JP6687416B2 - Magnetic resonance imaging equipment - Google Patents

Description

  Embodiments of the present invention relate to a magnetic resonance imaging (MRI: Magnetic Resonance Imaging) apparatus.

  In magnetic resonance imaging, nuclear spins of a subject placed in a static magnetic field are magnetically excited by an RF signal of Larmor frequency. Then, the image is reconstructed from the MR signal generated by the magnetic excitation of the nuclear spins.

  In a magnetic resonance imaging apparatus, for example, a superconducting magnet unit is used to form a static magnetic field. The superconducting magnet unit realizes a superconducting state by immersion cooling in a cooling container storing liquid helium, for example. In a magnetic resonance imaging apparatus, a refrigerator is installed in a superconducting magnet unit so that a predetermined amount of helium in a cooling container is maintained in a liquid state.

JP 2007-7393 A

  An object of the present invention is to provide a magnetic resonance imaging apparatus capable of reducing wasteful energy consumption while maintaining a required cooling capacity.

  According to an embodiment, a magnetic resonance imaging apparatus includes a cooling container, a cold head, a compressor, and an output unit. A superconducting coil is arranged inside the cooling container. The cold head cools the cooling container. The compressor outputs a refrigerant gas to the cold head at a first gas pressure. The output unit outputs information for changing from the first gas pressure to the second gas pressure corresponding to a predetermined cooling capacity based on the state of the cooling container.

FIG. 1 is a diagram showing the configuration of the magnetic resonance imaging apparatus according to the first embodiment. FIG. 2 is a diagram showing configurations of the superconducting magnet unit and the refrigerator unit shown in FIG. FIG. 3 is an experimental result showing the pressure of the refrigerant gas output from the compressor with respect to the power consumption of the compressor shown in FIG. FIG. 4 is an experimental result showing the magnet shield temperature and the heater power consumption with respect to the power consumption of the compressor and the pressure of the refrigerant gas output from the compressor when the compressor shown in FIG. 2 is driven. is there. FIG. 5 is a flowchart showing an operation when the gas pressure control circuit shown in FIG. 2 adjusts the pressure of the refrigerant gas. FIG. 6 is a flowchart showing another example of the operation when the gas pressure control circuit shown in FIG. 2 adjusts the pressure of the refrigerant gas. FIG. 7 is a diagram showing another configuration example of the superconducting magnet unit and the refrigerator unit shown in FIG. FIG. 8 is a diagram showing another configuration example of the superconducting magnet unit and the refrigerator unit shown in FIG. FIG. 9 is a diagram showing another configuration example of the superconducting magnet unit and the refrigerator unit shown in FIG. 1. FIG. 10 is a diagram showing another configuration example of the superconducting magnet unit and the refrigerator unit shown in FIG. 1. FIG. 11 is a diagram showing the configuration of the magnetic resonance imaging apparatus according to the second embodiment. FIG. 12 is a diagram showing the configurations of the superconducting magnet unit and the refrigerator unit shown in FIG. 11. FIG. 13 is a flowchart showing the operation of the control circuit executed when the magnetic resonance imaging apparatus shown in FIG. 11 is installed. FIG. 14 is an explanatory diagram showing a procedure for adjusting the compressor 3 when the magnetic resonance imaging apparatus shown in FIG. 11 is installed. FIG. 15 is a flowchart showing the operation of the control circuit executed when the refrigerating machine unit shown in FIG. 12 is readjusted. FIG. 16: is explanatory drawing which shows the procedure of readjusting the compressor which the refrigerant gas leaked. FIG. 17: is explanatory drawing which shows the procedure of readjusting a refrigerator unit with which the component parts are exhausted.

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

(First embodiment)
FIG. 1 is a schematic diagram showing the configuration of a magnetic resonance imaging apparatus 1 according to the first embodiment. The magnetic resonance imaging apparatus 1 shown in FIG. 1 includes a scanner device 10, a device body 20, a refrigerator unit 30, and a monitoring device 40.

  The scanner device 10 includes a superconducting magnet unit 11, a gradient magnetic field coil 12, a transmission / reception coil 13, and a bed 14. The superconducting magnet unit 11, the gradient magnetic field coil 12, and the transmission / reception coil 13 are provided in the gantry and are installed together with the bed 14 in an examination room (shield room).

  The superconducting magnet unit 11 receives a current supplied from the static magnetic field power supply circuit 21 and forms a static magnetic field around the subject P. Note that once the coil provided in the superconducting magnet unit 11 is excited, the current flowing through the coil becomes a permanent current. Therefore, the superconducting magnet unit 11 is not normally connected to the static magnetic field power supply circuit 21.

  The gradient magnetic field coil 12 is formed in a substantially cylindrical shape and is arranged inside the superconducting magnet unit 11. The gradient magnetic field coil 12 forms a gradient magnetic field in the X, Y, and Z axis directions orthogonal to each other by the current supplied from the gradient magnetic field power supply circuit 22.

  The transmission / reception coil 13 is arranged inside the gradient magnetic field coil 12. The transmission / reception coil 13 irradiates the subject P with an RF pulse based on the RF pulse current output from the transmission circuit 23. Further, the transmission / reception coil 13 receives the MR signal generated in the subject P due to the excitation of hydrogen nuclei by the RF pulse. The transmission / reception coil 13 may be provided with a coil for transmitting the RF pulse and a coil for detecting the MR signal separately.

  The bed 14 has a structure in which the top plate provided in the bed 14 can be inserted into the imaging space of the gantry. This allows the bed 14 to move the subject P to an arbitrary position in the body axis direction in order to set a desired imaging position.

  The apparatus main body 20 includes a static magnetic field power supply circuit 21, a gradient magnetic field power supply circuit 22, a transmission circuit 23, a reception circuit 24, a storage circuit 25, an arithmetic circuit 26, an input interface circuit 27, an output interface circuit 28, and a control circuit 29.

  The gradient magnetic field power supply circuit 22 supplies a pulse current to the gradient magnetic field coil 12 in the X-, Y-, and Z-axis directions according to the gradient magnetic field control signal supplied from the control circuit 29. As a result, the slice selection gradient magnetic field Gs, the phase encode gradient magnetic field Ge, and the read (or frequency encode) gradient magnetic field Gr are formed in arbitrary directions. The gradient magnetic field in each direction is superimposed on the static magnetic field formed by the superconducting magnet unit 11 and applied to the subject P.

  The transmission circuit 23 has the same frequency as the angular frequency determined by the static magnetic field strength of the superconducting magnet unit 11, and outputs the RF pulse current modulated by the selective excitation waveform to the transmission / reception coil 13.

  The reception circuit 24 performs signal processing such as A / D conversion on the MR signal received by the transmission / reception coil 13 and converts the MR signal into a digital signal. The reception circuit 24 temporarily stores the digital signal in the MR signal storage unit 251 of the storage circuit 25.

  The storage circuit 25 has a recording medium readable by a processor, such as a magnetic or optical recording medium or a semiconductor memory. The storage circuit 25 includes storage areas for the MR signal storage unit 251 and the image data storage unit 252. The MR signal storage unit 251 stores the MR signal digitally converted by the receiving circuit 24. The image data storage unit 252 stores image data obtained by reconstructing the MR signal.

  The arithmetic circuit 26 performs image reconstruction processing by, for example, two-dimensional Fourier transform on the MR signal once stored in the MR signal storage unit 251, and generates image data in real space. The arithmetic circuit 26 stores the generated image data in the image data storage unit 252.

  The input interface circuit 27 is realized by, for example, a mouse, a keyboard, and a touch pad that inputs an instruction by touching the operation surface. The input interface circuit 27 is connected to the control circuit 29, and outputs the object information, the acquisition condition of the MR signal, the display condition of the image data, the movement instruction of the top plate, the imaging start command, and the like, which are input by the operator, to an electric signal. The converted signal is output to the control circuit 29. In the present specification, the input interface circuit 27 is not limited to one having physical operation parts such as a mouse and a keyboard. For example, an electric signal processing circuit that receives an electric signal corresponding to an operation instruction input from an external input device provided separately from the magnetic resonance imaging apparatus 1 and outputs the electric signal to the control circuit 29 is also input. It is included in the example of the interface circuit 27.

  The output interface circuit 28 is realized by connection ports such as an HDMI (registered trademark) terminal, a DVI terminal, and a USB terminal, for example. The output interface circuit 28 is connected to, for example, the display circuit 50 and the like. The output interface circuit 28 outputs the video signal output from the control circuit 29 to the connected display circuit 50.

  The display circuit 50 is a general display output device having a display function of video information, such as a liquid crystal display or an OLED (Organic Light Emitting Diode) display. The display circuit 50 displays the video signal output from the control circuit 29.

  The control circuit 29 is a processor having a function of integrally controlling the magnetic resonance imaging apparatus 1. The control circuit 29 has a memory circuit (not shown). The memory circuit of the control circuit 29 is used for controlling the subject information, the information regarding the acquisition condition of the MR signal, the information regarding the display condition of the image data, the information regarding the image display format, and the circuit in the magnetic resonance imaging apparatus 1. The operation program and the like are stored. The control circuit 29 calls each operation program from the memory circuit and executes the called program to realize the sequence control function 291, the image creation function 292, and the refrigerator control function 293.

  The sequence control function 291 is a function of controlling the gradient magnetic field power supply circuit 22, the transmission circuit 23, and the reception circuit 24. In the sequence control function 291, the control circuit 29 creates pulse sequence information based on the information regarding the acquisition conditions of MR signals. The pulse sequence information is, for example, information about the magnitude of the pulse current applied to the gradient magnetic field coil 12 and the transmission / reception coil 13, the application time, the application timing, and the like. The control circuit 29 controls the gradient magnetic field power supply circuit 22, the transmission circuit 23, and the reception circuit 24 according to the created pulse sequence information.

  The image creating function 292 is a function of creating a video signal displayed on the display circuit 50 from the image data stored in the image data storage unit 252. In the image creating function 292, the control circuit 29 creates display data by synthesizing the image data read from the image data storage unit 252 and the supplementary information such as the subject information. The control circuit 29 converts the created display data into a video signal of a predetermined display format and outputs the video signal to the output interface circuit 28.

  The refrigerator control function 293 is a function of controlling the supply of current to the refrigerator unit 30.

