Operation terminal, operation terminal actuation method, and magnetic resonance imaging system

Abstract

To provide an operation terminal that allows a user to understand the state of a magnet correctly, and an operation terminal actuation method, and to provide a magnetic resonance imaging system equipped with the operation terminal.SOLUTION: An operation terminal of the present invention is an operation terminal of a magnetic resonance imaging device, and includes a processor. The processor acquires information showing the temperature of a magnet equipped to the magnetic resonance imaging device from the magnetic resonance imaging device, calculates a remaining cooling time, which is a time required before the magnet is cooled to a cooling completion state on the basis of the acquired information, and outputs information showing the calculated remaining cooling time.SELECTED DRAWING: Figure 10

Description

Technical Field

[0001] The present invention relates to an operation terminal of a magnetic resonance imaging apparatus, a method of operating the operation terminal, and a magnetic resonance imaging system, and particularly to a technique for notifying a cooling state of a magnet provided in the magnetic resonance imaging apparatus.

Background Art

[0002] In a magnetic resonance imaging apparatus (MRI apparatus, MRI: Magnetic Resonance Imaging), cooling of a superconducting magnet using liquid helium has been performed heretofore. In such an MRI apparatus, since highly specialized knowledge and techniques are required for control and adjustment of cooling of the superconducting magnet, specialized service personnel have been performing the work.

[0003] On the other hand, in recent years, techniques for reducing the amount of liquid helium used and techniques for cooling a magnet without using liquid helium have been developed, and it is expected that such techniques will continue to progress in the future. For example, Patent Document 1 describes an MRI apparatus in which a cooling container is liquid-helium-free.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In view of the progress of the above-described techniques for reducing the amount of liquid helium used and techniques for cooling a magnet without using liquid helium, it is preferable that not only specialized service personnel having highly specialized knowledge and techniques but also general users such as technicians who use an MRI apparatus in ordinary examinations and the like can correctly understand the state of the magnet and perform appropriate operations. However, the conventional techniques as shown in Patent Document 1 have not been such that general users can correctly understand the state of the magnet.

[0006] The present invention has been made in view of such circumstances, and an object thereof is to provide an operation terminal that allows a user to correctly understand the state of a magnet, a method of operating the operation terminal, and a magnetic resonance imaging system including such an operation terminal.

Means for Solving the Problems

[0007] In order to achieve the above-described object, an operation terminal according to a first aspect of the present invention is an operation terminal of a magnetic resonance imaging apparatus, and includes a processor. The processor acquires information indicating the temperature of a magnet included in the magnetic resonance imaging apparatus from the magnetic resonance imaging apparatus, calculates a remaining cooling time, which is the time required until the magnet is cooled to a cooled completion state, based on the acquired information, and outputs information indicating the calculated remaining cooling time.

[0008] According to the first aspect, since the remaining cooling time (the time required until the magnet is cooled to a cooled completion state) of the magnet is output, the user can correctly understand the state of the magnet.

[0009] An operation terminal according to a second aspect includes, in the first aspect, a non-transitory and tangible recording medium that records data of a cooling curve indicating the relationship between the time elapsed since the start of cooling of the magnet and the temperature of the magnet, which is generated based on measured values. The processor calculates the time by referring to the recorded data of the cooling curve. The second aspect defines a specific aspect of calculating the remaining cooling time.

[0010] An operation terminal according to a third aspect includes, in the second aspect, the recording medium that records, as data of the cooling curve, data of a plurality of cooling curves corresponding to the type of a cooling device that cools the magnet and the secular change of the cooling device. The processor interpolates the data of the plurality of cooling curves according to the type of the cooling device and the secular change of the cooling device and uses the interpolated data for calculating the remaining cooling time. By interpolating the data of the plurality of cooling curves as in the third aspect, the remaining cooling time can be accurately calculated.

[0011] In the fourth aspect, in the second or third aspect, the processor newly generates data of a cooling curve showing the relationship between the cooling time of the magnet and the temperature of the magnet based on the measured value of the temperature of the magnet, and records the generated data of the cooling curve on a recording medium. Although the change of the cooling curve depends on the characteristics of each cooling device and the installation conditions of the magnetic resonance imaging system, etc., by generating and recording the data of the cooling curve based on the measured value as in the fourth aspect, the remaining cooling time can be accurately calculated. Note that the method used for generating new data is not particularly limited, and for example, a machine learning method can be used.

