Quantifying the radiant exposure and effective dose in patients treated for actinic keratoses with topical photodynamic therapy using daylight and LED white light.

Quantifying the radiant exposure and effective dose in patients treated for actinic keratoses with topical photodynamic therapy using daylight and LED white light.
Phys Med Biol. 2017 Dec 01;:
Authors: Manley M, Collins P, Gray L, O'Gorman S, McCavana J
Abstract
Daylight photodynamic therapy (dl-PDT) is as effective as conventional PDT (c-PDT) for treating actinic keratoses but has the advantage of reducing patient discomfort significantly. Topical dl-PDT and white light-PDT (wl-PDT) differ from c-PDT by way of light sources and methodology. We measured the variables associated with light dose delivery to skin surface and influence of geometry using a radiometer, a spectral radiometer and an illuminance meter. The associated errors of the measurement methods were assessed. The spectral and spatial distribution of the radiant energy from the LED white light source was evaluated in order to define the maximum treatment area, setup and treatment protocol for wl-PDT. We compared the data with two red LED light sources we use for c-PDT. The calculated effective light dose is the product of the normalised absorption spectrum of the photosensitizer, protoporphyrin IX (PpIX), the irradiance spectrum and the treatment time. The effective light dose from daylight ranged from 3±0.4 to 44±6 J/cm2 due to varying weather conditions. The effective light dose for wl-PDT was reproducible for treatments but it varied across the treatment area betwee...

Source: Physics in Medicine and Biology - December 1, 2017 Category: Physics Authors: Manley M, Collins P, Gray L, O'Gorman S, McCavana J Tags: Phys Med Biol Source Type: research