Abstract
It is important to detect the near infrared emission of 1.27 IA in wavelength from the singlet oxygen, 1O2, to investigate and understand the mechanism of PDT. We detected this emission by means of a photon-counting system comprised with a high sensitive photomultiplier tube. For the efficient detection by this system, delayed detection time of 5μs from the onset of the laser irradiation and detection time duration of 5μs were necessary for the aqueous solution of photosensitizer PHE, and 8μs and 50μs were necessary for HeLa-tumor bearing mice injected with PHE (25mg/kg). The life time of the 1O2, was 5.3μs for the aqueous solution of PHE and 114μs for the HeLa-tumor bearing mice injected with PHE.
