ABSTRACT
This chapter suggests that combined photoacoustic, ultrasound, and elasticity imaging can possibly guide and monitor photothermal therapy. Photoacoustic imaging was demonstrated to identify the presence of photoabsorbers before therapy. Ex vivo tissue studies indicate that photoacoustic and ultrasound thermal imaging can be used to evaluate temperature change during the therapeutic procedure throughout the tissue with high sensitivity. Thermal damage assessed during therapy was consistent with observations of gross pathology. Elasticity imaging performed in conjunction with photoacoustic and ultrasound imaging further complements the developed imaging tool to assist photothermal therapy. Gold nanoparticles are commonly used as photoabsorbers in photothermal therapy. Photoacoustic temperature monitoring is more sensitive to measure temperature in the presence of photo-absorbers compared to ultrasound-based methods. By selection of a wavelength in the near infrared (NIR) spectral range and appropriately matched photoabsorbers, tumors at depths of a few centimeters can be treated photothermally.
