JPH0617089Y2 - Nuclear magnetic resonance probe - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a structure of a nuclear magnetic resonance probe used when performing a nuclear magnetic resonance (NMR) measurement by arranging a surface coil close to a measurement target, and particularly not only on the surface of the target, The present invention relates to a structure of a nuclear magnetic resonance probe that can be measured without exposing an internal organ or an organ to the outside.

The objects to be measured by the NMR apparatus are widespread, and recently, small animals such as mice and rats have been measured alive. In the case where the measurement is further performed on a local area of such a small animal, the surface coil method is used in order to capture only the information from the measurement site. In this technique, a small spiral transmission / reception coil (surface coil) is used, a small animal is brought into contact with this surface coil, a high frequency wave for observation is irradiated from this coil, and a resonance signal obtained after irradiation is detected. According to this surface coil method, resonance can be generated only in the vicinity of the coil, so that it is possible to obtain a resonance signal for a specific portion in contact with the coil and what component is included in that portion. Can be analyzed. FIG. 1 is a diagram showing the structure of a conventional nuclear magnetic resonance probe using a surface coil. In FIG. 1, 1 is a probe main body, 2 is a surface coil, 3 is a small animal, 4 is a bed for fixing the small animal 3, and 5 is a circuit which is combined with the surface coil 2 to form a tuning circuit.

However, in such a conventional device, since the surface coil 2 is fixed to the probe, (1) only a limited part of the surface of the animal can be measured, and (2) when measuring the organ of the animal, pull it out to the outside. It must be applied to the coil, and the damage to the animal is great. (3) It is difficult to reset the animal to the same position once removed from the bed 4. (4) The measurement position shifts when the animal moves. There was a problem such as being lost.

The present invention has been made in view of this point, and accommodates a measurement target in a nuclear magnetic resonance probe equipped with a surface coil that irradiates the measurement target with a high-frequency wave for observation and detects a resonance signal generated from the target by the irradiation. A holding portion for holding, a tuning capacitor connected to a winding start and a winding end portion of the surface coil, one end of which is connected to the connecting portion and the other end of which is attached to the probe main body through a connector and is housed in the holding portion. And a flexible cable having a length that allows the surface coil to be closely arranged to a desired portion of the measurement target. Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 2 shows an example of a nuclear magnetic resonance probe embodying the present invention, and the same components as those in FIG. 1 are designated by the same reference numerals. In FIG. 2, the surface coil 6 is fixed to the surface of the animal 3 with tape or the like. Reference numeral 7 is a tuning capacitor connected in parallel to the surface coil at the winding start and end of the surface coil, and a flexible coaxial cable 8 is connected to both ends of the capacitor. A connector 9 is attached to the other end of the coaxial cable 8, and the cable 9 is fixed to the main body 1 by the connector 9. Reference numeral 10 is a matching circuit for matching a tuning circuit composed of the surface coil 6 and the capacitor 7 with a transmission / reception circuit (not shown) outside the probe. FIG. 3 (a) is an enlarged view showing only the surface coil 6 and the cable 8, and the connection portion of the surface coil 6, the capacitor 7 and the cable 8 is covered with a transparent cover 11. FIG. 2B is an electric circuit diagram thereof.

With such a configuration, since the surface coil is attached to the tip of the flexible coaxial cable 8, it can be moved freely and can be attached to any position on the surface of the animal. Furthermore, for example, it is possible to insert a coil into the body by making a small hole in the skin, and the coil can be brought into close contact with any organ for measurement, and there is no need to pull out the organ to the outside as in the conventional case. Further, since the coil is attached to the animal, the coil will not be displaced even if it is removed from the bed and the animal moves.

Moreover, in the present invention, rather than simply attaching the surface coil to the tip of the cable, the tuning capacitor 7
Is connected to the beginning and end of winding of the surface coil 6, so that a tuning circuit is formed at the tip of the cable. If the surface coil is simply attached to the end of the cable, the cable itself becomes the inductance of the tuning circuit, so not only does the Q of the tuning circuit decrease, but the cable also acts as a detection coil and picks up noise. In any case, it is unavoidable that the SN ratio decreases. In that respect, as described above, in the present invention, since the tuning circuit is formed at the tip portion of the cable, Q does not decrease, and the cable portion does not act as a detection coil.

In addition, if necessary, the coupling capacitor 12 may be replaced with a third capacitor.
It may be arranged as shown by a broken line in FIG.
If space is available, the capacitor of the matching circuit 10 can be arranged at the tip of the cable 8.

Further, although a small animal is targeted in this embodiment, it goes without saying that a larger animal such as a human can be measured by enlarging the magnet.

[Brief description of drawings]

FIG. 1 is a diagram showing the structure of a conventional nuclear magnetic resonance probe using a surface coil, FIG. 2 is a diagram showing an example of a nuclear magnetic resonance probe embodying the present invention, and FIG. 3 (a) is a surface coil 6 3 is an enlarged view of the cable 8 and the electric circuit diagram of FIG. 3 (b). 1: Probe body, 3: Small animal, 4: Bed, 6: Surface coil, 7: Tuning capacitor, 8: Coaxial cable, 9: Connector, 10: Matching circuit.

 ─────────────────────────────────────────────────── --Continued from the front page (56) Reference JP-A-49-103693 (JP, A) JP-B-45-39673 (JP, B1) Alger et, al Science, Vol. 214 (1981) pp660-662

Claims (1)

[Scope of utility model registration request] 1. A nuclear magnetic resonance probe provided with a surface coil for irradiating an object to be measured with a high frequency wave for observation and detecting a resonance signal generated from the object by the irradiation, and a holding section for accommodating and holding the object to be measured, and the surface coil. Of the tuning coil connected to the winding start and end of the winding, and one end of the tuning capacitor connected to the connection part and the other end attached to the probe main body through the connector and housed in the holding part to the desired site of the measurement target surface coil And a flexible cable having a length capable of being arranged in close proximity to each other.