JP6101526B2 - Magnetic resonance imaging system - Google Patents

Description

  The present invention relates to a magnetic resonance imaging apparatus (hereinafter referred to as an MRI apparatus), and more particularly to a technique for reducing the capacity of a power source required to move the entire MRI apparatus.

  An MRI apparatus measures and calculates a signal obtained from a nuclear magnetic resonance (hereinafter referred to as “NMR”) phenomenon of a subject placed in a magnetic field, thereby calculating a nuclear spin density distribution and relaxation time in the subject. The distribution or the like is displayed as a tomographic image, and is used for various diagnoses or the like with the human body as a subject. In order to obtain a signal from the NMR phenomenon, the subject is placed in a spatially and temporally uniform static magnetic field, and the subject is irradiated with electromagnetic waves in a pulsed manner by a high-frequency coil. Receive by coil. Further, a gradient magnetic field is superimposed on the static magnetic field in order to give position information to the NMR signal.

  Therefore, in the MRI apparatus, various components such as a high-frequency amplification power supply, a gradient magnetic field power supply, an image reconstruction device, a filter box power supply device, a patient table, and an image display device are used. I needed a power supply.

  As described in Japanese Patent Application Laid-Open No. H10-260707, a conventional technology related to a power supply device in an MRI apparatus discloses a power supply unit adapted to supply DC power to each component. Specifically, a power supply unit adapted to supply DC power from an AC electric main line, a power bus adapted to supply DC power to the subunit, and DC power to the subunit by the power bus An MRI system having a control means for controlling the supply of the above is disclosed.

Special table 2012-507329 gazette

  However, although the above-described prior art discloses a technique for removing the power supply of each component and reducing the cost, how to reduce the capacity of the power supply when only one power supply is supplied to the MRI apparatus. No technology relating to this is disclosed.

  Therefore, an object of the present invention is to reduce the capacity of one power source when power supplied to each component (each component) constituting the MRI apparatus is supplied from one power source.

  In order to solve the above problems, the magnetic resonance imaging apparatus of the present invention has the following features.

  A transport unit that transports the subject to the imaging space, a high-frequency magnetic field generation unit that generates a high-frequency magnetic field in the imaging space, a gradient magnetic field generation unit that generates a gradient magnetic field in the imaging space, and a nuclear magnetic resonance signal generated from the subject A device that includes a receiving unit to detect, an image generating unit that creates a captured image using a nuclear magnetic resonance signal detected by the receiving unit, and a display unit that displays the generated captured image; A power supply device that supplies power to each of the components, and a power supply switching device that switches power supply to each device component, and the power supply capability of the power supply device is necessary to operate all of the device components The power supply switching device is set to be less than the power supply capacity, and the power supply switching device supplies power to the device constituent unit that is an operation target in each process of imaging and stops power supply to the device configuration unit that is not the operation target. And performing switching.

  In other words, the present invention is characterized in that some components constituting the MRI apparatus are not used at the same time, and the power supply to them is switched and used to reduce the capacity of a single power supply. To do.

  According to the present invention, when power supplied to each of the components (each component) constituting the MRI apparatus is supplied from one power source, the capacity of the one power source can be reduced.

It is a block block diagram which shows an example of the whole basic structure of the MRI apparatus which concerns on this invention. It is a schematic block diagram which shows the electric power supply line which concerns on Example 1 of this invention. It is a table | surface which shows each sequence operation | movement for every component which comprises an MRI apparatus, and electric power used.

  Hereinafter, preferred embodiments of the MRI apparatus of the present invention will be described in detail with reference to the accompanying drawings. Note that components having the same function are denoted by the same reference symbols throughout the drawings for describing the embodiments of the invention, and the repetitive description thereof is omitted.

First, an example of the overall outline of the MRI apparatus according to the present invention will be described with reference to FIG.
FIG. 1 is a block diagram showing the overall configuration of an embodiment of an MRI apparatus according to the present invention. This MRI apparatus obtains a tomographic image of a subject using the NMR phenomenon. As shown in FIG. 1, the MRI apparatus includes a static magnetic field generation system 2, a gradient magnetic field generation system 3, a transmission system 5, The receiving system 6, the signal processing system 7, the sequencer 4, and a central processing unit (CPU) 8 are provided.

  The static magnetic field generation system 2 generates a uniform static magnetic field in the direction perpendicular to the body axis in the space around the subject 1 if the vertical magnetic field method is used, and in the body axis direction if the horizontal magnetic field method is used. Thus, a permanent magnet type, normal conduction type or superconducting type static magnetic field generation source is arranged around the subject 1.

