Development of quantum dot-mediated fluorescence thermometry for thermal therapies.

As thermal therapies are frequently employed for management of tumors in various organs, there are growing demands for reliable and accurate intraoperative monitoring techniques of the thermal lesion. However, current monitoring techniques have limited accuracy, accessibility and are not capable of monitoring the thermal lesion in real-time during the procedure. In the present study, quantum dot-mediated fluorescence thermometry was developed and its performance was characterized to demonstrate the feasibility of spatiotemporal monitoring of thermal lesions. First, the temperature dependency of two different types of CdTe/ZnS quantum dots (QDs) were characterized in a temperature range relevant to hyperthermic therapies, and a temperature-intensity relationship was established for each QD. The spatial and temporal resolutions of the system were characterized by exposing QDs to a pre-determined spatial temperature gradient, and by monitoring the spatiotemporal temperature during gold nanoshell-mediated heating. The results demonstrated that QD-mediated thermometry is capable of measuring spatiotemporally varying temperature fields relevant for hyperthermic thermal therapies. Its implication for intraoperative image-guidance of thermal therapy was also discussed.