Photoacoustic and ultrasound imaging to guide photothermal therapy: Ex vivo study

Jignesh Shah, Suhyun Park, Salavat Aglyamov, Timothy Larson, Li Ma, Konstantin Sokolov, Keith Johnston, Thomas Milner, Stanislav Emelianov

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

6 Scopus citations


In photothermal therapy, a localized temperature increase is achieved by using a continuous wave laser and optically tuned metal nanoparticles. However, the successful outcome of therapy depends on identifying the presence of nanoparticles in the tumor before therapy and monitoring temperature rise during the photothermal procedure. In this paper, we investigate the utility of photoacoustic and ultrasound imaging to guide photothermal therapy. Differences in the optical properties of tissue, enhanced by the presence of nanoparticles, provide a contrast for photoacoustic imaging. Thus, an uptake of nanoparticles in the tumor can be detected by monitoring a photoacoustic image over time. A temperature rise causes the photoacoustic signal amplitude to increase. In addition, a temperature change also leads to time shifts in an ultrasound signal, primarily due to the change in speed of sound. Therefore, by measuring the change in the photoacoustic signal, and differential motion of ultrasound speckle, the temperature rise during photothermal therapy can be computed. Combined imaging was performed with a tunable pulsed laser and an array-based ultrasound transducer. Experiments were carried out on ex-vivo animal tissue injected with composite and broadly absorbing gold nanoparticles. The photoacoustic imaging identified the presence of nanoparticles in tissue. In addition, a localized temperature increase, obtained during therapy, was monitored using photoacoustic and ultrasound imaging. The temperature profiles, obtained by both imaging techniques, were spatially and temporally co-registered. Therefore, the experimental results suggest that photoacoustic and ultrasound imaging can be used to guide and monitor photothermal therapy.

Original languageEnglish
Title of host publicationPhotons Plus Ultrasound
Subtitle of host publicationImaging and Sensing 2008: The Ninth Conference on Biomedical Thermoacoustics, Optoacoustics, and Acousto-optics
StatePublished - 2008
Event9th Conference on Photons Plus Ultrasound: Imaging and Sensing 2008 - San Jose, CA, United States
Duration: 20 Jan 200823 Jan 2008

Publication series

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


Conference9th Conference on Photons Plus Ultrasound: Imaging and Sensing 2008
Country/TerritoryUnited States
CitySan Jose, CA


  • Exogenous contrast agents
  • Imaging
  • Nanoparticles
  • Optoacoustics
  • Photoacoustics
  • Photothermal therapy
  • Temperature monitoring
  • Thermal imaging
  • Thermoacoustics
  • Ultrasound


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