Electrocardiogram triggered motion compensation by dynamic focusing in intravital microscopy

Abstract

Intravital fluorescence microscopy has been actively applied in cell biology including cell dynamics thanks to its capability of acquiring high-resolution images of live animals. However, the motion artifacts induced by the cardiorespiratory motions result in the limitations of wider range of application. In this thesis, the repetitive axial movement of the sample is estimated during each electrocardiogram cycle by scanning the sample with an electrically tunable lens (ETL) at high frequency. The estimated motion is sent back to the ETL making the focus plane remain on the moving sample. The high-resolution images can be obtained even during the moving instant using this method. System configuration for the dynamic focusing, signal processing, and the optimized conditions for high quality images are delineated in detail. The proposed method allows minimally invasive motion compensation, which can be utilized in longitudinal studies, and will further broaden the application area of intravital imaging into moving organs.