Research On Adaptive Imaging Technologies Of Confocal Fluorescence Microendoscopy

In microscopic imaging in vivo, fluorescent concentrations on different lesion areas are quite different, the fluorescence microendoscopy in clinical are consistent with continuous scanning mechanism, the laser intensity and dwell time of each scanning point are the same, resulting the dynamic range of fluorescence images obtained is not big enough, the fluorescence signal intensity on the more obvious lesion areas(fluorescent contrast agent at high concentrations) reached saturation, while the fluorescence signal intensity on the not obvious lesion areas (low concentration of fluorescent contrast agent) is weak, and the details on not obvious lesion areas can not be seen clearly with a great image noise, and poor signal to noise ratio, affecting diagnostic accuracy. If the excitation light intensity is increased or the detector integration time is increased, the image detail on weak signal areas can be enhanced, but further expansion of the signal saturation region. On the contrary, if the image detail on saturation signal areas can be weaken, the weak signal regions are further expansion.A kind of fluorescence endomicroscopy which can be used in-vivo imaging in diagnosis and photodynamic therapy is described. Using DMD spatial light modulator and CCD image sensor according to the fluorescence signal intensity detected, the fluorescence endomicroscopy adjusts the excitation power in different regions rapidly using feedback algorithm, to obtain high SNR and high dynamic range images, and achieve interactive fluorescence diagnosis and photodynamic analysis. It can also adjust the light dose continuously according to the feedback treatment effect, to get the best results of photodynamic therapy, optical resolution is better than 2.2μm, and the image dynamic range can be enhanced more than 200 times. According to the programmable characteristics of DMD, adaptive scanning confocal imaging can be achieved, respectively, using composite point scanning and structured illumination to achieve high-resolution imaging scanning. Adaptive imaging approach is conducive to the observation of the details of the image saturation area and the weak image region, the fluorescence endomicroscopy can improve the details and SNR of fluorescence saturation regions and fluorescence weak regions, and improve diagnostic accuracy at the same time.This technology can also achieve interactive fluorescence diagnosis and photodynamic therapy analysis. Based on feedback of the fluorescence images, the light dose is adjusted continuously and adaptively, that provide a new technical methods for the study of photodynamic therapy, which will be the next step of the focus.