  The monitoring device 40 monitors the state of the superconducting magnet unit 11. The parameter indicating the state of the superconducting magnet unit 11 includes, for example, the pressure inside the cooling container 112 of the superconducting magnet unit 11 and the temperature of the shield of the cooling container 112. The shield is made of metal, for example. Hereinafter, the pressure inside the cooling container 112 will be referred to as the magnet internal pressure, and the shield temperature will be referred to as the magnet shield temperature. The pressure inside the magnet is measured by a pressure sensor provided in the cooling container 112. The magnet shield temperature is measured by a temperature sensor provided on the inner wall of the cooling container 112.

  The monitoring device 40 is connected to the pressure sensor and receives the detection signal output from the pressure sensor. The monitoring device 40 creates in-magnet pressure data based on the detection signal, and outputs the created in-magnet pressure data to the refrigerator unit 30. Further, the monitoring device 40 is connected to the temperature sensor and receives a detection signal output from the temperature sensor. The monitoring device 40 creates magnet shield temperature data based on the detection signal, and outputs the created magnet shield temperature data to the refrigerator unit 30.

  FIG. 2 is a schematic diagram showing a configuration example of the superconducting magnet unit 11 and the refrigerator unit 30 shown in FIG. In FIG. 2, the superconducting magnet unit 11 using a cylindrical magnet will be described as an example. The superconducting magnet unit 11 shown in FIG. 2 is represented by a sectional view taken along the central axis C of the cylinder.

  The superconducting magnet unit 11 has a vacuum container 111, a cooling container 112, a superconducting coil 113, and a bobbin (support member) 114.

  The vacuum container 111 is formed in a substantially cylindrical shape, and the inside of the cylindrical wall is kept in a vacuum state.

  The cooling container 112 is formed into a substantially cylindrical shape and is housed in the cylindrical wall of the vacuum container 111. Note that, as a general example, the cooling container 112 contains liquid helium in its cylindrical wall in order to keep the inside of the container at a sufficiently low temperature. In the cooling container 112, liquid helium and helium gas in which liquid helium is vaporized are in an equilibrium state.

  A heater (not shown) is provided inside the cooling container 112. The heater warms and vaporizes helium in the cooling container to adjust the pressure inside the magnet. The pressure in the magnet is adjusted, for example, to prevent unintended inflow of air into the cooling container. When the helium gas in the cooling container is cooled excessively, the proportion of liquid helium in the cooling container increases and the pressure in the magnet decreases. When the pressure inside the magnet decreases and becomes negative, air flows into the cooling container. The heater is controlled so that the value of the internal pressure of the magnet is within a preset range, and warms the helium in the cooling container 112.

  For example, the heater warms the helium with higher power consumption as the actual internal magnet pressure is lower than the target internal magnet pressure. In other words, the more liquid the helium in the cooling container is, the more the heater heats the helium with high power consumption in order to bring the magnet internal pressure to an appropriate value within a preset range. . That is, the power consumption of the heater can be considered as an index of the cooling capacity of the refrigerator unit 30.

  The superconducting coil 113 is wound around a groove provided on the bobbin 114 and is arranged on the bobbin 114. The superconducting coil 113 is arranged in the cylindrical wall of the cooling container 112 and immersed in liquid helium.

  The refrigerator unit 30 includes a compressor 32, a refrigerator body 33, a ventilation valve 34, an intake valve 35, a pressure measuring device 36, a gas pressure control circuit 37, an input interface circuit 38, an output interface circuit 39, and a buffer tank 310.

  The compressor 32 is connected to the refrigerator main body 33 by a supply pipe 321 and a discharge pipe 322. The compressor 32 compresses a refrigerant gas such as helium gas and supplies the refrigerant gas in a high pressure state to the refrigerator main body 33 via the supply pipe 321. Further, the compressor 32 collects the refrigerant gas expanded inside the refrigerator main body 33 via the discharge pipe 322.

  Further, the compressor 32 is connected to the buffer tank 310 via the ventilation valve 34 and the intake valve 35. The compressor 32 exhausts the refrigerant gas to the buffer tank 310 via the ventilation valve 34. The compressor 32 sucks the refrigerant gas filled in the buffer tank 310 via the intake valve 35.

  The refrigerator main body 33 includes a cold head. The refrigerator body 33 expands the high-pressure refrigerant gas supplied through the supply pipe 321 to cool the cooling container 112. When the cooling container 112 is cooled to a certain level or more, the helium gas in the cooling container 112 is recondensed into liquid helium. In addition, in FIG. 2, the case where one refrigerator main body 33 is installed in the superconducting magnet unit 11 is shown as an example, but the refrigerator main body 33 is not limited to one, and may be two or more in number. I don't mind.

  The ventilation valve 34 is an example of a pressure adjusting mechanism, and is provided in a pipe connecting the compressor 32 and the buffer tank 310. The ventilation valve 34 discharges the refrigerant gas in the compressor 32 to the buffer tank 310 according to the instruction from the gas pressure control circuit 37. Exhaust of the refrigerant gas in the compressor 32 reduces the pressure of the refrigerant gas supplied from the compressor 32 to the refrigerator main body 33. If the pressure of the refrigerant gas supplied from the compressor 32 to the refrigerator main body 33 can be lowered, the ventilation valve 34 may be provided other than the pipe connecting the compressor 32 and the buffer tank 310. I do not care. For example, the refrigerator main body 33 may be connected to the buffer tank 310, and the ventilation valve 34 may be provided in a pipe connecting the refrigerator main body 33 and the buffer tank 310.

  The intake valve 35 is an example of a pressure adjusting mechanism, and is provided in a pipe connecting the compressor 32 and the buffer tank 310. The intake valve 35 supplies the refrigerant gas with which the buffer tank 310 is filled to the compressor 32 according to an instruction from the gas pressure control circuit 37. By supplying the refrigerant gas to the compressor 32, the pressure of the refrigerant gas supplied from the compressor 32 to the refrigerator main body 33 rises. If the pressure of the refrigerant gas supplied from the compressor 32 to the refrigerator main body 33 can be increased, the intake valve 35 may be provided in a pipe other than the pipe connecting the compressor 32 and the buffer tank 310. I do not care. For example, the refrigerator main body 33 may be connected to the buffer tank 310, and the intake valve 35 may be provided in a pipe connecting the refrigerator main body 33 and the buffer tank 310.

  The buffer tank 310 is an example of a pressure adjusting mechanism, and is filled with a refrigerant gas. The refrigerant gas in the compressor 32 is exhausted to the buffer tank 310 via the ventilation valve 34. Further, the refrigerant gas filled in the buffer tank 310 is supplied to the compressor 32 via the intake valve 35.

  The pressure adjusting mechanism is not limited to the ventilation valve 34, the intake valve 35, and the buffer tank 310 as long as the pressure of the refrigerant gas supplied from the compressor 32 to the refrigerator main body 33 can be changed. For example, instead of the ventilation valve 34, the intake valve 35, and the buffer tank 310, a pipeline that bypasses the supply pipe 321 and the discharge pipe 322 may be provided, and a regulation valve may be provided in this pipeline. The adjusting valve adjusts the flow rate of the pipeline according to the instruction from the gas pressure control circuit 37. Further, instead of the ventilation valve 34, the intake valve 35 and the buffer tank 310, a pipeline in which gas is circulated in the compressor 32 is provided with a pipeline bypassing these pipelines, and a regulating valve is provided in this pipeline. It may be provided. The adjusting valve adjusts the flow rate of the pipeline according to the instruction from the gas pressure control circuit 37.

  The pressure measuring device 36 is realized by, for example, a pressure sensor. The pressure measuring device 36 measures the pressure of the refrigerant gas supplied from the compressor 32 to the refrigerator main body 33 at a preset cycle. The pressure measuring device 36 outputs the measured value to the gas pressure control circuit 37.

  The input interface circuit 38 is realized by, for example, a mouse, a keyboard, a touch pad for inputting an instruction by touching an operation surface, or the like. The input interface circuit 38 is connected to the gas pressure control circuit 37, converts, for example, a target value of the pressure of the refrigerant gas input from the operator into an electric signal, and outputs the electric signal to the gas pressure control circuit 37. . In the present specification, the input interface circuit 38 is not limited to the one including physical operation parts such as a mouse and a keyboard. For example, an electric signal processing circuit that receives an electric signal corresponding to an operation instruction input from an external input device provided separately from the magnetic resonance imaging apparatus 1 and outputs the electric signal to the gas pressure control circuit 37. Is also included in the example of the input interface circuit 38. Further, the refrigerator unit 30 does not necessarily have to have its own input interface circuit 38, and the input interface circuit 27 connected to the control circuit 29 may be shared with the device main body 20.

  The output interface circuit 39 is realized by connection ports such as an HDMI (registered trademark) terminal, a DVI terminal, and a USB terminal, for example. The output interface circuit 39 is an example of an output unit in the claims. The output interface circuit 39 is connected to, for example, the display circuit 60 or the like. The output interface circuit 39 outputs the video signal output from the gas pressure control circuit 37 to the connected display circuit 60. The refrigerator unit 30 does not necessarily have to have its own output interface circuit 39, and the output interface circuit 28 connected to the control circuit 29 may be shared with the device body 20.

  The display circuit 60 has a general display output device such as a liquid crystal display or an OLED display. The display circuit 60 is an example of the output unit in the claims. The display circuit 60 displays the information output from the gas pressure control circuit 37. The refrigerator unit 30 may share the display circuit 50 connected to the output interface circuit 28 with the device body 20.

  The gas pressure control circuit 37 is a processor having a function of integrally controlling the refrigerator unit 30. The gas pressure control circuit 37 has a storage circuit (not shown) in which an operation program for controlling the refrigerator unit 30 and the like are stored. The gas pressure control circuit 37 calls each operation program from the memory circuit and executes the called program to realize the pressure determination function 371, the pressure control function 372, and the differential pressure measurement function 373.

  The pressure determination function 371 is a function of determining the target pressure value of the refrigerant gas based on the in-magnet pressure data and the magnet shield temperature data transmitted from the monitoring device 40.

  Here, the target pressure value of the refrigerant gas will be described with reference to FIGS. 3 and 4. FIG. 3 is an experimental result showing the pressure of the refrigerant gas output from the compressor 32 with respect to the power consumption of the compressor 32. FIG. 4 is an experimental result showing the magnet shield temperature and the heater power consumption with respect to the power consumption of the compressor 32 and the pressure of the refrigerant gas output from the compressor 32 when the compressor 32 is driven. is there. It is assumed that FIGS. 3 and 4 are acquired in advance by an experiment on the magnetic resonance imaging apparatus 1 according to the first embodiment.

  In FIG. 3, circles represent pressure with respect to power consumption when the compressor 32 is being driven. The triangles represent the pressure when the operation of the compressor 32, which measures the pressure indicated by the circle, is stopped. Note that the compressor 32, which measures the pressure indicated by the triangle, does not consume power because it is stopped, but in FIG. 3, the triangle is displayed in parallel with the circle to indicate the operating pressure and the stopped pressure. I try to compare.

  According to FIG. 3, it can be seen that when the pressure of the refrigerant gas output from the compressor 32 increases, the power consumption by the compressor 32 also increases. That is, it is understood that the pressure of the refrigerant gas output from the compressor 32 and the power consumption of the compressor 32 have a correlation. Further, the pressure of the refrigerant gas when the compressor 32 is driven is higher than the pressure of the refrigerant gas when the compressor 32 is not driven.

  In FIG. 4, the circle indicates the magnet shield temperature, which corresponds to the power consumption of the compressor 32 and the pressure of the refrigerant gas output from the compressor 32. The triangle indicates the power consumption of the heater, which corresponds to the power consumption of the compressor 32 and the pressure of the refrigerant gas output from the compressor 32.

  According to FIG. 4, when the power consumption of the compressor 32 increases from WC2 [W] to WC4 [W], the magnet shield temperature decreases from around T5 [K] to T2 [K]. This means that when the pressure of the refrigerant gas output from the compressor 32 is increased from Pa [bar] to Pf [bar], the magnet shield temperature decreases from around T5 [K] to T2 [K]. it can.

  When the power consumption of the compressor 32 increases from WC2 [W] to WC4 [W], the power consumption of the heater increases from WH2 [VA] to around WH5 [VA]. In other words, if the pressure of the refrigerant gas output from the compressor 32 is increased from Pa [bar] to Pf [bar], the power consumption of the heater increases from WH2 [VA] to around WH5 [VA]. You can

  These facts show that the cooling capacity of the refrigerator unit 30 and the power consumption of the compressor 32 can be controlled by operating the pressure of the refrigerant gas at Pf [bar] or less. For example, when the pressure of the refrigerant gas is set to Pa [bar], it is possible to reduce the cooling capacity of the refrigerator unit 30 and reduce the power consumption of the compressor 32.

  Further, according to FIG. 4, when the power consumption of the compressor 32 increases to WC4 [W] or more, the magnet shield temperature starts to gradually increase with T2 [K] being the minimum value. This can be rephrased to mean that when the pressure of the refrigerant gas output from the compressor 32 is increased to Pf [bar] or higher, the magnet shield temperature starts a gentle increase with T2 [K] being the minimum value.

  When the power consumption of the compressor 32 increases to WC4 [W] or more, the power consumption of the heater starts to rapidly decrease with the maximum value near WH6 [VA]. This can be rephrased to mean that when the pressure of the refrigerant gas output from the compressor 32 is increased to Pf [bar] or higher, the power consumption of the heater starts to rapidly decrease with the maximum value near WH6 [VA].

  These facts indicate that the cooling capacity of the refrigerator unit 30 is maximum at Pf [bar] and the magnet shield temperature can be lowered most. That is, when the cooling capacity is improved by using the pressure of the refrigerant gas output from the compressor 32 as a parameter, the cooling capacity of the refrigerator unit 30 is not improved at Pf [bar] or higher. In other words, according to FIG. 4, Pf [bar] is the upper limit value when the gas pressure is used as a parameter.

  As described above, it can be seen from FIG. 4 that there is a correlation between the power consumption of the compressor 32, the pressure of the refrigerant gas output from the compressor 32, the magnet shield temperature, and the power consumption of the heater. Further, according to FIG. 4, by changing the gas pressure from Pa [bar] to Pf [bar], the power consumption value in the compressor 32 changes from WC2 [W] to WC4 [W]. . This change in power consumption is useful.

  In the pressure determination function 371, the gas pressure control circuit 37 sets the target pressure value according to the trends shown in FIGS. 3 and 4. The gas pressure control circuit 37 determines the target pressure value according to whether the imaging system in the magnetic resonance imaging apparatus 1, that is, the scanner apparatus 10 and the apparatus body 20 shown in FIG. 1 are operating, and the magnet shield temperature. To set.

  Specifically, the gas pressure control circuit 37 sets the normal range of the magnet shield temperature within a predetermined range centered on T4 [K], for example. When the magnet shield temperature exceeds the maximum value in the normal range while the imaging system in the magnetic resonance imaging apparatus 1 is operating, the gas pressure control circuit 37 sets the pressure value Pf [bar] having the maximum cooling capacity to the refrigerant. Set the target gas pressure value. Further, when the imaging system in the magnetic resonance imaging apparatus 1 is operating and the magnet shield temperature is within the normal range, the gas pressure control circuit 37 sets the pressure value Pc [bar] as the target pressure value. At this time, the pressure value Pc [bar] set as the target pressure value is such that the refrigerant gas output from the compressor 32 due to this pressure excessively cools the helium gas in the cooling container 112 when the imaging system is operating. The value should not be set. That is, in the present embodiment, it is not assumed that the magnet shield temperature falls below the normal range when the imaging system is operating.

  Further, when the magnetic shield temperature exceeds the maximum value in the normal range when the imaging system in the magnetic resonance imaging apparatus 1 is stopped, the gas pressure control circuit 37 causes the pressure value Pf [bar] having the maximum cooling capacity. Is set as the target pressure value. Further, when the magnetic shield temperature is within the normal range when the imaging system in the magnetic resonance imaging apparatus 1 is stopped, the gas pressure control circuit 37 sets the pressure value Pa [bar] as the target pressure value. At this time, the pressure value Pa [bar] set as the target pressure value is such that the refrigerant gas output from the compressor 32 due to this pressure excessively cools the helium gas in the cooling container 112 when the imaging system is stopped. The value should not be set. That is, in the present embodiment, it is not assumed that the magnet shield temperature falls below the normal range when the imaging system is stopped.

  The setting of the target pressure value by the gas pressure control circuit 37 is performed based on, for example, a correspondence table which is stored in advance in the storage circuit and represents the relationship between the target pressure value and the magnet shield temperature. Further, the gas pressure control circuit 37 may store, for example, a function representing the tendency shown in FIG. 4 in a storage circuit and set the target pressure value based on this function.

  Although not shown in FIGS. 3 and 4, when the compressor 32 is driven, the pressure value of the refrigerant gas output from the compressor 32 always fluctuates slightly. Therefore, the target pressure value set based on FIG. 4 may allow a predetermined width.

  The target pressure value may be set based on the pressure value input by the operator via the input interface circuit 38. The gas pressure control circuit 37 preferentially adopts the input pressure value over the pressure value set based on ON / OFF of the imaging system and the magnet shield temperature. The gas pressure control circuit 37 adopts the input pressure value as the target pressure value until the input pressure value is released.

  The pressure control function 372 is a function of controlling the pressure adjustment mechanism based on the target pressure value determined by the pressure determination function 371. In the pressure control function 372, the gas pressure control circuit 37 controls the ventilation valve 34 and the intake valve so that the pressure of the refrigerant gas supplied to the refrigerator main body 33 becomes the target pressure value determined by the pressure determination function 371. A control signal for controlling the opening degree of the ventilation valve 34 or the opening degree of the intake valve 35 is output to the valve 35.

  Specifically, the gas pressure control circuit 37 acquires the differential pressure between the target pressure value calculated by the differential pressure measuring function 373 described later and the pressure value measured by the pressure measuring device 36. The gas pressure control circuit 37 controls the opening degree of the ventilation valve 34 or the opening degree of the intake valve 35 so that the acquired differential pressure becomes zero.

  The gas pressure control circuit 37 may improve the control accuracy of the ventilation valve 34 and the intake valve 35 by, for example, feedback control. Specifically, the gas pressure control circuit 37 repeats the control of the ventilation valve 34 and the intake valve 35 until the differential pressure calculated by the differential pressure measuring function 373 becomes a predetermined value or less.

  The differential pressure measuring function 373 is a function of calculating the differential pressure between the target pressure value and the measured value of the pressure of the refrigerant gas. In the differential pressure measuring function 373, the gas pressure control circuit 37 acquires the measurement value output from the pressure measuring device 36 at a preset cycle. The gas pressure control circuit 37 converts the acquired measurement value into a pressure value, and calculates the difference between the converted pressure value and the target pressure value.

  Next, the operation of the refrigerator unit 30 configured as described above to adjust the pressure of the refrigerant gas will be described according to the processing procedure of the gas pressure control circuit 37. FIG. 5 is a flowchart showing an operation example when the gas pressure control circuit 37 according to the present embodiment adjusts the pressure of the refrigerant gas. In the description of FIG. 5, it is assumed that the target pressure value is set to Pc [bar] shown in FIG. 4 as the initial condition.

  The gas pressure control circuit 37 acquires a measurement value from the pressure measuring device 36. The gas pressure control circuit 37 calculates a pressure value from the acquired measured value. The gas pressure control circuit 37 causes the display circuit 60 to display the calculated pressure value (step S51).

  The gas pressure control circuit 37 acquires magnet shield temperature data from the monitoring device 40 (step S52). The gas pressure control circuit 37 determines whether or not the shield temperature data acquired from the monitoring device 40 is normally acquired data (step S53).

  When normally acquired (Yes in step S53), the gas pressure control circuit 37 determines whether the pressure value is manually input by the operator via the input interface circuit 38 (step S54). When not normally acquired (No of step S53), the gas pressure control circuit 37 judges whether the pressure value was manually input by the operator via the input interface circuit 38 (step S55).

  In step S54, if there is no manual input (No in step S54), the gas pressure control circuit 37 determines whether the imaging system of the magnetic resonance imaging apparatus 1 is operating (step S56). When there is manual input (Yes in step S54), the gas pressure control circuit 37 sets the manually input pressure value to the target pressure value (step S57).

  In step S56, when the imaging system of the magnetic resonance imaging apparatus 1 is operating (Yes in step S56), the gas pressure control circuit 37 determines that the magnet shield temperature supplied from the monitoring device 40 in step S52 is within the normal range. It is determined whether or not the maximum value in is exceeded (step S58). When the imaging system of the magnetic resonance imaging apparatus 1 is not operating (No in step S56), the gas pressure control circuit 37 determines that the magnet shield temperature supplied from the monitoring device 40 in step S52 has the maximum value in the normal range. It is determined whether or not it exceeds (step S59).

  When the magnet shield temperature exceeds the normal range in step S58 (Yes in step S58), the gas pressure control circuit 37 sets the target pressure value to Pf [bar] and starts the rapid cooling control (step S510). When the magnet shield temperature is within the normal range (No in step S58), the gas pressure control circuit 37 sets the target pressure value to Pc [bar] and starts the normal state control (step S511).

  When the magnet shield temperature exceeds the maximum value in the normal range in step S59 (Yes in step S59), the gas pressure control circuit 37 sets the target pressure value to Pf [bar] and starts the rapid cooling control (step S59). S512).

  When the magnet shield temperature is within the normal range (No in step S59), the gas pressure control circuit 37 sets the target pressure value to Pa [bar] and starts the power consumption reduction control (step S513). At this time, the gas pressure control circuit 37 and the pressure supplied from the pressure measuring device 36 in step S51 and Pa [bar] so that the pressure of the refrigerant gas output from the compressor 32 becomes Pa [bar]. The opening degree of the ventilation valve 34 is controlled on the basis of the pressure difference between and.

  The gas pressure control circuit 37 determines the target value pressure in step S57, step S510, step S511, step S512, and step S513, and when each control is started, the target pressure value and the pressure of the refrigerant gas acquired in step S51. The pressure difference with the value is calculated (step S514). The gas pressure control circuit 37 controls the opening degree of the ventilation valve or the opening degree of the intake valve 35 so that the calculated differential pressure becomes zero (step S515).

  For example, when the target pressure value is Pf [bar], the gas pressure control circuit 37 sets the differential pressure between the pressure supplied from the pressure measuring device 36 in step S51 and Pf [bar] to zero. The opening degree of the intake valve 35 is controlled. Further, when the target pressure value is Pc [bar], the gas pressure control circuit 37 sets the differential pressure between the pressure supplied from the pressure measuring device 36 in step S51 and Pc [bar] to zero. The opening degree of the ventilation valve 34 or the intake valve 35 is controlled. Further, when the target pressure value is Pa [bar], the gas pressure control circuit 37 sets the differential pressure between the pressure supplied from the pressure measuring device 36 in step S51 and Pa [bar] to be zero. The opening degree of the ventilation valve 34 is controlled. In addition, when the target pressure value is the input value, the gas pressure control circuit 37 sets the ventilation valve 34 or the vent valve 34 so that the pressure difference between the pressure supplied from the pressure measuring device 36 in step S51 and the input value becomes zero. The opening degree of the intake valve 35 is controlled.

  The gas pressure control circuit 37 acquires a measurement value output from the pressure measuring device 36 after a predetermined period has elapsed. The gas pressure control circuit 37 determines whether or not the differential pressure between the target pressure value and the pressure value calculated from the measured value is a predetermined value or less, for example, 0.5 [bar] or less (step S516). ).

  When the differential pressure between the target pressure value and the actually measured pressure value is equal to or less than the predetermined value (Yes in step S516), the gas pressure control circuit 37 shifts the processing to A and repeats the processing shown in FIG. When the difference between the target pressure value and the actually measured pressure value exceeds the predetermined value (No in step S516), the gas pressure control circuit 37 shifts the processing to step S515 until the differential pressure falls within the predetermined value. The processes of steps S515 and S516 are repeated.

  In step S55, when there is no manual input (No in step S55), the gas pressure control circuit 37 sets the target pressure value to Pc [bar] (step S517) and shifts the processing to step S514. When there is manual input (Yes in step S55), the gas pressure control circuit 37 sets the manually input pressure as the target pressure value (step S518), and shifts the processing to step S514.

  As described above, in the first embodiment, as shown in FIG. 4, the fluctuation tendency of other parameters with respect to the pressure fluctuation of the refrigerant gas has been clarified. Based on this tendency, the gas pressure control circuit 37 controls the pressure value of the refrigerant gas according to the monitoring result received from the monitoring device 40. As a result, the gas pressure control circuit 37 can control the cooling capacity of the refrigerator main body 33 and the power consumption of the compressor 32 according to the state of the superconducting magnet unit 11. Therefore, according to the magnetic resonance imaging apparatus 1 according to the first embodiment, it is possible to reduce unnecessary energy consumption while maintaining the required cooling capacity.

  In the first embodiment, the case where the gas pressure control circuit 37 sets the target pressure value based on the magnet shield temperature has been described as an example. However, it is not limited to this. FIG. 4 shows the magnet shield temperature with respect to the power consumption of the compressor 32 and the pressure of the refrigerant gas output from the compressor 32 when the compressor 32 is being driven. It has been found that the pressure inside the magnet also shows a similar fluctuation tendency to the fluctuation tendency of the magnet shield temperature in FIG. Therefore, the gas pressure control circuit 37 may set the target pressure value based on the magnet internal pressure instead of the magnet shield temperature.

  Furthermore, for example, the target pressure value may be set based on the eddy magnetic field characteristics and the gradient magnetic field strength. The eddy magnetic field characteristics are, for example, the eddy magnetic field strength and the time constant of the eddy magnetic field. The eddy magnetic field characteristics fluctuate with changes in the magnet shield temperature, and can be obtained based on the magnet shield temperature. For example, the power consumption of the compressor and the magnet shield temperature shown in FIG. 4 may be replaced with the power consumption of the compressor and the eddy magnetic field characteristics, or the relationship between the pressure of the refrigerant gas and the magnet shield temperature may be changed to the pressure of the refrigerant gas. It is also possible to replace it with the relationship with the eddy magnetic field characteristics. The measurement of the eddy magnetic field characteristics can be performed, for example, at the time of the quality check of the magnetic resonance imaging apparatus performed at the end or the beginning of the examination of the day.

  Since the eddy magnetic field is one of the factors that cause the deterioration of the image quality, it is possible to prevent the deterioration of the image quality by setting the target pressure value that suppresses the fluctuation of the magnet shield temperature based on the eddy magnetic field characteristics. .

  Further, when the gradient magnetic field strength is large, it becomes a factor of increasing the magnet shield temperature and the magnet internal pressure. Therefore, by setting a target pressure value that suppresses the magnet shield temperature based on the gradient magnetic field strength, it is possible to prevent deterioration of image quality.

  As described above, it is possible to set an appropriate target pressure value by measuring the internal state of the cooling container based on the magnet shield temperature, the magnet internal pressure, the eddy magnetic field characteristics, the gradient magnetic field strength, and the like.

  At this time, the gas pressure control circuit 37 sets the target pressure value in the pressure determination function 371 depending on whether or not the imaging system in the magnetic resonance imaging apparatus 1 is operating and the magnet internal pressure.

  Specifically, the gas pressure control circuit 37 sets, for example, the normal range of the internal pressure of the magnet within a predetermined range centered on P '[bar]. When the internal pressure of the magnet exceeds the maximum value in the normal range while the imaging system in the magnetic resonance imaging apparatus 1 is operating, the gas pressure control circuit 37 targets the pressure value Pf [bar] having the maximum cooling capacity. Set as a pressure value. Further, when the imaging system in the magnetic resonance imaging apparatus 1 is operating and the internal pressure of the magnet is within the normal range, the gas pressure control circuit 37 sets the pressure value Pc [bar] as the target pressure value.

  When the internal pressure of the magnet exceeds the maximum value in the normal range when the imaging system of the magnetic resonance imaging apparatus 1 is stopped, the gas pressure control circuit 37 causes the pressure value Pf [bar] having the maximum cooling capacity. Is set as the target pressure value. Further, when the internal pressure of the magnet is within the normal range when the imaging system of the magnetic resonance imaging apparatus 1 is stopped, the gas pressure control circuit 37 sets the pressure value Pa [bar] as the target pressure value.

  FIG. 6 is a flowchart showing an operation example when the gas pressure control circuit 37 according to the present embodiment adjusts the pressure of the refrigerant gas based on the internal pressure of the magnet. The operation of the gas pressure control circuit 37 in FIG. 6 is similar to the operation of the gas pressure control circuit 37 in FIG. 5 illustrates the case where the gas pressure control circuit 37 sets the target pressure value based on the magnet shield temperature, and FIG. 6 illustrates the case where the target pressure value is set based on the magnet internal pressure. However, the gas pressure control circuit 37 may set the target pressure based on the magnet shield temperature and the magnet internal pressure.

  Further, in the first embodiment, the case where the tendencies shown in FIGS. 3 and 4 are acquired by the preliminary experiment has been described as an example. However, it is not limited to this. For example, the tendencies shown in FIGS. 3 and 4 may be acquired when the magnetic resonance imaging apparatus 1 is installed. At this time, the refrigerator unit 30 is equipped with the power consumption measuring device 311 as shown in FIG. The power consumption meter 311 measures the power consumption consumed by the compressor 32 in a preset cycle, and outputs the measured power consumption to the gas pressure control circuit 37. The gas pressure control circuit 37 controls the ventilation valve 34 and the intake valve 35 to operate the pressure of the refrigerant gas output by the compressor 32, and the power consumption measured by the power consumption measuring device 311 at that time, and The pressure data in the magnet, the magnet shield temperature, and the power consumption of the heater acquired by the monitoring device 40 are acquired. The gas pressure control circuit 37 acquires the tendency shown in FIGS. 3 and 4 based on the acquired data. The power consumption meter 311 may output the measured power consumption to the apparatus body 20.

  Further, in the first embodiment, the case where the target pressure value of the refrigerant gas is set based on the tendency shown in FIG. 4, that is, the tendency when the compressor 32 is driven has been described as an example. However, it is not limited to this. As shown by the triangles in FIG. 3, it has been confirmed that the same tendency as that shown in FIG. 4 is obtained even when the compressor 32 stops operating. The gas pressure control circuit 37 may set the target pressure value of the refrigerant gas based on the tendency acquired when the compressor 32 stops operating. However, when controlling the pressure of the refrigerant gas output from the compressor 32 using this target pressure value, it is necessary to stop the compressor 32 when measuring the pressure of the refrigerant gas with the pressure measuring device 36. is there.

