JP2011024803A - Medical image diagnostic apparatus and magnetic resonance imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To readily and reliably suppress noise generated when capturing a medical image. <P>SOLUTION: The exterior of a rack apparatus includes: an exterior member 2 of high vibration transmission; and a piezoelectric element 3 which vibrates the exterior member 2 to generate sound from the exterior member 2. A noise storage unit 34a stores, for each of sequence information in capturing a magnetic resonance image, data of noise generated inside the rack apparatus 10 when performing imaging by a pulse sequence based on the sequence information. An input unit 36 receives sequence information on an image-capturing condition for capturing the magnetic resonance image from an operator. A control unit 37 obtains from the noise storage unit 34a data of noise corresponding to the sequence information transferred from the input unit 35 and transmits the data of noise to a vibration generation unit 15 via an interface unit 31. The vibration generation unit 15 applies to the piezoelectric element 3 an opposite phase noise voltage signal for generating vibration of a phase opposite the phase of the received data of noise. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a medical image diagnostic apparatus and a magnetic resonance imaging apparatus.

  Conventionally, in imaging using a medical image diagnostic apparatus such as an X-ray computed tomography apparatus (hereinafter referred to as X-ray CT apparatus, CT; Computed Tomography) or a magnetic resonance imaging (MRI) apparatus, it is moved into a gantry apparatus. A medical image is generated by collecting data from the subject.

  Specifically, in imaging by an X-ray CT apparatus, an X-ray CT image is generated by collecting projection data of X-rays that have passed through a subject with a gantry apparatus. Further, in imaging by an MRI apparatus, a high-frequency magnetic field and a gradient magnetic field are generated based on a pulse sequence corresponding to imaging conditions, and thereby magnetic resonance signals generated from the subject are collected by a gantry device, thereby obtaining a magnetic resonance image. Is generated.

  By the way, in the gantry device, noise is generated due to a mechanical operation or electromagnetic force at the time of data collection. Therefore, it is necessary to suppress the noise so as not to cause discomfort to the subject.

  Therefore, by constructing the exterior of the gantry device with sound-absorbing material, the method of using the exterior of the gantry device as a soundproof wall and the sound of the opposite phase of the noise generated by the gantry device are generated from the speaker installed outside the gantry device. The method of making it known is known.

  However, the method of using the exterior of the gantry device as a soundproof wall can suppress high-frequency components but cannot suppress low-frequency components. In addition, the method of generating an anti-phase sound from a speaker installed outside the gantry device may obtain a high noise suppression effect, but the degree of the noise suppression effect often depends on the spatial position, Some positions do not have a noise suppression effect. In particular, the method of generating a sound of opposite phase from a speaker installed outside the gantry device has a large influence on the spatial position in the low-frequency component for which noise is to be suppressed, but the position of the subject in the gantry device is the imaging region. Because it changes depending on the noise, it could not be an effective noise suppression method.

  On the other hand, in the MRI apparatus, it is known that a main noise source in the gantry apparatus is a vibration of a gradient magnetic field coil that generates a gradient magnetic field based on a pulse sequence. For this reason, there is known an MRI apparatus that attaches a piezoelectric element to a gradient magnetic field coil and generates vibration from the piezoelectric element that cancels the vibration of the gradient magnetic field coil (see, for example, Patent Document 1).

  There is also known an MRI apparatus in which a vibrator is attached to a bed on which a subject is placed and a vibration that cancels the vibration of the gradient magnetic field coil is generated from the vibrator (for example, see Patent Document 2).

JP-A-8-257008 JP 2008-220647 A

  By the way, in the technique for suppressing the vibration of the gradient magnetic field coil by the piezoelectric element attached to the gradient magnetic field coil, it is necessary to separately install a power supply device for applying a voltage to the piezoelectric element attached to the gradient magnetic field coil. Further, in the technology for suppressing the vibration caused by the generation of the gradient magnetic field by the vibrator attached to the bed, since the gradient magnetic field coil is also present on the upper part of the subject, the noise generated from the upper part of the gantry device is suppressed. I could not.

  That is, the above-described conventional technique has a problem that it is not possible to easily and reliably suppress noise generated when a magnetic resonance image is captured.

  In addition, since the above-described conventional technique is specialized for vibration generated by the gradient magnetic field coil during imaging of the MRI apparatus and noise caused by the vibration, generally noise generated during imaging of medical images is suppressed. It wasn't something to do.

  Therefore, the present invention has been made to solve the above-described problems of the prior art, and a medical image diagnostic apparatus and a magnetic resonance device that can easily and reliably suppress noise generated when taking a medical image. An object is to provide an imaging apparatus.

