Real-time photodynamic therapy monitoring with ultrasound-guided photoacoustic imaging

As photodynamic therapy is reliant on endogenous tumor oxygen to be successful, personalizing treatment to the patient is a necessary step to improving overall efficacy. We have demonstrated the feasibility of functionally imaging PDT in real-time, by mapping oxygen saturation as a surrogate marker for PDT progression with ultrasound-guided photoacoustic imaging in vivo. Particularly, we have deciphered the spatial map of the oxygen depletion rate during PDT as a function of fluence rate. Photoacoustic imaging importantly provides the temporal and spatial resolution, providing a novel platform for monitoring that can be used to inform personalized treatment in future work.