JPH03109046A - Magnetic resonance diagnostic apparatus - Google Patents

Abstract

PURPOSE:To make an apparatus smaller by supporting a top plate with a three- dimensional movable support mechanism, which advances and retreats the top plate to and from a gantry, transfers it horizontally in an orthogonal direction to that of the advance-retreat motion and also raises and lowers it in a vertical direction. CONSTITUTION:By supporting a top plate 5 with a three-dimensional movable support mechanism 6, the top plate 5 can be advanced and retreated to and from an opening 3 of a gantry 1 as depicted in A, B by engaging rollers 14, 14 fitted to a top plate supporting metal 15 with guide rails 13, transferred horizontally as depicted in C, D by engaging rollers 12, 12 fitted to the top and rear end parts of the guide rails 13 with guide rails 11, 11 fitted to top and rear end parts of a table supporting frame 10, and raised and lowered vertically as depicted in E, F by a stretch and contraction of a rod 9 fitted to a bottom face of the table supporting frame 10 and driven by a power cylinder 8. It is possible, therefore, to position a zone of interest 19 in a subject's body 2 so as to coincide it with the center 18 of measurement zone 4 and to avoid a measurement of imaging in a peripheral part of the measurement zone 4, wherein an uniformity of magnetic field strength is lowered, so that a good diagnostic image with little image distortion can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic resonance diagnostic apparatus that uses the NMR (nuclear magnetic resonance) phenomenon to obtain an image of a diagnostic region of a subject, and particularly relates to a magnetic resonance diagnostic apparatus that uses the NMR (nuclear magnetic resonance) phenomenon to obtain an image of a diagnostic region of a subject. The present invention relates to a magnetic resonance diagnostic apparatus that can move a top plate in three dimensions within an opening of a gantry.

[Conventional technology]

Conventional magnetic resonance diagnostic equipment consists of a gantry that has an opening in the center into which the subject is inserted and generates a static magnetic field and a gradient magnetic field, and a horizontal gantry that allows the subject to be placed on the gantry and moves in and out of the opening of the gantry. It consisted of a top plate. The top plate simply moves forward and backward toward the opening of the gantry.

[Problem to be solved by the invention]

However, in such conventional magnetic resonance diagnostic equipment, the top plate on which the subject is placed simply moves forward and backward toward the opening of the gantry. All it did was get into the opening. At this time, a measurement region with substantially uniform magnetic field strength is formed approximately at the center of the opening, but it is necessary to align the subject and the receiving coil with the center of the measurement region. However, the measurement area is generally not very wide, and depending on the top plate simply moving in and out of the opening in one dimension,
It was difficult to align the subject with the center of the measurement area. In such cases, the height was adjusted by placing a mat of appropriate thickness on the top of the tabletop and placing the subject on it, but the area of interest for diagnosis of the subject was If it is biased to one side, lateral adjustment is not possible and a total of 711'
It was not possible to align it to the center of the l area. and,
Because the uniformity of the magnetic field strength decreases around the measurement area, image distortion occurs and good diagnostic images may not be obtained.

To deal with this, it would be possible to widen the measurement area where the magnetic field strength is approximately uniform, but in order to do so, the magnet body that generates the static magnetic field must be made large, which would increase the size of the entire device and increase the size of the magnet. , which was expensive.

SUMMARY OF THE INVENTION An object of the present invention is to solve these problems and provide a magnetic resonance diagnostic apparatus in which a top plate on which a subject is placed can be moved in three dimensions within an opening of a gantry.

[Means for Solving the Problems] In order to achieve the second object, a magnetic resonance diagnostic apparatus according to the present invention includes a gantry that has an opening in the center into which a subject is inserted and generates a static magnetic field and a gradient magnetic field. and a horizontal top plate on which a subject is placed and which moves in and out of the opening of the gantry, wherein the top plate retreats toward the opening of the gantry and It is supported by a three-dimensional movement support mechanism that moves laterally in a direction orthogonal to this forward and backward direction and moves up and down in the vertical direction.

