The lack of accurate and robust photodynamic therapy dosimetry is one of the obstacles for the widespread clinical applications. In this study, we propose a methodology to monitor the production of reactive oxygen species in real-time using the phosphorescent spectra of metalloporphyrin based photosensitizer. The correlation among the phosphorescence intensity, the 1O2 quantum yield (ΦΔ) and the oxygen concentration [O2] was established. A method of determining ΦΔ with different [O2] was studied based on comparative spectrophotometry, and the quantum yield ΦΔ of gadolinium metalated hematoporphyrin mono ether (Gd-HMME) in methanol was determined for different [O2]. With our method, both [O2] and ΦΔ could be monitored simultaneously using the phosphorescence spectra. The photochemical reactions in a liquid phantom composed of Gd-HMME and 1O2 capture 1,3-diphenylisobenzofuran (DPBF) were correlated using the kinetics equations of singlet oxygen generation and reaction. Using our method, the 1O2 quantum yield becomes observable and the 1O2 dose rate could be calculated by the product of photosensitizer absorption and its 1O2 quantum yield. Moreover, this 1O2 dosimetry could be observed by spectral imaging intuitively without complex analysis, and is especially suitable for precise customized photodynamic treatment.
All Science Journal Classification (ASJC) codes
- Atomic and Molecular Physics, and Optics