What is Multi Photon Detection (MPD)? A patented method for enhancing detection sensitivity for some radioisotopes by a factor of 1,000 to 10,000. Four classes of superior performance, low cost instruments Computer-controlled instruments with simple user interfaces The MPD Principle MPD reduces background using several techniques:   MPD Prior-art Passive shielding (composite) Pulse Height Analysis Pulse Shape Analysis   Coincidence Detection   Multi Photon Isotopes BioTraces can select from a broad range of useful isotopes (over 180 potential usable isotopes) Demonstrated MPD Advantages Zeptomole (10-21mole) quantitation Comparison with an internal standard Nine logs (109) of dynamic range Non-regulated amounts of radiolabel Multiple Labels ("Multi-color") capability Spatially resolving and imaging capabilities Safety/Regulatory Issues MPD technology is far below the exemption level (which for 125I is 1 microCi) ... Typical human 0.1 microCurie Exemption limit 1 microCurie Glass of water 0.01 microCurie MPD limit of detection 0.0000001 microCurie