Photodynamic Therapy-Induced Microvascular Changes in a Nonmelanoma Skin Cancer Model Assessed by Photoacoustic Microscopy and Diffuse Correlation Spectroscopy

One of the main mechanisms of action for photodynamic therapy (PDT) is the destruction of tumor vasculature. We observed the PDT-induced vasculature destruction in a mouse model of skin cancer using two techniques: Photoacoustic microscopy (PAM) and diffuse correlation spectroscopy (DCS). PAM showed high-resolution images of the abnormal microvasculature near the establishing tumor area at pre-PDT, as well as the subsequent destruction of those vessels post-PDT. DCS indicated a significant blood flow decrease after PDT, confirming the vascular destruction. Noninvasive assessment of vascular changes may be indicative of therapy response.