  Since it is not necessary to stop the compressor 32 by setting the target pressure value of the refrigerant gas based on the tendency when the compressor is being driven, for example, exhaustion of parts by repeatedly stopping the compressor 32 is performed. Can be prevented. In addition, it is possible to prevent a loss of working time due to stopping the compressor 32. Furthermore, for example, the temperature inside the magnet rises even while the compressor 32 is stopped, so it is preferable to set the target pressure value of the refrigerant gas while the compressor 32 is operating.

  Further, the tendency shown in FIG. 4 is an example derived from the test results using one example. The numerical value obtained by the experiment depends on the characteristics of the refrigerator unit 30 actually used, the characteristics of the magnetic resonance imaging apparatus 1 to which the refrigerator unit 30 is attached, and the like. Therefore, the target pressure value set by the gas pressure control circuit 37 needs to be appropriately adjusted according to the refrigerator unit and the magnetic resonance imaging apparatus to which the refrigerator unit is attached.

  Further, in the first embodiment, the case where the refrigerator unit 30 and the monitoring device 40 are provided in the magnetic resonance imaging apparatus 1 has been described as an example, but the present invention is not limited to this. The refrigerator unit 30 may include the monitoring device 40 as a part of the refrigerator unit 30 as shown in FIG. 8.

  Further, in the first embodiment, as shown in FIG. 2, the case where the refrigerator unit 30 includes the gas pressure control circuit 37 has been described as an example. However, it is not limited to this. The gas pressure control circuit 37 may be provided in the compressor 32 as shown in FIG. When the monitoring device 40 is provided in the refrigerator unit 30, the gas pressure control circuit 37 may be provided in the monitoring device 40 as shown in FIG. 10.

  Further, in the first embodiment, the case where the control circuit 29 includes a storage circuit has been described as an example, but the present invention is not limited to this. Various information and operation programs stored in the storage circuit provided in the control circuit 29 may be stored in the storage circuit 25 of the apparatus body 20. In this case, the control circuit 29 reads out the information and operation program necessary to realize the function from the storage circuit 25 and uses them.

  Further, in the first embodiment, the case where the gas pressure control circuit 37 includes the storage circuit has been described as an example, but the present invention is not limited to this. Various information and operation programs stored in the storage circuit provided in the gas pressure control circuit 37 may be stored in the storage circuit provided independently in the refrigerator unit 30. In this case, the gas pressure control circuit 37 reads out the information and operation program necessary to realize the function from the storage circuit provided in the refrigerator unit 30 and uses it.

(Second embodiment)
In the first embodiment, the case where the gas pressure control circuit 37 controls the pressure of the refrigerant gas output from the compressor 32 in accordance with the internal magnet pressure or the magnet shield temperature has been described as an example. In the second embodiment, it is possible to reduce unnecessary energy consumption while maintaining a required cooling capacity without providing a mechanism for automatically controlling the pressure of the refrigerant gas output from the compressor. The resonance imaging apparatus will be described.

  FIG. 11 is a schematic diagram showing the configuration of the magnetic resonance imaging apparatus 1A according to the second embodiment. The magnetic resonance imaging apparatus 1A shown in FIG. 11 includes a scanner device 10, a device body 20A, a refrigerator unit 30A, and a monitoring device 40.

  The apparatus main body 20A includes a static magnetic field power supply circuit 21, a gradient magnetic field power supply circuit 22, a transmission circuit 23, a reception circuit 24, a storage circuit 25A, an arithmetic circuit 26, an input interface circuit 27, an output interface circuit 28, a control circuit 29A, and a communication interface. The circuit 210 is provided.

  The storage circuit 25A has a recording medium or the like that can be read by a processor, such as a magnetic or optical recording medium or a semiconductor memory. The storage circuit 25A includes storage areas of an MR signal storage unit 251, an image data storage unit 252, a characteristic storage unit 253, and a measurement result storage unit 254. The MR signal storage unit 251 stores the MR signal digitally converted by the receiving circuit 24. The image data storage unit 252 stores image data obtained by reconstructing the MR signal.

  The characteristic storage unit 253 stores characteristic information about a characteristic curve indicating the relationship between the pressure value of the refrigerant gas output from the compressor 32A and the magnet shield temperature, and the magnet shield temperature X [K]. The characteristic curve is approximated by, for example, a higher-order equation including a quartic equation and a quadratic equation in which x is a pressure value and y is a magnet shield temperature. In the initial state, characteristic information predicted based on theoretical values, measured values, empirical rules, or the like is stored in advance in a general magnetic resonance imaging apparatus. The characteristic information stored in advance is updated with the characteristic information unique to the magnetic resonance imaging apparatus 1A predicted by the control circuit 29A described later. The magnet shield temperature X [K] is a minimum temperature at which the magnetic resonance imaging apparatus 1A can be continuously used even under the harshest possible environment, in other words, a problem with respect to pressure inside the magnet and vortex adjustment. Is a temperature at which the power consumption can be reduced and the power consumption can be reduced. The magnet shield temperature X [K] is used as a target value of the magnet shield temperature when setting the gas pressure specific to the compressor 32A provided in the magnetic resonance imaging apparatus 1A.

  The measurement result storage unit 254 stores the refrigerant gas pressure data acquired by the refrigerator unit 30A, the heater power consumption data acquired by the monitoring device 40A, and the magnet shield temperature data. The data stored in the measurement result storage unit 254 is utilized as log information, for example.

  The communication interface circuit 210 is realized by, for example, a communication port and connection ports such as an HDMI (registered trademark) terminal, a DVI terminal, and a USB terminal. The communication interface circuit 210 is connected to, for example, a hospital LAN (Local Area Network) via a communication port. The communication interface circuit 210 converts the data output from the control circuit 29A according to a preset method, and outputs the converted data to the in-hospital LAN. The communication interface circuit 210 is connected to, for example, a service terminal owned by the operator through the connection port. The service terminal may be composed of any terminal such as a laptop PC as a portable terminal, a stationary desktop PC, or a tablet terminal.

  The communication interface circuit 210 outputs the data output from the control circuit 29A to the service terminal 70. The communication interface circuit 210 also outputs an instruction input from the service terminal 70 to the control circuit 29A.

  The control circuit 29A is a processor having a function of integrally controlling the magnetic resonance imaging apparatus 1A. The control circuit 29A has a storage circuit (not shown). The memory circuit of the control circuit 29A is for controlling the subject information, the information regarding the acquisition condition of the MR signal, the information regarding the display condition of the image data, the information regarding the image display format, and the circuit within the magnetic resonance imaging apparatus 1A. The operation program and the like are stored. The control circuit 29A calls each operation program from the storage circuit and executes the called program to execute a sequence control function 291, an image creation function 292, a refrigerator control function 293, an information presentation function 294, a characteristic prediction function 295, and a characteristic update. A function 296, a determination function 297, and a communication control function 298 are realized.

  The information presentation function 294 is a function for displaying information necessary for setting the refrigerator unit 30A, for example, change information for changing the gas pressure in the compressor 32A, on the service terminal 70 via the communication interface circuit 210. is there. The characteristic prediction function 295 is a function of predicting the characteristics of the magnetic resonance imaging apparatus 1A based on the measured magnet shield temperature and the like. The characteristic update function 296 is a function of updating the characteristic stored in the characteristic storage unit 253 of the storage circuit 25A with the characteristic predicted by the characteristic prediction function 295. The determination function 297 is a function of determining that the refrigerant gas has leaked from the compressor 32A, or that the components of the refrigerator unit 30A have been consumed at a certain level or more. Here, among the components forming the refrigerator unit 30A, the consumed components are, for example, the refrigerator main body 33, the compressor 32A, and the cool storage material. Further, the consumption of the components of the refrigerator unit 30A above a certain level means that the components of the refrigerator unit 30A are consumed to the extent that the cooling capacity set at the time of installation cannot be maintained, for example. The communication control function 298 is a function of outputting information and the like necessary for setting the refrigerator unit 30A to the communication interface circuit 210.

  The monitoring device 40A monitors the magnet shield temperature of the cooling container 112 of the superconducting magnet unit 11 and the power consumption of the heater provided in the cooling container 112. The monitoring device 40A receives the detection signal output from the temperature sensor provided in the cooling container 112. The monitoring device 40A creates magnet shield temperature data based on the detection signal, and outputs the created magnet shield temperature data to the device body 20A. The monitoring device 40A acquires the power consumption of the heater by monitoring the power supplied to the heater. The monitoring device 40A creates heater power consumption data based on the acquired power consumption of the heater, and outputs the created power consumption data to the device body 20A.

  FIG. 12 is a schematic diagram showing a configuration example of the superconducting magnet unit 11 and the refrigerator unit 30A shown in FIG. The refrigerator unit 30A shown in FIG. 12 includes a compressor 32A, a refrigerator body 33, and a pressure measuring device 36A.

  The compressor 32A is connected to the refrigerator main body 33 by a supply pipe 321 and a discharge pipe 322. The compressor 32A compresses a refrigerant gas such as helium gas at a set pressure, and supplies the refrigerant gas in a high pressure state to the refrigerator main body 33 via the supply pipe 321. Further, the compressor 32 collects the refrigerant gas expanded inside the refrigerator main body 33 via the discharge pipe 322.

  The compressor 32A includes a gas inlet / outlet port 323 for the operator to inject or exhaust the refrigerant gas. The operator supplies the gas from the compressor 32A to the refrigerator main body 33 by injecting the gas from the gas inlet / outlet 323 or discharging the gas from the gas inlet / outlet 323 according to the instruction content displayed on the service terminal 70. Adjust the pressure of the refrigerant gas.

  The pressure measuring device 36A is realized by, for example, a pressure sensor. The pressure measuring device 36A measures the pressure of the refrigerant gas output from the compressor 32 to the refrigerator main body 33 at a preset cycle. The pressure measuring device 36A outputs the measured value to the device body 20A.

  Next, the operation of the control circuit 29A in the magnetic resonance imaging apparatus 1A configured as described above will be described in detail separately for installation and operation.

(At installation)
FIG. 13 is a flowchart showing an example of operations of the information presenting function 294, the characteristic predicting function 295, and the characteristic updating function 296 executed when the magnetic resonance imaging apparatus 1A shown in FIG. 11 is installed. FIG. 14 is an explanatory diagram schematically showing a procedure for adjusting the compressor 32A when the magnetic resonance imaging apparatus 1A is installed.

