X-ray computerized tomography apparatus for obtaining consecutive tomographic images in either a forward or backward direction without performing interpolation for views over an entire 360

摘要

In a helical scanning X-ray CT apparatus, views at an m-th slice position are obtained by interpolating 360° views in a range next to the slice position in a forward direction in which the slice position number increases and 360° views in a range next to the slice position in the backward direction, and m-th tomographic image is reconstructed based on the interpolated views at the m-th slice position. An m-th backward image (mBI) is reconstructed based on the 360° views in the range next to the m-th slice position in the backward direction without interpolation and an m-th forward image (mFI) is reconstructed based on the 360° views in the range next to the m- th slice position in the forward direction without interpolation. An (m+1) BI is obtained by BP [CONV (a-b)] on the mBI and (m+1)FI is obtained by BP [CONV (c-a)] on the mFI. Here, BP: back projection, CONV: convolution, a: a view at the m-th slice position, b: a view which is separated from "a" by 360° , and c: a view which is separated from "a" by 360. degree.. An (m+1)th image is obtained as follows:PP(m+1) I=mI+DW×(m+1) FI-(m+1)BI}PPwhere DW is an inclination of the coefficients of the interpolation (primary interpolation).