Rapid volumetric imaging

Point-scan 3D fluorescent imaging requires long acquisition times due to the large number of voxels that must be scanned when using the conventional scheme where a motorized stage is stepped between image planes to acquire raster-scanned frames in sequence. The introduction of a continuous focal change during the frame scanning process creates 3D patterns which are repeatable and tile without multiply sampling voxels when appropriately timed. The sparse distribution of scanned voxels when using this pattern enables incompletely scanned volumes to be interpolated to completion using an inpainting algorithm. This method, called 3D Fast Acquisition Scan via z-Translating Raster (3D-FASTR) is shown to provide up to a 4x speed increase as compared to conventional stage-step acquisition. This theoretical framework was implemented into a modified commercial confocal microscope using an ultrafast laser for two-photon excitation and an electrically tunable lens to implement this method and image live cells and capture diffusive motion in 3D.

Johnson, C., Exell, J., Kuo, J. & Welsher, K. Continuous focal translation enhances rate of point-scan volumetric microscopy. Opt. Express 27, 36241-36258 (2019) arXiv:1909.12893.