  First, the magnetic resonance imaging apparatus 1A is loaded. An operator in charge of loading the magnetic resonance imaging apparatus 1A connects the service terminal 70 to the communication interface circuit 210. The operator operates the service terminal 70 to operate the refrigerator unit 30A.

When the refrigerator unit 30A is operated, the pressure measuring device 36A of the refrigerator unit 30A measures the pressure of the refrigerant gas output from the compressor 32A and outputs the measured value to the device body 20A. The measured value at this time is defined as P _start [bar]. The measured value P _start [bar] is stored in the storage circuit 25A of the apparatus main body 20A and is displayed on the service terminal 70 according to an instruction from the control circuit 29A (step S131). Note that in FIG. 14, the measured value P _start [bar] represents the gas pressure at which the cooling capacity of the refrigerator unit 30A is maximized. However, the gas pressure initially measured after operating the refrigerator unit 30A is not limited to the gas pressure that maximizes the cooling capacity, and may take other values.

The control circuit 29A reads the characteristic information stored in advance from the storage circuit 25A. The solid line shown in FIG. 14 is a characteristic curve representing the relationship between the pressure value and the magnet shield temperature, which is defined by the characteristic information read at this time. The control circuit 29A calculates the gas pressure P _X [bar] when the magnet shield temperature X [K] is reached, using the read characteristic information (step S132). The control circuit 29A calculates the differential pressure between the measured value P _start [bar] and the gas pressure P _X [bar], and changes the calculated differential pressure and the increasing / decreasing direction from the gas pressure P _start [bar]. Is displayed on the service terminal 70 (step S133). The control circuit 29A may display the calculated gas pressure P _X [bar] as change information. Further, the control circuit 29A may display only the increasing / decreasing direction, or an approximate differential pressure such as a number [bar] and the increasing / decreasing direction as change information.

The operator refers to the change information displayed on the service terminal 70 and discharges the refrigerant gas from the gas inlet / outlet 323 of the compressor 32A. The monitoring device 40A monitors the magnet shield temperature at a predetermined cycle and outputs the magnet shield temperature data to the device body 20A. After the gas pressure P _X [bar] is newly set, for example, about one day is waited until the magnet shield temperature of the magnetic resonance imaging apparatus 1A becomes stable.

When the magnet shield temperature stabilizes, the control circuit 29A causes the service terminal to display the magnet shield temperature X ₁ [K] at that time (step S134). The control circuit 29A determines whether the difference between the magnet shield temperature X ₁ [K] and the magnet shield temperature X [K] is equal to or less than a preset threshold value (step S135). When it is less than or equal to the threshold value (Yes in step S135), the control circuit 29A ends the process. When it exceeds the threshold value (No in Step S135), the control circuit 29A sets the measured value P _start [bar], the gas pressure P _X [bar], and the gas pressure P _X [bar] to the magnet shield temperature X _1. The relationship between the pressure value and the magnet shield temperature is predicted based on [K] (step S136). The broken line shown in FIG. 14 is a characteristic curve representing the relationship between the pressure value and the magnet shield temperature predicted at this time. The control circuit 29A stores the predicted characteristic curve in the storage circuit 25A as new characteristic information (step S137). The control circuit 29A uses the new characteristic information to calculate the gas pressure P _X1 [bar] when the magnet shield temperature X [K] is reached (step S138). The control circuit 29A calculates the differential pressure between the gas pressure P _X [bar] and the gas pressure P _X1 [bar], and calculates the differential pressure and the increase / decrease direction from the gas pressure P _X [bar] as change information. Is displayed on the service terminal 70 (step S139). The control circuit 29A may display the calculated gas pressure P _X1 [bar] as change information.

  The operator refers to the change information displayed on the service terminal 70 and injects the refrigerant gas into the gas inlet / outlet port 323 of the compressor 32A. The monitoring device 40A monitors the magnet shield temperature at a predetermined cycle and outputs the magnet shield temperature data to the device body 20A.

When the magnet shield temperature stabilizes, the control circuit 29A causes the service terminal to display the magnet shield temperature X ₂ [K] at that time (step S1310). The control circuit 29A determines whether or not the difference between the magnet shield temperature X ₂ [K] and the magnet shield temperature X [K] is less than or equal to a preset threshold value (step S1311). When it is less than or equal to the threshold value (Yes in step S1311), the control circuit 29A sets the newly stored characteristic information as characteristic information unique to the magnetic resonance imaging apparatus 1A, and updates the characteristic information stored in advance with this characteristic information. Then (step S1312), the process ends. When it exceeds the threshold value (No in step S1311), the control circuit 29A causes the process to proceed to step S136. In the case shown in FIG. 14, the magnet shield temperature X [K] is presented in step S1310, and in step S1312, the characteristic information stored in advance is updated with the characteristic information indicated by the broken line.

Although FIG. 14 shows an example in which the magnet shield temperature X ₁ [K] is higher than the magnet shield temperature X [K], the magnet shield temperature X ₁ [K] is equal to the magnet shield temperature X [K]. The control circuit 29A can perform the same processing even if the temperature is lower than the above.

  As described above, in the magnetic resonance imaging apparatus 1A according to the second embodiment, the control circuit 29A, based on the characteristics set for the magnetic resonance imaging apparatus 1A, has the lowest temperature X at which no abnormality occurs even in the worst case. The gas pressure corresponding to [K] is calculated. The control circuit 29A causes the service terminal 70 to display change information for changing the current gas pressure to the calculated gas pressure. When the magnet shield temperature of the cooling container 112 cooled by the gas pressure changed based on the change information is more than a predetermined value away from X [K], the control circuit 29A determines the magnetic resonance imaging apparatus 1A based on the acquired data. Predict new properties for. When the magnet shield temperature of the cooling container 112 cooled by the gas pressure changed based on the change information is substantially equal to X [K], the control circuit 29A determines the set characteristic to be unique to the magnetic resonance imaging apparatus 1A. The characteristics of This makes it possible to set the gas pressure that actually realizes the minimum temperature X [K] that does not cause an abnormality even in the worst case, as the gas pressure of the compressor 32A during installation. That is, since the gas pressure that actually realizes the magnet shield temperature X [K] can be set in the compressor 32A, it is possible to perform cooling according to the required cooling capacity.

  Therefore, according to the magnetic resonance imaging apparatus 1A of the second embodiment, it is possible to reduce unnecessary energy consumption while maintaining the required cooling capacity.

Note that, in FIG. 13, in consideration of the possibility that the preset characteristic information and the characteristic information unique to the magnetic resonance imaging apparatus 1A match, in step S135, the magnet shield temperature X ₁ [K], It is determined whether or not the difference from the magnet shield temperature X [K] is less than or equal to a preset threshold value. However, it is not limited to this. The control circuit 29A may omit the determination in step S135, assuming that the preset characteristic information does not match the characteristic information unique to the magnetic resonance imaging apparatus 1A. This makes it possible to set the gas pressure of the compressor 32A at the time of installation while suppressing the processing load of the control circuit 29A.

Further, in FIG. 13, the case where the characteristic information unique to the magnetic resonance imaging apparatus 1A is predicted and the gas pressure of the compressor 32A is set based on the predicted characteristic information has been described as an example. However, it is not limited to this. The control circuit 29A may display the magnet shield temperature X ₁ [K] when the magnet shield temperature is stable in step S134 on the service terminal, and may accept the injection or discharge of the refrigerant gas from the operator. This makes it possible to set the gas pressure of the compressor 32A at the time of installation while suppressing the processing load of the control circuit 29A.

(During operation)
The characteristic information unique to the magnetic resonance imaging apparatus 1A set at the time of installation is utilized when the magnetic resonance imaging apparatus 1A is in operation, for example, when the refrigerator unit 30A is inspected and maintained. The cooling capacity of the refrigerator unit 30A decreases with the passage of time. The reason why the cooling capacity of the refrigerator unit 30A is lowered is, for example, the leakage of the refrigerant gas from the compressor 32A, the consumption of the components forming the refrigerator unit 30A, and the like. Below, the procedure at the time of readjusting the compressor 32A in which the refrigerant gas has leaked and the procedure at the time of readjusting the refrigerator unit 30A in which the components have been worn to a certain extent or more will be described.

  FIG. 15 is a flowchart showing an example of operations of the information presentation function 294, the characteristic prediction function 295, the characteristic update function 296, and the determination function 297, which are executed when the refrigerating unit 30A or the compressor 32A is readjusted. FIG. 16: is explanatory drawing which shows typically the procedure of readjusting the compressor 32A which the refrigerant gas leaked. FIG. 17: is explanatory drawing which shows typically the procedure of readjusting the refrigerator unit 30A whose component parts are exhausted.

At the time of periodic inspection of the magnetic resonance imaging apparatus 1A, the inspector reads out the magnet shield temperature of the magnetic resonance imaging apparatus 1A from the measurement result storage unit 254. The control circuit 29A determines whether or not the read magnet shield temperature is equal to or higher than a preset X _error [K] (step S151). When the read magnet shield temperature is equal to or higher than the preset X _error [K] (Yes in step S151), the control circuit 29A determines the gas pressure when the magnet shield temperature X _error [K] is measured. The data is read from the storage unit 254 (step S152). In FIGS. 16 and 17, since the magnet shield temperature reaches X _error [K], the gas pressure at this time is read from the measurement result storage unit 254. The read gas pressure is the gas pressure P _error [bar] in FIG. 16 and the gas pressure P _x [bar] in FIG. 17. When the read magnet shield temperature is lower than the preset X _error [K] (No in step S151), the control circuit 29A ends the process.

Following step S152, the control circuit 29A determines whether the difference between the read gas pressure and the gas pressure P _x [bar] set when the magnetic resonance imaging apparatus 1A is installed is within a preset range. Is determined (step S153). If it is within the preset range (Yes in step S153), the control circuit 29A determines that the components of the refrigerator unit 30A have been consumed at a certain level or more (step S154). In the example shown in FIG. 17, the read-out gas pressure _P x [bar], it is equal to the magnetic resonance imaging apparatus 1A set when installing the gas pressure _P x [bar]. Therefore, the control circuit 29A determines that the components of the refrigerator unit 30A have been consumed to a certain extent or more.

