Abstract
Photodynamic therapy (PDT) is a medical treatment which use photodynamic action between photosensitizer in tumor and laser light, so it is essential for light to reach tumor. To examine about possibility of PDT for the tumor that exists in deep part, we investigated laser transmission and scattering in tissue using optical parametriic oscillator pumped by third harmonics of Nd: YAG laser (YAG-OPO laser, Ishikawajima-Harima Heavy Industries Co., Ltd.). The intensity of the light through the tissue sample was detected by a photodetector. Besides, the tissue temperature during laser exposure was measured by embedded thermocouples. When the sample was a 10mm thick slice of cattle tissue, the transmitted light of 664nm laser is about 10 times as intense as that of 630nm laser. When the tissue sample was a slice of pig tissue, the transmitted light of 664nm laser and 630nm laser were of equal intensity. These results suggest that the transmission of laser light depends on absorption by the porphyrin in tissue.
