JP3144791B2 - Magnetic resonance imaging diagnostic equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial application field) The present invention relates to a magnetic resonance imaging diagnostic apparatus, and particularly, can easily align a subject during imaging. The present invention relates to a magnetic resonance image diagnostic apparatus that allows easy confirmation of a scan position.

(Related Art) A magnetic resonance image diagnostic apparatus (hereinafter, referred to as an MRI apparatus) that destructively scans the inside of a subject such as a living body and displays the image as an image is widely used as a medical device for diagnosis.

An MRI apparatus is an apparatus that takes a tomographic image using a nuclear magnetic resonance (NMR) phenomenon generated inside a subject placed in a magnetic field.

As an MRI apparatus using a permanent magnet as a magnet for forming a magnetic field, for example, an open-type apparatus as shown in FIGS. 5 and 6 is installed in a hospital or the like.

The MRI apparatus includes a pair of permanent magnets 2a and 2b provided to face each other in the up-down direction with the imaging space 1 interposed therebetween.
The apparatus is provided with a magnet base 3 holding 2b and a bed 5 for inserting a subject 4 into a magnetic field formed in the imaging space 1 by the permanent magnets 2a and 2b.

The magnet base 3 is configured by supporting an upper magnetic circuit board 6a and a lower magnetic circuit board 6b with four columns 7. Further, magnetic shunts (pole pieces) 8a and 8b are attached to the photographing space 1 side of the permanent magnets 2a and 2b, respectively.
a and 8b have the function of adjusting the direction of the magnetic field lines and forming a uniform magnetic field in the imaging space 1.

On the other hand, the subject 4 is placed on the
A top plate 9 slidably movable in the direction is provided. A positioning display lamp 10 for displaying the relative position of the subject 4 with respect to the magnet gantry 3 is provided on the top of the bed 5 outside the magnet gantry 3.

When capturing an image, the subject 4 placed on the top 9 is moved and inserted into the imaging space 1 as shown in FIG. 6, so that the scan target portion of the subject 4 becomes the center of the magnetic field. Scan is performed after positioning. In performing this positioning, the position of the subject 4
The posture of the subject is adjusted by a small amount with reference to the position of the positioning light 11 applied to the surface.

By the way, in order to obtain a clear and high-precision image in the MRI apparatus, it is extremely important to set the scanning target portion at the center of the magnetic field where the intensity of the magnetic field lines is small and a uniform magnetic field is formed.

(Problems to be Solved by the Invention) However, in the conventional MRI apparatus, only a positioning display lamp is provided outside the magnet mount as shown in FIG. In the operation of determining the scan position of the subject far from the positioning light with reference to the positioning light irradiated to the object, an error easily occurs, and the scan target portion of the subject can be set with high positional accuracy around the magnetic field center. It was difficult. As a result, there is a disadvantage that the image quality of the obtained diagnostic image is likely to be reduced, and the reliability of the diagnosis is reduced.

Therefore, after inserting the subject into the imaging space, the posture of the subject is further changed little by little, actual scanning is performed on a trial basis, and the obtained positioning image is evaluated to determine whether the scanning position is appropriate for the first time. A complicated operation of doing so was required. Therefore, there is a problem that a great deal of labor and time are required for positioning the scan target portion, and particularly, the work load of the operator increases.

The present invention has been made in order to solve the above-described problems, and a magnetic resonance imaging diagnostic apparatus capable of extremely easily positioning a scan target portion of a subject and quickly obtaining an image with excellent resolution is provided. The purpose is to provide.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, a magnetic resonance imaging diagnostic apparatus according to the present invention is provided so as to be vertically opposed to each other with an imaging space therebetween, and is provided within the imaging space. In a magnetic resonance imaging diagnostic apparatus including a magnet that forms a magnetic field, a gantry holding the magnet, and a bed that inserts a subject into the magnetic field, at least one of a horizontal direction and a vertical direction of the magnetic field A positioning light projector for displaying a center position with position display light illuminated on the surface of the subject is provided on the gantry.

(Operation) According to the magnetic resonance imaging diagnostic apparatus having the above configuration, the position indicating light emitted from the positioning light projector is displayed on the surface of the subject, so that the operator matches the scan target portion of the subject with the position indicating light. The scan target position can be quickly set at the center of the magnetic field only by slightly correcting the posture position of the subject.

