JPH05317305A - X ray ct device - Google Patents

Abstract

PURPOSE:To obtain an X-ray CT device which can eliminate the needs of scanogram projection by creating a scanogram by using the three dimensional volume data collected by three dimensional scanning. CONSTITUTION:A memory 2 for storing the three dimensional volume data from a projection data collecting device, a reconfiguration processing means 3 for serving the three dimensional volume data to reconfiguration processing to creat a slice image, and an image controller 4 are connected to CPU 1, and an image memory 5 and a CRT display 6 are connected to the image controller 4. Further, a projection plane setting means 7 and a scanogram generating means 8 are connected to CPU through a bus 9. The projection plane setting means 7 is adapted to creat a cylindrical three dimensional model patterning after a tested body and a model space image containing a projection plane for generating a scanogram and display the same. The scanogram generating means 8 selectively extracts a required projection data string from the memory 2 according to the angle information supplied from the projection plane setting means 7 and arrays the same on the two dimensions so as to generate a scanogram.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray CT apparatus for obtaining a slice image of a desired slice plane by performing three-dimensional scanning, collecting three-dimensional volume data, and subjecting this three-dimensional volume data to reconstruction processing. .

[0002]

2. Description of the Related Art Such an X-ray CT apparatus is a fan beam X that spreads in a fan shape if it is the third generation (R / R method).
An X-ray source that radiates a pulse in a pulsed manner and a plurality of X-ray detection elements that are arranged in opposition to the X-ray source through an imaging region and that detect X-rays that have passed through a subject are arranged in parallel. It has a multi-channel type X-ray detector and a bed provided with a linearly movable top plate, and synchronizes the X-ray source and the X-ray detector with this rotation scan while rotating around the subject. The top plate is intermittently or continuously driven along the body axis direction of the subject to move its scan position for three-dimensional scanning, and multi-directional projection data of the subject in three-dimensional real space (hereinafter By collecting "three-dimensional volume data") and subjecting the three-dimensional volume data to reconstruction processing, a slice image of a desired slice plane can be obtained.

FIG. 7 is a diagram showing a general flow of the inspection work from the start of inspection to the generation of slice images when using this conventional X-ray CT apparatus. This inspection work starts with a subject positioning work S11 in which spot light with a scale is projected from an external light projector onto the subject and the approximate position of the subject is determined by visual measurement from this position. When the position of the subject is determined, the scanogram is imaged before the three-dimensional scan (S12). The scanogram is a projected image that is referred to when drafting a scan plan including items such as the scan range, slice pitch, and slice angle and setting the slice plane, and stops the rotation of the X-ray source and X-ray detector. Moreover, these are collected while moving along the body axis direction of the subject. When the scan plan is determined with reference to this scanogram (S13),
A three-dimensional scan is executed according to this scan plan, and three-dimensional volume data is collected (S14). When the collection of the three-dimensional volume data is completed, the slice image generation operation is started. First, by referring to the scanogram and designating a slice plane at a desired position and in a desired direction (S15), the projection data necessary for generating a slice image of the slice plane in the three-dimensional volume data is used for reconstruction processing. Then, a slice image of the slice plane is generated (S16) and is used for diagnosis. When slice images at other positions and directions are required, the above steps S15 and S16 are repeated.

As described above, the scanogram is very effective for drafting a scan plan and setting the slice plane in the inspection work, but since the scan work is required to obtain the scanogram, the dose of radiation to the subject is increased. However, the problem is that the inspection time and the subject restraint time are prolonged. Further, since the scanogram obtained by one scanogram photographing is one image in one direction, when the scanograms in a plurality of directions are required, this scanogram photographing must be repeated several times, and the above problem is further increased.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to address the above-described circumstances, and its purpose is to create a scanogram by using a scanogram using three-dimensional volume data collected by a three-dimensional scan. An object of the present invention is to provide an X-ray CT apparatus that does not require imaging work.

[0006]

An X-ray CT apparatus according to the present invention is an X-ray source for irradiating X-rays arranged facing each other through an imaging area and an X-ray detector for detecting the X-rays. While rotating the circumference of the subject within the imaging area and moving the scan position along the axial direction of the subject, the three-dimensional projection data of the three-dimensional region of the subject An X-ray CT apparatus for collecting volume data and subjecting a slice image of a slice plane set with reference to the scanogram of the subject to reconstruction processing of the three-dimensional volume data, wherein the scanogram is the above-mentioned 3 The X-ray tube in the dimensional volume data is generated from the data collected at the same position.

