JPH0556948A - Inspecting device using nuclear magnetic resonance - Google Patents

Abstract

PURPOSE:To provide a structure which retains the shape as a coil and can be curved by bonding a copper plate to a 'Teflon(R)' plate by using 'Teflon(R)' of a melting type, then constituting a coil pattern by etching. CONSTITUTION:An electrode constituting inductance is formed of the copper plate having about 0.2mm thickness and the surface thereof is coated with the foamed 'Teflon(R)' in the coil part 1 of a detector. The potential of the electrode is dropped and the loss by the floating capacity with a patient is decreased by dividing inductances 4, 5, 6, 7 by capacitors 8, 9, 10. The capacitors 8, 9, 10 are constituted by attaching the electrode 5 of the copper plate to the 'Teflon(R)' 11 and inserting the thin 'Teflon(R)' 12 between the electrode 5 and the electrode 6. The electrode 6 is coated with the 'Teflon(R)' 13 and the capacitor is formed of the electrodes 5 and 6. The capacity of the capacitors is determined by the thickness and dielectric constant of the 'Teflon(R)' 12 and the superposed areas of the electrode plates 5, 6. The constant of the divided capacitors is determined by selecting these at adequate conditions.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nuclear magnetic resonance phenomenon, and relates to a nuclear magnetic resonance apparatus suitable for obtaining medically more effective diagnostic information than a subject, that is, a tomographic enhancement and a spectrum of a specific portion of the subject. Regarding the detector.

[0002]

2. Description of the Related Art The conventional technique for manufacturing a surface detector case is to use a strong structure such as plastic, for example, FRP, ABS, acrylic, or to make a patent application of Japanese Patent Application No. 61-5.
As described in detail in No. 04144, "Nuclear Magnetic Resonance Imaging System" of the invention, it is flexibly made of a film or the like.

When it is made of plastic or the like, it may not be possible to obtain a signal up to the sensitivity region originally desired because it does not match the shape of the imaged region of the patient. Further, since it is a hard case, it is necessary to insert a sponge or the like so as not to cause pain to the patient.

In the case of flexible manufacturing,
Fixation is possible at the part that is wrapped around the human body such as the knees and the whole body, but in the case of radiographing the jaw and shoulder joints, it is not easy because the coil cannot be wrapped. Further, when a coil is wound around a human body for photographing, the coil approaches the human body, which causes uneven reception sensitivity and deteriorates a photographed image. Therefore, it is impossible to use a hard case or a structure with a sponge inside.

[0005]

As described in the section of the prior art, when the detector is made of a hard case structure, the detector does not match the shape of the imaged region in the optimum shape. There is a problem that the sensitivity is lowered. In addition, if it is fixed in contact with the patient, it will cause pain to the patient. Therefore, there arises a problem that it is necessary to insert a sponge or the like between them or fix the coil with a support.

Further, if the detector is made flexible, it becomes extremely difficult to hold the coil at a site such as a jaw joint or a shoulder joint. Further, when photographing a knee or a torso, it is worn by winding a coil, but due to uneven reception sensitivity of the coil, only the approaching portion of the coil can be obtained with high sensitivity, which causes a problem that the photographed image deteriorates. .. Further, in the case of a normal thin film, there is a safety problem such as electric shock when it is torn.

[0007]

In order to solve the above-mentioned technical problems, for example, a Teflon plate having a thickness of about 1 to 3 mm is used with a fusion type Teflon, and the thickness is, for example, 0.1 to 0.2 mm.
A copper plate of a certain degree is bonded and a coil pattern is formed by etching. At the same time, the circuit pattern of the preamplifier can also be manufactured by etching. After that, a Teflon is further adhered on it to manufacture a detector.

Therefore, by appropriately changing the thickness, width, etc. of the Teflon, it is possible to realize a structure in which the shape of the coil is maintained and the coil is bendable. Therefore, the cage joint,
The coil can be easily attached to the imaging site even for shoulder joints. In addition, since it is covered with LAFLON, safety issues such as electric shock do not occur. Further, since the pattern of the preamplifier is simultaneously produced on the same surface as the electrodes of the coil, the preamplifier can be produced integrally with the coil.

When the resonance frequency is 10 MHz or more, the loss due to the rise in the coil potential due to the inductance, that is, the sensitivity is reduced. Normally, this is dealt with by preventing the rise of the potential by a disassembly tuning coil in which the inductance is divided in series by the capacitance.

[0010]

[Function] Since the detector electrode is covered with Teflon to maintain a shape such as a circle and has an elastic structure, it can be easily installed on a curved imaging region of a patient. Can be done. For example, it can be easily attached to a shoulder joint, an eyeball, a jaw joint, or the like.