  In order to solve the above-described problems and achieve the object, the present invention according to claim 1 is a medical image diagnostic apparatus that collects data from a subject moved into a gantry and generates a medical image. A part or all of the exterior of the gantry device is made of a material having a high vibration transmission property, a vibration element that vibrates the material having a high vibration transmission property, and a phase opposite to the phase of the sound generated in the gantry device. Vibration generating means for generating the above vibration in the vibration element.

  According to a seventh aspect of the present invention, there is provided a magnetic resonance imaging apparatus for generating a magnetic resonance image by collecting magnetic resonance signals from a subject moved into the gantry apparatus, and a part of the exterior of the gantry apparatus Alternatively, all are made of a material having a high vibration transmission property, and a vibration element that vibrates the material having a high vibration transmission property and a vibration having a phase opposite to the phase of the sound generated in the gantry device are generated in the vibration element. And a vibration generating means.

  According to the first or seventh aspect of the present invention, it is possible to easily and reliably suppress the noise generated when taking a medical image.

FIG. 1 is a diagram for explaining the configuration of the MRI apparatus according to the first embodiment. FIG. 2 is a view for explaining the exterior of the gantry device. FIG. 3 is a view for explaining the configuration of the opening exterior. FIG. 4 is a diagram for explaining the configuration of the vibration generating unit according to the first embodiment. FIG. 5 is a diagram for explaining the noise storage unit. FIG. 6 is a diagram for explaining noise suppression by the vibration generating unit. FIG. 7 is a diagram for explaining a vibration generating unit according to the second embodiment. FIG. 8 is a diagram for explaining the intercom function by the vibration generating unit. FIG. 9 is a diagram for explaining a vibration generating unit according to the third embodiment. FIG. 10 is a diagram for explaining a vibration correction function by the vibration generator. FIG. 11 is a diagram for explaining a vibration generating unit according to the fourth embodiment. FIG. 12 is a diagram for explaining a modification.

  Exemplary embodiments of a medical image diagnostic apparatus and a magnetic resonance imaging apparatus according to the present invention will be described below in detail with reference to the accompanying drawings. In the following, a magnetic resonance imaging apparatus according to the present invention will be described as an example. Hereinafter, a magnetic resonance imaging apparatus is referred to as an “MRI apparatus”.

  First, the configuration of the MRI apparatus in the first embodiment will be described. FIG. 1 is a diagram for explaining the configuration of the MRI apparatus according to the first embodiment. As shown in FIG. 1, the MRI apparatus 100 according to the present embodiment includes a gantry device 10, a bed 20, a top plate 21, a bed control unit 22, a gradient magnetic field power supply 23, a transmission unit 24, and a reception unit 25. And a computer system 30.

  The gantry device 10 is provided with an opening in which the subject P is inserted in the front surface and collects magnetic resonance signal data from the subject P inserted into the opening. The magnetic field coil 12, the transmission RF coil 13, the reception RF coil 14, and the vibration generator 15 are included.

  The static magnetic field magnet 11 is a magnet that generates a uniform static magnetic field in the internal space. For example, when a superconducting magnet or the like is used, it is mainly formed in a hollow cylindrical shape. Etc. are also used.

  The gradient coil 12 is disposed inside the static magnetic field magnet 11. In the case of the most commonly used hollow cylindrical shape, the gradient coil 12 is similarly molded into a hollow cylindrical shape. The gradient magnetic field coil 12 is formed by combining three coils corresponding to the X, Y, and Z axes orthogonal to each other, and these three coils individually supply current from a gradient magnetic field power source 23 described later. In response, a gradient magnetic field whose magnetic field intensity changes along each of the X, Y, and Z axes is generated. The Z-axis direction is the same as the static magnetic field.

  Further, the gradient magnetic fields of the X, Y, and Z axes generated by the gradient magnetic field coil 12 correspond to, for example, the slice selection gradient magnetic field Gs, the phase encoding gradient magnetic field Ge, and the frequency encoding gradient magnetic field Gr, respectively. The slice selection gradient magnetic field Gs is used to arbitrarily determine an imaging section. The phase encoding gradient magnetic field Ge is used to change the phase of the magnetic resonance signal in accordance with the spatial position. The frequency encoding gradient magnetic field Gr is used to change the frequency of the magnetic resonance signal in accordance with the spatial position.

  The transmission RF coil 13 is a coil disposed inside the gradient magnetic field coil 12, and generates a high-frequency magnetic field by a high-frequency pulse supplied from the transmission unit 24.

