Oxygen saturation and perfusion changes during dermatological methylaminolaevulinate photodynamic therapy

Tyrrell, Jessica; Thorn, Clare; Shore, Angela C.; Campbell, S.; Curnow, Alison

doi:10.1111/j.1365-2133.2011.10554.x

Cited by 20 publications

(19 citation statements)

References 36 publications

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“…Our previous studies have also observed significant interpatient variations as once again observed here. This is thought to be the result of numerous external factors (especially the overall health of the patient), which may potentially alter the capacity for photochemical reactions and therefore the relationship between PpIX photobleaching and oxygen saturation [24]. For example, the age, body temperature and general well being of a patient can affect their tissue oxygenation status.…”

Section: Discussionmentioning

confidence: 99%

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Effect of an oxygen pressure injection (OPI) device on the oxygen saturation of patients during dermatological methyl aminolevulinate photodynamic therapy

et al. 2012

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Methyl aminolevulinate photodynamic therapy (MAL-PDT) (a topical treatment used for a number of pre-cancerous skin conditions) utilizes the combined interaction of a photosensitizer (protoporphyrin IX (PpIX)), light of the appropriate wavelength and molecular oxygen to produce singlet oxygen and other reactive oxygen species which induce cell death. During treatment localized oxygen depletion occurs and is thought to contribute to decreased efficacy.The aim of this study was to investigate whether an oxygen pressure injection (OPI) device had an effect on localized oxygen saturation levels and/or PpIX fluorescence of skin lesions during MAL-PDT. This study employed an OPI device to apply oxygen under pressure to the skin lesions of patients undergoing standard MAL-PDT. Optical reflectance spectrometry and fluorescence imaging were used to non-invasively monitor the localized oxygen saturation and PpIX fluorescence of the treatment area respectively. No significant changes in oxygen saturation were observed when these data were combined for the group with OPI and compared to the group that received standard MAL-PDT without OPI. Additionally no significant difference in PpIX photobleaching or clinical outcome at three months between the groups of patients was observed although the group that received standard MAL-PDT demonstrated a significant increase (p<0.05) in PpIX fluorescence initially and both groups produced a significant decrease (p<0.05) after light irradiation. In conclusion, with this sample size this OPI device was not found to be an effective method with which to improve tissue oxygenation during MAL-PDT. Further investigation is therefore required to find a more effective method of MAL-PDT enhancement.3

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Section: Discussionmentioning

confidence: 99%

“…In a recent study which used an ORS system to monitor the oxygen saturation of 60 patients during standard MAL-PDT, a significant decrease was observed following the first minute of irradiation [24]. This decrease was attributed to the consumption of oxygen during the photochemical reactions.…”

Section: Discussionmentioning

confidence: 99%

Effect of an oxygen pressure injection (OPI) device on the oxygen saturation of patients during dermatological methyl aminolevulinate photodynamic therapy

et al. 2012

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“…We recognize that there is no generally accepted independent evidence for this effect; measurements of blood flow during PDT have been inconclusive. [16][17][18][19][20] Although this reduction in perfusion has a significant effect on observed fluorescence, the effect on singlet oxygen dose is relatively small as shown in Fig. 6 in which the results of Fig.…”

Section: Treatment Simulationsmentioning

confidence: 95%

Comparison of photodynamic therapy with different excitation wavelengths using a dynamic model of aminolevulinic acid-photodynamic therapy of human skin

2012

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Abstract. Different wavelength light sources are used in photodynamic therapy (PDT) of the skin to treat different conditions. Clinical studies show inconsistent results for the effectiveness of aminolevulinic acid (ALA)-PDT performed at different wavelengths. In order to understand the effect of treatment wavelength, a theoretical study was performed to calculate time-resolved depth-dependent distributions of PDT components including ground-state oxygen, sensitizer, and reacted singlet oxygen for different treatment wavelengths (405, 523, and 633 nm) using a numerical model of ALA-PDT of human skin. This model incorporates clinically relevant features of the PDT process including light attenuation, photobleaching, oxygen consumption, and diffusion, as well as tissue perfusion. The calculations show that the distributions of these quantities are almost independent of the treatment wavelength to a depth of about 1 mm. In this surface region, PDT-induced hypoxia is the dominant process. At greater depths, the production of singlet -oxygen is governed by the penetration of the treatment light. Two noninvasive PDT dosimetry approaches: the cumulative singlet oxygen luminescence (CSOL) and the fractional fluorescence bleaching metric, were investigated and compared for all three wavelengths. Although CSOL was more robust, both metrics provided correlations with the singlet oxygen dose in the upper dermis that were almost independent of treatment wavelength. This relationship breaks down at greater depths because light penetration depends on wavelength.

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“…Both skin autofluorescence and PpIX fluorescence were measured. Since optical properties are known to change during PDT [37][38][39][40], we measured PpIX fluorescence at various time-points during PDT.…”

Section: Introductionmentioning

confidence: 99%

Correction for tissue optical properties enables quantitative skin fluorescence measurements using multi-diameter single fiber reflectance spectroscopy

Middelburg

Hoy

Neumann

et al. 2015

Journal of Dermatological Science

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Oxygen saturation and perfusion changes during dermatological methylaminolaevulinate photodynamic therapy

Abstract: Background: Methyl-aminolevulinate photodynamic therapy (MAL-PDT) is a

Cited by 20 publications

References 36 publications

Effect of an oxygen pressure injection (OPI) device on the oxygen saturation of patients during dermatological methyl aminolevulinate photodynamic therapy

Effect of an oxygen pressure injection (OPI) device on the oxygen saturation of patients during dermatological methyl aminolevulinate photodynamic therapy

Comparison of photodynamic therapy with different excitation wavelengths using a dynamic model of aminolevulinic acid-photodynamic therapy of human skin

Correction for tissue optical properties enables quantitative skin fluorescence measurements using multi-diameter single fiber reflectance spectroscopy

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