title: Image filtering for two-photon deep imaging of lymphonodes.
abstract: Non-linear excitation microscopy is considered an ideal spectroscopic method for imaging thick tissues in vivo due to the reduced scattering of infrared radiation. Although imaging has been reported on brain neocortex at 600-800 microm of depth, much less uniform tissues, such as lymphonodes, are characterized by highly anisotropic light scattering that limits the penetration length. We show that the most severe limitation for deep imaging of lymphonodes appears to be the tissue scattering and the diffuse fluorescence emission of labeled cell (lymphocytes) in layers above the focusing plane. We report a study of the penetration depth of the infrared radiation in a model system and in ex vivo lymphonodes and discuss the possibility to apply Fourier filtering to the images in order to improve the observation depth.
authors.affiliation: Dipartimento di Fisica, Università di Milano Bicocca, Milan, 20125, Italy.
authors.forename: Michele
authors.initials: M
authors.lastname: Caccia
authors.forename: Laura
authors.initials: L
authors.lastname: Sironi
authors.forename: Maddalena
authors.initials: M
authors.lastname: Collini
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Chirico
authors.forename: Ivan
authors.initials: I
authors.lastname: Zanoni
authors.forename: Francesca
authors.initials: F
authors.lastname: Granucci
mesh_terms: D000818:Animals; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008198:Lymph Nodes / Q000166:cytology*; D051379:Mice; D008810:Mice, Inbred C57BL; D036641:Microscopy, Fluorescence, Multiphoton / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity