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Nonlinear optoacoustic readings from diffusive media at near‐infrared wavelengths
Author(s) -
MalekzadehNajafabadi Jaber,
Prakash Jaya,
Ntziachristos Vasilis
Publication year - 2018
Publication title -
journal of biophotonics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.877
H-Index - 66
eISSN - 1864-0648
pISSN - 1864-063X
DOI - 10.1002/jbio.201600310
Subject(s) - fluence , optics , photoacoustic effect , nonlinear system , wavelength , materials science , laser , signal (programming language) , photoacoustic imaging in biomedicine , scattering , microscopy , physics , quantum mechanics , computer science , programming language
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/cm 2 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.