Remote Focal Controlling Optical Projection Tomography

Fluorescence imaging is widely used in the field of bioscientific and biomedical research because of its some advantages,such as good specificity,satisfactory sensitivity and high optical contrast.In these research areas,in order to acquire more visually understanding of the individual biological process,the increasingly trend is mesoscopic biological systems(e.g.complete organ,in vitro embryos and small animal models)and their internal areas.Optical projection tomography(OPT)has been developed for these mesoscopic samples.At present,OPT only could image the whole sample at the same time.OPT imaging process requires the depth of field covers the half of sample at least.This results in a trade-off between sample size and the spatial resolution in OPT system.Therefore,the spatial resolution of OPT depends on sample size.Research fields in bioscientific and biomedical research want to obtain whole samples of three-dimensional information at the same time,also require the sub-volume three-dimensional same sample.Here we present a global focal scanning OPT system which improve the resolution of the depth of field and the spatial resolution,a local focal scanning OPT system which provide a sub-volume three-dimensional imaging information,and applications of these improved OPT system in biomedical researches.The global focal scanning OPT system combining the electronically tunable lens realize a widely focal scanning range of 4.78 mm with 4 times magnification and 0.13 numerical aperture,where improves the trade-off between the depth of field and spatial resolution.With an average diameter of 1 ?m fluorescent beans testing physical properties of the OPT system,the experimental and reconstructed result show that compared with the traditional OPT imaging system,the spatial precision of the global focal scanning OPT system is increased by 47%,where shows that OPT with electronically tunable lens obtains high spatial precision and large depth of field at the same time.Based on the global focal scanning OPT system and the basis imaging principle of OPT,we establish a precisely focal tracking physical model and write the corresponding hardware drivers to make OPT system have capacities to focal tracking precisely and focal scanning tracking a sub-volume of the sample.With an average diameter of 1 ?m fluorescent beans testing physical properties of the sub-volume OPT system,the experimental and reconstructed result show that when we compare the projective sinogram of the whole fluorescent beads with the projective sinogram of its sub-volume,the field of view of sub-volume OPT system is only one sinogram which is assigned to image.The reconstructed spatial resolution of sub-volume OPT system is increased by 40%.Finally,we explore the OPT applications in the biomedical researches,which are three-dimensional fluorescence imaging information of the mice,such as a brain slice,a lung of mice,and pancreas.Above shows that the improved OPT technologies including global focal scanning OPT and focal sub-volume OPT enable quickly and conveniently three-dimensional imaging of mesoscopic sample with non-injury and high spatial resolution,which have widely potential in biomedical research.