Further, in order to obtain the resonance frequency of coil detection by division tuning by capacitance, electrodes are produced by etching and Teflon is inserted to form capacitors, and thin and elastic coils with less loss can be produced.

Further, since the detector has a structure sealed by Teflon, there is no problem of electric shock.

[0013]

Embodiments of the present invention will be described below with reference to FIGS. 1, 2 and 3. FIG. 1 is an external view of a circular RF coil showing an embodiment of the present invention. The coil part 1 of the detector is
The electrodes that make up the inductance of the detector are about 0.2 m thick
It is made of m copper plate, the surface of which is covered with Teflon foam. The thickness of 1 is about 2-3 mm. Therefore, the circular shape is maintained even when cantilevered. The second part contains a capacitor for matching the resonance frequency and impedance. 3 is a connector. FIG. 2 shows a schematic circuit diagram of the RF coil shown in FIG. By dividing the inductances 4, 5, 6 and 7 by the capacitors 8, 9 and 10, the potential of the electrodes is lowered to reduce the loss due to the stray capacitance with the subject. Here capacitors 8, 9, 1
0 is shown in the sectional view of FIG. A Teflon 11 is provided with a copper plate electrode 5, and a thin Teflon 12 is sandwiched between the electrode 5 and the electrode 6. Furthermore, the electrode 6 is Teflon 1
Covered with 3. Therefore, the electrodes 5 and 6 form a capacitor. The capacity of the capacitor is naturally determined by the thickness and dielectric constant of the Teflon 12 and the area where the electrode plates 5 and 6 overlap. By selecting this as an appropriate condition, the constant of the dividing capacitor can be determined. Also,
By keeping the thickness and width of the Teflons 11 and 12 to be appropriate dimensions, for example, by reducing the width of the coil portion 1 of the detector to about 20 mm and the thickness to 2 to 3 mm, the circular shape is maintained,
Furthermore, it is possible to manufacture a detector that bends when a force is applied.

An application example of this embodiment is shown in FIG. FIG. 4 shows a mounting state in the case of photographing a shoulder joint. In the case of photographing a shoulder joint, a signal can be obtained with high sensitivity if the photograph is taken through the shoulder to improve the filling factor 7.
In this case, if the film is thin, the coil shape cannot be held and it is difficult to fix the coil shape, and the coil cannot be mounted at the shoulder joint position. In addition, if it is made of a hard material such as a plastic case, it will cause patient distress. In this example,
It has a small thickness of 2 to 3 mm and is elastic enough to hold the coil shape, and the coil can be easily installed in the shoulder joint without causing pain to the patient. Further, another application example of this embodiment is shown in FIG. FIG. 5 shows an example in which the eyeball and the optic nerve are imaged. As described above, since the coil has a structure with elasticity, the coil can be fixed with a belt or the like according to the shape of the face, the filling factor can be improved, and a highly sensitive captured image can be obtained. ..

An embodiment of the coil manufacturing method of the present invention is shown in FIGS. 6, 7 and 8. As shown in FIG. 6, a copper plate is adhered to the Teflon 11 as a base material by using a fusion type Teflon. After that, electrodes are formed by etching into 4 and 6 shapes. After that, as shown in FIG. 7, the Teflon 12 is adhered to the thickness to obtain a desired capacitor by using a melt type Teflon. Further, Teflon is suitable as a capacitor because it has a relative dielectric constant of about 2 and a small dielectric loss. Further, the use of foamed Teflon further reduces the dielectric loss. Figure 8
As shown in, the electrode plates 5 and 7 are manufactured in the same manner,
Further, Teflon B is adhered on it. The coil produced by the above manufacturing method is hermetically sealed and has a waterproof effect, and the withstand voltage of Teflon is about 19 KV / mm, and it is possible to take measures against safety problems such as electric shock to the patient. Also, 300
It was able to withstand the bending test about 0 times and maintain the coil shape. Further, when the electrode plates 4 and 7 are manufactured by etching, the circuit pattern of the preamplifier can be simultaneously etched and manufactured. As a result, the detector, that is, the RF coil and the preamplifier can be integrally manufactured. As a result, the transmission loss of the cable is reduced and a highly sensitive signal is obtained.

Furthermore, another embodiment is shown in FIGS. 9, 10 and 1.
Shown in 1. The detector of this embodiment is a detector for the jaw joint. In the case of radiographing the jaw joints, it is desirable to take both radiographs simultaneously because the left and right jaw joints are clinically symmetrically compared and diagnosed.

