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Towards dosimetry for photodynamic diagnosis with the low-level dose of photosensitizer.

Authors :
Buzalewicz I
Hołowacz I
Ulatowska-Jarża A
Podbielska H
Source :
Journal of photochemistry and photobiology. B, Biology [J Photochem Photobiol B] 2017 Aug; Vol. 173, pp. 333-343. Date of Electronic Publication: 2017 Jun 15.
Publication Year :
2017

Abstract

Background: Contemporary medicine does not concern the issue of dosimetry in photodynamic diagnosis (PDD) but follows the photosensitizer (PS) producers recommendation. Most preclinical and clinical PDD studies indicate a considerable variation in the possibility of visualization and treatment, as e.g. in case of cervix lesions. Although some of these variations can be caused by the different histological subtypes or various tumor geometries, the issue of varying PS concentration in the tumor tissue volume is definitely an important factor. Therefore, there is a need to establish the objective and systematic PDD dosimetry protocol regarding doses of light and photosensitizers.<br />Methods: Four different irradiation sources investigated in PDD (literature) were used for PS excitation. The PS luminescence was examined by means of the non-imaging (spectroscopic) and imaging (wide- and narrow-field of view) techniques. The methodology for low-level intensity photoluminescence (PL) characterization and dedicated image processing algorithm for PS luminescence images analysis were proposed. Further, HeLa cells' cultures penetration by PS was studied by a confocal microscopy.<br />Results: Reducing the PS dose with the choice of proper photoexcitation conditions decreases the PDD procedure costs and the side effects, not affecting the diagnostic efficiency. We determined in vitro the minimum incubation time and photosensitizer concentration of Photolon for diagnostic purposes, for which the Photolon PL can still be observed. It was demonstrated that quantification of PS concentration, choice of proper photoexcitation source, appropriate adjustment of light dose and PS penetration of cancer cells may improve the low-level luminescence photodynamic diagnostics performance.<br />Conclusions: Practical effectiveness of the PDD strongly depends on irradiation source parameters (bandwidth, maximum intensity, half-width) and their optimization is the main conditioning factor for low-level intensity and low-cost PDD.<br /> (Copyright © 2017 Elsevier B.V. All rights reserved.)

Details

Language :
English
ISSN :
1873-2682
Volume :
173
Database :
MEDLINE
Journal :
Journal of photochemistry and photobiology. B, Biology
Publication Type :
Academic Journal
Accession number :
28641204
Full Text :
https://doi.org/10.1016/j.jphotobiol.2017.06.007