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

An X-ray computerized tomography apparatus for acquiring views by helical scanning, comprising:

• means for obtaining a tomographic image at a first slice position by reconstructing views at the first slice position which are obtained by interpolating 360.degree. views in a first range next to the first slice position in a backward direction in which a slice position number decreases and 360.degree. views in a second range next to the first slice position in a forward direction in which the slice position number increases;
• means for obtaining a first backward image by reconstructing the views in the first range without interpolation processing;
• means for obtaining a first forward image by reconstructing the views in the second range without interpolation processing;
• and
• means for obtaining a tomographic image at a second slice position which is separated from the first slice position by 360.degree. in the backward direction by multiplying a difference between the first forward image and the first backward image by a coefficient, and subtracting the result of multiplication from the tomographic image at the first slice position.

An X-ray computerized tomography apparatus for acquiring views by helical scanning, comprising:

• first memory means for obtaining a tomographic image at a first slice position by reconstructing views at the first slice position which are obtained by interpolating 360.degree. views in a first range next to the first slice position in a backward direction in which a slice position number decreases and 360.degree. views in a second range next to the first slice position in a forward direction in which the slice position number increases;
• second memory means for obtaining a first backward image by reconstructing the views in the first range without interpolation processing;
• third memory means for obtaining a first forward image by reconstructing the views in the second range without interpolation processing;
• means for obtaining a second backward image by reconstructing a view obtained by subtracting a view at a position separated from the first slice position by 360.degree. in a backward direction from a view at the first slice position, and adding the result of reconstruction to the first backward image;
• means for obtaining a second forward image by reconstructing a view obtained by subtracting a view at the first slice position from a view at a position separated from the first slice position by 360.degree. in the forward direction, and adding the result of reconstruction to the first forward image;
• writing means for obtaining a tomographic image at a second slice position which is separated from the first slice position by 360.degree. in the forward direction by multiplying a difference between the second forward image and the second backward image by a coefficient, and adding the result of multiplication to the tomographic image obtained at the first slice position and for writing the tomographic image obtained at the second slice position into said first memory means;
• and
• fourth memory means for storing tomographic images obtained by performing contrast scale conversion of the tomographic images obtained at the first and second slice positions and stored in said first memory means.

An X-ray computerized tomography apparatus for acquiring views by helical scanning, comprising:

• first memory means for obtaining a tomographic image at a first slice position by reconstructing views at the first slice position which are obtained by interpolating 360.degree. views in a first range next to the first slice position in a backward direction in which a slice position number decreases and 360.degree. views in a second range next to the first slice position in a forward direction in which the slice position number increases;
• second memory means for obtaining a backward image by reconstructing the views in the second range without interpolation processing;
• third memory means for obtaining a forward image by reconstructing the views in the first range without interpolating processing;
• writing means for obtaining a tomographic image at a second slice position which is separated from the first slice position by 360.degree. in the backward direction by multiplying a difference between the forward image and the backward image by a coefficient, and subtracting the result of multiplication from the tomographic image obtained at the first slice position and for writing the tomographic image obtained at the second slice position into said first memory means;
• and
• fourth memory means for storing tomographic images obtained by performing contrast scale conversion of the tomographic images obtained at the first and second slice positions and stored in said first memory means.