[0012] In the fifth aspect, in any one of the second to fourth aspects, the processor causes the display device to display the data of the cooling curve. According to the fifth aspect, the user of the operation terminal can easily grasp the cooling curve visually.

[0013] In the sixth aspect, in any one of the first to fifth aspects, the cooling completion state is a state in which the superconducting state of the magnet is maintained and it is possible to start exciting the magnet.

[0014] In the seventh aspect, in any one of the first to sixth aspects, the processor outputs information by at least one of a display output and an audio output.

[0015] In the eighth aspect, in any one of the first to seventh aspects, the processor outputs information discretely according to the remaining cooling time.

[0016] In the ninth aspect, in any one of the first to eighth aspects, the processor determines a smaller granularity stepwise according to the remaining cooling time for the information, and outputs the information with the determined granularity. In the ninth aspect, the "granularity" is the output unit of the information, and the shorter the remaining cooling time, the smaller the granularity can be.

[0017] To achieve the above object, a method for operating an operation terminal according to a tenth aspect of the present invention is a method for operating an operation terminal of a magnetic resonance imaging apparatus. The operation terminal includes a processor. The processor acquires information indicating the temperature of a magnet included in the magnetic resonance imaging apparatus from the magnetic resonance imaging apparatus, calculates a remaining cooling time, which is the time required until the magnet is cooled to a cooled state, based on the acquired information, and outputs information indicating the calculated remaining cooling time. According to the tenth aspect, similar to the first aspect, the user can correctly understand the state of the magnet.

[0018] To achieve the above object, a magnetic resonance imaging system according to an eleventh aspect of the present invention includes an operation terminal according to any one of the first to ninth aspects and a magnetic resonance imaging apparatus. According to the eleventh aspect, similar to the first and tenth aspects, the user can correctly understand the state of the magnet.

[0019] The magnetic resonance imaging system according to a twelfth aspect further includes a cooling device for cooling the magnet and a thermometer for measuring the temperature of the magnet in the eleventh aspect, and the magnet is a superconducting magnet for generating a static magnetic field.

Advantages of the Invention

[0020] As described above, according to the operation terminal, the method for operating the operation terminal, and the magnetic resonance imaging system of the present invention, the user can correctly understand the state of the magnet.

Brief Description of the Drawings

[0021]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Figure 16

Figure 17

Figure 18

Figure 19

Figure 20

Figure 21

Figure 22

Figure 23

Embodiments for Carrying Out the Invention

[0022] Hereinafter, with reference to the accompanying drawings, a preferred embodiment of an operation terminal, a method of operating the operation terminal, and a magnetic resonance imaging system according to the present invention will be described. In the accompanying drawings, for convenience of explanation, illustration of some components may be omitted.

[0023] [First Embodiment] [Configuration of Magnetic Resonance Imaging System] FIG. 1 is a diagram showing the overall configuration of a magnetic resonance imaging system 10 (magnetic resonance imaging system; MRI system) according to the first embodiment. In the figure, the magnetic resonance imaging system 10 includes a magnetic resonance imaging apparatus 100 (magnetic resonance imaging apparatus, MRI apparatus), an operation terminal 200 (operation terminal, first terminal device; on-site operation terminal) installed close to the magnetic resonance imaging apparatus 100, and an operation terminal 300 (operation terminal, second terminal device; service site operation terminal) installed away from the magnetic resonance imaging apparatus 100. The magnetic resonance imaging apparatus 100, the operation terminal 200, and the operation terminal 300 can communicate with each other via a network (not shown).

