JPH02172447A - X-ray ct device - Google Patents

Abstract

PURPOSE:To prevent erroneous diagnosing of the photographing sectional position of a body to be inspected by a method wherein the distance, in a direction extending at right angles with a cross section to be photographed, of the body to be inspected is inputted as the moving distance of a table to an input part, and a central control device computes it as a moving distance in a horizontal direction from a relation between a distance in a direction extending at right angles with the cross section to be photographed and the inclination angle of a gantry, and moves the table. CONSTITUTION:A body 100 to be inspected is placed on a table 7 and the table is moved to a gantry, and an inclination angel theta of a gantry 1 and the table 7 are set to the reference position of the body 100 to be inspected. A distance Pm in a direction extending at right angles with a cross section to be photographed and a slice thickness equal to the distance Pm are inputted as a distance to positioned (a)-(c) of a cross section to be photographed to an input part 12. A central control device 9 reads the inclination angle theta of the gantry 1 and the position of the table 7 at a current point of time, and from a relation between the inputted distance Pm and the inclination angle theta, a moving distance Pt in a horizontal direction of the table 7 is determined, and according to the determined moving distance Pt, the table 7 is moved. The cross section to be photographed at the determined moving distance Pt of the body 100 to be inspected is displayed on a picture display part 11 of the central control device 9.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an X-ray CT apparatus, and more particularly to one having an X-ray source and a detector and a tiltably installed gantry.

[Conventional technology]

A conventional X-ray CT apparatus includes a gantry that is equipped with an X-ray source and a detector and is tiltably installed, a table that is movable horizontally relative to the insertion hole of the gantry, and a central unit that drives and controls the table and the gantry. It has a control device and an input section for inputting the amount of movement of the table and the like.

During the inspection, first place the subject on the table, move the table to the gantry, set the tilt angle of the gantry and the table to the reference position of the subject, and then input the following information to the input section as shown in Figure 3. The horizontal movement distance Pm of the table is defined as the distance from the position a to c of each photographed cross section of the subject.

When the slice thickness 2, etc. are input, the central controller reads the current table position and sequentially moves the table to the desired position on the gantry, thereby imaging each of the specified positions a to C of the subject. This allows cross-sectional images to be obtained.

[Problem to be solved by the invention]

By the way, in the conventional technology, as described above, when the operator specifies the movement distance of the table in the input section, the central control device determines the position a of each specified imaging section of the subject, regardless of the tilt angle of the gantry. ~C simply move the table.

Therefore, as shown in Fig. 3, when the tilt angle of the gantry is 0 degrees, the direction of movement of the table is the same as the direction perpendicular to the photographed cross section, that is, the two slice thickness directions of the photographed cross section. Therefore, there is no problem because the table can be moved sequentially to the specified positions a - c, but if the tilt angle of the gantt is 0
If the angle is changed to a different angle than the angle, the following problem arises.

For example, in the conventional technology, when the gantry is tilted at an angle θ different from 0 degrees, as shown in FIG.
Moreover, since the slice thickness in two directions changes depending on the tilting angle of the gantry, when diagnosing a photographed cross-sectional image, there is a risk of misdiagnosing the entire position of the photographed cross-sectional image.

Furthermore, when the gantry is tilted at an angle θ as shown in Fig. 4, if it is sequentially moved in the horizontal direction by a distance z (=PL) corresponding to the specified slice thickness, one photographed section and the adjacent photographed section As a result, an overlapping portion W is generated as shown in the figure, and as a result, there is a problem that the amount of X-rays to which the subject is exposed increases accordingly.

In particular, the larger the tilting angle θ of the gantry, the larger the overlapping portion W becomes, which is a bottleneck in reducing the amount of X-ray exposure.

In view of the above circumstances, it is an object of the present invention to provide an X-ray system that can prevent misdiagnosis of the imaging cross-sectional position of a subject and reliably reduce the amount of X-ray exposure of the subject, regardless of the tilting angle of the gantry. The purpose of the present invention is to provide a CT device.