  The reception RF coil 14 is a coil disposed inside the gradient magnetic field coil 12 and receives a magnetic resonance signal radiated from the subject P due to the influence of the high-frequency magnetic field. When receiving the magnetic resonance signal, the reception RF coil 14 outputs the received magnetic resonance signal to the receiving unit 25.

  The vibration generating unit 15 is a circuit that generates vibration for the exterior of the gantry device 10. The vibration generator 15 will be described in detail later.

  The couch 20 is a device that includes a couchtop 21 on which the subject P is placed. Under the control of the couch control unit 22, the couchtop 20 is placed on the gantry 10 with the subject P placed thereon. Into the opening (inside the cavity of the gradient coil 12). The bed 20 is installed such that its longitudinal direction is parallel to the central axis of the static magnetic field magnet 11.

  The couch controller 22 is a device that controls the movement of the couch 20 and drives the couch 20 to move the top plate 21 in the longitudinal direction and the vertical direction.

  The gradient magnetic field power supply 23 is a device that supplies a current to the gradient magnetic field coil 12 based on a pulse sequence sent from the computer system 30. The gradient magnetic field coil 12 uses a current supplied from the gradient magnetic field power supply 23 to generate a pulse sequence. A gradient magnetic field corresponding to

  The transmission unit 24 is a device that transmits a high-frequency pulse corresponding to the Larmor frequency to the transmission RF coil 13 based on a pulse sequence transmitted from the computer system 30, and includes an oscillation unit, a phase selection unit, a frequency conversion unit, and an amplitude modulation unit. And a high-frequency power amplifier.

  The oscillation unit generates a high-frequency signal having a resonance frequency unique to the target nucleus in the static magnetic field. The phase selection unit selects the phase of the high-frequency signal. The frequency conversion unit converts the frequency of the high-frequency signal output from the phase selection unit. The amplitude modulation unit modulates the amplitude of the high-frequency signal output from the frequency modulation unit according to, for example, a sinc function. The high frequency power amplification unit amplifies the high frequency signal output from the amplitude modulation unit. As a result of the operation of each of these units, the transmission unit 24 transmits a high-frequency pulse corresponding to the Larmor frequency to the transmission RF coil 13.

  The receiving unit 25 is a device that generates magnetic resonance signal data by frequency-converting and A / D converting the magnetic resonance signal output from the reception RF coil 14 based on the pulse sequence sent from the computer system 30. The generated magnetic resonance signal data is transmitted to the computer system 10.

  The computer system 30 is a device that performs overall control of the MRI apparatus 100, data collection, image reconstruction, and the like. As shown in FIG. 1, an interface unit 31, a data collection unit 32, a data processing unit 33, A storage unit 34, an output unit 35, an input unit 36, and a control unit 37 are included.

  The interface unit 31 is connected to the vibration generation unit 15, the bed control unit 22, the gradient magnetic field power supply 23, the transmission unit 24, and the reception unit 25 of the gantry device 10, and between these connected units and the computer system 30. A processing unit that controls input / output of signals to be exchanged.

  The data collection unit 32 collects the magnetic resonance signal data transmitted from the reception unit 25 via the interface unit 31, and arranges the collected magnetic resonance signal data in the k space to obtain k space data. It is. Then, the data collection unit 32 stores the k space data in the storage unit 34.

  The data processing unit 33 is a processing unit that reconstructs image data (magnetic resonance image) by performing post-processing, that is, reconstruction processing such as Fourier transform, on k-space data stored in the storage unit 34.

  The storage unit 34 is a storage unit that stores, for each subject P, k-space data received from the data collection unit 32, magnetic resonance images reconstructed by the data processing unit 33, and the like.

  Moreover, although the memory | storage part 34 memorize | stores the data used for the process of the vibration generation part 15 mentioned later, this is explained in full detail later.

  The output unit 35 includes a monitor such as a CRT (Cathode Ray Tube) display or a liquid crystal display that displays various information such as a magnetic resonance image, a microphone that outputs sound emitted by an operator, and the like under the control of the control unit 37.

  The input unit 36 receives various operations and information inputs from an operator, has a mouse, a trackball, a keyboard, and the like, and cooperates with the output unit 35 to provide a user interface for receiving various operations as the MRI apparatus 100. Provide to the operator. The input unit 36 receives information for controlling the operation of the vibration generating unit 15 from the operator. This will be described in detail later.

  The control unit 37 is a processing unit that has a CPU, a memory, and the like (not shown) and controls the MRI apparatus 100 in a comprehensive manner.

  For example, the control unit 37 generates pulse sequence information (sequence information) based on the imaging conditions input from the operator via the input unit 36, and the generated sequence information is input to the gradient magnetic field via the interface unit 31. Transmission to the power source 23, the transmission unit 24, and the reception unit 25 causes the magnetic resonance image to be captured. The control unit 37 controls processing performed by the data processing unit 33. Further, the control unit 37 controls screen display in the output unit 35. The control unit 37 controls the vibration generating unit 15 via the interface unit 31, which will be described in detail later.

  As described above, the MRI apparatus 100 according to the first embodiment collects magnetic resonance signal data from the subject moved into the gantry device 10 and generates a magnetic resonance image. The exterior of the gantry device 10 will be described below. In addition, the main feature is that noise generated during imaging of a magnetic resonance image can be easily and reliably suppressed by installing the vibration generating unit 15. This main feature will be described with reference to FIGS. 2 is a diagram for explaining the exterior of the gantry device, FIG. 3 is a diagram for explaining the configuration of the opening exterior, and FIG. 4 is the configuration of the vibration generating unit in the first embodiment. FIG. 5 is a diagram for explaining the noise storage unit, and FIG. 6 is a diagram for explaining noise suppression by the vibration generating unit.

  First, as shown in FIG. 2, the exterior of the gantry device 10 according to the first embodiment is divided into a plurality of parts such as a front surface exterior and an opening exterior. For example, when the opening of the gantry device 10 has a length of “150 cm” in the insertion direction of the subject P, the opening of the gantry device 10 is configured in a form in which three 50 cm long opening exteriors are arranged. .

  Here, as shown in FIG. 3, the opening exterior includes a frame 1, an exterior material 2, and a piezo element 3. In FIG. 3, the shapes of the frame 1, the exterior material 2, and the piezo element 3 are respectively shown as rectangles, but actually, these shapes are curved according to the shape of the opening exterior.

  The exterior material 2 is made of, for example, a honeycomb sandwich material having a high vibration transmission property, and the frame 1 is an outer frame in which the exterior material 2 is incorporated. The piezo element 3 is a piezoelectric element that vibrates the exterior material 2 and is molded, for example, in a shape that covers the inside of the exterior material 2 as shown in FIG. The exterior material 2 comes into contact with the piezo element 3 by being attached to the frame 1.

  The vibration generating unit 15 applies a voltage to the piezo element 3 to generate a vibration having a phase opposite to the phase of the sound generated in the gantry device 10 in the piezo element 3. Sound is generated by the vibration generated.

  Here, in order to cause the piezo element 3 to generate a vibration having a phase opposite to that of the sound generated in the gantry device 10, the storage unit 34 according to the first embodiment includes a noise storage unit 34 a as illustrated in FIG. 4. .

  The noise storage unit 34a stores sound generated in the gantry device 10 for each imaging condition when imaging a magnetic resonance image. Specifically, when the noise storage unit 34a executes imaging with a pulse sequence (for example, Echo Planar Imaging, Fast Field Echo, etc.) based on the sequence information for each sequence information when imaging a magnetic resonance image. The noise data generated in the gantry device 10 is stored in For example, as illustrated in FIG. 5, the noise storage unit 34 a stores, as “D1”, noise data generated inside the gantry device 10 when “sequence information: 1” is executed. Similarly, the noise storage unit 34a stores noise data corresponding to “sequence information: 2” as “D2”, and stores noise data corresponding to “sequence information: 3” as “D3”.

  Here, the noise data is recorded in the noise storage unit 34a by recording in advance the noise generated inside the gantry device 10 when photographing based on each sequence information is performed by a sound collecting microphone installed in the opening. Stored. Note that the noise data may be recorded individually by each sound collecting microphone installed at each position where the opening exterior is attached. For example, if the opening exterior is divided into three, the noise data “D1” corresponding to “sequence information: 1” is “D1-1, D1-2, D1” for each position of the opening exterior. -3 "and stored in the noise storage unit 34a.

  Returning to FIG. 4, the input unit 36 receives sequence information of imaging conditions for imaging a magnetic resonance image from the operator of the MRI apparatus 100, and the control unit 37 corresponds to the sequence information transferred from the input unit 36. Noise data is acquired from the noise storage unit 34a.

  Then, the control unit 37 transmits the noise data acquired from the noise storage unit 34 a to the vibration generating unit 15 in the gantry device 10 via the interface unit 31.