When it exceeds the preset range (No in step S153), the control circuit 29A determines that the refrigerant gas has leaked from the compressor 32A (step S155). In the example shown in FIG. 16, there is a predetermined difference between the read gas pressure P _error [bar] and the gas pressure P _x [bar] set when the magnetic resonance imaging apparatus 1A is installed. Therefore, the control circuit 29A determines that the refrigerant gas has leaked from the compressor 32A.

When the control circuit 29A determines in step S155 that the refrigerant gas has leaked from the compressor 32A, for example, the gas pressure P _error [bar] read from the measurement result storage unit 254 and the magnetic resonance imaging apparatus 1A are installed. The differential pressure with the gas pressure P _x [bar] set at that time and the increasing / decreasing direction from the gas pressure P _x [bar] are displayed on the service terminal 70 as change information (step S156), and the process is ended. The control circuit 29A may display the calculated gas pressure P _error [bar] as change information.

  The inspector refers to the change information displayed on the service terminal 70 and injects the refrigerant gas into the gas inlet / outlet port 323 of the compressor 32A.

  When the refrigerant gas leaks from the compressor 32A, the gas pressure of the refrigerant gas filled in the compressor 32A decreases. Therefore, the ability to cool the helium gas in the cooling container 112 is lowered, and the magnet shield temperature is raised. According to the magnetic resonance imaging apparatus 1A of the second embodiment, the control circuit 29A uses the characteristic information stored in the characteristic storage unit 253 to determine whether the refrigerant gas has leaked from the compressor 32A. I am trying to do it. Thereby, the inspector can easily detect that the refrigerant gas has leaked from the compressor 32A. When the control circuit 29A determines that the refrigerant gas has leaked from the compressor 32A, the control circuit 29A causes the service terminal 70 to display change information for changing the current gas pressure to the gas pressure set at the time of installation. . This facilitates the inspector to return the gas pressure of the compressor 32A to the state before the leak.

  When the control circuit 29A determines in step S154 that the components of the refrigerator unit 30A have been consumed at a certain level or more, the control circuit 29A acquires log information regarding the power consumption of the heater from the measurement result storage unit 254 (step S157). . The control circuit 29A determines whether or not the power consumption of the heater is constantly 0 [W] based on the acquired log information (step S158). Note that the case where the power consumption of the heater constantly becomes 0 [W] means, for example, when the total of the periods when the power consumption of the heater becomes 0 [W] exceeds a predetermined time within a preset period. Say. For example, when the power consumption of the heater is 0 [W] for a predetermined time or more as a result of the periodic log information of the power consumption of the heater, the power consumption of the heater is constantly 0 [W]. Can be regarded as

The dashed-dotted line shown in FIG. 17 is a characteristic curve showing the relationship between the pressure value in the magnet and the power consumption of the heater when the magnetic resonance imaging apparatus 1A is installed. When the constituent parts of the refrigerator unit 30A are consumed to a certain extent or more, the characteristic of the power consumption of the heater is shifted downward as shown by the chain double-dashed line in FIG. If the power consumption of the heater constantly exceeds 0 [W] at the magnet pressure corresponding to the set gas pressure P _x [bar], the components of the refrigerator unit 30A need not be replaced yet. It is judged that there is. On the other hand, in the three-dot chain line shown in FIG. 17, the power consumption of the heater is 0 [W] at the magnet pressure corresponding to the set gas pressure P _x [bar]. In such a case, the magnet performance cannot be guaranteed.

When the power consumption of the heater is not constantly 0 [W] (No in step S158), that is, when the power consumption of the heater changes as indicated by the chain double-dashed line in FIG. 17, the control circuit 29A Predicts the relationship between the pressure value and the magnet shield temperature from the magnet shield temperature X _error [K] and the gas pressure P _x [bar] at this time (step S159). The broken line shown in FIG. 17 is a characteristic curve representing the relationship between the pressure value and the magnet shield temperature predicted at this time. The control circuit 29A stores the predicted characteristic curve in the storage circuit 25A as new characteristic information (step S1510). The control circuit 29A uses the new characteristic curve to calculate the gas pressure P _error1 [bar] when the magnet shield temperature X [K] is _reached (step _S1511 ). The control circuit 29A calculates the differential pressure between the gas pressure P _X [bar] and the gas pressure P _error1 [bar], and _changes the calculated differential pressure and the increasing / decreasing direction from the gas pressure P _X [bar]. Is displayed on the service terminal 70 (step S1512). The control circuit 29A may display the calculated gas pressure P _error1 [bar] as change information.

  The inspector refers to the change information displayed on the service terminal 70 and injects the refrigerant gas into the gas inlet / outlet jig 323 of the compressor 32A. The monitoring device 40A monitors the magnet shield temperature at a predetermined cycle and outputs the magnet shield temperature data to the device body 20A.

When the magnet shield temperature stabilizes, the control circuit 29A causes the service terminal to display the magnet shield temperature X ₁ [K] at that time (step S1513). The control circuit 29A determines whether the difference between the magnet shield temperature X ₁ [K] and the magnet shield temperature X [K] is equal to or less than a preset threshold value (step S1514). When it is less than or equal to the threshold value (Yes in step S1514), the control circuit 29A sets the newly stored characteristic information as the characteristic information after readjustment, and updates the characteristic information stored in advance with this characteristic information (step S1514). (S1515), the process is ended. When it exceeds the threshold value (No in step S1514), the control circuit 29A shifts the processing to step S159. In the case shown in FIG. 17, the magnet shield temperature X [K] is presented in step S1513, and in step S1515, the characteristic information stored in advance is updated with the characteristic information indicated by the broken line.

In step S158, when the power consumption of the heater is constantly 0 [W] (Yes in step S158), that is, when the power consumption of the heater changes as indicated by the three-dot chain line in FIG. The control circuit 29A causes the service terminal 70 to display information prompting the replacement of the components of the refrigerator unit 30A (step S1516). However, there are cases where it is not possible to immediately respond to replacement of parts, such as a shortage of inventory of components. Therefore, the control circuit 29A may cause the service terminal 70 to display information regarding the first aid in addition to or instead of the displayed information prompting the replacement. The first aid is to charge the compressor 32A with a refrigerant gas of 2 [bar] or more within a range not exceeding P _max [bar], for example.

  When the components forming the refrigerator unit 30A are consumed to a certain extent or more, the cooling capacity of the refrigerator unit 30A deteriorates. Therefore, the characteristics of the magnetic resonance imaging apparatus 1A differ from the characteristics set at the time of installation. In such a case, charging the refrigerant gas to the compressor 32A, as in the case of dealing with the leakage of the refrigerant gas, is not sufficient. According to the magnetic resonance imaging apparatus 1A according to the second embodiment, the control circuit 29A uses the characteristic information stored in the characteristic storage unit 253 to determine whether the components of the refrigerator unit 30A have been consumed by a certain amount or more. I try to judge whether or not. As a result, the inspector can easily detect that the components of the refrigerator unit 30A have been consumed more than a certain amount. Further, when the control circuit 29A determines that the components of the refrigerator unit 30A are consumed to a certain extent or more, it presents information prompting replacement of the components of the magnetic resonance imaging apparatus 1A, or a gas pressure value based on a new characteristic. I am trying to present you. This makes it possible to readjust the refrigerator unit 30A when the constituent parts of the refrigerator unit 30A are consumed to a certain extent or more.

Note that, in FIG. 15, in step S158, the control circuit 29A outputs information prompting the replacement of the components of the refrigerator unit 30A when the power consumption of the heater is constantly 0 [W]. Although the description has been made by taking the case of displaying in the above as an example, the present invention is not limited to this. When the control circuit 29A determines in step S154 in FIG. 15 that the components of the refrigerator unit 30A have been consumed by a certain amount or more, the magnet shield temperature X as shown in step S159 regardless of the power consumption of the heater. The relationship between the pressure value and the magnet shield temperature may be predicted from the _error [K], the gas pressure P _x [bar] at this time, etc., and the processing of steps S1510 to S1515 may be performed. When the control circuit 29A updates the characteristic information of the magnetic resonance imaging apparatus 1A in this way, the curve regarding the power consumption of the heater shown in FIG. 17 is gradually shifted downward every time the characteristic information is updated. The control circuit 29A, for example, when the curve regarding the power consumption of the heater is shifted to the extent shown by the thin line in FIG. 17, that is, the gas pressure to be readjusted and P _max [bar] that is the maximum value of the gas pressure are set. If the difference is less than a preset value, the service terminal 70 is caused to display information prompting replacement of the components of the refrigerator unit 30A. As a result, it becomes possible to extend the replacement time of the component parts while suppressing the power consumption of the compressor 32A.

  In addition, when the control circuit 29A determines in step S154 in FIG. 15 that the components of the refrigerator unit 30A are consumed to a certain extent or more, the components of the refrigerator unit 30A are replaced regardless of the power consumption of the heater. The information prompting the user may be displayed on the service terminal 70. This makes it possible to immediately deal with the possibility that the components of the refrigerator unit 30A are consumed to a certain extent or more.

  Further, in FIG. 15, the case where the refrigerator unit 30A is readjusted during the periodic inspection of the magnetic resonance imaging apparatus 1A has been described as an example. However, the operation shown in FIG. 15 may be executed in cases other than the regular inspection. For example, the control circuit 29A may acquire the magnet shield temperature at a predetermined cycle such as once every several months, and automatically execute the processing of steps S151 to S1516 described in FIG. The control circuit 29A determines, by the communication control function 298, as a result of the inspection automatically executed, for example, that there is a refrigerant gas leak, a countermeasure against the refrigerant gas leak, and a certain amount or more of the components of the refrigerator unit 30A. It is determined that there is exhaustion, or information such as countermeasures against the exhaustion of the components of the refrigerator unit 30A is output to the in-hospital LAN via the communication interface circuit 210. This information is notified from the communication equipment provided in the hospital to the service terminal owned by the maintenance person and the maintenance company. As a result, the control circuit 29A can automatically notify the service terminal or the like of information required for maintenance.

