Optical Dosimeter-guided Photodynamic Therapy

Project Summary AbstractPhotodynamic TherapyPDTis a promising modality for cancer treatmentTypicallya laser is used to photo excite a photosensitizerPSthat subsequently collides with oxygen molecules promoting them to the metastable singlet delta state OSinglet oxygen molecules are believed to be the species that destroys cancerous cells during PDTDespite the benefit of targeted PDT that kills tumors selectively with minimum effect on surrounding healthy tissuesat the present time it is difficultif not impossibleto predict the response of an individual to PDTThis has inhibited the acceptance of PDT for clinical usesIn this Phase II SBIRPhysical Sciences IncPSIproposes to extend the successful Phase I results and develop aD imaging sensor for PS fluorescence and singlet oxygen luminescenceUnder previous NCI SBIR fundingPSI has developedearly prototypein vivo capable dosimeters for PDTThese devices required pulsed lasers and temporally gated detectorsThe overall goal of our proposed program is to produce an integratedimaging PDT dosimeter that will enable real time feedback to control PDT light dose during the treatmentIn Phase Iwe demonstrated a newly introducedDnear infrared imaging camera and obtained simultaneous in vivo images of singlet oxygen and the photosensitizerBased on the Phase I resultswe have developed a strategy for singlet oxygen and photosensitizer dosimetry that can be used with conventionalcontinuous wavecwPDT excitation sourcesIn Phase II the combined PDT system will be designedbuiltand extensively tested for performance verification by in vitro and in vivo studiesThese studies will be completed in collaboration with Dartmouth Collegeour Phase I and Phase II partnerAn accurate dosimeter to optimize the individual treatment response of PDT is necessary to improve the outcomes of PDT in a clinical environmentA fully developed instrument will be a valuable toolfirst for PDT researchers and subsequently for clinical PDT uses Project NarrativeThe proposed research has the potential to significantly improve clinical PDT applications and outcomesReal time feedback of the distributions of PS and singlet oxygen during treatment will be a valuable tool for PDT researchers and cliniciansThere is a long standing need for PDT dosimetryA successful Phase II program will resolve this unmet needEventuallyit could lead to much higher efficacy in PDT treatments in the clinic by enabling physicians to intelligently adapt individual light doses for PDT to match the different responses of individual patients