  When receiving an imaging start request for magnetic resonance images from the operator, the control unit 37 transmits the Siemens information to the gradient magnetic field power source 23, the transmission unit 24, and the reception unit 25 to start imaging, and the vibration generation unit 15 The process based on the noise data acquired from the noise storage unit 34a is started. In addition, the vibration generation part 15 is installed for every exterior of the divided gantry device 10.

  As shown in FIG. 4, the vibration generating unit 15 includes an AudioCODEC 15a, a DSP 15b, a DAC 15c, an AGC 15d, and an amplifier 15e.

  The AudioCODEC 15a receives the noise data acquired from the noise storage unit 34a, performs frequency analysis on the received noise data, and converts it into noise digital data.

  The DSP 15b is a processor (Digital Signal Processor) for processing a digital signal, and generates noise digital data with reverse phase (hereinafter referred to as anti-phase noise digital data) by inverting the noise digital data received from the AudioCODEC 15a. To do.

  The DAC 15c is a D / A converter that converts a digital signal into an analog signal, and converts the anti-phase noise digital data received from the DSP 15b into analog data of voltage level (hereinafter referred to as an anti-phase noise voltage signal).

  The AGC 15d is a device (Auto Gain Control) that adjusts the gain of the antiphase noise voltage signal received from the DAC 15c.

  The AudioCODEC 15a adjusts the voltage level of the anti-phase noise voltage signal after gain adjustment received from the AGC 15d.

  The amplifier 15e amplifies the anti-phase noise voltage signal whose voltage level has been adjusted received from the Audio CODEC 15a, and applies the amplified anti-phase noise voltage signal to the piezo element 3.

  As a result, the vibration generating unit 15 generates vibration in the piezo element 3 with a phase opposite to the phase of the noise data estimated to be generated in the gantry device 10, and the exterior material 2 is generated by the vibration of the piezo element 3. Generates noise in the opposite phase to the phase of the noise data. That is, as shown in FIG. 6, the estimated noise in the gantry device is canceled by the antiphase noise generated from the exterior material 2, thereby suppressing the noise generated in the gantry device 10 during photographing.

  As described above, in the first embodiment, the exterior of the gantry device 10 (in this embodiment, the opening exterior) is made from the exterior material 2 having high vibration transmission and the exterior material 2 by vibrating the exterior material 2. And a piezo element 3 for generating And the noise memory | storage part 34a memorize | stores the noise data which generate | occur | produce inside the gantry 10 when imaging | photography is performed by the pulse sequence based on the said sequence information for every sequence information at the time of imaging | photography of a magnetic resonance image.

  The input unit 36 receives sequence information of imaging conditions for imaging a magnetic resonance image from the operator, and the control unit 37 acquires noise data corresponding to the sequence information transferred from the input unit 36 from the noise storage unit 34a. This is transmitted to the vibration generating unit 15 via the interface unit 31. Then, the vibration generating unit 15 applies to the piezo element 3 an anti-phase noise voltage signal for generating vibration having a phase opposite to the phase of the received noise data.

  Therefore, in the first embodiment, an area in which the subject P is taken in the exterior of the gantry device 10 is provided with an acoustic effect without separately installing a power source for suppressing the vibration of the gradient magnetic field coil 12 during imaging of the MRI apparatus 100. It is configured as a high speaker, and noise having a phase opposite to that estimated to be generated at the time of imaging can be generated from the entire exterior material 2 to the subject P. As described above, at the time of imaging a magnetic resonance image The generated noise can be easily and reliably suppressed.

  In the second embodiment, the case where the vibration generating unit 15 described in the first embodiment is used as an intercom between the operator and the subject P will be described with reference to FIGS. 7 and 8. FIG. 7 is a diagram for explaining a vibration generating unit in the second embodiment, and FIG. 8 is a diagram for explaining an intercom function by the vibration generating unit.

  In the second embodiment, as in the first embodiment, the noise data acquired from the noise storage unit 34a is transmitted to the vibration generating unit 15, but the instruction voice data designated by the operator or the operator outputs the output data. Instruction voices uttered to the 35 microphones are also transmitted to the vibration generator 15.

  Specifically, as shown in FIG. 7, the storage unit 34 includes an instruction voice data storage unit 34 b together with a noise storage unit 34 a, and the instruction voice data storage unit 34 b indicates the state of the subject P. Instruction voice data to be stored is stored. For example, the instruction voice data storage unit 34b stores instruction voice data such as “Please hold your breath” and “Please breathe slowly”.

  The control unit 37 acquires the instruction voice data designated by the operator through the input unit 36 from the instruction voice data storage unit 34b, and transmits the acquired voice instruction data to the vibration generation unit 15 through the interface unit 31. To do. Alternatively, as illustrated in FIG. 7, the control unit 37 transmits an instruction voice uttered by the operator to the microphone of the output unit 35 to the vibration generating unit 15 via the interface unit 31.

  Here, when processing the noise data, the vibration generating unit 15 according to the second embodiment generates the antiphase noise digital data in the DSP 15b under the control of the control unit 37. However, when the vibration generating unit 15 in the second embodiment processes the voice instruction data acquired from the storage unit 34b or the instruction voice uttered by the operator to the microphone of the output unit 35, the control of the control unit 37 The following processing is executed.

  That is, the AudioCODEC 15a performs frequency analysis on the received instruction voice and converts it into instruction voice digital data.

  When the DSP 15b receives the instruction voice digital data from the AudioCODEC 15a, the DSP 15b transmits the instruction voice digital data to the DAC 15c as it is. The DAC 15c converts the instruction voice digital data received from the DSP 15b into analog data at a voltage level (hereinafter referred to as an instruction voice voltage signal).

  The AGC 15d adjusts the gain of the instruction voice voltage signal received from the DAC 15c, the Audio CODEC 15a adjusts the voltage level of the instruction voice voltage signal after gain adjustment received from the AGC 15d, and the amplifier 15e has adjusted the voltage level received from the Audio CODEC 15a. The instruction voice voltage signal is amplified and the amplified instruction voice voltage signal is applied to the piezo element 3.

  As a result, the vibration generating unit 15 generates noise having a phase opposite to the phase of the noise data from the exterior material 2 and generates an instruction voice of the operator from the exterior material 2. That is, as shown in FIG. 8, the estimated noise in the gantry device is canceled by the antiphase noise generated from the exterior material 2, and further, the instruction voice is generated from the exterior material 2 together with the antiphase noise, thereby The noise can be almost only the instruction voice.

  As described above, in the second embodiment, the vibration generating unit 15 applies the instruction sound voltage signal to the piezo element 3 together with the anti-phase noise voltage signal, so that the anti-phase noise and the instruction sound are output from the exterior material 2. Can be generated, the noise generated when the magnetic resonance image is taken can be suppressed, and the subject P can clearly hear the instruction from the operator.

  In the third embodiment, a case where the vibration generated by the vibration generating unit 15 in the piezo element 3 is corrected will be described with reference to FIGS. 9 and 10. FIG. 9 is a diagram for explaining a vibration generation unit in the third embodiment, and FIG. 10 is a diagram for explaining a vibration correction function by the vibration generation unit.

  The vibration generating unit 15 in the third embodiment has the noise suppression function using the noise data described in the first and second embodiments and the intercom function described in the second embodiment. Further, the exterior material shown in FIG. 2 has a correction function using noise collected by the external sound collecting microphone 5 attached to the outside.

  The external sound collecting microphone 5 is a piezo microphone made from a piezo element, and is attached to the outside of the exterior material 2 via a rubber 6 for preventing vibration of the exterior material 2 from being transmitted as shown in FIG. It has been. The external sound collecting microphone 5 collects noise generated outside the gantry device 10 and converts it into a voltage signal (hereinafter referred to as an external noise voltage signal).

  In addition to the Audio CODEC 15a, DSP 15b, DAC 15c, AGC 15d, and amplifier 15e described in the first and second embodiments, the vibration generator 15 according to the third embodiment includes an amplifier 15f as shown in FIG. And AGC15g and DAC15h. The Audio CODEC 15a, the DSP 15b, the DAC 15c, the AGC 15d, and the amplifier 15e perform the same processing described in the first and second embodiments on the noise data and the instruction voice, and thus the description thereof is omitted.

  First, the amplifier 15f amplifies the external noise voltage signal converted by the external sound collecting microphone 5. Then, the AGC 15g adjusts the gain of the amplified external noise voltage signal received from the amplifier 15f. Then, the AudioCODEC 15a performs frequency analysis on the gain-adjusted external noise voltage signal received from the AGC 15g and converts it into external noise digital data.

  The DSP 15b according to the third embodiment generates corrected digital data obtained by correcting the anti-phase noise digital data that has already been generated, using the external noise digital data received from the AudioCODEC 15a.

  For example, as shown in FIG. 10, the DSP 15b generates reverse phase external noise digital data obtained by inverting the phase of the external noise digital data. Then, as shown in FIG. 10, the DSP 15 b generates corrected digital data by adding the antiphase external noise digital data and the antiphase noise digital data that has already been generated.

