JP2016059435A - Headphone unit for mri - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a headphone unit having a good sound quality and mounted on an extremely narrow space between a gantry to be used for examining a head or the like with MRI and the head of a subject.SOLUTION: A diaphragm 2 which has an area larger than an area of a ceramic oscillator 1 is integrally attached in the sound emission direction, using a small-sized ceramic vibration element 1, and the back surface of the ceramic oscillator 1 is attached with a first noise control material which is molded by a sound absorption material having a characteristic of absorbing sound, and a characteristic of being deformed by receiving pressure, such as noise control urethane. The peripheries of the ceramic oscillator 1 and the diaphragm 2 are provided with a third noise control material and a fourth noise control materia 7 which are constituted in a doughnut shape by a sound absorption material, such as noise control urethane, so as to cover the peripheries of the ceramic oscillator 1 and the diaphragm 2.SELECTED DRAWING: Figure 1

Description

The present invention provides a one-way call and a two-way call between a subject who is diagnosed in a noisy environment of an MRI apparatus (Magnetic Resonance Imaging system) and a doctor (examiner) who operates the MRI apparatus. The present invention relates to an MRI (nonmagnetic) headphone unit worn by a subject.

In recent years, the diagnostic performance of MRI devices has been improved, and high-definition diagnostic images for advanced diagnosis have been obtained. Many hospitals (subjects) have been introduced every day as important devices in the medical field with the introduction of MRI devices in many hospitals. It is used for diagnosis.

As is well known, an MRI apparatus is an advanced apparatus capable of detecting and diagnosing a change in cells with a high-definition image by generating a high magnetic field and irradiating the affected area of a subject with a magnetic field.

  However, in order to obtain a high-definition image, a high magnetic field must be generated. In order to generate this high magnetic field, it is generated by intermittently applying a high voltage to the coil of the MRI apparatus. However, when a high voltage is intermittently applied to the coil, a large current flows through the coil, and at the same time a large noise is generated. Will occur.

    Since the current MRI apparatus is a system in which a large current is intermittently applied to the coil as described above, various efforts have been made to reduce this noise, but it is difficult to eliminate the noise at the present time.

    Diagnosis by MRI requires that the subject be diagnosed in such an MRI noise environment, and the normal diagnosis time is short, 15 minutes longer, and requires 30 to 40 minutes. During this time, the subject must be fixed and unable to move, and bear the burden of having to put up with noise, and the pain is unpredictable.

In addition, it has been proposed to install an MRI room monitor speaker in the conventional MRI apparatus room as a means for transmitting information from the doctor who is the examiner to the subject by voice. When the diagnosis of the MRI apparatus is stopped, the noise level is low and quiet, and the subject can hear the doctor's voice through the MRI room monitor speaker.

However, once the MRI system starts operation, the MRI noise level increases, and the doctor's instructions are masked by noise, making it difficult for the subject to hear the doctor's voice through the MRI room monitor speaker. It was.

Also, in a very loud noise, the examining doctor must ask the subject and give instructions such as `` Please relax '' or `` I will end soon '', but normal headphones are magnetic materials Therefore, it cannot be used with MRI because it adversely affects MRI images. For this reason, headphones made of non-magnetic material have been proposed, but due to the use of ceramic elements, there are disadvantages such as strong high sound and very difficult to hear.

In order to inspect the head and the like by MRI, a device called a gantry for fixing the subject's head is used, but there is only a very narrow space of about 10 mm between the gantry and the subject's head. Even when trying to use headphones with good sound quality, headphones with good sound quality are relatively thick, so headphones that fit in a narrow space could not be used.

JP 2005-245580 A JP 2006-148295 A

      According to the present invention, it is difficult to hear instructions from a doctor performing a test to a patient who is a subject due to noise generated during operation of the MRI apparatus, or mental compression such as claustrophobia caused by a subject being fixed in a narrow space. Even when sounds and music that calmed down to remove were played, there were drawbacks such as being masked by noise and very difficult to hear.

  In addition, headphones that the subject listens to must be put in the gantry that covers the head, but the gap between the inner surface of the gantry and the surface of the subject's skin is extremely narrow, about 10 mm, and normal headphones must be inserted. Was almost impossible.

  Japanese Patent Laid-Open No. 2005-245580 shown in Patent Document 1 describes a headphone worn by an MRI subject, and it is also proposed to use bone conduction. However, recent MRI increases the strength of the magnetic field in order to obtain a good image, and the gap between the subject and the gantry is set very narrow, so that the noise is further increased and the gap between the gantry and the subject is large. Because it is only about 10 mm, headphones with a normal structure are very difficult to push in even during this time, even if they use bone conduction, and the periphery of the human ear and the inner surface of the gantry are also curved. Therefore, the space is also curved, and it is almost impossible to insert headphones made of a hard material into this gap.

