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Journal of Biomedical Optics • Open Access

Optical property measurements establish the feasibility of photodynamic therapy as a minimally invasive intervention for tumors of the kidney
Author(s): Timothy M. Baran; Jeremy D. Wilson; Soumya Mitra; Jorge L. Yao; Edward M. Messing; David Waldman; Thomas H. Foster

Paper Abstract

We measured the optical properties of freshly excised kidneys with renal parenchymal tumors to assess the feasibility of photodynamic therapy (PDT) in these patients. Kidneys were collected from 16 patients during surgical nephrectomies. Spatially resolved, white light, steady-state diffuse reflectance measurements were performed on normal and neoplastic tissue identified by a pathologist. Reflectance data were fit using a radiative transport model to obtain absorption (μ a ) and transport scattering coefficients (μ ′ s ), which define a characteristic light propagation distance, δ . Monte Carlo (MC) simulations of light propagation from cylindrical diffusing fibers were run using the optical properties extracted from each of the kidneys. Interpretable spectra were obtained from 14 kidneys. Optical properties of human renal cancers exhibit significant inter-lesion heterogeneity. For all diagnoses, however, there is a trend toward increased light penetration at longer wavelengths. For renal cell carcinomas (RCC), mean values of δ increase from 1.28 to 2.78 mm as the PDT treatment wavelength is increased from 630 to 780 nm. MC simulations of light propagation from interstitial optical fibers show that fluence distribution in tumors is significantly improved at 780 versus 630 nm. Our results support the feasibility of PDT in selected renal cancer patients, especially with photosensitizers activated at longer wavelengths.

Paper Details

Date Published: 17 September 2012
PDF: 8 pages
J. Biomed. Opt. 17(9) 098002 doi: 10.1117/1.JBO.17.9.098002
Published in: Journal of Biomedical Optics Volume 17, Issue 9
Show Author Affiliations
Timothy M. Baran, Univ. of Rochester (United States)
Jeremy D. Wilson, Univ. of Rochester (United States)
Soumya Mitra, Univ. of Rochester (United States)
Jorge L. Yao, Univ. of Rochester (United States)
Edward M. Messing, Univ. of Rochester (United States)
David Waldman, Univ. of Rochester (United States)
Thomas H. Foster, Univ. of Rochester (United States)

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