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Updated: Jun 24, 2026

An In Vitro Approach to Photodynamic Therapy
Published on: August 17, 2018
Topical methyl aminolevulinate photodynamic therapy using red light-emitting diode light for multiple actinic
Rolf-Markus Szeimies1, Robert T Matheson, Steven A Davis
1Department of Dermatology, Universitätsklinikum Regensburg, Regensburg, Germany. Rolf-Markus.Szeimies@klinik.uni-regensburg.de
Background:
Photodynamic therapy (PDT) is an effective treatment for actinic keratoses (AKs). Light-emitting diodes (LEDs) offer practical advantages when treating multiple lesions.
Objective:
To evaluate the efficacy and tolerability of PDT using a LED and topical methyl aminolevulinate (MAL) for treatment of multiple AKs.
Methods And Materials:
One hundred thirty-one patients with four to 10 non-pigmented, previously untreated thin or moderately thick AKs on the face or scalp were enrolled in this multicenter, double-blind, randomized, placebo-controlled study. MAL or matching placebo cream was applied to the débrided lesion surface for 3 hours before illumination with noncoherent red light (630 nm, light dose 37 J/cm(2)). Treatment was repeated 1 week later.
Results:
Efficacy was evaluated in 57 patients with 418 lesions treated with MAL PDT and 58 with 414 lesions treated with placebo PDT. Sixteen patients were excluded as protocol violators (not randomized). MAL PDT was superior (p< .001) to placebo PDT in lesion complete response rates (83.3%, 95% confidence interval (CI)=79.3-86.7%, vs 28.7%, 95% CI=24.4-33.4%) and patient complete response rates (all lesions showing complete response; 68.4%, 95% CI=54.8-80.1% vs 6.9%, 95% CI=1.9-16.7%).
Conclusions:
Topical MAL PDT using a LED is an effective treatment for multiple AKs.
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