  In addition, headphones such as ceramics have been proposed for MRI. However, due to structural limitations, even if sound comes out, there is a drawback that it is biased to the high range and very difficult to hear, and the sound quality is good. A headphone that is easy to hear even under MRI noise has been desired.

In the head unit for MRI according to the invention of claim 1, the small ceramic vibrating element 1 is used, and the diaphragm 2 having an area larger than the area of the ceramic vibrator 1 is integrally attached in the sound emitting direction. On the back surface of the ceramic vibrator 1, a first soundproofing material 3 formed by a sound absorbing material having a property of absorbing sound such as soundproofing urethane and a property of deforming when subjected to pressure is attached. .
Further, a bent plate 4 made of a non-magnetic material such as flexible vinyl chloride and having a larger area than the first soundproof material is integrally attached to the back surface of the first soundproof material 3. .
Further, a second soundproofing material 5 made of soundproofing urethane or the like for enhancing the soundproofing effect is attached to the back surface of the bending plate 4 as a single body.
Around the ceramic vibrator 1 and the diaphragm 2, a third soundproof material 6 made of a sound absorbing material such as soundproof urethane is provided in a donut shape, and covers the circumference of the ceramic vibrator 1 and the diaphragm 2. It is configured as follows.

  Furthermore, in the sound emission direction of the third soundproof material 6, a fourth donut-shaped soundproof material 7 having an inner diameter smaller than that of the third soundproof material 6 is provided so that the diaphragm 2 can come into contact with the ear of the subject. When the headphone of the present invention is worn so that the subject can be examined by MRI, the ear of the subject can be heard from the hole provided in the central portion of the fourth soundproof material 7. It is inserted and configured to come into contact with the diaphragm 2.

When the listener's ear shell is inserted into the center hole, the fourth sound insulating material 7 covers the periphery of the ear shell and seals the periphery of the ear so that noise does not reach the listener. Is.
In the state where the listener's ear shell is inserted into the central hole of the fourth soundproof material 7 and listens, the ear shell and its surroundings are in direct contact with the diaphragm 1, and the vibration of the diaphragm is the ear shell. It will be transmitted directly to the listener through the contacted part.

  The head unit for MRI according to the invention of claim 2 is the ceramic resonator, diaphragm, bent plate, first soundproof material, second soundproof material, third soundproof material, and signal line of the invention of claim 1 All components are made of non-magnetic material, and all of them are made of non-magnetic material, so that they can be used in MRI with a high magnetic field, and the image quality of images taken with MRI. There is no adverse effect on the system.

  The headphone unit for MRI according to the invention of claim 3 presses the diaphragm against the ear from the outside of the second soundproof material, and the first to fourth soundproof materials and bent plates of the entire headphone. Is the one that presses against the ear from the outside of the second soundproof material located on the outermost side, so that the deformation due to the bending of the entire headphones can be used, and the inner shape of the gantry and the head of the subject The entire headphones bend according to the shape, and the gantry and the head of the subject can be worn in any state.

  The headphone unit for MRI according to the invention of claim 4 uses one having a different acoustic characteristic to be absorbed by the soundproofing material that is a component of the headphone, and the MRI noise that enters from outside by varying the frequency to be absorbed. A soundproof effect is effectively obtained by absorbing a place with high energy according to the frequency characteristics.

In the headphone unit for MRI according to the invention of claim 5, the first soundproofing material, the second soundproofing material, and the fourth soundproofing material, which are the components of the headphones, are made of urethane having a soundproofing effect, thereby providing soundproofing. The present invention provides a headphone that is excellent in effect and flexibility and can be inserted into a narrow space in a compressed state.

In the headphone unit for MRI according to the invention of claim 6, the headphone is sandwiched between the head of the subject and the inner wall of the gantry, and the shape of the head of the subject is bent by bending the soundproof material made of an elastic material. In addition, regardless of the shape of the inner wall of the gantry, the soundproofing effect against MRI noise and the transmission of voice signals can be satisfactorily performed.

In the headphone for MRI according to the invention of claim 7, the basic configuration is the same as that of the headphone of claim 1, but the headphone unit of claim 7 has a first diaphragm and a second diaphragm sandwiching a ceramic vibration element. The diaphragm is provided, and the vibration of the ceramic vibrating element is converted into sound efficiently by adjusting the acoustic characteristics by the two diaphragms, and a good sound is reproduced.

