Medical Applications of The Wide Band Tunable Coherent Light Source Operated on Optical Parametric Oscillation

Abstract

The optical parametric oscillator(OPO), which employed a BBO crystal as a nonlinear optical frequency conversion medium pumped at 355nm, could be tuned in the wavelengths from 400 to 2550nm continuously by rotating the crystal. The output energy was obtained to be more than 6mJ from 620 to 680nm, and approximately 1mJ at 405nm. We investigated the combination effectivity of photosensitizers and radiation wavelengths in the PDT researches. After two photosensitizers of Pheophorbide a(Phd) and Photosan-3(Ph-3, hematoporphyrin-derivative) were injected to Wister rat livers respectively, the output beams from the OPO at 670nm and 630nm with the energy of 25, 50, and 100J/cm2 were irradiated to the liver tissues. The liver under the combination of Phd and 670nm was observed to be necrosed more deeply than the combination of Ph-3 and 630nm. In another experiment, the combined cytodamage-effect of CPT-11 and light against HeLa cells was examined by radiation of wavelengths from 355nm to 680nm in vitro. Remarkable combined effect in the radiation at 540nm was observed. The PDT and CPT-11 combined therapy used by HeLa cell tumors in BALB/c nude mice was remarkably effective in vivo. The result was expected to demonstrate Yoshida's MAT theory(1985).