Development of an integrated endoscopic device for multiplexed low coherence interferometry (LCI) measurements of microbicide gel thickness
Microbicide gels are topical products that have recently been developed to combat sexually transmitted diseases including HIV/AIDS. The extent of gel coverage, thickness, and structure are crucial factors in gel effectiveness. It is necessary to be able to monitor gel distribution and behavior under various circumstances, such as coatis, and over an extended time scale in vivo. We have developed a multiplexed, Fourier-domain low coherence interferometry (LCI) system as a practical method of measuring microbicide gel distribution, with precision and accuracy comparable to currently used fluorometric techniques. The multiplexed system achieved a broad scanning area without the need for a mechanical scanning device, typical of OCT systems, by utilizing six parallel channels with simultaneous data collection. We now propose an imaging module, which will allow the integration of the multiplexed LCI system into the current fluorescence system in conjunction with an endoscope. The LCI imaging module will meet several key criteria in order to be compatible with the current system. The fluorescent system features a 4-mm diameter rigid endoscope enclosed in a 19-mm diameter polycarbonate tube, with a water immersion tip. Therefore, the LCI module must be low profile as well as water-resistant to fit inside the current design. It also must fulfill its primary function of delivering light from each of the six channels to the gel and collecting backscattered light. The performance of the imaging module will be characterized by scanning a calibration socket which contains grooves of known depths, and comparing these measurements to the fluorimetric results. © 2009 SPIE.
