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Proceedings Paper

Design of PDT protocols using delta-aminolevulinic acid (5ALA)
Author(s): Steven L. Jacques; Xiao-Yan He; Gary Gofstein
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Paper Abstract

The kinetics of protoporphyrin IX (PPIX) synthesis, bioconversion to other metabolic products, and photobleaching were measured in cell cultures after incubation in media containing the metabolic precursor for heme synthesis, (delta) -aminolevulinic acid (5 ALA). A compartmental model described the kinetics in terms of rate constants for the three processes. The maximum amount of PPIX that can be attained in the cells and the concentration of 5 ALA in the medium that obtains this maximum were determined. Using this information, two dosimetry protocols are outlined which both involve complete photobleaching of the PPIX: (1) the classical acute protocol using maximum 5 ALA to produce maximum PPIX and a light treatment of about 0.5 - 1 hr, and (2) a novel prolonged protocol using continuous low-level 5 ALA delivery to produce only slightly elevated PPIX and an extended light exposure time of over 24 hrs.

Paper Details

Date Published: 18 June 1993
PDF: 10 pages
Proc. SPIE 1881, Optical Methods for Tumor Treatment and Detection: Mechanisms and Techniques in Photodynamic Therapy II, (18 June 1993); doi: 10.1117/12.146299
Show Author Affiliations
Steven L. Jacques, Univ. of Texas M.D. Anderson Cancer Ctr. (United States)
Xiao-Yan He, Univ. of Texas M.D. Anderson Cancer Ctr. (United States)
Gary Gofstein, Univ. of Texas M.D. Anderson Cancer Ctr. (United States)


Published in SPIE Proceedings Vol. 1881:
Optical Methods for Tumor Treatment and Detection: Mechanisms and Techniques in Photodynamic Therapy II
Thomas J. Dougherty, Editor(s)

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