  Further, in FIG. 15, an example is described in which the control circuit 29A automatically determines the leakage of the refrigerant gas from the compressor 32A and the consumption of the components of the refrigerator unit 30A above a certain level by the determination in step S153. did. However, it is not limited to this. An inspector may determine whether the refrigerant gas has leaked from the compressor 32A. In this case, the control circuit 29A causes the service terminal 70 to display the change information necessary to eliminate the leakage of the refrigerant gas, for example. Further, the inspector may judge whether or not the constituent parts of the refrigerator unit 30A have been consumed to a certain extent or more. In this case, the control circuit 29A, for example, predicts new characteristic information based on the measurement information, and sets the gas pressure based on the predicted characteristic information. Alternatively, the control circuit 29A causes the service terminal 70 to display information that prompts replacement of the exhausted component or information regarding first aid. As a result, it becomes possible to eliminate the leakage of the refrigerant gas from the compressor 32A, or to deal with the components of the refrigerating machine unit 30A that have been consumed to a certain extent or more, while suppressing the processing load of the control circuit 29A.

Further, in FIG. 15, the case where the refrigerator unit 30A is readjusted during the periodic inspection of the magnetic resonance imaging apparatus 1A has been described as an example. However, it is not limited to this. The control circuit 29A uses the communication control function 298 to notify that the magnet shield temperature has reached the preset X _error [K], through the communication interface circuit 210 and the in-hospital LAN, the service terminal owned by the maintenance person, the maintenance company, etc. May be notified. Note that this notification may be sent from the monitoring device 40A to the service terminal, the maintenance company, etc. via the in-hospital LAN. As a result, the control circuit 29A can automatically notify the service terminal or the like of the information indicating that the inspection is required. Upon receiving this notification, the maintenance person visits a medical institution where the magnetic resonance imaging apparatus 1A is installed for maintenance of the magnetic resonance imaging apparatus 1A. The maintenance person inspects the magnetic resonance imaging apparatus 1A, and discovers that, for example, the refrigerant gas leaks from the compressor 32A, or the constituent parts of the refrigerator unit 30A are consumed for a certain amount or more. When it is determined that the refrigerant gas leaks from the compressor 32A, the control circuit 29A causes the service terminal 70 to display, for example, the change information necessary to eliminate the refrigerant gas leak. Further, when it is determined that the components of the refrigerator unit 30A have been consumed to a certain extent or more, the control circuit A predicts new characteristic information based on the measurement information, and determines the gas pressure based on the predicted characteristic information. Set. Alternatively, the control circuit 29A causes the service terminal 70 to display information that prompts replacement of the exhausted component or information regarding first aid.

  In the second embodiment, the case where the control circuit 29A causes the service terminal 70 to display information necessary for setting the refrigerator unit 30A has been described as an example. However, it is not limited to this. The control circuit 29A may cause the display circuit 50 to display information necessary for setting the refrigerator unit 30A. As a result, the information necessary for setting the refrigerator unit 30A can be displayed to the operator without the service terminal 70 or the like.

  Further, in the second embodiment, the case where the magnet shield temperature X [K] is a fixed value has been described as an example. However, it is not limited to this. The magnet shield temperature X [K] may be changed during inspection or maintenance, for example. The magnet shield temperature X [K] is a minimum temperature at which the magnetic resonance imaging apparatus 1A can be continuously used even under the harshest possible environment, in other words, a problem with respect to pressure inside the magnet and vortex adjustment. Is a temperature at which the power consumption can be reduced and the power consumption can be reduced. However, the assumed environment varies depending on the environment in which the magnetic resonance imaging apparatus 1A is installed. The control circuit 29A refers to the log information stored in the measurement result storage unit 254 by the characteristic updating function 296 to acquire the proper temperature X '[K] unique to the magnetic resonance imaging apparatus 1A. The proper temperature X '[K] may be input by the inspector after checking the log information. The control circuit 29A updates the magnet shield temperature X [K] stored in advance with the acquired appropriate temperature X '[K]. This makes it possible to set a gas pressure more suitable for the environment in which the magnetic resonance imaging apparatus 1A is installed, which contributes to the reduction of power consumption.

  The word "processor" used in the above description is, for example, a CPU (central processing unit), a GPU (Graphics Processing Unit), or an application specific integrated circuit (ASIC), a programmable logic device (for example, , Simple Programmable Logic Device (SPLD), Complex Programmable Logic Device (CPLD), and Field Programmable Gate Array (FPGA). The processor realizes the function by reading and executing the program stored in the memory circuit. It should be noted that each processor of the present embodiment is not limited to the case where each processor is configured as a single circuit, and a plurality of independent circuits may be combined and configured as one processor to realize its function. Good. Further, a plurality of constituent elements in FIGS. 1, 2, and 7 to 9 may be integrated into one processor to realize its function.

  While some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. For example, the gas pressure adjustment at the time of installation described in the second embodiment may be performed by the magnetic resonance imaging apparatus 1 according to the first embodiment. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the scope equivalent thereto.

  1, 1A ... Magnetic resonance imaging device, 10 ... Scanner device, 11 ... Superconducting magnet unit, 111 ... Vacuum container, 112 ... Cooling container, 113 ... Superconducting coil, 114 ... Bobbin, 12 ... Gradient magnetic field coil, 13 ... Transceiver coil, 14 ... Bed, 20, 20A ... Device main body, 21 ... Static magnetic field power supply circuit, 22 ... Gradient magnetic field power supply circuit, 23 ... Transmission circuit, 24 ... Reception circuit, 25, 25A ... Storage circuit, 251 ... Signal storage unit, 252 ... Image data storage unit, 253 ... Characteristic storage unit, 254 ... Measurement result storage unit, 26 ... Arithmetic circuit, 27 ... Input interface circuit, 28 ... Output interface circuit, 29, 29A ... Control circuit, 291 ... Sequence control function, 292 ... Image creation function, 293 ... Refrigerator control function, 294 ... Information presentation function, 295 ... Characteristic prediction function, 296 ... Characteristic update function No. 297 ... Judgment function, 298 ... Communication control function, 210 ... Communication interface circuit, 30, 30A ... Refrigerator unit, 32 ... Compressor, 321 ... Supply pipe, 322 ... Discharge pipe, 323 ... Gas inlet / outlet jig, 33 ... Refrigerator body, 34 ... Vent valve, 35 ... Intake valve, 36, 36A ... Pressure measuring device, 37 ... Gas pressure control circuit, 371 ... Pressure determining function, 372 ... Pressure control function, 373 ... Differential pressure measuring function, 38 ... Input interface circuit, 39 ... Output interface circuit, 310 ... Buffer tank, 311 ... Power consumption measuring device, 40, 40A ... Monitoring device, 50, 60 ... Display circuit.

Claims (14)

A cooling container with a superconducting coil inside,
A cold head for cooling the cooling container,
A compressor for outputting a refrigerant gas to the cold head at a first gas pressure;
An output unit that outputs information for changing from the first gas pressure to a second gas pressure corresponding to a predetermined cooling capacity based on the state of the cooling container;
Equipped with
The state of the cooling container includes at least a magnet shield temperature,
Magnetic resonance imaging system.   A cooling container with a superconducting coil inside,
  A cold head for cooling the cooling container,
  A compressor for outputting a refrigerant gas to the cold head at a first gas pressure;
  An output unit that outputs information for changing from the first gas pressure to a second gas pressure corresponding to a predetermined cooling capacity based on the state of the cooling container;
  Equipped with
  The state of the cooling container includes at least eddy magnetic field characteristics,
  Magnetic resonance imaging system. A storage unit that stores in advance characteristic information that is a relationship between the cooling capacity and the gas pressure of the refrigerant gas,
A pressure determination unit that determines the second gas pressure based on the state of the cooling container and the characteristic information;
With
Magnetic resonance imaging apparatus according to claim 1 or 2. The pressure determination unit obtains the second gas pressure based on information on whether or not the imaging system of the magnetic resonance imaging apparatus is operating,
The magnetic resonance imaging apparatus according to claim 3. A cooling container with a superconducting coil inside,
A cold head for cooling the cooling container,
A compressor for outputting a refrigerant gas to the cold head at a first gas pressure;
An output unit that outputs information for changing from the first gas pressure to a second gas pressure corresponding to a predetermined cooling capacity based on the state of the cooling container;
A storage unit that stores in advance characteristic information that is a relationship between the cooling capacity and the gas pressure of the refrigerant gas,
A measuring unit for measuring the state of the cooling container,
A characteristic updating unit that updates the characteristic information stored in the storage unit based on the information measured by the measuring unit,
Equipped with
The output unit determines the second gas pressure based on the characteristic information updated by the characteristic updating unit,
Magnetic resonance imaging system. The output unit is an interface connectable to an external terminal,
The magnetic resonance imaging apparatus according to claim 1 , 2, or 5 . The output unit has a display function of video information,
The magnetic resonance imaging apparatus according to claim 1 , 2, or 5 . The output unit outputs information for changing the first gas pressure lowered due to the refrigerant gas leaking from the compressor to the second gas pressure before the refrigerant gas leaks,
The magnetic resonance imaging apparatus according to claim 1 , 2, or 5 . The output unit outputs information that prompts replacement of the cold head or the compressor,
The magnetic resonance imaging apparatus according to claim 1 , 2, or 5 . A storage unit which is a relational characteristic information between the gas pressure of the refrigerant gas and the cooling capacity has been stored pre Me,
Based on the characteristic information, a determination unit that determines whether the refrigerant gas has leaked from the compressor, whether the cold head or the compressor is consumed at a certain level or more,
Further equipped with,
Magnetic resonance imaging apparatus according to claim 1 or 2. A pressure adjusting mechanism for adjusting the gas pressure output to the cold head,
A pressure control unit for controlling the pressure adjusting mechanism,
Further equipped with,
The pressure control unit controls the pressure adjusting mechanism so that the cooling container has the second gas pressure.
The magnetic resonance imaging apparatus according to claim 1 , 2, or 5 . The pressure adjusting mechanism includes a ventilation valve, an intake valve, and a buffer tank,
The pressure control unit opens the vent valve to discharge the refrigerant gas to the buffer tank when the pressure of the refrigerant gas is lowered, and opens the intake valve when the pressure of the refrigerant gas is raised to open the intake tank. Intake refrigerant gas from
The magnetic resonance imaging apparatus according to claim 11.   The magnetic resonance imaging apparatus according to claim 1, wherein the state of the cooling container further includes at least one of power consumption of a heater and gradient magnetic field strength.   Based on the characteristic information, further comprising a determination unit that determines whether the refrigerant gas leaks from the compressor, or whether the cold head or the compressor is consumed at a certain level or more.
  The magnetic resonance imaging apparatus according to claim 5.