In the headphone unit for MRI according to the invention of claim 8, in the headphone of claim 7, the first diaphragm and the second diaphragm have different areas, respectively, and by making the areas different, resonance inherent to the diaphragm The frequency can be varied, and the frequency characteristics of the headphones can be adjusted by adjusting the area of each diaphragm as appropriate. It is something that can be done.

In the headphone unit for MRI according to the invention of claim 9, the thicknesses of the first and second diaphragms are made different, and the resonance frequency changes depending on the thickness, so the resonance frequencies of the two diaphragms Can be adjusted appropriately to obtain headphones having good frequency characteristics.

The headphone unit for MRI according to the invention of claim 10 is configured to make the materials of the first and second diaphragms of claim 7 different, and to make the resonance frequency of each diaphragm different depending on the material, A headphone having good frequency characteristics can be obtained, for example, by appropriately adjusting the resonance frequency of the two diaphragms to widen the band.

In the headphones of the present invention, the entire headphone unit is made of a non-magnetic material, and the constituents other than the ceramic vibrator 1 and the diaphragm are made of a deformable soundproofing material, and are made of a flexible material in between. By providing the bent version, the headphone shape is maintained in the non-wearing state, and when the subject wears in the MRI gantry, it corresponds to the shape of the subject's head and the inside of the gantry. Even if the shape inside the gantry differs for each manufacturer, it can be mounted.

In addition, since the diaphragm attached integrally with the ceramic vibrator 1 is in contact with at least a part of the subject's ear shell, it is possible to transmit the sound to the subject through the ear shell even under noise.

Furthermore, by surrounding the diaphragm with soundproofing material and surrounding the ear with soundproofing material, the noise generated by MRI can be cut off efficiently and synergistic with the effect of conducting through the earshell. Thus, the subject can listen to the doctor's instructions or listen to music that can be relaxed in a clear voice in an environment with relatively little noise.

In particular, by providing a second soundproofing material on the outer side of the bending plate and in contact with the inner wall of the gantry in a state where this part is compressed, it is possible to effectively prevent noise transmitted to the subject through the gantry. Is.

In addition, in the present invention, the ceramic vibrator 1 is attached to the diaphragm 2 so that a larger area is vibrated than when the small ceramic vibrator 1 is used alone as headphones, thereby improving sound quality. In addition, the sound pressure is also increased.

It is the Example of the unit regarding the headphones for MRI of this invention, (a) Sectional drawing, (b) Front view. It is the schematic which shows the use condition of the headphones for MRI of this invention. It is a figure which shows the communication state with the test subject in MRI. It is an operation | movement block diagram of the headphones for MRI. It is (a) sectional drawing and (b) front view in the other Example of the unit regarding the headphone for MRI of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a first embodiment of an MRI headphone according to the present invention, in which FIG. 1 (a) is a sectional view and FIG. 1 (b) is a front view of the headphone unit as viewed from the sound output side.
In the figure, reference numeral 1 denotes a small ceramic resonator element, and a diaphragm 2 having an area larger than the area of the ceramic resonator 1 is attached integrally with an adhesive or the like in the direction of sound emission. Is attached with a first soundproofing material 3 formed of a sound-absorbing material having a characteristic of absorbing sound such as soundproofing urethane and a characteristic of deforming when subjected to pressure.
Furthermore, the back surface of the first soundproof material 3 is composed of a non-magnetic material such as vinyl chloride having flexibility, and a bent plate 4 having an area larger than that of the first soundproof material is integrally attached thereto. A second soundproofing material 5 made of a material such as soundproofing urethane for enhancing the soundproofing effect is integrally attached to the back surface of the bent plate 4.

This bending plate 4 has rigidity capable of maintaining the shape of the entire headphones, and is deformed to fit the space between the inside of the gantry and the subject's head when the headphones are mounted in the gantry. It has the characteristic to do.
Around the ceramic vibrator 1 and the diaphragm 2, a third donut-shaped soundproofing material 6 made of a sound absorbing material such as soundproof urethane is provided to cover the circumference of the ceramic vibrator 1 and the diaphragm 2. It is configured as follows.

Further, in the sound emitting direction of the third soundproofing material 6, a fourth donut-shaped soundproofing material having an inner diameter smaller than that of the third soundproofing material 6 having a hole with a size enough to allow insertion of the ear of the subject. 7 is affixed integrally with the third soundproof material 6, and a hole provided in the center of the fourth soundproof material 7 when the subject wears the headphones of the present invention in order to be examined by MRI. The ears of the subject are inserted and come into contact with the diaphragm 2.