[0024] Note that the operation terminal 200 can be installed, for example, in the examination room where the magnetic resonance imaging apparatus 100 is installed, or in a location adjacent to the examination room where the inside of the examination room can be visually recognized. Hereinafter, the examination room and the location where the inside of the examination room can be visually recognized may be collectively referred to as the "site". On the other hand, the operation terminal 300 is installed at a service site, such as another floor of the same building as the examination room, a building different from the examination room, or a site different from the examination site of the examination room. The operation terminal 300 (operation terminal for service site) may be capable of communicating with a plurality of magnetic resonance imaging apparatuses 100 and operation terminals 200 (operation terminals for site). Also, one magnetic resonance imaging apparatus 100 and operation terminal 200 may be capable of communicating with a plurality of operation terminals 300. Note that the operation terminal 200 is connected to (capable of communicating with) a control unit 103 described later, but exists as a separate entity from the control unit 103. Also, the operation terminal 300 is also connected to the control unit 103, but exists as a separate entity from the control unit 103.

[0025] The magnetic resonance imaging apparatus 100 includes a magnet 110 that is a superconducting magnet for generating a static magnetic field. The magnet 110 includes a vacuum vessel configured to block external heat, and a heat shield and a cooling vessel are provided in the vacuum vessel, and the inside of the cooling vessel is maintained in a vacuum. That is, the cooling vessel has a configuration without liquid helium. And a superconducting coil is provided in this cooling vessel. The superconducting coil is wound around a bobbin (support member). The refrigerator 101 cools the superconducting coil wound around the bobbin by expanding the refrigerant gas compressed by the compressor 102 to generate cold heat and directly cooling the bobbin. The magnetic resonance imaging apparatus 100 may include a plurality of refrigerators 101.

[0026] The magnet 110 is provided with a pressure measurement unit 104 and a shield temperature measurement unit 106, all of which are controlled by the control unit 103. The temperature of the magnet 110 is measured by a magnet temperature measurement unit 107 (thermometer, temperature sensor). Also, an ammeter 108 and a voltmeter 109 are connected to the magnet 110, and these devices measure the current and voltage applied to the coil of the magnet 110 (the voltage between the lead terminals of the magnet 110). The data received from each of the above measurement units (including temperature, current, and voltage data) is transmitted by the control unit 103 to the processor 212 (arithmetic unit 212A) and used for determining the actual state of the magnet 110. Note that the magnetic resonance imaging apparatus 100 includes, in addition to the magnet 110 (superconducting coil), a gradient magnetic field generating coil and a high-frequency coil (also referred to as an RF (radio frequency) coil) (both not shown).

[0027] Also, the control unit 103 controls the energization from a power source (not shown) according to an instruction from the processor 212 to excite the magnet 110. The magnet 110 can take any one of a plurality of states (demagnetized state, cooling state, cooled state, exciting state, and excited state) depending on the cooling and exciting conditions.

[0028] Note that the magnetic resonance imaging apparatus 100 includes an image generation unit (not shown) that generates a magnetic resonance image of a subject. This image generation unit may be provided in the operation terminal 200 (for example, it may be a function of the processor 212), or may be provided separately from the operation terminal 200. Also, the magnetic resonance imaging apparatus 100 includes a bed device 120 on which the subject is placed. The bed device 120 may be detachable from the main body of the magnetic resonance imaging apparatus 100.

[0029] [Configuration of Local Operation Terminal] FIG. 2 is a diagram showing a configuration example of the operation terminal 200 (on-site operation terminal). As shown in the figure, the operation terminal 200 includes a display 202 (display device), a microphone 204 (voice input device), a speaker 206 (voice output device), a keyboard 208 (input device), and a mouse 210 (input device). The user can input instructions to the operation terminal 200 using these devices, and the operation terminal 200 can output the acquired information and notify the state of the magnet using these devices. The display 202 may be configured as a touch panel type display and used as an input device. The operation terminal 200 can be realized as a computer including the elements illustrated in FIG. 2.

[0030] Further, the operation terminal 200 may be provided with a rotating light or a warning light (sometimes referred to as "Rotary Beacon Light" in English) called Patlite (registered trademark) or Patlamp, and this rotating light or warning light may be used to notify the state of the magnet, give a warning, output the urgency of replacing the refrigerator, etc. A plurality of such rotating lights or warning lights having different colors may be provided corresponding to different states of the magnet, the importance of the warning, the urgency of replacing the refrigerator, etc. For example, the demagnetized state, the cooling state, and the magnetized state may be notified or output corresponding to different colors (for example, green or blue, yellow, red, etc.). The same applies to the operation terminal 300.

