Work

Combined influences of chromatic aberration and scattering in depth-resolved two-photon fluorescence endospectroscopy

Year: 2010

Type: article

Abstract: The influence of chromatic aberration of an objective lens in two-photon fluorescence (TPF) endospectroscopy of scattering media has been systematically investigated through both experiments and numerical simulations. Experiments were carried out on a uniform 3D scattering gelatin phantom embedded with TiO(2) granules (to mimic tissue scattering) and fluorescein-tagged polystyrene beads. It was found that fluorescence spectral intensity and lineshape varied as a function of depth when measured with a gradient-index (GRIN) lens which has severe chromatic aberration. The spectral distortion caused by the chromatic aberration became diminishing as the imaging depth increased. Ray tracing analysis and Monte Carlo simulations were carried out to study the interplay of chromatic aberration and scattering in the depth-resolved TPF spectra. The simulation results suggest that the collected fluorescence signals from deeper layers included more out-of-focus photons that experienced a few or multiple scatterings, which diminish the influence of chromatic aberration on the measured TPF spectra. The simulated collection efficiencies of TPF at different wavelengths and depths can be used to properly recover the true depth-resolved TPF spectra of a relatively uniform scattering medium.

Source: Biomedical Optics Express

DOI: 10.1364/boe.1.001234

Authors: Yicong Wu, Xingde Li

Institution: Johns Hopkins University

Language: English

Topic: Advanced Fluorescence Microscopy Techniques

Subfield: Biophysics

Field: Biochemistry, Genetics and Molecular Biology

Domain: Life Sciences

Open Access status: green

Funders: National Science Foundation, National Institutes of Health, National Cancer Institute

Awards: Molecular Contrast Agents Based on Gold Nanocages for OCT Imaging of Cancer, OCT Image-guided Biopsy Needle