When the listener's ear is inserted into the center hole, the fourth soundproofing material 7 covers the periphery of the ear by the third soundproofing material 6 and the fourth soundproofing material 5, and MRI noise passes through the space. It is soundproof so that it does not reach the listener.

Further, when the listener's ear is inserted from the center hole of the fourth soundproof material 7, the listener's ear shell is in direct contact with the diaphragm 1, and the vibration of the ceramic vibrator 1 is caused by the diaphragm. 2 is transmitted to the ear shell in contact in an amplified form, and is transmitted directly to the listener through the portion of the ear shell in contact with the diaphragm.

In this embodiment, the first soundproofing material 3 and the fourth soundproofing material 7 are separately made and assembled, but the first soundproofing material 3 and the fourth soundproofing material are integrally molded, The ceramic vibrator 1 and the diaphragm 2 may be attached after molding.
In addition, in order to efficiently absorb the MRI noise and enhance the soundproofing effect, each of the first to fourth soundproofing materials or a part thereof is made of a material having different soundproofing characteristics, thereby enabling more effective listening. It is also possible to provide sound insulation for the person.
The material of diaphragm 2 can be selected from materials that are suitable for obtaining desired acoustic characteristics such as sound quality improvement, such as paper, plastic, carbon fiber sheet, etc. Is.

FIG. 2 is a view conceptually showing a state in which the subject inserts the head 11 into the gantry 9 and places the head 11 on the headrest 10, and the gantry 9 shows only half of its cross section. . The space between the head 11 and the gantry 9 is a very narrow space, which is only about 10 mm, and shows the state in which the headphones of the present invention are compressed and mounted between them, as shown in FIG. The earlobe is inserted through the central hole provided in the fourth soundproofing material 7 of the headphone, and the whole headphone is compressed and bent into an arc-shaped space between the inside of the gantry 9 and the side surface of the head 11 This indicates that it is attached.

The internal shape of the gantry 9 is shown in an arc shape in the figure, but it differs depending on the model of MRI. Depending on the internal shape of the gantry 9, the gap between the head 11 and the lower side of the figure is wide, Some have a trapezoidal shape with a narrow upper side.
In the headphones of the present invention, the entire headphone unit is configured by the flexible sound absorbing material and the bent plate 4, so that all the headphone units are formed regardless of the shape of the space formed by the gantry 9 and the head 11 of the subject. It can correspond to the model.

The one shown in FIG. 3 is an outline of MRI, in which a subject 15 is sleeping on a moving bed (examination table), and in this state, moves into the MRI apparatus 14 to shoot an image. is there.
The subject 15 wears headphones 17 on the head in the gantry and wears a microphone 16 provided at a position where the subject's voice can be picked up so as to be able to communicate, and is magnetically shielded with an MRI installed. And a person who conducts an examination such as a doctor from the outside of the room gives an instruction to the subject 15 with the microphone 20, and a response from the subject 15 is picked up with the microphone 16 and output from the speaker 19 as a sound. It is.

4 is a schematic block diagram showing an electric circuit of a headphone used for the MRI in FIG. 3. As a sound source, a sound source 23a for listening to music to a subject, a device 23b for listening to sound for examination, There is an inspection microphone 23c and the like, and an audio signal is supplied to the headphones 17 through an equalizer 22 and an amplifier 21 for obtaining acoustic characteristics adapted to each.

FIG. 5 shows another embodiment of the headphone of the present invention. As in FIG. 1, (a) is a side sectional view, and (b) is a front view of the headphone unit as viewed from the sound emission side. FIG.
In this embodiment, the configurations of the first soundproof material 3a to the fourth soundproof material 7a and the configuration of the bent plate 4a are the same as those shown in FIG. The soundproofing material 5a is a second soundproofing material.
In the figure, the ceramic vibrator 1a is composed of a first diaphragm 2a integrally attached to the sound emitting side with an adhesive or the like, and a second diaphragm 2b integrally attached to the back side of the ceramic vibrator 1a. The vibration part is configured, and the area of the second diaphragm 2b is larger than the area of the first diaphragm 2a.

In this embodiment, the ceramic vibrator 1a is sandwiched between two diaphragms, and the areas of the first and second diaphragms are different, so that the resonance frequency of each diaphragm is different, By appropriately changing the area of each diaphragm, the acoustic characteristics can be adjusted, such as making the frequency characteristics of the reproduced sound wide, and headphones with better sound quality can be provided.
Furthermore, the reproduced sound can be tuned to the optimum by changing the material of the first and second diaphragms or changing the thickness.

