JP2545353B2 - Reconstruction method of X-ray CT refu- matting image - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention is used in the field of digital image processing.

The present invention relates to the reconstruction of a reformatted image by an X-ray CT apparatus.

(B) Prior art An image obtained by an X-ray CT apparatus is usually a cross section orthogonal to the body axis, but a cross section parallel to the body axis may be clinically necessary. As a method for realizing this, a means for extracting and reconstructing corresponding pixel information from a large number of continuous tomographic images is adopted. The image obtained in this way is called a refraux mating image, and there are a sagittal conversion image, a coronal conversion image, and the like.

(C) Problems to be Solved by the Invention Such a refuomatating image is normally formed by scanning on an axis orthogonal to the body axis, and is an image based on a reconstructed image of a transverse section which is the axial section. It is configured.

However, scanning may not be performed on the axis orthogonal to the body axis, and scanning may be performed at an angle inclined from that axis, that is, the gantry is inclined for the convenience of the subject. In this case, the reconstructed refuomatting image that has not been corrected according to this gantry tilt angle is
It appears as a distorted image.

It is an object of the present invention to provide a method for reconstructing a distortion-free refrough mating image of a tomographic image obtained by tilting a gantry.

(D) Means for Solving the Problems In order to achieve the above object, according to claim 1, a large number of slice data obtained by inclining a gantry and scanning the slice data are obtained for each slice data. It was reconfigured by shifting the gantry tilt angle.

Further, in claim 2, the image data obtained by reconstructing a large number of slice data obtained by tilting the gantry and scanning is stored in a memory, and the stored data is stored at the time of display. The reading was performed diagonally according to the angle.

(E) Action In Claim 1, the reconstructed image for each slice data is shifted by the tilt angle of the gantry.

As a result, although the display image of the reconstructed ref-u- mating image is rotated by the tilt angle of the gantry, the ref-u- mating image without distortion can be obtained.

According to the second aspect of the invention, image data obtained by reconstructing projection data obtained by tilting the gantry is read obliquely according to the tilt angle of the gantry.

As a result, although the reconstructed image is distorted, the reformatted image without distortion can be displayed by obliquely reading and displaying.

(F) Embodiment A preferred embodiment of the present invention will be described with reference to FIGS. 1 and 2.

FIG. 4 is an explanatory diagram of an example of a conventional reconstruction method. FIG. 3 is a diagram showing an example of scanning mode commonly performed in the conventional example and the method according to the present invention.

In FIG. 3, 1 is an X-ray beam, 2 is an object,
3 is an X-ray tube and 4 is a detector. The subject 2 moves in the arrow direction with an inclination angle θ of a gantry (not shown) and is irradiated with the X-ray beam 1.

In this case, FIG. 4 shows an example of a mode in which the sagittal image is reconstructed without correcting the tilt angle. The thin line indicates each slice plane, and interpolation processing is performed between the slices to reconstruct the image as illustrated. When the sagittal image is reconstructed with the gantry tilted CT image without tilt angle, the distortion becomes an image like this.

FIG. 1 is an explanatory view showing one embodiment of the present invention. As shown in the figure, each slice data is reconstructed by shifting by the gantry tilt angle, and the shape of the subject can be accurately represented. This is achieved by preparing a program for this.

FIG. 2 is an explanatory view showing another embodiment of the present invention.
FIG. 2A shows an example embodiment producing a reconstructed, and thus distorted, image without correction of the gantry tilt angle. This image is stored in memory. Therefore, as indicated by the thick dotted line in FIG. 2A, this memory is read obliquely. Specifically, a program for specifying the address of the memory by calculation is prepared. FIG. 2B shows an image obtained by such a memory read, ie without distortion.

(G) Effect According to the present invention, a distortion-free refraction image can be reconstructed even for a CT image obtained by tilting the gantry, and therefore even if the gantry is tilted, the influence is not exerted. Has the effect of being easy.

[Brief description of drawings]

FIG. 1 is a diagram for explaining the essential points of one embodiment of the present invention, FIG. 2 is a diagram similar to the other embodiments, FIG. 3 is an example diagram of a scanning mode, and FIG. 1 is an X-ray beam, 2 is a subject, 3 is an X-ray tube, and 4 is a detector.

Claims (2)

(57) [Claims] 1. A large number of slice projection data obtained by inclining the gantry from an axis orthogonal to the body axis and scanning the sliced data,
A method of reconstructing an X-ray CT re-u- mating image, characterized by reconstructing a re-u-foaming image by shifting the tilt angle of the gantry for each slice data. 2. A large number of slice projection data obtained by inclining the gantry from an axis orthogonal to the body axis and scanning
Image data obtained by reconstruction is stored in a memory, and the stored data is read out obliquely according to the tilt angle of the gantry to obtain a re-shaped mating image. A method for reconstructing the Oumatsuuing image.