[Effect]

In the magnetic resonance diagnostic apparatus configured in this way, the top plate supported by the three-dimensional movement support mechanism moves forward and backward toward the openings of the guns 1 to 1, and at the same time moves in a direction perpendicular to the forward and backward direction. It will move laterally and move up and down. As a result, the subject placed on the top plate is placed at an approximately average magnetic field strength ΔI formed within the opening of the gantt.
It can be aligned to the center of area II.

〔Example〕

EMBODIMENT OF THE INVENTION Below, one embodiment of the present invention will be described in detail based on the accompanying drawings.

FIG. 1 is a side view showing an embodiment of the magnetic resonance diagnostic apparatus according to the present invention, and FIG. 2 is a cross-sectional view taken along the line ■--■ in FIG. In the figure, a gantry 1 is used to insert a subject 2 and obtain an image of the diagnostic region of the subject. 2 is inserted into the opening 3, which has a horizontally long rectangular shape, for example.

Around this opening 3, a main magnet for generating a static magnetic field and x
, y, and z directions, and an irradiation coil that irradiates high-frequency pulses. As shown in FIG. 2, the main magnet forms a measurement region 4 in the space of the opening 3 in which the magnetic field strength is approximately uniform.

A top plate 5 is provided horizontally on one side of the gantry 1. This top plate 5 allows the subject 2 to be placed on its upper surface to move in and out of the opening 3 of the gantry 1, and is supported by a three-dimensional movement support mechanism 6 in the present invention. This three-dimensional movement support mechanism 6 moves the top plate 5 forward and backward toward the opening 3 of the gantry 1 in the directions of arrows A and B, and also in directions perpendicular to the forward and backward directions of arrows C and D. (see FIG. 2) and vertically move up and down as shown by arrows E and F. An example of its specific structure is shown in FIG. 1.

That is, a drive cylinder 8 operated by, for example, hydraulic pressure is installed on the floor surface 7, and a table support frame 10 is horizontally provided at the upper end of a rod 9 that extends and contracts in the vertical direction of the drive cylinder 8. and.

At the front end and rear end of the upper surface of this table support frame 10,
Each of the first guide rails 11 has an inverted letter shape when viewed from the side.
11 are erected. Above the table support frame 10, there are first rollers 12, 12 extending in the longitudinal direction of the table support frame 10 and sandwiching the first guide rail 11, 11 from above and below at its front and rear ends. A second guide rail 13 is stretched. The first rollers 12, 12 are rotatably provided on the outer surface of a bent piece bent downward at a substantially right angle at the front and rear ends of the second guide rail 13. , the second guide rail 13 is provided with second rollers 14, 1 that sandwich the second guide rail 13 from above and below.
A top plate support fitting 15 having 4 is combined. The top plate 5 is supported by the three-dimensional movement support mechanism 6 by connecting the rear end of the lower surface of the top plate 5 to the upper end surface of the top plate support fitting 15. In FIG. 1, reference numeral 16 indicates a mat placed on the top surface of the top plate 5.

Further, reference numeral 17 indicates a receiving coil for measuring the NMR signal emitted from the subject 2, and it can be set at a desired part of the subject 2.

By supporting the top plate 5 with the three-dimensional movement support mechanism 6 having such a structure, the top plate 5 can be moved between the second rollers 14, 14 provided on the top plate support fitting 15 and the second guide rail 1.
3 by mating with arrow A.

Move forward and backward toward the opening 3 of the gantry 1 as shown in B,
First rollers 12, 12 provided at the front end and rear end of the second guide rail 13, and first guide rail 11 provided at the front end and rear end of the table support frame 1o.
．． 11, the rod 9 of the drive cylinder 8, which is connected to the lower surface of the table support frame 1o, expands and contracts, thereby moving laterally as shown by the arrows C and D shown in FIG. It becomes scales that go up and down like E and F.

Therefore, using the magnetic resonance diagnostic apparatus of the present invention,
When inspecting a diagnostic region, the three-dimensional movement support mechanism 6 shown in FIG.
is advanced in the direction of arrow A and inserted into the opening 3 of the gantry 1, and further the top plate 5 is moved laterally in the directions of arrows C and D, and then the top plate 5 is moved laterally in the directions of arrows C and D.

