JPS6148341A - X-ray tomographic apparatus - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an X-ray tomography apparatus using an X-ray sensor array.

Conventional configuration and its problems Traditionally) X-ray tomography used for 5J diagnosis, so-called Butsky imaging, takes images while moving an X-ray generator and an X-ray film relative to each other around a specific plane. This is a photographing method in which only the image of a specific plane in the object to be inspected is transferred onto the X-ray film, and the other parts are completely blurred. This method actively utilizes the "blur" of an image on a specific plane, and is a method for obtaining surface information on the X-ray film surface.

Therefore, if the X-ray sensor is a surface sensor, X-ray tomography can be easily performed, but if the X-ray sensor is a one-dimensional X-ray sensor array, X-ray tomography can be performed using the same principle as above. Unable to take pictures.

OBJECTS OF THE INVENTION An object of the present invention is to provide an X-ray tomography apparatus capable of performing X-ray tomography using a one-dimensional X-ray sensor array.

Structure of the Invention In order to achieve the above object, the Xt9 tomography apparatus of the present invention includes an Xt9 generator that generates fan beam X-rays, and a -dimensional X-ray sensor array, and a The X-ray generator and one-dimensional XI sensor array are rotated around a rotation axis that lies within the irradiation plane of the X-ray beam, and the rotation axis and the object to be inspected are aligned so that the rotation axis passes through the inside of the object to be inspected. By relatively moving, rotation 141+1
This is to obtain a tomographic image of a plane in which + passes through the inside of the object to be inspected.

Description of examples Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a configuration diagram of an X-ray tomography apparatus according to an embodiment of the present invention. A fan beam 2 generated from an X-ray generator 1 is detected by a one-dimensional X-ray sensor array 3. The X-ray generator 1 and the one-dimensional X-ray sensor array 3 are fixed to each other by an arm 4, and rotate relative to each other in an arc shape around a rotation axis 5. X-ray irradiation and rotational movement are controlled by the X-in controller 9, which controls the X-ray controller 7 and the rotational movement controller 6.
controlled through. The object to be inspected 13 is moved across the rotation axis 5 during the rotational movement, and the data from the one-dimensional sensor array 3 at that time is transmitted through the data transmission section 8 and the main controller 9 and subjected to image processing by the arithmetic processing section 1Q. Afterwards...-The tocobee 11 or the display 12 allows viewing of a tomographic image of a plane in which the axis of rotation crosses the subject.

FIG. 2 is a principle diagram for performing tomography, and is a view seen in the direction of the rotation axis. The relationship between the X-ray generator 21, the fan beam X-ray 22, and the -dimensional X-ray sensor array 23 is rotated in an arc around the rotation axis 25 as shown by the arrow, and the positions 21', 22', and 23' are respectively set. When the axis of rotation 2 is moved between the
Projected images in the vicinity of 5 are always received by the one-dimensional X-ray scanner, but the remaining portions are all blurred. That is, if the Xi transmission image output detected by each sensor of the -dimensional X-ray sensor array 23 is rotated around the rotation axis 25 and integrated, the rotation axis 25 will appear on the blurred image, that is, the noise signal component.
A signal in which neighboring projection images are superimposed is obtained.

FIG. 3 is a perspective view showing the principle shown in FIG. 2 in three dimensions. Using the same concept as in Figure 2, the X-ray generator 21 is
', the -dimensional X-ray sensor array 23 is rotated in an arc around the rotation axis 25 to the position 23', and the -dimensional
When the integral value of the signal from the line sensor array is obtained, the integral value is a value superimposed on the noise signal, but it is a transmitted image of the vicinity of the rotation axis 25 within the inspected object 24. With such a method, one-dimensional information inside the object to be inspected can be obtained using a -dimensional X-ray sensor array.

FIG. 4 shows a diagram of the principle for obtaining two-dimensional tomographic images.

