Multispectral singlet oxygen luminescent dosimetry (MSOLD) for Photofrin-mediated PDT

Multispectral singlet oxygen dosimetry (MSOLD) provides a mean for direct detection of singlet oxygen, responsible for tumor kill for type II PDT. An InGaAs spectrometer or an InGaAs detector coupled with to narrow beam filters (1200, 1240, 1250, 1270, 1300 nm) via 1 mm optical fibers are used to measure singlet oxygen (SO) luminescent spectrum in in-vitro and in-vivo conditions. The spectrum, after fitted to a phosphorescence background a gaussian function for the singlet oxygen peak, is used to determine the singlet oxygen (SO) emission signal. The MSOLD signal is then compared with the singlet oxygen explicit dosimetry (SOED) results, based on direct measurements of light fluence (rate), Photofrin concentration, and tissue oxygenation concentration. MSOLD signal is affected by tissue absorption and scattering and is increasing with increasing Photofrin concentration and light fluence rate. MSOLD is feasible in vitro and in vivo for detecting SO directly.