[Means to solve the problem]

In order to achieve the above object, the X-ray CT apparatus of the present invention includes a gantry which is provided with an X-ray source and a detector and is tiltably installed, and a table which is movable horizontally with respect to the opening of the gantry. , and a central control unit that drives and controls the table and the gantry. In the aCT apparatus, the input section is manually inputted with the distance in the direction perpendicular to the cross section of the object to be imaged as the movement distance of the table, and the central control device inputs the distance in the perpendicular direction and the tilting angle of the gantry. The table is moved by calculating the horizontal movement distance of the table based on the relationship.

[Effect]

Assume that the gantry is now tilted at an angle of θ. First, the subject is placed on a table, the table is moved to the gantry, and the operator sets the tilt angle of the gantry and the table to the reference position of the subject in the input section. When the distance in the direction perpendicular to the cross-section to be photographed is input as the distance of the cross-section to be photographed, the central controller reads the current f1 movement of the gantry and the position of the table, and calculates the relationship between the input distance and the tilt angle. The horizontal movement distance of the table is determined from the relationship, and the table is moved according to the calculated movement distance. As a result, a photographed cross-sectional image at a desired position can be obtained.

As a result, the human power department inputs the distance in the direction perpendicular to the cross section to be photographed, and calculates the horizontal movement distance of the table from the relationship between the input distance and the tilt angle of the gantry.
Since the table is moved, if the tilt angle changes, it is possible to reliably obtain a photographed cross-sectional image corresponding to the changed angle, thereby preventing misdiagnosis of the positional relationship between the photographed cross-sectional image and the subject. In addition, when images are taken at intervals of the slice thickness, regardless of the tilt angle,
Since one photographed section and the adjacent photographed section can be prevented from overlapping, the amount of X-ray exposure of the subject can be reliably reduced.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. FIG. 1 is a block diagram showing one embodiment of the invention, and FIG. 2 is an explanatory diagram showing the principle of the invention.

The X47j ICT device of the embodiment includes a gantry 1, a table 7, and a central control device 9, as shown in FIG.

Specifically, the gantry 1 is installed so as to be tiltable in the direction of arrow A about its center. Further, an insertion hole 1a is formed in the center of the gantry 1 so that the subject 100 can be inserted therethrough, and a half-meter X-ray hole 1a is formed in the upper part of the gantry 1 to emit X-rays to the subject 100. source 2
At the same time, a detector 3 for detecting the X-rays (3) transmitted through the subject 100 is provided at a position facing the X-ray source 2 at the bottom thereof. Furthermore, a collimator 4 is provided below the X-ray source 2 for determining the slice thickness of the photographed cross section of the subject 100 by changing the radiation range of X-rays toward the subject 100.

The slice thickness of the collimator 4 and the tilt angle of the gantry 1 are controlled by the control section 5, and the X-ray source 2 is controlled by the control section 6.

The table 7 is for placing the subject 100 thereon, and is movable in the horizontal direction toward the insertion hole 1a of the gantry l, and its moving distance is controlled by the control unit 8. There is.

On the other hand, the central controller 9 operates the gantry 1. The X-ray source 2 and detector 3゜table 7, control unit 5
・When the X-ray data from the detector 3 is sent, it performs calculations for image reconstruction based on the data, and transmits the image resulting from the calculations to an external device. It is stored in the storage section 10 and displayed on the image display section 11.

The input unit 12 allows the operator to enter, in addition to the moving distance of the table 7, the dimensions of the slice thickness of the photographed cross section of the subject 100, the tube voltage and tube current of X'uA #2, etc. when inspecting the subject 100. It is supposed to be entered.

However, in the present invention, the distance in the direction perpendicular to the cross section of the subject 100 to be imaged is inputted to the input 12 as the moving distance of the table 7, and the central control device 9 inputs the distance in the direction perpendicular to the cross section of the object 100 to be photographed. The table 7 is moved by calculating the horizontal movement distance of the table 7 based on the relationship with the tilting angle of the gantt I71.

For example, as shown in FIG. 2, when the gantry l is tilted at an angle of θ with respect to the vertical plane, the input section 12 allows the user to input the movement distance of the subject 100 from the predetermined reference position of the table 7. When the distance Pm in the direction orthogonal to the I-contrast section, in other words, the slice m of the imaging section is input, the distance Pm is calculated from the relationship with the tilt angle θ of the gantry 1 using the following formula, and the horizontal direction The distance pt is calculated, and Pm/cos θ=PL The table 7 is moved by the distance Pt via the table control unit 8.