Therefore, as shown in FIG. 9, an example in which two pairs of coils are arranged in parallel is shown. A schematic circuit diagram is shown in FIG. The coil portions 13 and 14 are integrated with the Teflon and the copper electrode plate. The case 15 is made of, for example, plastic and retains the curved shape.
3, 14 are fixed. Therefore, 13 and 14 can be fitted to the imaging site by pulling with a belt or the like as shown in FIG. 11, even if the width of the patient's head is different,
Furthermore, since it is elastic and has a circular shape, it can be easily mounted. Capacitors 18,1
9 is manufactured as shown in FIGS. 6, 7, and 8 described above.

[0018]

EFFECTS OF THE INVENTION Since the electrodes of the detector maintain a coil shape such as a circular shape and have elasticity, the detector can be easily attached in accordance with the shape of the patient and the imaged region which are different between individuals. Therefore, the coil can be used with a high filling factor, and the affected area can be imaged with high sensitivity. Also, because it can be manufactured thin (2 to 3 mm) and lightweight, it is easy to mount the detector and the operability is good. In addition, since it is elastic, it does not cause any pain and discomfort to the patient.

Further, since it is covered with Teflon, it is waterproof and there is no danger of electric shock to the patient.

Further, the preamplifier can also be manufactured at the same time as the electrode plate and can be integrated with the coil, so that the signal transmission loss is small and the sensitivity is high.

[Brief description of drawings]

FIG. 1 is an external view showing an embodiment of the present invention.

FIG. 2 is a schematic circuit diagram showing an embodiment of the present invention.

FIG. 3 is a cross-sectional view of a capacitor section showing one embodiment of the present invention.

FIG. 4 is a diagram showing one application example of one embodiment of the present invention.

FIG. 5 is a diagram showing another application example of the first embodiment of the present invention.

FIG. 6 is a diagram showing a manufacturing method by etching the detector of the present invention.

FIG. 7 is a diagram showing a manufacturing method by the same etching.

FIG. 8 is a diagram showing a manufacturing method by the same etching.

FIG. 9 is an external view showing another embodiment of the present invention.

FIG. 10 is a schematic circuit diagram showing another embodiment of the present invention.

FIG. 11 is a diagram showing an application example of another embodiment of the present invention.

[Explanation of symbols]

1 ... Detector coil part, 2 ... Tuning box, 3
... Connector, 4, 5, 6, 7 ... Electrode, 8, 9, 10 ... Capacitor, 11, 12, 13 ... Teflon, 14 ... Coil part of detector, 15 ... Case, 18, 19 ... Capacitor.

Continuation of the front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location 9118-2J G01N 24/06 Y 7621-2J G01R 33/22 N

Claims (8)

[Claims] 1. A combination of magnetic field means for applying a uniform static magnetic field to a subject and magnetic field means for producing a gradient magnetic field having different strengths depending on the position to generate a high frequency magnetic field for causing a nuclear magnetic resonance phenomenon in the subject. And a detector for detecting a nuclear magnetic resonance signal, an amplifier for amplifying the signal, a computer for performing arithmetic processing on the amplified signal, and a display means for displaying the arithmetically processed signal. As a detector,
An inspection apparatus using nuclear magnetic resonance, which is characterized by a structure in which an electrode plate is covered with Teflon (Teflon below fluororesin) to maintain a shape as a detector and has an appropriate bending strength, that is, elasticity. 2. The inspection apparatus using nuclear magnetic resonance according to claim 1, wherein a Teflon is sandwiched between the electrode plates to form a capacitor to form a resonance circuit of split tuning. 3. An inspection apparatus using nuclear magnetic resonance according to claim 1, wherein the Teflon is a fusion type Teflon as an adhesive and is bonded to a copper plate. 4. An inspection apparatus using nuclear magnetic resonance according to claim 3, wherein a copper plate or phosphor bronze bonded to Teflon is etched to form an electrode plate of the detector. 5. The inspection apparatus using nuclear magnetic resonance according to claim 4, wherein the circuit pattern of the preamplifier is also etched on the Teflon at the same time when the electrode plate is etched. 6. An inspection apparatus using nuclear magnetic resonance according to claim 1, wherein expanded Teflon is used as Teflon. 7. The detector according to claim 1, wherein the bending strength is made appropriate by appropriately adjusting the thickness or width of the electrode plate and the thickness of Teflon. Inspection device using magnetic resonance. 8. An inspection apparatus using nuclear magnetic resonance according to claim 1, wherein a flexible material such as a sponge is attached to the outside of the Teflon.