Characteristics of a dual-detector charge coupled device (CCD) based optical fluorescence imaging system

A unique dual-detector charge coupled device (CCD) system has been developed and it has been previously shown to possess a high temporal resolution and the capability to perform ratio imaging on gel phantoms [1]. We used this CCD system to analyze differences in fluorescence intensity ratios at different levels of pH. We found that the ratio of emissions at 532 nm and 635 nm was similar to 3.8 in gels of pH 6.1, corresponding to cancerous tissue, and similar to 3.5 in gels of pH 7.2, corresponding to normal tissue. In addition, the accuracy of these intensity results was verified by calculating noise and dark current. We found that dark current intensity never exceeded I arbitrary unit, which is a negligible percentage of the intensity levels of the gel phantoms. Our system is very capable of accurately performing certain biomedical experiments, such as cancer detection.