Singlet oxygen (~1O_2) is widely considered as the major cytotoxic species generated during Type-Ⅱ photochemical reactionof photodynamic therapy (PDT), and its production is crucial for the treatment outcome of PDT. However, it is still achallenging task for direct detection of ~1O_2 by using an optical system as its extremely weak luminescence at 1270 nm.In previous study, a high-sensitivity optical fiber detection system has been developed to measure the time-resolved ~1O_2luminescence spectra. In this study, an optical phantom of skin tissue has been built to simulate the skin optical propertiesfor research in photodynamic therapy (PDT). The phantom consists of an absorber (ink) and a scatterer (Intralipid) andphosphate buffer saline (PBS). Rose Bengal (RB) was utilized as the model photosensitizer to generate ~1O_2. The timeresolved~1O_2 luminescence spectroscopy were measured by using a ~1O_2 luminescence detection system with a fiber proberin tissue phantom. Furthermore, the effect of absorption coefficient (μa) and scattering coefficient (μs) on thephotosensitizer triple state lifetime (τT) and ~1O_2 luminescence lifetime (τD) was investigated as well. The results indicatedthat the integrated intensity of ~1O_2 luminescence decrease with the increase of μa and μs. Μa has no significant effect on τT and τD. τT increase with the increase of μs, and it finally stabilized around 1.6 μs. Meanwhile, τD decrease firstly and then increase slowly, and it finally stabilized around 14 μs. This result indicates that this system for ~1O_2 luminescence have a potential for clinical applications in PDT dosimetry.
展开▼
