Share Email Print
cover

Proceedings Paper

"Spiral-planar equivalence" of steady state photon diffusion associated with a cylindrical applicator
Format Member Price Non-Member Price
PDF $17.00 $21.00
cover GOOD NEWS! Your organization subscribes to the SPIE Digital Library. You may be able to download this paper for free. Check Access

Paper Abstract

We predict the phenomenon of "spiral-planar equivalence" for steady-state photon diffusion associated with a cylindrical applicator. Recently we have derived a unified theory of steady-state photon diffusion in a homogenous medium bounded either externally (referred to as a concave geometry) or internally (referred to as a convex geometry) by an infinitely long circular cylindrical applicator [JOSAA, 27(3): 648-662 (2010)]. Despite the idealization of the geometry by assuming an infinite length of the applicator, the analytic prediction withholds the quantitative examinations based on experimental measurements, and finite-element solution of photon diffusion. An interesting finding is that the decay of photon fluence in a concave boundary is smaller in the azimuth direction but greater along the longitudinal direction, in comparison with that in a semi-infinite geometry along a straight line, for the same line-of-sight distance between the source and the detector. Conversely, the decay of photon fluence in a convex boundary is greater in the azimuth direction but smaller along the longitudinal direction, in comparison with that in a semi-infinite geometry along a straight line, for the same line-of-sight source-detector distance. These findings suggest that on the cylindrical applicator interface there should exist a spiral direction (oblique to both the azimuthal and longitudinal directions), along which the rate of photon fluence decay follows that along a straight line on a planar semi-infinite interface---which is called the "spiral-planar equivalence". The "spiral-planar equivalence" is derivable analytically, and subject to quantitative evaluations. Validating the "spiral-planar equivalence" not only enriches the understanding of photon diffusion in cylindricalinterface geometry, but also provides unique semi-infinite-based imaging application in trans-lumenal diffuse optical sensing. The "spiral-planar equivalence" may be applicable to time-resolved photon-diffusion.

Paper Details

Date Published: 17 February 2011
PDF: 8 pages
Proc. SPIE 7896, Optical Tomography and Spectroscopy of Tissue IX, 78960V (17 February 2011); doi: 10.1117/12.874898
Show Author Affiliations
Anqi Zhang, Oklahoma State Univ. (United States)
Daqing Piao, Oklahoma State Univ. (United States)
Charles F. Bunting, Oklahoma State Univ. (United States)


Published in SPIE Proceedings Vol. 7896:
Optical Tomography and Spectroscopy of Tissue IX
Bruce Jason Tromberg; Arjun G. Yodh; Mamoru Tamura; Eva Marie Sevick-Muraca; Robert R. Alfano, Editor(s)

© SPIE. Terms of Use
Back to Top