METHOD FOR BUILDING COMPUTER TOMOGRAMS Russian patent published in 2001 - IPC

FIELD: medical engineering. SUBSTANCE: method involves building a number shadow projections of a layer under study by exposing object at various angles, transforming projection data into digital signal, making input into computer memory, reconstructing picture of the layer under study using computer by applying reversed projection method involving spreading shadow image of each projection over the picture plane represented in the computer in selected memory cells, summing sequentially digital signals of the reversed projections, saving the obtained results into the selected memory cells and displaying the tomogram on monitor display unit. The shadow projections of the layer under study are built with linear reduction coefficient in defective zone having value many times as big when compared to one in a zone of the same layer having no defects. The reduction coefficient value in the defective part is assumed to have the same value in the whole defect zone. Defect-representing memory cells are selected according to a formula U= k*n*D, where U is the signal value in a memory cell, k is the transformation coefficient of X-ray tomograph measuring unit, n is the number of reversed projection (n=1,2,...), D is the linear defect reduction coefficient. Signal value in other memory cells is assumed to be equal to zero. EFFECT: simplified process for producing computer tomograms.