By raising and lowering it in the F direction, as shown in Fig. 2,
The region of interest 19 of the subject 2 can be positioned so as to match the center 18 of the measurement region 4 formed within the opening 3 .

In this case, for more detailed positioning, 1, for example, 3rd
As shown in the figure, positioning images of the subject 2 are measured from two orthogonal directions and displayed on the display of the device,
All you have to do is align.

Here, FIG. 3(a) shows an image of the region of interest 19 of the subject 2 measured in a plane parallel to the body axis direction, and FIG. An image measured in a cross section is shown. Then, on the screen of the display, an area 4' corresponding to the position of the measurement area 4 shown in FIG. 2 and a center 18' of this area 4' (a point corresponding to the center 18 of the measurement area 4 shown in FIG. ) is displayed. Therefore, in FIGS. 3(a) and (b).

When the setting mark 20 appearing on each display image is aligned with the region of interest 19 of the subject 2, the distance Lt+Li2 from the center 18' of the region 4' is calculated by a calculation means not shown.
La is calculated and displayed on the display screen. Seeing this display, the operator appropriately operates the three-dimensional movement support mechanism 6 shown in FIG.
It is only necessary to move it up and down in a three-dimensional direction, and as a result, the region of interest 19 of the subject 2 can be accurately aligned with the center 18 of the measurement region 4, as shown in FIG.

Note that the three-dimensional movement of the top plate 5 by the three-dimensional movement support mechanism 6 may be performed by either manual operation or power-driven operation. Figure 3 shows distances LX, L2. L
By determining s, the top plate 5 is automatically moved in the three-dimensional direction by the required amount, and the subject 2 is moved to the center 18 of the measurement area 4.
Alternatively, the positioning may be performed.

〔Effect of the invention〕

Since the present invention is configured as described above, the top plate 5 supported by the three-dimensional movement support mechanism 6 can be moved forward and backward toward the opening 3 of the gantry 1, and at the same time, it can be moved in a direction perpendicular to the forward and backward direction. It can be moved laterally and raised and lowered in the vertical direction. Thereby, the subject 2 placed on the top plate 5 can be aligned with the center 18 of the measurement region 4 formed within the opening 3 of the gantry 1 and having approximately equal magnetic field strength. Therefore, it is possible to eliminate the need to measure an image at the periphery of the measurement region 4 where the uniformity of the magnetic field strength is reduced, and to obtain a good diagnostic image with less image distortion. Furthermore, since the size of the measurement area 4 with uniform magnetic field strength may be wide enough to cover the region of interest 19 of the subject 2, the width of the upper and lower measurement areas 4 may be relatively narrow. The main magnet that generates the static magnetic field can be downsized, the entire device can be downsized, and costs can be reduced.

[Brief explanation of drawings]

FIG. 1 is a side view showing an embodiment of the magnetic resonance diagnostic apparatus according to the present invention, FIG. 2 is a sectional view taken along the line ■-■ in FIG. FIG. 2 is an explanatory diagram showing a positioning image for accurate positioning. 1... Gantry, 2... Subject, 3... Opening,
4... Measurement area, 5... Top plate, 6... Three-dimensional movement support mechanism, 8... Drive cylinder, 10... Table support frame, 11 First guide rail, 12... Third 1 roller, 13... Second guide rail, 14... Second roller, 15... Top plate support fitting, 17... Receiving coil, 18... Center of measurement area, 19... ...Region of interest of the subject. Third

Claims (1)

[Claims] 1. Equipped with a gantry having an opening in the center for inserting the subject and generating a static magnetic field and a gradient magnetic field, and a horizontal top plate on which the subject is placed and moved in and out of the opening of the gantry. In the magnetic resonance diagnostic apparatus, the top plate is supported by a three-dimensional movement support mechanism that moves backward toward the opening of the gantry, moves laterally in a direction perpendicular to the forward and backward direction, and moves up and down in the vertical direction. A magnetic resonance diagnostic device characterized by: