Photoacoustic imaging of intravenously injected photosensitizer in rat burn models for efficient antibacterial photodynamic therapy

Yasuyuki Tsunoi, Shunichi Sato, Hiroshi Ashida, Mitsuhiro Terakawa

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

5 Citations (Scopus)

Abstract

For efficient photodynamic treatment of wound infection, a photosensitizer must be distributed in the whole infected tissue region. To ensure this, depth profiling of a photosensitizer is necessary in vivo. In this study, we applied photoacoustic (PA) imaging to visualize the depth profile of an intravenously injected photosensitizer in rat burn models. In burned tissue, pharmacokinetics is complicated; vascular occlusion takes place in the injured tissue, while vascular permeability increases due to thermal invasion. In this study, we first used Evans Blue (EB) as a test drug to examine the feasibility of photosensitizer dosimetry based on PA imaging. On the basis of the results, an actual photosensitizer, talaporfin sodium was used. An EB solution was intravenously injected into a rat deep dermal burn model. PA imaging was performed on the wound with 532 nm and 610 nm nanosecond light pulses for visualizing vasculatures (blood) and EB, respectively. Two hours after injection, the distribution of EB-originated signal spatially coincided well with that of blood-originated signal measured after injury, indicating that EB molecules leaked out from the blood vessels due to increased permeability. Afterwards, the distribution of EB signal was broadened in the depth direction due to diffusion. At 12 hours after injection, clear EB signals were observed even in the zone of stasis, demonstrating that the leaked EB molecules were delivered to the injured tissue layer. The level and time course of talaporfin sodium-originated signals were different compared with those of EB-originated signals, showing animal-dependent and/or drug-dependent permeabilization and diffusion in the tissue. Thus, photosensitizer dosimetry should be needed before every treatment to achieve desirable outcome of photodynamic treatment, for which PA imaging can be concluded to be valid and useful.

Original languageEnglish
Title of host publicationOptical Methods for Tumor Treatment and Detection
Subtitle of host publicationMechanisms and Techniques in Photodynamic Therapy XXI
DOIs
Publication statusPublished - 2012
EventOptical Methods for Tumor Treatment and Detection: Mechanisms and Techniques in Photodynamic Therapy XXI - San Francisco, CA, United States
Duration: 2012 Jan 212012 Jan 22

Publication series

NameProgress in Biomedical Optics and Imaging - Proceedings of SPIE
Volume8210
ISSN (Print)1605-7422

Other

OtherOptical Methods for Tumor Treatment and Detection: Mechanisms and Techniques in Photodynamic Therapy XXI
Country/TerritoryUnited States
CitySan Francisco, CA
Period12/1/2112/1/22

Keywords

  • Burn wound infection
  • Photoacoustic imaging
  • Photodynamic therapy
  • Photosensitizer
  • Vascular permeability

ASJC Scopus subject areas

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

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