  The gradient magnetic field generation system 3 includes a gradient magnetic field coil 9 that applies gradient magnetic fields in the three-axis directions of X, Y, and Z, which are coordinate systems (stationary coordinate systems) of the MRI apparatus, and gradient magnetic fields that drive the respective gradient magnetic field coils. A gradient power supply Gx, Gy, Gz is applied in the X, Y, and Z triaxial directions by driving the gradient magnetic field power supply 10 of each coil in accordance with a command from the sequencer 4 described later. . At the time of imaging, a slice direction gradient magnetic field pulse (Gs) is applied in a direction orthogonal to the slice plane (imaging cross section) to set a slice plane for the subject 1, and the remaining two orthogonal to the slice plane and orthogonal to each other. A phase encoding direction gradient magnetic field pulse (Gp) and a frequency encoding direction gradient magnetic field pulse (Gf) are applied in one direction, and position information in each direction is encoded in the echo signal.

  The sequencer 4 is a control unit that repeatedly applies a high-frequency magnetic field pulse (hereinafter referred to as “RF pulse”) and a gradient magnetic field pulse in a predetermined pulse sequence. The sequencer 4 operates under the control of the CPU 8 and collects tomographic image data of the subject 1. Various commands necessary for the transmission are sent to the transmission system 5, the gradient magnetic field generation system 3, and the reception system 6.

  The transmission system 5 irradiates the subject 1 with an RF pulse in order to cause nuclear magnetic resonance to occur in the nuclear spins of the atoms constituting the living tissue of the subject 1, and includes a high-frequency oscillator 11, a modulator 12, and a high-frequency amplifier. 13 and a high frequency coil (transmission coil) 14a on the transmission side. The RF pulse output from the high-frequency oscillator 11 is amplitude-modulated by the modulator 12 at a timing according to a command from the sequencer 4, and after the amplitude-modulated RF pulse is amplified by the high-frequency amplifier 13, the RF pulse is arranged close to the subject 1. By supplying to the high frequency coil 14a, the subject 1 is irradiated with the RF pulse.

  The receiving system 6 detects an echo signal (NMR signal) emitted by nuclear magnetic resonance of nuclear spins constituting the living tissue of the subject 1. The receiving system 6 receives a high-frequency coil (receiving coil) 14 b on the receiving side and a signal amplifier 15. And a quadrature phase detector 16 and an A / D converter 17. After the NMR signal of the response of the subject 1 induced by the electromagnetic wave irradiated from the high frequency coil 14a on the transmission side is detected by the high frequency coil 14b arranged close to the subject 1 and amplified by the signal amplifier 15, The signals are divided into two orthogonal signals by the quadrature detector 16 at the timing according to the command from the sequencer 4, converted into digital quantities by the A / D converter 17, and sent to the signal processing system 7.

  The signal processing system 7 performs various data processing and display and storage of processing results. The signal processing system 7 includes an external storage device such as an optical disk 19, a magnetic disk 18, a ROM 21, and a RAM 22, and a display 20 including a CRT. When data from the reception system 6 is input to the CPU 8, the CPU 8 executes processing such as signal processing and image reconstruction, and displays the tomographic image of the subject 1 as a result on the display 20 and an external storage device. On the magnetic disk 18 or the like.

  The operation unit 25 inputs various control information of the MRI apparatus and control information of processing performed by the signal processing system 7 and includes a trackball or mouse 23 and a keyboard 24. The operation unit 25 is arranged in the vicinity of the display 20, and the operator controls various processes of the MRI apparatus interactively through the operation unit 25 while looking at the display 20.

  In FIG. 1, the high-frequency coil 14a and the gradient magnetic field coil 9 on the transmission side are opposed to the subject 1 in the static magnetic field space of the static magnetic field generation system 2 into which the subject 1 is inserted. If the horizontal magnetic field method is used, the subject 1 is installed so as to surround it. The high-frequency coil 14b on the receiving side is installed so as to face or surround the subject 1.

  At present, the radionuclide to be imaged by the MRI apparatus is a hydrogen nucleus (proton) which is a main constituent material of the subject as widely used clinically. Information on the spatial distribution of the proton density and the spatial distribution of the relaxation time of the excited state is imaged, thereby imaging the form or function of the human head, abdomen, limbs, etc. two-dimensionally or three-dimensionally.

  Next, Embodiment 1 of the MRI apparatus of the present invention will be described. In this embodiment, the power consumption of the entire apparatus is reduced by switching the power supply to each component constituting the MRI apparatus. Note that the present embodiment relates to a mode (hereinafter referred to as a first mode) in which power is supplied to or stopped from each device constituent unit during the creation of a captured image. The embodiment will be described in detail based on the above.

  FIG. 2 is a schematic configuration diagram showing a power supply line in the MRI apparatus.

  The power supply line includes a magnetic circuit 201, a patient table 202, a filter box power supply device 203, a high frequency amplification power supply 204, a gradient magnetic field power supply 205, an image reconstruction device 206, an image display device 207, a power supply switching device 208, and a facility power supply 209. This is a line for supplying power to each component. The power supply line is indicated by a thick solid line in the figure, but a signal line transmitted between the image reconstruction device 206 and the image display device 207 is indicated by a thin solid line.

In order for the MRI apparatus to capture a tomographic image, it is necessary to supply power from the facility power source 209 to each of the above components and operate each component necessary for imaging.
Here, the total power required for imaging by the MRI apparatus can be obtained as the sum of the power required for each component from the magnetic circuit 201 to the image display apparatus 207 to operate.

  By the way, in a facility such as a hospital, if the total power receiving capacity of the lamp (AC100V) and power (AC200V) is less than 50 KVA, it will be subject to a low-voltage power receiving contract, and the contract fee and power receiving equipment can be suppressed. It is possible to reduce the equipment burden cost on the hospital side.

  Therefore, since the hospital uses electric power for other medical equipment and hospital equipment other than the MRI apparatus, it is beneficial for the hospital to reduce the power consumed by the MRI apparatus.

  FIG. 3 shows the power used for the imaging sequence for each component constituting the MRI apparatus. The imaging sequence name is described in the column direction in the figure, and each component name is described in the row direction. That is, in the imaging sequence, first, the apparatus is started, patient information is registered, then the patient is moved to the imaging area of the MRI apparatus, and imaging is started. Subsequently, the MRI image is transferred to the image reconstruction device 206 at the time of imaging or after imaging, and the image is displayed on the image display device 207. Finally, the patient is moved out of the imaging area of the MRI apparatus.

  Next, switching of power supply to each component constituting the MRI apparatus used at the time of imaging will be described with reference to FIG.

  In order to start imaging, the power switching device 208 first supplies power to the image display device 207 and registers patient information. At this time, as shown in the figure, power is supplied only to the image display device 207, and no power is supplied to other components.

  Next, the power supply switching device 208 stops power supply to the image display device 207 and supplies power to the patient table 202 in order to move the subject 1 to the imaging space in the magnetic circuit 201. At this time, as shown in the figure, power is supplied only to the patient table 202, and no power is supplied to other components.

  Subsequently, the power supply switching device 208 performs imaging, switches the power supply to acquire an image, and supplies power to each of the filter box power supply device 203, the high frequency amplification power supply 204, the gradient magnetic field power supply 205, and the image reconstruction device 206. do. At this time, as shown in the figure, power is supplied only to the above four devices, and power is not supplied to other components.

Next, the image reconstruction device 206 transfers the acquired image to the image display device 207. At this time, as shown in the figure, power is supplied only to the image reconstruction device 206 and the image display device 207, and power is not supplied to other components.
Here, the image display device 207 is used by an inspection engineer for image interpretation.

  Finally, the patient table 202 is powered to move the patient.

  At the bottom of FIG. 3, the maximum power required for each component is displayed. For example, it can be seen that the patient table requires 2 KVA power, the filter box power supply device requires 1 KVA power, and the gradient power supply requires 3.5 KVA power.

  Considering the power required for each of the above components, 0.5 KVA power is required for the entire MRI apparatus when the apparatus is started, and when the next patient is moved (the patient is brought into and out of the imaging area) 2KVA power is required for the next imaging, 7.5KVA (1 + 2 + 3.5 + 1 (KVA) total) is required for the next imaging, and 1.5KVA (1 + 0.5 (KVA) for image transfer) Total) is required, and 0.5 KVA power is required for image display. Therefore, the maximum power used in the imaging sequence is 7.5 KVA at the time of imaging. On the other hand, conventionally, 10 KVA (total of 2 + 1 + 2 + 3.5 + 1 + 0.5 (KVA)) in which the power used by all components is added is required.

  From the above, in this embodiment, it is sufficient if there is a power source capable of supplying 7.5 KVA power for the entire MRI apparatus, but a 10 KVA power source has been conventionally required. That is, in the case of the present embodiment, the power capacity of 25% can be reduced.

  A switching algorithm of power supply to each component of the power supply switching device 208 will be described with reference to FIGS.

  First, the imaging sequence shown in FIG. 3 and the power used by each component are stored in advance in a storage device such as the magnetic disk 18 and the optical disk 19 shown in FIG.

  Input to the storage device can be performed from the operation unit 25.

  In this embodiment, the information is stored in the storage device in advance, but may be input from the operation unit at the start of imaging.

  At the start and end of each operation in the imaging sequence, a signal is transmitted to the central processing unit (CPU) 8, and information on the power used by each component is transmitted to the power supply switching device 208 in accordance with the imaging sequence. Based on the transmitted information, as shown in FIG. 3, the power supply switching device 208 cuts off the power supply of components that do not require power and supplies power only to components that require power. At that time, the supplied power supplies only the maximum used power required in the corresponding sequence.

The present embodiment is characterized by including a mode (hereinafter referred to as a second mode) in which power is continuously supplied to some components even after imaging.
That is, imaging by an MRI apparatus is not only performed in the daytime in facilities such as hospitals, but when there is an emergency patient at night or the like, imaging of the patient may be urgently required.
At that time, if the components of the entire MRI apparatus are kept in an operation stopped state, some components may take time to start up, and it may not be possible to respond to an emergency situation.

Moreover, even if it is not nighttime as mentioned above, the case where a test | inspection is urgently required according to a patient's condition may arise.
In preparation for such a situation, the minimum necessary power is always supplied without stopping the power supply to components that mainly take time to start up.

For example, the gradient magnetic field power supply 205 is always supplied with necessary power to reduce the time required for emergency startup.
Switching to the above-described mode can be performed using the power supply switching device 208.

  In the first to third embodiments described above, a technique for reducing the capacity of one power source when power supplied to each of the components constituting the MRI apparatus is supplied from one power source is described. However, it is not necessary to supply the surplus power again to an electric lamp or power outside the MRI apparatus.

DESCRIPTION OF SYMBOLS 1 ... Subject, 2 ... Static magnetic field generation system, 3 ... Gradient magnetic field generation system, 4 ... Sequencer, 5 ... Transmission system, 6 ... Reception system, 7 ... Signal processing system, 8 ... Central processing unit (CPU), 9 ... Gradient magnetic field coil, 10 ... Gradient magnetic field power source, 11 ... High frequency oscillator, 12 ... Modulator,
DESCRIPTION OF SYMBOLS 13 ... High frequency amplifier, 14a ... High frequency coil (transmission coil), 14b ... High frequency coil (reception coil), 15 ... Signal amplifier, 16 ... Quadrature phase detector, 17 ... A / D converter, 18 ... Magnetic disk, 19 ... Optical disk, 20 ... Display, 21 ... ROM, 22 ... RAM, 23 ... Trackball or mouse, 24 ... Keyboard, 25 ... Operation unit,
DESCRIPTION OF SYMBOLS 201 ... Magnetic circuit, 202 ... Patient table, 203 ... Filter box power supply device, 204 ... High frequency amplification power supply, 205 ... Gradient magnetic field power supply, 206 ... Image reconstruction device, 207 ... Image display device, 208 ... Power supply switching device, 209 ... Equipment power supply.

Claims (4)

A transport unit for transporting the subject to the imaging space;
A high frequency magnetic field generating unit for generating a high frequency magnetic field to the IMAGING space,
A gradient magnetic field generating unit for generating a gradient magnetic field to the IMAGING space,
A receiver for detecting a nuclear magnetic resonance signal generated from the subject;
An image generator that creates a captured image using the nuclear magnetic resonance signal detected by the receiver;
A display unit for displaying the generated captured image, and a device configuration unit including
A power supply for supplying power to each of the device components;
A power supply switching device that switches power supply to each device component,
Power supply capacity of the power supply, the device components are set smaller than the power supply capacity required to operate all of the power switching exchange example device, the device configuration to be running object in each process in the imaging It performs power sWITCHING example to stop the power supply to the device components not running object supplies power to the parts,
The power supply switching device supplies power to each device component during creation of the captured image, or
Is the first mode to stop,
Continue to supply power to a part of each device component even after creating the captured image
A magnetic resonance imaging apparatus having a second mode . The magnetic resonance imaging apparatus according to claim 1, wherein information related to electric power required by each of the apparatus constituent units is stored in a storage unit in advance. The second mode is applied to a device configuration unit that requires more time to start up the device than the other device configuration units among the respective device configuration units, so that an emergency inspection can be handled. Term
3. A magnetic resonance imaging apparatus according to 2. Magnetic resonance imaging apparatus according to claim 2, wherein applying said second mode to said gradient magnetic field generating unit.

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