title: Mapping optical fluence variations in highly scattering media by measuring ultrasonically modulated backscattered light.
abstract: Knowledge of the local optical fluence in biological tissue is of fundamental importance for biomedical optical techniques to achieve quantification. We report a method to noninvasively measure the local optical fluence in optically inhomogeneous scattering media. The concept is based on two aspects: the local tagging of light using ultrasonic modulation and the photon path reversibility principle. Our method has advantages over known computational-based fluence mapping techniques, for its purely experimental nature and without the requirement of prior knowledge of the optical properties of the medium. We provide a theoretical formalism and validation of the method with experiments in tissue-like phantoms. Further, we combine our method with photoacoustic imaging and compensate the photoacoustic signals for fluence variations in optically inhomogeneous media.
authors.forename: Altaf
authors.initials: A
authors.lastname: Hussain
authors.forename: Khalid
authors.initials: K
authors.lastname: Daoudi
authors.forename: Erwin
authors.initials: E
authors.lastname: Hondebrink
authors.forename: Wiendelt
authors.initials: W
authors.lastname: Steenbergen
mesh_terms: D002138:Calibration; D008027:Light; D055095:Optics and Photonics; D019047:Phantoms, Imaging; D061088:Photoacoustic Techniques / Q000379:methods*; D017785:Photons; D015203:Reproducibility of Results; D012542:Scattering, Radiation; D014465:Ultrasonics