  The DAC 15h converts the corrected digital data received from the DSP 15b into voltage level analog data (corrected voltage signal).

  The AGC 15g adjusts the gain of the correction voltage signal received from the DAC 15h, the AudioCODEC 15a adjusts the voltage level of the correction-adjusted correction voltage signal received from the AGC 15g, and the amplifier 15e adjusts the voltage level received from the AudioCODEC 15a. The correction voltage signal is amplified and the amplified correction voltage signal is applied to the piezo element 3.

  As described above, in the third embodiment, the vibration generating unit 15 converts the vibration that suppresses the noise that is not suppressed by the antiphase noise generated based on the noise data, by the external sound collecting microphone 5. It can be generated by the piezo element 3 using an external noise voltage signal, and it is possible to more surely suppress noise generated when a magnetic resonance image is taken.

  In the first to third embodiments described above, the case where noise suppression processing is performed using noise data estimated to occur during the imaging of the magnetic resonance image inside the gantry device 10 has been described, but in the fourth embodiment, the gantry device. A case where noise suppression processing is performed using noise actually generated during imaging of a magnetic resonance image in the interior of the apparatus 10 will be described with reference to FIG. In addition, FIG. 11 is a figure for demonstrating the vibration generation part in Example 4. FIG.

  The vibration generating unit 15 in the fourth embodiment has a correction function using the intercom function described in the second embodiment and the external sound collection microphone 5 described in the third embodiment. However, the vibration generating unit 15 in the fourth embodiment does not have the noise suppression function using the noise data described in the first to third embodiments, but the internal sound collecting microphone 7 attached to the inside of the exterior member 2 illustrated in FIG. It has a noise suppression function using collected noise.

  The internal sound collecting microphone 7 is a piezo microphone made of a piezo element, like the external sound collecting microphone 5, and is provided with a rubber 8 for preventing the vibration of the exterior material 2 from being transmitted as shown in FIG. It is attached to the inside of the exterior material 2 via. The internal sound collecting microphone 7 collects noise generated inside the gantry device 10 and converts it into a voltage signal (hereinafter referred to as an internal noise voltage signal). The internal sound collection microphone 7 is attached to the center position on the upper surface of the opening exterior.

  As shown in FIG. 9, the vibration generator 15 in the fourth embodiment includes the Audio CODEC 15a, the DSP 15b, the DAC 15c, the AGC 15d, the amplifier 15e, the amplifier 15f, the AGC 15g, the DAC 15h, and the audio codec 15a described in the third embodiment. In addition, an amplifier 15 i connected to the internal sound collection microphone 7 is provided. Note that the AudioCODEC 15a, DSP 15b, DAC 15c, AGC 15d, amplifier 15e, amplifier 15f, AGC 15g, and DAC 15h are examples of the instruction sound and the external noise voltage signal converted by the external sound collecting microphone 5. Since the same processing as described in the second and third embodiments is performed, the description thereof is omitted.

  First, the amplifier 15i amplifies the internal noise voltage signal converted by the internal sound collection microphone 7. The AGC 15g adjusts the gain of the amplified internal noise voltage signal received from the amplifier 15i. Then, the AudioCODEC 15a performs frequency analysis on the gain-adjusted internal noise voltage signal received from the AGC 15g and converts it into internal noise digital data.

  The DSP 15b inverts the internal noise digital data received from the AudioCODEC 15a, thereby generating digital data having a phase opposite to that of the internal noise digital data (hereinafter referred to as reverse phase internal noise digital data).

  The DAC 15c converts the antiphase internal noise digital data received from the DSP 15b into analog data of voltage level (hereinafter referred to as an antiphase internal noise voltage signal).

  The AGC 15d adjusts the gain of the anti-phase internal noise voltage signal received from the DAC 15c, and the AudioCODEC 15a adjusts the voltage level of the anti-phase internal noise voltage signal after gain adjustment received from the AGC 15d.

  The amplifier 15e amplifies the anti-phase internal noise voltage signal whose voltage level has been adjusted received from the AudioCODEC 15a, and applies the amplified anti-phase internal noise voltage signal to the piezo element 3.

  As a result, the vibration generating unit 15 generates vibration in the piezo element 3 with a phase opposite to the phase of the noise generated in the gantry device 10, and the exterior material 2 is actually driven by the vibration of the piezo element 3. Generates noise that is opposite in phase to the noise that is occurring.

  As described above, in the fourth embodiment, the vibration generating unit 15 generates vibrations using the internal noise voltage signal converted by the internal sound collecting microphone 7 in the piezo element 3, so that it is actually generated during shooting. Thus, noise having a phase opposite to that of the generated noise can be generated from the exterior material 2, and noise generated when a magnetic resonance image is captured can be more reliably suppressed.