[0007]

According to the X-ray CT apparatus of the present invention, X in the three-dimensional volume data obtained by the three-dimensional scan
It is possible to generate a scanogram from the data collected at the same position of the wire tube and use it for setting the slice plane.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An X-ray CT according to the present invention will be described below with reference to the drawings.
A first embodiment of the device will be described. FIG. 1 is a block diagram showing the arrangement of the image generation processing apparatus of the first embodiment apparatus.
The apparatus according to the present embodiment includes the image generation processing apparatus and the projection data collection apparatus. The projection data collection apparatus is an apparatus for performing three-dimensional scanning and collecting three-dimensional volume data, and the image generation processing unit is a projection unit. It is a device for processing three-dimensional volume data supplied from a data acquisition device to create a slice image or a scanogram (projection image).

The projection data acquisition apparatus is an apparatus mainly composed of structural elements of an X-ray CT apparatus necessary for acquiring three-dimensional volume data, and is, for example, a third generation (R / R).
System), an X-ray source that radiates a fan-shaped X-ray that spreads in a fan shape in a pulsed manner and an X-ray source that is arranged to face the X-ray source via an imaging area and detect X-rays that have passed through the subject. A multi-channel X-ray detector having a plurality of one-dimensionally arranged X-ray detection elements, a bed having a slidable top plate, and a scan plan including items such as a scan range, slice pitch, and slice angle. And a console box and the like for rotating the X-ray source and the X-ray detector and performing sequence control of the movable parts such as the slide of the top plate according to this scan plan. Note that the three-dimensional scan is a scan for collecting data on a three-dimensional space, and for example, a helical scan for performing continuous imaging by a spiral motion as shown in FIG. 2 or a mainstream of the current scan method is used. Multi-slice scan in which imaging is intermittently repeated for each occupied scan plane, or two-dimensional arrangement of an X-ray source that radiates cone-shaped X-rays and a plurality of X-ray detection elements There is a scanning method such as cone beam scanning performed using an array X-ray detector, and any method may be adopted. It should be noted that although the generation of the scanogram in the case of the helical scan is described here, the method of generating the scanogram in the multi-slice scan is basically the same as that of the helical scan.

The image generation processing apparatus is a storage medium such as a magnetic tape, a magnetic disk, an optical disk for storing three-dimensional volume data supplied from the projection data collection apparatus to the CPU 1 via the data / control bus 9. An image controller 4 is connected to a memory 2 including a memory, a reconstruction processing unit 3 that reconstructs three-dimensional volume data in the memory 2 to create a slice image, and an image controller 4. A memory 5 and a CRT (cathode ray tube) display are connected. FIG. 3A is a diagram schematically showing a data array in the memory space of the memory 2, in which the three-dimensional volume data is stored in the memory space as 1
The projection data strings T for n channels are grouped for each scan (one rotation), arranged and stored in the order of sampling angles.

Further, similarly, the projection plane setting means 7 and the scanogram generating means 8 which are characteristic components of the present embodiment are connected to the CPU 1 via the bus 9.
The projection plane setting means 7 creates and displays a model space image including a cylindrical three-dimensional model M imitating a subject as shown in FIG. 4 and a projection plane TP for generating a scanogram.
The projection plane TP can be rotated along the peripheral edge of the three-dimensional model M as indicated by an arrow by operating an input device such as a mouse or a trackball (not shown). The angle .theta. Shown in FIG. 4 is the reference line L0 corresponding to the scan start position and the line L indicating the position of the projection plane TP (the contact point between the projection plane TP and the three-dimensional model D and the cross section of the three-dimensional model M). The angle with the line connecting the centers C), and this angle information is the scanogram generating means 8
Is supplied to. Since this model space corresponds to the real space, a desired scanogram can be easily obtained by setting the projection plane TP in the model space.

The scanogram generating means 8 selectively extracts a required projection data string T from the memory 2 based on the angle information supplied from the projection surface setting means 7, and arranges it on a two-dimensional surface. Generate a scanogram. FIG. 3 is a diagram schematically showing selection of the projection data sequence T and generation of a scanogram. That is, the scanogram generating means 8
3A, the projection data sequence T11, T21, T31 ... Held at the position of the angle θ of each scan in the memory space based on the angle information, and the angle θ.
Projection data string T1 held at a position of 180 degrees from
2, T22 ... are selected, and as shown in FIG. 3B, these projection data sequences T11, T21, T31 ... and projection data sequences T12, T22 ... A scanogram SG is generated by arraying accordingly. This scanogram SG is supplied to the image controller 4 and is displayed together with the cursor indicating the position of the slice plane in C.
It is displayed on the RT display 6. In addition, as a method of displaying the scanogram, one scanogram may be displayed as a single display, or as shown in FIG. 5, a multi-display of a plurality of types of scanograms, here, a side view scanogram SV viewed from the side direction. The multi-display with the top view scanogram TV projected from the front direction may be appropriately changed.

