JPH0630923A - X-ray CT system - Google Patents

Abstract

(57) [Abstract] [Purpose] An object of the present invention is to provide an X-ray CT apparatus capable of preventing degradation of the decomposed brain by reducing scattered radiation crosstalk in the slice thickness direction. [Configuration] Detector array 6 in which detection elements are arranged in a fan shape
X arranged in the slice thickness direction a of the subject P
The X-ray CT apparatus including the line detector 2 is characterized in that a slit 7 is provided between the detector rows 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray optical system of an X-ray CT apparatus capable of capturing a plurality of tomographic images in one scan.

[0002]

2. Description of the Related Art Generally, an X-ray CT apparatus rotates an X-ray tube and an X-ray detector, which are arranged to face each other with the subject interposed therebetween, while rotating the X-ray detector around the subject while exposing the X-ray to the X-ray tube. Is collected by an X-ray detector, and one tomographic image is reconstructed for each scan. In this case, as the X-ray detector, a one-dimensional detector in which a plurality of detector elements are arranged in a fan shape to form a detector element group and only one detector element row is provided in the slice thickness direction is used. On the other hand, there is a demand for an X-ray CT apparatus capable of reconstructing two or more tomographic images in one scan.

In the case of an X-ray CT apparatus capable of reconstructing two tomographic images in one scan (hereinafter referred to as double slice CT), a plurality of detection elements are used as a fan as an X-ray detector 101 as shown in FIG. A detector array 102 in which two detector arrays 102 are arranged in a slice shape to form a detection element group in the slice thickness direction a is applied. Further, in the case of an X-ray CT apparatus (hereinafter referred to as volume CT) capable of reconstructing a plurality of tomographic images in one scan, the X-ray detector 10 as shown in FIG.
As one example, a two-dimensional detector having a plurality of detector rows 102 arranged in the slice thickness direction a is applied.

Such an X-ray detector 101 and an X-ray tube 10
3 are arranged so as to face each other across the subject P, and while rotating around the subject P, the X-rays emitted from the X-ray tube 103 are detected by the X-ray detector 101 to collect imaging data. , Reconstruct a tomographic image.

[0005]

However, in the double slice CT and the volume CT, the detector array 1 is used.
Since the X-ray detector 101 in which two or more rows of 02 are provided is not a single slice, in addition to the conventional scattered ray crosstalk in the channel direction, slices between slices as shown in FIG. Scattered ray crosstalk in the thickness direction occurs. Therefore, there is a problem that the resolution brain of the obtained tomographic image is lowered.

The present invention has been made in order to solve the above-mentioned problems of the prior art, and an object thereof is to prevent the degradation of the decomposed brain by reducing the scattered radiation crosstalk in the slice thickness direction. An object of the present invention is to provide an X-ray CT apparatus such as a double-slice CT or a volume CT that can be used.

[0007]

In order to achieve the above object, in the present invention, a plurality of detector rows in which detector elements are arranged in a fan shape are arranged in the slice thickness direction of an object X. An X-ray CT apparatus equipped with a line detector is characterized in that a slit is provided between the detector rows.

[0008]

In the X-ray CT apparatus of the present invention having the above structure, since slits are provided between the detector rows, scattered rays in the slice thickness direction can be eliminated to reduce scattered ray crosstalk. Therefore, the decomposition of the obtained tomographic image can be prevented from lowering the brain. Therefore, even when an image such as a sagittal image, a coronal image, or an oblique image is reconstructed from continuous axial images, the influence of scattered radiation is not exerted, so that the degradation of the brain of these images can be prevented.

