Despite its clinical effectiveness, PDT is currently underutilized because of the non-fully satisfied and expensive PS, unclear dose-efficiency relationship, and difficulties in translating proof-of-principle research. To further improve PDT efficacy, ongoing research is being pursued to develop the multifunctional nano-PS, wearable LED and self-excited light sources, and the spatiotemporal multimodal optical imaging platform for monitoring and optimizing dosimetric parameters for pre-, during-, and post-PDT.