  In the first to fourth embodiments described above, the case where the present invention is applied to the exterior of the opening located above the subject P in the opening of the gantry device 10 into which the subject P is inserted has been described. However, if the exterior part of the gantry device 10 to which the present invention is applied is a part that is supposed to suppress noise to the subject P, such as an opening exterior located under the subject P, the MRI apparatus It can be arbitrarily selected by 100 designers.

  Further, the present invention specializes in the intercom function between the operator of the MRI apparatus 100 and the subject P, and the ear of the subject P is located in the exterior of the opening of the gantry device 10 as shown in FIG. The case where the vicinity of the region is constituted by the exterior material 2 having a high vibration transmission property such as a honeycomb sandwich material may be used. In addition, FIG. 12 is a figure for demonstrating a modification.

  That is, although the noise suppressing effect inside the gantry device 10 is slightly reduced by installing the vibration generating unit 15 described in the above-described Examples 2 to 4 with respect to the opening exterior having the shape shown in FIG. The instruction voice from the person can be heard clearly by the subject P.

  In the first to fourth embodiments described above, the case where the present invention is applied to an MRI apparatus has been described. However, the present invention uses, for example, data collected in a gantry apparatus such as an X-ray CT apparatus to generate a medical image. The present invention can be applied to any medical image diagnostic apparatus that is generated.

  Further, each component of each illustrated apparatus is functionally conceptual, and does not necessarily need to be physically configured as illustrated. In other words, the specific form of distribution / integration of each device is not limited to that shown in the figure, and all or a part thereof may be functionally or physically distributed or arbitrarily distributed in arbitrary units according to various loads or usage conditions. Can be integrated and configured. Further, all or any part of each processing function performed in each device may be realized by a CPU and a program analyzed and executed by the CPU, or may be realized as hardware by wired logic.

  As described above, the medical image diagnostic apparatus and the magnetic resonance imaging apparatus according to the present invention are useful for generating a medical image by collecting data from a subject moved into the gantry, and in particular, a medical image. Suitable for easily and reliably suppressing noise generated during shooting.

DESCRIPTION OF SYMBOLS 1 Frame 2 Exterior material 3 Piezo element 15 Vibration generating part 15a AudioCODEC
15b DSP
15c DAC
15d AGC
15e amplifier 31 interface unit 34 storage unit 34a noise storage unit 36 input unit 37 control unit 100 MRI apparatus

Claims (7)

A medical image diagnostic apparatus that collects data from a subject moved into a gantry and generates a medical image,
Part or all of the exterior of the gantry device is made of a material with high vibration transmission,
A vibration element that vibrates the material having high vibration transmission property;
Vibration generating means for generating, in the vibration element, vibration having a phase opposite to the phase of the sound generated in the gantry device;
A medical image diagnostic apparatus comprising: Sound storage means for storing sound generated in the gantry device for each imaging condition when imaging the medical image;
When receiving the imaging conditions for capturing the medical image, the vibration generating unit acquires a sound corresponding to the received imaging condition from the sound storage unit, and the vibration having an opposite phase to the acquired sound The medical image diagnostic apparatus according to claim 1, wherein the medical image diagnostic apparatus is generated in a vibration element. In-device sound collecting means for collecting sound generated in the gantry device,
The medical image diagnostic apparatus according to claim 1, wherein the vibration generating unit generates vibration in the vibration element having a phase opposite to that of the sound collected by the internal sound collecting unit. The apparatus further comprises a device outside sound collecting means for collecting sound generated outside the gantry device,
The medical image diagnostic apparatus according to claim 2, wherein the vibration generating unit corrects vibration generated in the vibration element based on sound collected by the external sound collecting unit.   The medical image according to any one of claims 1 to 4, further comprising audio output control means for controlling to output sound for instructing the subject from the vibration generating means. Diagnostic device.   The medical image diagnostic apparatus according to claim 5, wherein a region near an area where the ear of the subject is located is formed of the material having high vibration transmission property in the exterior of the gantry device. A magnetic resonance imaging apparatus for generating a magnetic resonance image by collecting magnetic resonance signals from a subject moved into a gantry device,
Part or all of the exterior of the gantry device is made of a material with high vibration transmission,
A vibration element that vibrates the material having high vibration transmission property;
Vibration generating means for generating, in the vibration element, vibration having a phase opposite to the phase of the sound generated in the gantry device;
A magnetic resonance imaging apparatus comprising:

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