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Journal of Biomedical Optics • Open Access

Noninvasive fluorescence monitoring of protoporphyrin IX production and clinical outcomes in actinic keratoses following short-contact application of 5-aminolevulinate
Author(s): Christine B. Warren; Sara Lohser; Lauren C. Wene; Brian W. Pogue; Philip Bailin; Edward Maytin

Paper Abstract

Topical 5-aminolevulinic acid (ALA) is widely used in photodynamic therapy (PDT) of actinic keratoses (AK), a type of premalignant skin lesion. However, the optimal time between ALA application and exposure to light has not been carefully investigated. Our objective is to study the kinetics of protoporphyrin IX (PpIX) accumulation in AK after short contact ALA and relate this to erythemal responses. Using a noninvasive dosimeter, PpIX fluorescence measurements (5 replicates) were taken at 20-min intervals for 2 h following ALA application, in 63 AK in 20 patients. Data were analyzed for maximal fluorescent signal obtained, kinetic slope, and changes in erythema. Our results show that PpIX accumulation was linear over time, becoming statistically higher than background in 48% of all lesions by 20 min, 92% of lesions by 1 h, and 100% of lesions by 2 h. PpIX accumulation was roughly correlated with changes in lesional erythema post-PDT. We conclude that significant amounts of PpIX are produced in all AK lesions by 2 h. The linear kinetics of accumulation suggest that shorter ALA application times may be efficacious in many patients. Noninvasive fluorescence monitoring of PpIX may be useful to delineate areas of high PpIX accumulation within precancerous areas of the skin.

Paper Details

Date Published: 1 September 2010
PDF: 8 pages
J. Biomed. Opt. 15(5) 051607 doi: 10.1117/1.3484255
Published in: Journal of Biomedical Optics Volume 15, Issue 5
Show Author Affiliations
Christine B. Warren, The Cleveland Clinic (United States)
Sara Lohser, The Cleveland Clinic (United States)
Lauren C. Wene, The Cleveland Clinic (United States)
Brian W. Pogue, Dartmouth College (United States)
Philip Bailin, The Cleveland Clinic (United States)
Edward Maytin, The Cleveland Clinic (United States)

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