JPH032873Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to the structure of a coil used when performing nuclear magnetic resonance (NMR) measurements by arranging a measurement coil close to the measurement target, and specifically selects only resonance signals in a specific direction. The present invention relates to the structure of a coil that can be measured visually.

The objects to be measured by NMR devices are expanding, and recently, for example, small animals such as mice and rats are being measured while they are still alive. When measuring a more local part of a small animal like this, in order to capture only information from the measurement site,
The Surf S coil method is used. This involves attaching a small movable coil (Surf S coil) to the surface of a small animal or a desired location within the body, emitting high-frequency waves for observation from this coil, and detecting the resonance signal obtained after the irradiation. . According to this SURF S coil method, it is possible to cause resonance only in the vicinity of the coil, so it is possible to obtain a resonance signal for a specific organ to which the coil is attached, such as the liver or the heart, and to determine the type of resonance in each organ. It is possible to analyze whether the ingredients are included or not.

The present inventor manufactured various shapes of SURF S coils and conducted actual measurements. Figure 1a shows a flat, spiral-shaped SURFS coil.The distribution of the high-frequency magnetic field generated when a high-frequency current is passed through this SURFS coil is flat over a relatively wide range, as shown in Figure 1b. As can be seen from the change in magnetic field strength along the coil central axis O shown in Figure c, the attenuation in the central axis direction is relatively gentle. Therefore, although the measurement area with this coil covers a relatively wide range of the biological surface, by selecting the high-frequency pulse width appropriately, it is possible to select and measure any depth from the surface to relatively deep parts. , and has excellent sensitivity.
Note that the numerical values in FIG. 1a represent relative intensities.

Figure 2a shows the coil in Figure 1a with its central part protruding and formed into a conical shape.The distribution of the high frequency magnetic field generated by this coil is as shown in Figure 2b at the tip A with a small diameter. Only a narrow region in the vicinity is strong, and moreover, the attenuation in the direction of the central axis is steep, as seen from the change in magnetic field strength along the coil central axis O shown in c in the figure. Therefore, if the tip A of this coil is brought into contact with the surface of the living body, it is possible to measure only the area close to the surface of the living body, but it is possible to limit the measurement area to a narrow area near the tip A.

As described above, the coils shown in FIG. 1a and FIG. 2a each have their own characteristics, and it is necessary to use them properly depending on the purpose. Therefore, when the purpose of the probe changes, conventionally it is necessary to take out the nuclear magnetic resonance probe, remove the coil attached to it, and attach a new coil, which is cumbersome.

This invention was made in view of this point,
By providing a means for moving the center of the spiral coil in the direction of the central axis of the spiral coil, a single spiral coil can take the shape shown in FIG. 1a and the shape shown in FIG. It is distinctive in that it is no longer necessary. Hereinafter, the present invention will be explained in detail using the drawings.

FIG. 3a shows an embodiment of the SURF S coil embodying the present invention, and FIG. 3b is a sectional view taken along the line C-C. In both figures, reference numeral 1 denotes a cylindrical base whose lower part is fixed to a nuclear magnetic resonance probe (not shown), and a coil mounting plate 2 is erected in the center thereof. A hole 3 is drilled in the center of this plate, and a SURF S coil 4 with an outer diameter larger than this hole is inserted.
The center axis is aligned with this hole, and only the outer periphery is fixed with adhesive 5, for example. Reference numeral 6 denotes a conical body disposed so as to be in contact with the center of the SURF S coil from the back side of the plate 2, and a lead wire 4a at the center of the SURF S coil 4.
is taken out to the back side of the plate 2 through the inside thereof, and further guided to the probe together with the other lead wire 4b via a passage 7 passing through the base 1. Reference numeral 8 denotes a moving mechanism for moving the cone body 6 in the axial direction of the coil, which includes a fixing plate 9 and a cone body 6 screwed thereto.
It consists of a screw body 10 that presses.

In the above-described configuration, the state shown in FIG. 3b corresponds to the shape shown in FIG. 1a, and measurements can be performed that take advantage of the characteristics of the SURF S coil having this shape. When the conical body is moved to the position indicated by the broken line in FIG. 3b by rotating the screw body 10, the coil 4 changes to the shape shown in FIG. 2a. Therefore, in this state, it is possible to perform measurements that take advantage of the characteristics of the SURF S coil having the shape shown in FIG. 2a.

As described above, in the present invention, the shape of the SURF S coil can be changed by an extremely simple operation of rotating the screw body 10, so the work is easier and takes less time than the conventional method in which the coil is replaced.

In the above embodiment, the coil was deformed by moving the cone 6, but it is not necessary to use a cone, and it is sufficient to use a coil that can move the center of the coil 4 in the direction of the central axis O. For example, a rod-shaped body may be fixed to the center of the coil 4 and moved in the axial direction. At this time, if you make it possible not only to push the center of the coil 4 but also to pull it, the coil will dent in the opposite direction.
It also becomes possible to carry out measurements using the bottom part B of the SurfS coil in FIG. 2a.

[Brief explanation of the drawing]

Figures 1 a, b, and c are diagrams showing the shape of a flat SURF S coil, the intensity distribution of the high-frequency magnetic field generated by the SURF S coil, and the intensity change on the axis O, respectively;
Figures 2a, b, and c are diagrams showing the shape of the conical SURFS coil, the intensity distribution of the high-frequency magnetic field generated by the SURFS coil, and the intensity change along the axis O, and Figure 3a is a diagram showing the present invention. FIG. 3b is a cross-sectional view taken along the line C-C, showing an example of the surf coil. 1... Base, 2... Coil mounting plate, 3...
Hole, 4...Surf S coil, 5...Adhesive, 6
...Conical body, 9...Fixing plate, 10...Screw body.

Claims (1)

[Scope of utility model registration request] A coil for nuclear magnetic resonance measurement, characterized in that it is provided with means for moving the center of the spiral coil in the direction of the central axis of the spiral coil.