The best research on IPL comes out of Germany.
http://onlinelibrary.wiley.com/doi/10.1 ... 0/abstract
Intense pulse light and 5-ALA PDT: Phototoxic effects in vitro depend on the spectral overlap with protoporphyrine IX but do not match cut-off filter notations
Tim Maisch PhD1,*, Anne C.E. Moor PhD2, Johannes Regensburger PhD1, Christoph Ortland PhD2, Rolf-Markus Szeimies MD, PhD1,3, Wolfgang Bumler PhD1Article first published online: 7 MAR 2011
Lasers in Surgery and Medicine
Volume 43, Issue 2, pages 176–182, February 2011
Maisch, T., Moor, A. C., Regensburger, J., Ortland, C., Szeimies, R.-M. and Bumler, W. (2011), Intense pulse light and 5-ALA PDT: Phototoxic effects in vitro depend on the spectral overlap with protoporphyrine IX but do not match cut-off filter notations. Lasers in Surgery and Medicine, 43: 176–182. doi: 10.1002/lsm.20970
1Department of Dermatology, Regensburg University Hospital, 93053 Regensburg, Germany
2Photonamic GmbH & Co. KG, 22880 Wedel, Germany
3Clinic for Dermatology, Hospital Vest GmbH, 45657 Recklinghausen, Germany
Email: Tim Maisch PhD (firstname.lastname@example.org)
*Correspondence: Tim Maisch PhD, Department of Dermatology, Regensburg University Hospital, Franz-Josef-Strauss-Allee 11, 93053 Regensburg, Germany.
Background and Objectives
Successful photodynamic therapy (PDT) requires a light source by which light is absorbed by the photosensitizer. Such absorption is achieved by adapting the emission spectrum of the lamp to the absorption-spectrum of the photosensitizer. Intense pulsed light sources (IPLs) are widely used in dermatology, but a standardized protocol for IPL-PDT is not available. Five different IPLs were chosen to evaluate their efficacy for PDT in vitro and the possibility for developing a standard protocol for PDT.
Materials and Methods
Emission-spectra of IPLs were measured with an optical spectrograph and compared with the absorption spectrum of protoporphyrine IX (PpIX). Keratinocytes were incubated with 5-ALA and illuminated with the IPLs. Cell viability was determined for radiant exposures ranging from 0 to 504 J/cm2 and pulse durations from 8 to 100 milliseconds. A standard LED light source was used as a reference.
Cell viability is less effectively reduced by 5-ALA-PDT with IPLs than by a LED light source. Radiant exposures of the five IPLs ranged between 80 and 311 J/cm2 to achieve the EC50 value. This value correlated with the spectral overlap of the respective IPL and the absorption-spectrum of PpIX but not with the cut-off filter notations supplied by the manufacturer.
All IPLs assessed emit different spectra because of different filter technologies. Different radiant exposures (J/cm2) were necessary to achieve a photodynamic effect with 5-ALA in vitro depending on these spectra similar to the photodynamic effect of the standard LED light source. IPLs may be applicable in clinical PDT but radiant exposure protocols must be separately evaluated for each single IPL despite similar cut-off filter specifications. Such protocols are highly important for clinical practice to avoid a potential mismatch of excitation wavelengths and to prevent photothermal side effects when light intensities of up to hundreds of W/cm2 are applied. Lasers Surg. Med. 42:176–182, 2011 © 2011 Wiley-Liss, Inc.