[0009]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the schematic arrangement of an X-ray CT apparatus according to the present invention. In the figure, in the X-ray CT apparatus, an X-ray tube 1 that irradiates the subject P with X-rays and an X-ray detector 2 that detects the X-rays are arranged to face each other across the subject P. The X-ray tube 1 and the X-ray detector 2 are configured to be rotatable around the subject P. The X-rays that have passed through the subject P are detected by the X-ray detector 2, and the data acquisition unit 3
And is sent to the image reconstruction unit 4. Then, on the basis of this data, the image reconstruction unit 4 examines the subject P.
Can be reconstructed and the reconstructed tomographic image can be displayed on the screen of the display unit 5.

As shown in FIGS. 2 and 3, the X-ray detector 2 has two detector rows 6 in which detector elements (not shown) are arranged in a fan shape in the slice thickness direction a of the subject P. And slits 7 for removing scattered radiation are provided between the detector rows 6. This slit 7 is a pedestal cover 8
Make it as high as possible without hitting.

In the double-slice CT having such a structure, since the slits 7 are provided between the detector rows 6, as shown in FIG. 4, scattered rays in the slice thickness direction a are removed and scattered in the slice thickness direction a. It is possible to reduce line crosstalk. By increasing the slit 7,
The scattered radiation crosstalk in the slice thickness direction a can be further reduced.

Next, the volume CT to which the X-ray detector 2 having the detector rows 6 arranged in a plurality of rows is applied is shown in FIGS.
Will be described with reference to. In the X-ray detector 2 applied to the volume CT, as shown in FIG. 5, detector rows 6 in which the detection elements are arranged in a fan shape are arranged in a plurality of rows in the slice thickness direction a, and each detector row is arranged. A slit 7 for removing scattered radiation is provided between the six. Therefore, as in the case of the double slice CT, scattered rays in the slice thickness direction a can be removed. Also in the volume CT, although the slits are made as high as possible, the grid ratio 1 / d in the slice thickness direction a (l is the height of the slits, d is the interval between the slits) and the grid ratio in the channel direction b are as equal as possible. Is desirable. The angle at which scattered rays can be removed depends on the grid ratio. By removing scattered radiation in this way, scattered radiation crosstalk in the slice thickness direction a can be reduced.

Therefore, even when two or more tomographic images are reconstructed in one scan, it is possible to prevent the deterioration of the decomposed brain of the obtained tomographic images, and the image reconstructing unit 4
Even when images such as sagittal images, coronal images, and oblique images are reconstructed from continuous axial images in (1), since the influence of scattered rays is not exerted, it is possible to prevent the degradation of the brain of these images.

[0015]

The X-ray CT apparatus of the present invention has the above-described configuration and operation. By reducing the scattered ray crosstalk in the slice thickness direction, two or more tomographic images can be reconstructed in one scan. Even when configured, it is possible to prevent the degradation of the tomographic image of the brain. Therefore, even when images such as a sagittal image, a coronal image, and an oblique image are reconstructed from continuous axial images, it is possible to prevent degradation of the decomposed brain of these images.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of an X-ray CT apparatus according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a configuration of an X-ray detector in the double slice CT of this embodiment.

FIG. 3 is a front view showing a configuration of an X-ray detector in the embodiment.

FIG. 4 is a front view showing the configuration of a double slice CT according to the same embodiment.

FIG. 5 is a perspective view showing a configuration of an X-ray detector in the volume CT of this embodiment.

FIG. 6 is a front view showing a configuration of an X-ray detector in the embodiment.

FIG. 7 is a perspective view showing a configuration of a double slice CT in a conventional example.

FIG. 8 is a perspective view showing a configuration of a volume CT in a conventional example.

FIG. 9 is a front view showing the configuration of a double slice CT in a conventional example.

[Explanation of symbols]

 1 X-ray tube 2 X-ray detector 6 Detector array 7 Slit P Subject

Claims (1)

[Claims] 1. An X-ray CT apparatus equipped with an X-ray detector comprising a plurality of detector rows in which detector elements are arranged in a fan shape and arranged in a slice thickness direction of a subject, and a slit is provided between the detector rows. An X-ray CT apparatus characterized by comprising: