Dependence of light fluence on treated depth with photosensitization reaction shortly after photosensitizer injection in rabbit myocardial tissue in vivo

T. Suenari, H. Matsuo, A. Ito, S. Miyoshi, T. Arai

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

We investigated experimentally dependence of light fluence on treated depth with photosensitization reaction shortly after photosensitizer injection in rabbit myocardial tissue in vivo. In this particular photosensitization reaction scheme, the photosensitizer accumulation characteristics for target region are not available. Meanwhile, the photosensitizer dose and hospitalization period under restricted light circumstance might be reduced. Since both photosensitizer and oxygen supply are governed by blood flow, this photosensitization reaction is influenced significantly by blood flow variation in particular blood vessel occlusion. We employed the myocardial tissue to keep tissue blood flow during the photosensitization reaction because vessel blood flow speed in myocardial tissue is fast to resist vascular occlusion. Surgically exposed rabbits myocardial tissues were irradiated with the light fluence ranging 25-100 J/cm2 by a 663 nm diode laser 30 min after the injection of 2 mg/kg water soluble chlorin photosensitizer, Talaporfin sodium. Two weeks after the irradiation, the rabbits were sacrificed and the histological specimens of the irradiated area were made to measure scar layer thickness. The scar layer tissue thickness of 0.2-3.0 mm was observed microscopically by the light fluence ranging 25-100 J/cm2. The scarring threshold in the deposit light fluence was estimated to 15-25 J/cm3 based on the above mentioned relation assuming constant and uniform myocardial effective attenuation coefficient of 0.72 mm-1. The estimated scarring threshold in the deposit light fluence was lower than the threshold of conventional PDT. Large variation of the estimated threshold value might be attributed to unconsidered PDT parameter such as flow rate inhomogeneity in the myocardial tissue. These results suggested that the photosensitization reaction investigated in this study would be available to apply arrhythmia therapy such as atrial fibrillation.

Original languageEnglish
Title of host publicationOptical Methods for Tumor Treatment and Detection
Subtitle of host publicationMechanisms and Techniques in Photodynamic Therapy XIX
DOIs
Publication statusPublished - 2010 May 3
EventOptical Methods for Tumor Treatment and Detection: Mechanisms and Techniques in Photodynamic Therapy XIX - San Francisco, CA, United States
Duration: 2010 Jan 232010 Jan 25

Publication series

NameProgress in Biomedical Optics and Imaging - Proceedings of SPIE
Volume7551
ISSN (Print)1605-7422

Other

OtherOptical Methods for Tumor Treatment and Detection: Mechanisms and Techniques in Photodynamic Therapy XIX
CountryUnited States
CitySan Francisco, CA
Period10/1/2310/1/25

Keywords

  • Deposit energy density
  • Myocardial tissue
  • Photodynamic therapy
  • Photosensitization reaction
  • Talaporfin sodium

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics
  • Biomaterials
  • Radiology Nuclear Medicine and imaging

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  • Cite this

    Suenari, T., Matsuo, H., Ito, A., Miyoshi, S., & Arai, T. (2010). Dependence of light fluence on treated depth with photosensitization reaction shortly after photosensitizer injection in rabbit myocardial tissue in vivo. In Optical Methods for Tumor Treatment and Detection: Mechanisms and Techniques in Photodynamic Therapy XIX [755114] (Progress in Biomedical Optics and Imaging - Proceedings of SPIE; Vol. 7551). https://doi.org/10.1117/12.843902