Document Type



A system and method is provided for optimizing a laser light fractionation during photodynamic therapy of a tumor. The tumor is destroyed through the production of singlet oxygen and successful photodynamic therapy treatment requires the maintenance of tumor oxygen above a specified critical level. Depending on the tumor, the photosensitizer concentration, and the laser fluence, sustained irradiation of the tumor will deplete the oxygen below the critical level. When the laser is turned off, oxygen diffuses into the tumor to provide sustained levels of singlet oxygen. The control system controls the operation cycle of the laser and the various surgical parameters. Data regarding the sensitizer, the laser characteristics, and the oxygen features of the tumor are input into the control system for simulation of the PDT treatment. As part of the simulation, the optimal fractionation cycle for the laser is predicted. The data may be adjusted for conducting additional simulations. The simulation data and results are stored in the control system for controlling the actual PDT treatment cycle. A computer is linked to the laser and a beam splitter or other cycling device to control the fractionated photodynamic therapy irradiation process for optimal treatment of a specific tumor.

Patent Country


Patent Number


Publication Date



The University of Toledo

Application Number


Filing Date

April 1995

Primary Class


Secondary Class

378/65; 378/151


These materials are free of copyright restrictions and are in the public domain within the United States only. The USPTO reserves the right to assert copyright protection internationally.


The University of Toledo


University of Toledo Libraries

Digital Publisher

Digital Initiatives