X-ray computerized tomography apparatus

Claim 2

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 which are obtained by interpolating 360° views in a first range next to the first slice position in a backward direction in which a slice position number decreases and 360° 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; 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° in the 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° in the forward direction, and adding the result of reconstruction to the first forward image; and means for obtaining a tomographic image at a second slice position which is separated from the first slice position by 360° 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 at the first slice position.

Claim 3

An X-ray computerized tomography apparatus according to claim 2, characterized by further comprising: means for updating the first forward image by reconstructing a view obtained by subtracting a view at a position separated from the first slice position by one view angle in the forward direction from a view at a position separated from the first slice position by 360° plus one view angle in the forward direction.

Claim 4

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° views in a first range next to the first slice position in a backward direction in which a slice position number decreases and 360° 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° 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.

Claim 5

An X-ray computerized tomography apparatus according to claim 4, characterized by further comprising: means for updating the first backward image by reconstructing a view obtained by subtracting a view at a position separated from the first slice position by one view angle in the backward direction from a view at a position separated from the first slice position by 360° plus one view angle in the backward direction.

Claim 6

An X-ray computerized tomography apparatus for acquiring views by helical scanning, comprising: first memory means for obtaining a first tomographic image at a first slice position by reconstructing views at the first slice position which are obtained by interpolating 360° views in a first range next to the first slice position in a backward direction in which a slice position number decreases and 360° 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° in the 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° in the forward direction, and adding the result of reconstruction to the first forward image; writing means for obtaining a first tomographic image at a second slice position which is separated from the first slice position by 360° 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 first tomographic image at the first slice position and for writing the first tomographic image at the second slice position into said first memory means; and fourth memory means for storing a tomographic image obtained by performing contrast scale conversion of the first image stored in said first memory means.

Claim 7

An X-ray computerized tomography apparatus according to claim 6, characterized in that said writing means writes first images at all slice positions into said first memory means, and all the tomographic images stored in said fourth memory means are displayed.

Claim 8

An X-ray computerized tomography apparatus according to claim 6, characterized in that said writing means writes first images at slices with a predetermined interval, and all the tomographic images stored in said fourth memory means are displayed.

Claim 9

An X-ray computerized tomography apparatus according to claim 6, characterized by further comprising: means for picking-up and displaying a scannogram; and means for displaying a linear cursor on the scannogram which designates the first slice position and the second slice position.

Claim 10

An X-ray computerized tomography apparatus according to claim 6, characterized in that said fourth memory means comprises: means for storing plural tomographic images; means for designating a desired slice position; and means for obtaining a coronal, sagittal or oblique image based on the tomographic image at the position designated by said designating means.

Claim 11

An X-ray computerized tomography apparatus for acquiring views by helical scanning, comprising: first memory means for obtaining a first tomographic image at a first slice position by reconstructing views at the first slice position which are obtained by interpolating 360° views in a first range next to the first slice position in a backward direction in which a slice position number decreases and 360° 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 interpolation processing; writing means for obtaining a first tomographic image at a second slice position which is separated from the first slice position by 360° 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 first tomographic image at the first slice position and for writing the first tomographic image at the second slice position into said first memory means; and fourth memory means for storing a tomographic image obtained by performing contrast scale conversion of the first image stored in said first memory means.

Claim 12

An X-ray computerized tomography apparatus according to claim 11, characterized by further comprising: means for updating the backward image stored in said second memory means by reconstructing a view obtained by subtracting a view at a position separated from the first slice position by one view angle in the backward direction from a view at a position separated from the first slice position by 360° plus one view angle in the backward direction, and adding the result of reconstruction to the backward image stored in said second memory means.

Claim 13

An X-ray computerized tomography apparatus according to claim 11, characterized in that said writing means writes first images at all slice positions into said first memory means, and all the tomographic images stored in said fourth memory means are displayed.

Claim 14

An X-ray computerized tomography apparatus according to claim 11, characterized in that said writing means writes first images at slices with a predetermined interval, and all the tomographic images stored in said fourth memory means are displayed.

Claim 15

An x-ray computerized tomography apparatus according to claim 11, characterized by further comprising: means for picking-up and displaying a scannogram; and means for displaying a linear cursor on the scannogram which designates the first slice position and the second slice position.

Claim 16

An X-ray computerized tomography apparatus according to claim 11, characterized in that said fourth memory means comprises: means for storing plural tomographic images; means for designating a desired slice position; and means for obtaining a coronal, saggital or oblique image based on the tomographic image at the position designated by said designating means.