That is, the operator can recognize the center of the magnetic field by visually observing the position display light, and can quickly perform the positioning of the scan target portion, without taking a positioning image in advance as in the related art. The imaging of the diagnostic unit can be performed directly, and the work load of the operator due to the positioning of the subject and the like can be greatly reduced. In addition, since the scan target portion can be set at the center of the magnetic field with high magnetic field uniformity with high positional accuracy, a diagnostic image with high resolution can always be obtained.

(Example) Next, an example of the present invention will be described with reference to the accompanying drawings. FIG. 1 and FIG. 2 are a cross-sectional view and a main part perspective view, respectively, showing an embodiment of the present invention. The same elements and parts as those of the conventional example shown in FIGS. 5 and 6 are denoted by the same reference numerals, and the description thereof will not be repeated.

That is, the magnetic resonance imaging diagnostic apparatus according to the present embodiment is provided so as to be vertically opposed to each other with the imaging space 1 therebetween, and a pair of permanent magnets 2a and 2b that form a magnetic field in the imaging space 1 and the permanent magnets 2a and 2b. In a magnetic resonance imaging apparatus provided with a magnet base 3 for holding a magnetic field and a bed 5 for inserting a subject 4 into a magnetic field, the magnetic field has horizontal and vertical center positions Ch and Cv.
Is applied to the surface of the subject 4 in a cross-shaped position indicating light 12h, 12h.
Positioning projectors 13h and 13v indicated by v are provided inside the magnet mount, respectively.

As shown in FIG. 2, the positioning light projector 13h for displaying the center of the magnetic field in the horizontal direction is provided with a magnetic shunt plate 8a in the magnet base 3.
On the other hand, the positioning light projector 13v for displaying the center of the magnetic field in the vertical direction is mounted at the center of the side surface of the lower magnetic circuit board 6b in the magnet mount 3,
It is configured to be rotatable around a rotation shaft 14 provided in 6b.

Furthermore, as the light source of each positioning projector 13h, 13v,
It is constructed using a high-luminance halogen lamp or laser light having excellent convergence.

When capturing a tomographic image of the patient's head as the subject 4 using the above-described magnetic resonance image diagnostic apparatus, the top plate 9 on which the patient is placed is moved from the bed 5 to the imaging space 1 in the magnet mount 3 in one direction. To slide. At this time, cross-shaped position display lights 12h and 12v emitted from the positioning light projectors 13h and 13v are displayed on the front and side surfaces of the patient's head, respectively. The intersections of the cross-shaped position indicating lights 12h and 12v indicate the horizontal and vertical center positions Ch and Cv of the magnetic field formed in the imaging space 1 by the permanent magnets 2a and 2b, respectively. The operator corrects the posture of the patient so as to match the scan target site with the intersection of each of the visible position display lights 12h and 12v, and executes the scan.

As described above, according to the magnetic resonance imaging apparatus according to the present embodiment, the position indicating lights 12h and 12v emitted from the positioning light projectors 13h and 13v are displayed on the surface of the patient's head as the subject 1, so that the operator Indicates the horizontal and vertical positions of the scan target part of the head, respectively, with position display lights 12h and 12v
The scan target position can be quickly set to the center of the magnetic field by only slightly modifying the posture position of the patient so that the position of the scan target coincides with.

That is, the operator indicates the center of the magnetic field as the position display light 12h, 12h.
v, it is possible to perform quick positioning of the scanning target portion, and it is possible to directly perform imaging of the diagnostic unit without previously capturing a positioning image as in the related art. It is possible to greatly reduce the workload of the operator involved in the positioning of the subject and the like, and to significantly reduce the time required for the positioning. In addition, since the scan target portion can be set at the center of the magnetic field with high magnetic field uniformity with high positional accuracy, a diagnostic image with high resolution can always be obtained.

Further, by configuring the positioning light projector 13v to be tiltable as in the present embodiment, when the device is not used, it can be tilted in the horizontal direction as indicated by the imaginary line. Therefore, when performing maintenance and inspection of the device, etc.
v does not hinder maintenance work.

Next, another embodiment of the present invention will be described with reference to FIG.