[0031] Further, the operation terminal 200 includes a processor 212 (processor), a ROM 214 (ROM: Read Only Memory), and a RAM 216 (RAM: Random Access Memory). The arithmetic unit 212A and the remote transmission / reception unit 212B described above are components of the processor 212, and the processor 212 may include components or functions other than the arithmetic unit 212A and the remote transmission / reception unit 212B. For example, the processor 212 may have a function of generating an image from measurement data. As will be described in detail later, the processor 212 performs processes such as determination of the magnet state, prediction (calculation) of the remaining cooling time and output thereof, safety confirmation and excitation start when exciting the magnet 110. Note that these processes may be performed by the analysis unit 312B of the operation terminal 300. The processor 212 transmits, as necessary, the collected data (parameters of the magnet 110) and its processing results (such as the state of the magnet 110) to the operation terminal 300 via the input / output interface 218 and a network (not shown).

[0032] In addition, the arithmetic unit 212A (processor 212) calculates each received data, outputs an ON / OFF command for the compressor 102 to the control unit 103 based on the calculation result, and controls the pressure within a certain range so as to bring the output of the heater closer to 0. The arithmetic unit 212A uses the display 202 of each local operation terminal 200 to display each acquired data and the urgency of the chiller replacement. Also, the arithmetic unit 212A uses the remote transmission / reception unit 212B (processor 212) to transmit each acquired data and the urgency of the chiller replacement to the remote transmission / reception unit 312A (processor 312) of the operation terminal 300 (operation terminal for service site) via a communication path such as wireless communication or a data transmission line. The remote transmission / reception unit 312A receives data via the input / output interface 318 and transmits the received data to the analysis unit 312B (processor 312). Similarly, the analysis unit 312B analyzes the data received from other local facilities (magnetic resonance imaging apparatus 100 and operation terminal 200) and analyzes the optimal timing for chiller replacement. The processor 312 may perform processes such as determination of the magnet state, prediction (calculation) of the remaining cooling time and output thereof, safety confirmation at the time of exciting the magnet 110, and start of excitation. Also, the analysis unit 312B can display the received data, analysis data, messages to the user, etc. on the display 302 of the operation terminal 300 or output them via the speaker 306.

[0033] Each part of the operation terminal 200 described above is connected via the bus 222.

[0034] [Examples of Information Recorded in the Recording Device] The recording device 220 (non-transitory and tangible recording medium) includes a non-transitory and tangible recording medium such as a magnetic disk, an optical disk, or a semiconductor memory and its control unit, and records various types of information. FIG. 3 is a diagram showing an example of information recorded in the recording device 220. In the example shown in the figure, a magnetic resonance image 220A, cooling curve data 220B, user information 220C, magnet information 220D, and specific operation information 220E are recorded in the recording device 220. Other information may be recorded in the recording device 220.

[0035] The magnetic resonance image 220A is an image obtained by imaging a subject with the magnetic resonance imaging apparatus 100. The cooling curve data 220B is data of a cooling curve showing the relationship between the time since the start of cooling of the magnet 110 (a superconducting magnet for generating a static magnetic field) and the temperature of the magnet 110, which is generated based on measured values and is used for predicting (calculating) the remaining cooling time (see FIG. 12 and the like described later). The user information 220C is information in which the identification information of the user of the operation terminal 200 and information indicating the user's occupation divided into a plurality of levels are associated (see FIG. 8 and the like described later). The magnet information 220D is information in which values of parameters (temperature, current, voltage, etc.) related to the magnet 110 and the states that the magnet 110 can take are associated (see FIG. 10 and the like described later). The specific operation information 220E (specific operation information) is information in which the user's level (occupation) and the operations that can be performed by users at each level are associated (see FIG. 18 and the like described later). Details of the processing using these pieces of information will be described later.

