio.201600310. Epub 2017 Oct 4.

Authors

Jaber Malekzadeh-Najafabadi¹, Jaya Prakash^{1

2}, Vasilis Ntziachristos^{1

2}

Affiliations

¹ Chair of Biological Imaging, Technical University of Munich, Munich, Germany.
² Institute of Biological and Medical Imaging, Helmholtz Zentrum München, Neuherberg, Germany.

PMID: 28787111
DOI: 10.1002/jbio.201600310

Abstract

Optoacoustic (photoacoustic) imaging assumes that the detected signal varies linearly with laser energy. However, nonlinear intensity responses as a function of light fluence have been suggested in optoacoustic microscopy, that is, within the first millimeter of tissue. In this study, we explore the presence of nonlinearity deeper in tissue (~4 mm), as it relates to optoacoustic mesoscopy, and investigate the fluence required to delineate a switch from linear to nonlinear behavior. Optoacoustic signal nonlinearity is studied for different materials, different wavelengths and as a function of changes in the scattering and absorption coefficient of the medium imaged. We observe fluence thresholds in the mJ/cm² range and preliminary find that different materials may exhibit different nonlinearity patterns. We discuss the implications of nonlinearity in relation to image accuracy and quantification in optoacoustic tomography.

Keywords: nonlinearity; optical imaging; optical parameters; optoacoustic (photoacoustic) imaging.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Diffusion
Image Processing, Computer-Assisted
Infrared Rays*
Nonlinear Dynamics*
Photoacoustic Techniques / methods*