As described above, the apparatus of the present embodiment generates the scanogram from the three-dimensional volume data obtained by the three-dimensional scan, so that the scanographing work is not required, and therefore the flow of the inspection work is simplified as shown in FIG. Can be That is, in the inspection work, first, a spot light with a scale is projected from the external light projector onto the subject,
From this projected position, the position of the subject on the top plate is determined by visual measurement, and a scan plan including items such as the scan range, slice pitch and slice angle is set (S1). When the object positioning and the setting of the scan plan are completed, the three-dimensional scan is executed according to the scan plan and the three-dimensional volume data is collected (S
2).

When the collection of the three-dimensional volume data is completed, the scanogram generation operation is started. That is, the projection plane setting means 7 is activated to display the model space image shown in FIG. 4 on the CRT display 6, and the input plane such as a mouse or a trackball is operated to set the projection plane TP at a desired position ( S3), the angle information is supplied to the scanogram generating means 8 and the memory 2 is based on this angle information.
The required projection data sequence is selectively extracted from the sequence, and this projection data sequence is rearranged to generate a scanogram (S
Four ). It should be noted that the above operations S3 and S4 are executed again and the projection plane T
If P is reset, a scanogram in another direction can be easily obtained, and multi-display as shown in FIG. 5 can be dealt with.

Then, as in the prior art, by referring to this scanogram and designating a slice plane at a desired position (S5), reconstruction processing is performed on the slice plane to generate a slice image, and the CRT display 6 is displayed.
It is displayed on the screen (S6) and can be used for diagnosis.

As described above, according to the present embodiment, the scanogram can be obtained from the three-dimensional volume data collected by the three-dimensional scan without performing the scanogram photography as in the prior art, so that the need for the scanogram photography is eliminated. It is possible to solve the problems of exposure dose, subject restraint time, and examination time. The present invention is not limited to the above-described embodiments, but can be modified in various ways.
For example, various image processing such as interpolation processing means may be added to the scanogram generation means, and interpolation processing may be performed on projection data selected from the three-dimensional volume data to generate a smooth scanogram.

[0017]

As described above, according to the present invention, since the scanogram is obtained from the three-dimensional volume data collected by the three-dimensional scan, there is no need for the scanogram photography, and as a result, the subject is conventionally scanned by the scanogram photography. It is possible to solve the problems of the exposure dose, the inspection time, and the subject restraint time that have been received.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.

FIG. 2 is a diagram illustrating a helical scan as an example of a three-dimensional scan.

FIG. 3 is a diagram for explaining a scanogram generation method by the scanogram generation means shown in FIG.

FIG. 4 is a CR created by the projection plane setting means shown in FIG.
The figure which shows an example of the model space displayed on a T display.

FIG. 5 is a diagram showing a display example of a scanogram.

FIG. 6 is a diagram showing a flow of inspection work by the apparatus of this embodiment.

FIG. 7 is a diagram showing a flow of inspection work by a conventional X-ray CT apparatus.

[Explanation of symbols]

1 ... CPU, 2 ... Memory, 3 ... Reconstruction processing means, 4 ... Image controller, 5 ... Image memory, 6 ... CRT display, 7 ... Projection plane setting means, 8 ... Scanogram generating means, 9 ... Data / control bus.

Claims (1)

[Claims] 1. An X-ray source for radiating X-rays and an X-ray detector for detecting the X-rays, which are arranged to face each other through an imaging area, are rotated around a subject in the imaging area. At the same time, while moving the scan position along the opposite axis direction of the subject, three-dimensional volume data consisting of multi-directional projection data of the three-dimensional region of the subject is collected, and the scanogram of the subject is referred to. In an X-ray CT apparatus that obtains a slice image of a slice plane set by performing the three-dimensional volume data reconstruction process, the scanogram is collected at the same position of the X-ray tube in the three-dimensional volume data. An X-ray CT apparatus, which is generated from the obtained data.