FIG. 4a is a method that is completely similar in principle to FIG. 2, and
By rotating the ray generator 21 and the one-dimensional X-ray sensor array 23 in an arc shape in the direction of the arrow and integrating the output of the -dimensional X-ray sensor array, a transmitted image of the area near the rotation axis 25 inside the object 24 to be inspected can be obtained. It will be done. Next, as shown in FIG. By rotating the ray sensor array 23 in an arc shape to positions 2a and 23', respectively, and integrating the output of the -dimensional X-ray sensor array, a transmitted image in the vicinity of the rotation axis 26 can be obtained. By moving the object to be inspected while repeating rotational movements in this manner, it is possible to obtain a two-dimensional tomographic image of a plane in which the axis of rotation crosses the object to be inspected. The object to be inspected may be moved by moving it a certain distance each time the rotational movement is forward and backward, or each time it is reciprocated, or by performing the rotational movement while moving at a constant speed.

In the two-dimensional 1ffT layer transmission image obtained here, the transmission image of the tomographic plane is superimposed on the noise signal component due to the surrounding "blur", but the noise signal component due to this °°blur n K is
X transmitted through the volume where the fan beam X-ray traverses the inspected object
Since it is a line average value, it contains only very low spatial frequency components, and is very different from the spatial frequency component region of a two-dimensional tomographic transmission image. Therefore, the details of the obtained image can be sufficiently used for diagnosis as a two-dimensional tomographic transmission image.

Due to the quality of the two-dimensional tomographic images obtained by this method,
The spatial resolution is the fan beam X-ray beam tp > and -
It depends on the thickness of each element of the dimensional X-ray sensor array and the amount of movement of the object to be inspected. In order to reduce the scattering of the X-rays that pass through the object to be inspected, it is better to use a fan beam X-ray with a width of K or JS. However, the smaller the size of each element, the better, and for this reason, for the selection of 7.5 mm, there are two options: (1) phosphor photodiode array, which can be arrayed at high density, or (2)
) A half-barrel detector array is suitable. High-density array compared to conventional fluorescent plate By making it thinner, it is possible to obtain better image quality than conventional tomography using a magnetic plate and X-ray film. In other words, in conventional tomography using a fluorescent plate and X-ray film, the image quality deteriorates significantly due to scattered radiation from the object being inspected because the X-rays are focused on the area, but if fan beam X-rays are used, 1. This is because the influence of scattered X-rays can be greatly reduced.

In addition, as a practical method of tomography according to the present invention, the X-ray generator and the one-dimensional X-ray sensor array are kept facing each other, and the relative positional relationship between them is controlled around one axis rather than rotationally. It is also possible to obtain the same effect as that obtained by the above method by performing parallel movement while maintaining the same.

Effects of the Invention As described above, according to the present invention, it is possible to perform tomography (Butsky imaging) using conventional X-ray film using a -dimensional X-ray sensor array, and compared to conventional tomography, there is no adverse effect due to X-ray scattering. It is possible to perform tomography with less turbulence. Furthermore, according to the present invention, since the -dimensional X-ray sensor array converts X-ray intensity into electrical signals and performs image processing, it is possible to obtain images that have been subjected to various types of processing that cannot be obtained with X-ray film. It is also possible to obtain three-dimensional tomographic information by overlapping the obtained tomographic planes in the vertical direction.

[Brief explanation of the drawing]

Fig. 1 is a configuration diagram of the X-ray tomography apparatus of the present invention, Fig. 2 is a diagram of the principle of how to perform tomography, Fig. 3 is a perspective view of Fig. 2, and Fig. 4 is a two-dimensional tomographic image obtained. This is a diagram of the principle of failure. 1.21...X-ray generator, 2,22...
・Fan beam
．． 24...Seal/Subject O Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
figure

Claims (1)

[Claims] an X-ray generator that generates fan beam X-rays; and an X-ray sensor array that detects the fan beam X-rays; the rotation axis is parallel to the X-ray sensor array and is located within the fan beam X-rays; The X-ray generator and the X-ray sensor array are rotated, and the object to be inspected, the X-ray generator, and the X-ray sensor array are moved relative to each other so that the axis of rotation crosses the inside of the object to be inspected. An X-ray tomography apparatus characterized by obtaining a tomographic image of an internal plane of an object to be inspected through which a rotation axis passes.