In the MRI apparatus according to the present embodiment, the positioning light 11 from the existing positioning display lamp 10 provided outside the magnet mount 3 is branched, and the branched positioning light 11a is applied to the subject at the center position of the magnetic field in the horizontal direction. Reflector that reflects in four directions
15 is attached to the lower surface of the magnetic shunt plate 8a, and the positioning floodlight 13h
Is composed. Similarly, a positioning light projector 13v indicating the vertical center position of the magnetic field is also provided with a positioning light 11 from a light projector 10a for indicating a height direction, which is attached to the column 7, and branched by a reflector (not shown) in a lateral direction. Is configured to irradiate the subject from the

The same effects as those of the embodiment shown in FIG. 1 and FIG. 2 can be exerted by the apparatus of this embodiment, but in particular, by forming the reflecting mirror 15 with a non-magnetic material, the reflecting mirror can be formed in the magnetic field forming space. In this case, a high-quality image can be obtained with less risk of deteriorating the uniformity of the magnetic field.

In the above embodiment, the positioning floodlights 13h and 13v respectively display the horizontal and vertical center positions of the magnetic field.
In this example, the position indicating lights 12h and 12v are arranged so that the optical axes of the position indicating lights 12h and 12v are orthogonal to the body axis of the subject 4 in the magnet mount 3. However, the positioning projector 13v that displays only the center position in the vertical direction of the magnetic field does not necessarily need to emit the position display light 12v from a direction perpendicular to the body axis of the subject 4, but from an oblique direction with respect to the body axis. Irradiation may be performed. Therefore, as shown in FIG. 4, the positioning projector 13v may be integrally attached to the column 7 of the magnet base 3.

In this case, since no projection is formed on the open side surface of the magnet mount 3, there is no possibility that the field of view of the subject 4 is obstructed, and there is no possibility that a hindrance will occur during the maintenance work of the apparatus.

Although illustration is omitted, as each positioning projector,
A similar effect can be obtained even when the other ends of a large number of optical fiber cables derived from one light source are laid so as to be directed in the directions corresponding to the horizontal and vertical center positions of the magnetic field, respectively, to form a projector. Can be demonstrated.

〔The invention's effect〕

As described above, according to the magnetic resonance imaging diagnostic apparatus of the present invention, the position display light emitted from the positioning projector is displayed on the surface of the subject, so that the operator sets the scan target portion of the subject to the position display light. The scan target position can be quickly set at the center of the magnetic field by only slightly correcting the posture position of the subject to make them coincide with each other.

That is, the operator can visually check the center of the magnetic field with the position display light, and can quickly position the scan target portion. Can be performed, and the work load of the operator due to the positioning of the subject and the like can be greatly reduced. In addition, since the scan target portion can be set at the center of the magnetic field with high positional accuracy and excellent magnetic field uniformity, it is possible to obtain a diagnostic image with high resolution at all times. It is effective.

[Brief description of the drawings]

FIG. 1 is a side view showing an embodiment of a magnetic resonance image diagnostic apparatus according to the present invention, FIG. 2 is a perspective view of a main part showing a state in which a magnetic field center position is displayed on a subject by a positioning projector, and FIG. FIG. 4 is a side view showing another embodiment of the present invention, FIG. 4 is a side view showing another embodiment of the present invention, and FIGS. 5 and 6 are perspective views each showing a configuration of a conventional open type MRI apparatus. It is a figure and a side view. 1 ... imaging space, 2a, 2b ... permanent magnet, 3 ... magnet mount, 4 ... subject, 5 ... bed, 6a ... upper magnetic circuit board, 6b ... lower magnetic circuit board, 7 ... Prop, 8a, 8b ... Magnetic shunt plate, 9 ... Top plate, 10 ... Positioning indicator lamp, 10a ...
… Emitter, 11a, 11b… Positioning light, 12h, 12v… Position indicating light, 13h, 13v… Locating emitter, 14… Rotary axis, 1
5 ... Reflector, Ch ... Center position of magnetic field in horizontal direction, Cv ...
... the vertical center position of the magnetic field.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) A61B 5/055

Claims (1)

(57) [Claims] 1. A magnet which is provided vertically opposed to an imaging space and forms a magnetic field in the imaging space, a gantry holding the magnet and having an open side surface; A magnetic resonance image diagnostic apparatus comprising: a bed for inserting a subject into the subject; and a first center provided on the gantry, wherein a horizontal center position of the magnetic field is displayed by position indicating light applied to the surface of the subject.
A light projecting means, and a second light projecting means, which is provided on the gantry so as to be tiltable and displays a center position of the magnetic field in a vertical direction on the surface of the subject using position display light. Magnetic resonance imaging apparatus.