Abstract:
A method has been developed for using local tomography to study the morphology and dynamics of cells and subcellular structures, the propagation of optical radiation in which is described by the equations of diffraction tomography. It has been proven that the advantage of local tomography is that it is possible to quickly calculate the desired distribution at a point or region of interest of an object without conducting a complete reconstruction of the entire section, as well as to study biological cells whose size exceeds the field of view of the tomograph. An algorithm for detecting the coordinates of local density changes inside an object has been developed. Using mathematical modeling methods, an analysis of the sensitivity of local algorithms to changes within a cell model was performed, the parameters of which were chosen to be close to the characteristics of a native cell. Particular attention was paid to the comparison of local back-projection (Radon) and back-propagation (Devaney) algorithms for diffraction projections. The sensitivity of the algorithms to device phase noise and microscopic displacement of the object was studied for various observation time points. The results of experimental testing of the algorithms are presented using a set of local differential tomograms obtained during a study of changes in the leech Retzius neuron under the influence of the neurotransmitter glutamate. Measurements were performed on a differential tomograph over a 10-minute period. Analysis of the results showed that the developed method allows for the investigation of localized changes within the cell.
Keywords:diffraction tomography, local algorithms, living cell, dynamic density change.
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