0
SPECIAL ISSUE HONORING BRITTON CHANCE

Optical computed tomography in a turbid medium using early arriving photons

[+] Author Affiliations
Kun Chen, Lev T. Perelman, Qingguo Zhang, Ramachandra R. Dasari, Michael S. Feld

Laser Biomedical Research Center, G. R. Harrison Spectroscopy Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts?02139

J. Biomed. Opt. 5(2), 144-154 (Apr 01, 2000). doi:10.1117/1.429981
History: Received Sep. 15, 1999; Revised Feb. 4, 2000; Accepted Mar. 10, 2000
Text Size: A A A

Abstract

We employ photon migration to image absorbing objects embedded in a turbid medium. For improved resolution, we use early arriving photons (a few hundred picoseconds in excess of the time of flight), a regime in which the diffusion approximation breaks down. Our image reconstruction method is based on extension of x-ray computed tomography (CT) to the optical regime. The CT algorithm must be generalized to take into account the distributions of photon paths. We express the point spread function (PSF) in terms of the Green’s function for the transport equation. This PSF then provides weighting functions for use in a generalized series expansion method of x-ray CT. Experiments were performed on a turbid medium with scattering and absorption properties similar to those of human breast tissue. Multiple absorbers were embedded into the medium to mimic tumors. Coaxial transmission scans were collected in two projections, and the early-time portions were analyzed. Through accurate modeling, we could remove the blurring associated with multiple scattering and obtain high-resolution images. Our results show that the diffusion approximation PSF is inadequate to describe the early arriving photons. A PSF incorporating causality is required to reconstruct accurate images of turbid media. © 2000 Society of Photo-Optical Instrumentation Engineers.

© 2000 Society of Photo-Optical Instrumentation Engineers

Citation

Kun Chen ; Lev T. Perelman ; Qingguo Zhang ; Ramachandra R. Dasari and Michael S. Feld
"Optical computed tomography in a turbid medium using early arriving photons", J. Biomed. Opt. 5(2), 144-154 (Apr 01, 2000). ; http://dx.doi.org/10.1117/1.429981


Access This Article
Sign In to Access Full Content
Please Wait... Processing your request... Please Wait.
Sign in or Create a personal account to Buy this article ($20 for members, $25 for non-members).
 
Your Session has timed out. Please sign back in to continue.
Sign In to Access Full Content

Figures

Tables

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging & repositioning the boxes below.

Related Book Chapters

Topic Collections

PubMed Articles
Advertisement

Buy this article ($18 for members, $25 for non-members).
Sign In