Local physiological changes during photodynamic therapy.

Theresa M Busch

doi:10.1002/lsm.20355

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Local physiological changes during photodynamic therapy.

Theresa M Busch

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Abstract

BACKGROUND AND OBJECTIVE: Herein an overview is provided of the causes, consequences, and significance of photodynamic therapy (PDT)-mediated effects on tumor oxygenation and blood flow during illumination. STUDY DESIGN/MATERIALS AND METHODS: Techniques particularly valuable to this research have included tissue oxygen tension measurement by the Eppendorf pO2 Histograph; spatial quantification of hypoxia by EF3 and EF5; and tissue oxygenation/blood flow monitoring by diffuse reflectance/correlation spectroscopy. RESULTS: Severe hypoxia was measured in vivo during PDT and is shown to be a consequence of photochemical oxygen consumption and/or compromised vascular perfusion. Oxygen depletion can be controlled by treatment regimen, occurs in a spatially-definable pattern, and is therapy-limiting. PDT-induced changes in tumor oxygenation during illumination are correlated with outcome. In PDT-treated tissues, blood flow also is determined by treatment regimen and correlates with treatment response. CONCLUSIONS: Photodynamic therapy creates distinct, measurable changes in tumor oxygen and blood flow during illumination. These physiological changes may ultimately affect treatment efficacy.

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Animals Hypoxia Neoplasms Oxygen Consumption Photochemotherapy Reactive Oxygen Species Regional Blood Flow Journal Article Research Support, N.I.H., Extramural Review

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Theresa M Busch. 2006. Local physiological changes during photodynamic therapy.. https://doi.org/10.1002/lsm.20355

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