 The present invention is most suitable when communication is required between a subject and a doctor who performs an examination under high noise, such as an MRI apparatus, and can be used for industries such as manufacturing MRI.

1: Ceramic vibration element 2: Diaphragm 3: First soundproof material 4: Bending plate 5: Second soundproof material 6: Third soundproof material 7: Fourth soundproof material 8: Signal line 9: Gantry 10: Headrest 11: Subject's head 12: Subject's earlobe 13: Wearing headphone 14: MRI device 15: Subject 16: Microphone 17: Headphone 18: Bulkhead 19: Speaker 20: Microphone 21: Amplifier 22: Equalizer 23a: Sound source 23b : Audio device 23c: Microphone for inspector
2a: First diaphragm
2b: Second diaphragm

Claims (11)

A ceramic vibration element, a vibration plate made of a nonmagnetic material having a larger vibration area than the ceramic vibration element, a first soundproofing material disposed on the back surface of the vibration plate, and further having flexibility provided on the back surface A hole is formed in the center consisting of a bent plate, a third soundproofing material provided on the outer periphery of the diaphragm so as to cover the ceramic vibrating element and the whole diaphragm, and a sound absorbing material provided in the sound emission direction of the diaphragm. An MRI headphone unit comprising: a fourth soundproof material having a second soundproof material provided on a back surface of the bent plate and configured to cover the entire bent plate. . 2. The headphone for MRI according to claim 1, wherein the ceramic vibrator, the diaphragm, the bent plate, the first soundproof material, the second soundproof material, and the third soundproof material are all made of a nonmagnetic material. unit. 3. The head unit for MRI according to claim 1, wherein the diaphragm is pressed against the ear from the outside of the second soundproofing material. Of the first soundproofing material, the second soundproofing material, and the fourth soundproofing material, at least the first soundproofing material and the second soundproofing material are composed of materials having different sound frequency bands, respectively. The head unit for MRI according to any one of claims 1 to 3. 5. The MRI headphone unit according to claim 1, wherein the first soundproof material, the second soundproof material, and the fourth soundproof material are made of urethane. 7. The MRI headphone unit according to claim 1, which is mounted in an MRI gantry, is sandwiched between an ear of a subject and an inner wall of the gantry, and is pressed against the ear of the subject. A ceramic vibration element connected to a signal line made of a non-magnetic material for supplying an electric signal; a first vibration plate made of a non-magnetic material having a surface area larger than that of the ceramic vibration element and bonded integrally with the ceramic vibration element; The second diaphragm is disposed so as to sandwich the ceramic vibration element together with the first diaphragm, and is bonded integrally with the ceramic vibrator, and the first and second are disposed on the back surface of the second diaphragm. A first soundproof material having an outer periphery larger than the outer periphery of the diaphragm, a bent plate made of a nonmagnetic material having flexibility provided on the back surface of the first soundproof material, and a further back surface of the bent plate A second soundproofing material provided with a sound absorbing material and a vibration plate provided on the sound emission side of the first soundproofing material, the first vibration plate, the ceramic element, and the second vibration plate bonded together Slightly thicker than the unit thickness A third sound absorber made of a donut-shaped sound absorber having a hole capable of accommodating the diaphragm unit in the center, and an inner diameter smaller than the inner diameter of the third sound absorber, provided on the sound emission side of the third sound absorber. A headphone unit for MRI made of a non-magnetic material, characterized in that it comprises a fourth soundproofing material made of a soundproofing material and has a first diaphragm pressed against a listener's ear. 2. The head unit for MRI according to claim 1, wherein the first diaphragm and the second diaphragm have different areas and have different resonance frequencies. 2. The head unit for MRI according to claim 1, wherein the first diaphragm and the second diaphragm have different thicknesses and different resonance frequencies. 2. The head unit for MRI according to claim 1, wherein the first and second diaphragms are made of different materials and have different resonance frequencies. In a headphone unit having a sound generator comprising a ceramic vibrator and a diaphragm integrally provided with the ceramic vibrator, a sound absorbing member having a space surrounding the sound generator and into which an earshell is inserted in a worn state on a sound emitting side An MRI headphone unit comprising: a soundproof body made of a material; a bent plate made of a flexible material provided on a back surface of the soundproof body; and a soundproof material provided on a back surface of the bent plate.

Images