Development of two wavelength excitation system for photodynamic therapy

Research Project

Project/Area Number	62870098
Research Category	Grant-in-Aid for Developmental Scientific Research
Allocation Type	Single-year Grants
Research Field	医学一般
Research Institution	Tokyo University of Agriculture and Technology
Principal Investigator	NISHISAKA Tsuyoshi Tokyo University of Agriculture and Technology, Professor, Health Science Center, 保健管理センター, 教授 (40101084)
Co-Investigator(Kenkyū-buntansha)	OHKURA Ichiro Tokyo Institute of Technology, Professor, Faculty of Engineering,, 工学部, 助教授 (90089821)
Project Period (FY)	1987 – 1988
Project Status	Completed (Fiscal Year 1988)
Budget Amount *help	¥6,300,000 (Direct Cost: ¥6,300,000) Fiscal Year 1988: ¥1,500,000 (Direct Cost: ¥1,500,000) Fiscal Year 1987: ¥4,800,000 (Direct Cost: ¥4,800,000)
Keywords	photodynamic therapy / triplet state / マイクロプロセッサー / 三重項状態
Research Abstract	The advantages of photosensitization process over photodynamic action has been desired. In this study we developed the two-step excitation system for photodynamic therapy using the CW laser and compared with the conventional one-step excitation method. The system consist of following components. 1) Argon ion laser. 2) Microprocessor controlled variable beam splitter which splits the laser light. One light is for singlet state excitation and other for DCM dye laser pumping source. 3) Beam combiner which combine Argon and dye lasers light. 4) Collimating lenses for fiber optics. Output power of two laser light is monitored on CRT screen during the irradiation period. The cytocidal effect in HeLa cell was found to be higher than that of conventional method. Results obtained on the C3H/MH-134 solid tumor model seem to indicate a better tumor response as compared with that of conventional one. This systems can be optimized for any given sensitizers choosing suitable excitation wavelengths for the two step excitation.