Therefore, the central control device 9 is designed to be able to read not only the position of the table 7 but also the tilting angle θ of the gantry l, and store these data in the external storage section 10.

Furthermore, when the object 100 is cross-sectionally photographed by moving the table 7 according to the path 1pt, the central control device 9 transmits the distance Pm input to the input section to the image display section 1.
I also have it displayed on page 1.

Next, the operation of the X-ray CT apparatus of the embodiment will be described.

Assume that the gantry l is now tilted at an angle of θ degrees.

First, the subject 100 is placed on the table 7, the table is moved to the gantry, and the operator
After setting the tilting angle θ of When P m and the slice thickness of the same dimension as the distance Pm are input, the central controller 9
Read the current tilting angle θ of the gantry l and the position of the table 7, and calculate the horizontal movement distance P of the table 7 using the above formula from the relationship between the input distance Pm and the tilting angle θ.
Calculate L and use the table 7 according to the calculated travel distance PL.
move.

As a result, the image display unit 11 of the central control device 9 displays a photographed cross-sectional image of the calculated movement distance Pt of the subject 100.

Therefore, the input distance Pm in the direction perpendicular to the cross section to be photographed
Since the table 7 is moved by the horizontal movement distance Pt of the table 7, which is determined from the relationship between It is possible to obtain cross-sectional images, which prevents misdiagnosis of the position of the entire cross-sectional image when making a diagnosis.Moreover, when images are taken at intervals of the slice thickness, the position of one of the photographed cross-sections can be adjusted regardless of the tilt angle. It is possible to prevent the overlap between the entire image and the entire imaged cross section adjacent to it.
It is possible to reliably reduce the radiation exposure of the subject lOO.

Furthermore, when the central control device 9 displays the photographed cross-sectional image on the image display section 11, the input distance Pm is displayed on the image display section 12, so that the operator can confirm the input distance Pm. This makes it possible to more accurately know the positional relationship between the photographed cross-sectional image and the subject, which is convenient.

〔Effect of the invention〕

As described above, the present invention causes the input unit to input the distance in the direction perpendicular to the cross section of the object to be imaged as the movement distance of the table, and the central control device Since the table is moved by calculating the horizontal movement distance of the table in relation to the tilting angle of the gantry, even if the tilting angle changes, it is possible to obtain a photographed cross-sectional image corresponding to the changed angle. This prevents misdiagnosis of the positional relationship between the photographed cross-sectional image and the subject when making a diagnosis.Moreover, when images are taken at intervals of the slice thickness, the whole photographed cross-section image can be compared to the entire photographed cross-section image of one side, regardless of the tilt angle. Since it is possible to prevent this from overlapping the whole of the adjacent photographed cross-sections, it is possible to reliably reduce the X-ray exposure 851 of the subject.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing an embodiment of the present invention, Fig. 2 is an explanatory drawing showing the principle of the invention, Fig. 3 is an explanatory drawing when the gantry is not tilted, and Fig. 4 is a block diagram showing an embodiment of the present invention. FIG. l... Gantry, 2... X-ray source, 3... Detector,
7...Table, 9...Central control unit, 12...
Input part, Pm...Distance orthogonal to the cross section to be photographed, P
... Distance the table moves. Figure 1 Patent Applicant Hitachi Medical Co., Ltd. Agent Patent Attorney Tadashi Akimoto Actual Figure Figure

Claims (1)

[Claims] 1. A gantry equipped with an X-ray source and a detector and installed in a tiltable manner, a table movable in a horizontal direction with respect to the opening of the gantry, a central control device for driving and controlling the table and the gantry, and a table. an input section for inputting a movement amount of the table, the input section inputs a distance in a direction perpendicular to a cross section of the object to be imaged as the movement distance of the table, and the central control device An X-ray CT apparatus characterized in that the table is moved by calculating the horizontal movement distance of the table from the relationship between the distance in the orthogonal direction and the tilt angle of the gantry.