[0036] [Configuration of the Operation Terminal for the Service Site] FIG. 4 is a diagram showing the configuration of the operation terminal 300 (operation terminal for the service site). Similar to the above-described operation terminal 200 (local operation terminal), the operation terminal 300 includes a display 302 (display device), a microphone 304 (voice input device), a speaker 306 (voice output device), a keyboard 308 (input device), and a mouse 310 (input device). A user can input an instruction to the operation terminal 300 using these devices, and the operation terminal 300 can output the acquired information and notify the state of the magnet using these devices. The display 302 may be configured as a touch panel type display and used as an input device. Each part of these operation terminals 300 is connected via a bus 322.

[0037] In addition, the operation terminal 300 includes a processor 312 (processor), a ROM 314, and a RAM 316. The remote transmission / reception unit 312A and the analysis unit 312B described above are components of the processor 312. Using such a processor 312, the operation terminal 300 can analyze the urgency and replacement timing of the refrigerator replacement based on the data collected from the operation terminal 200 and display it on the display 302. Similar to what was described above for the processor 212, the processor 312 may have a function of generating an image from the measurement data. The recording device 320 includes a non-temporary and tangible recording medium such as a magnetic disk, an optical disk, or a semiconductor memory, and its control unit, and records various types of information. The information recorded in the recording device 320 may be the same as or different from the information recorded in the recording device 220. Information received from a plurality of operation terminals 200 may be recorded in the recording device 320.

[0038] Note that the user can perform the same operations as the operation terminal 200 using the operation terminal 300.

[0039] [Configuration of the Processor in the Operation Terminal] In the present embodiment, the hardware structures of the processors 212 and 312 that execute the above-described processing are, for example, various types of processors (processors) as shown below. This "various types of processors" includes a CPU (Central Processing Unit), which is a general-purpose processor that functions as various processing units by executing software (program), a programmable logic device (PLD), such as an FPGA (Field Programmable Gate Array), which is a processor whose circuit configuration can be changed after manufacturing, and an application-specific integrated circuit (ASIC), which is a dedicated electric circuit that is a processor having a circuit configuration designed specifically for executing specific processing.

[0040] Processor 212 and processor 312 may be constituted by one of these various processors, or may be constituted by two or more processors of the same type or different types (for example, a plurality of FPGAs, or a combination of a CPU and an FPGA). Further, a plurality of processing units (including the arithmetic unit 212A, the remote transmission / reception unit 212B, the remote transmission / reception unit 312A, and the analysis unit 312B) may be constituted by one processor. As an example of constituting a plurality of processing units by one processor, first, as represented by a computer such as a client or a server, one processor is constituted by a combination of one or more CPUs and software, and this processor functions as a plurality of processing units. Second, as represented by a System On Chip (SoC), there is a form in which a processor that realizes the functions of the entire system including a plurality of processing units is used with one IC (Integrated Circuit) chip. Thus, various processing units can be configured by using one or more of the above various processors as a hardware structure.

[0041] Further, the hardware structure of these various processors is, more specifically, an electric circuit (circuitry) combining circuit elements such as semiconductor elements. When various processors operate, programs and data recorded on non-temporary and tangible recording media such as ROM 214 and 314 can be referred to, and recording media such as RAM 216 and 316 and internal memory can be used as a temporary working area during operation.

[0042] [Operator's use case] FIG. 5 is a diagram showing the use case of an operator (user) of the magnetic resonance imaging system 10. This use case shows the relationship between the state of the magnetic resonance imaging system 10, the processing in the magnetic resonance imaging system 10, and the operations of the user corresponding to these states and processes. In FIG. 5, the solid line portions indicate the state of the system and the processing of the system (including the output of information), and the dotted line portions indicate the operations (tasks) of the operator.

[0043] [Processing in magnetic resonance imaging system] Next, an aspect of the processing in the magnetic resonance imaging system 10 (operation method of the magnetic resonance imaging system 10) will be described. FIGS. 6 and 7 are flowcharts showing the processing in the magnetic resonance imaging system 10. Hereinafter, mainly the mode in which the operation terminal 200 (local operation terminal, first terminal device) performs the processing will be described, but the operation terminal 300 (service site operation terminal, second terminal device) may perform the processing.

[0044] [User authentication] The processor 212 of the operation terminal 200 authenticates the user (step S100). The processor 212 can authenticate the user by comparing the information input via devices such as the keyboard 208, the mouse 210, or the microphone 204 (login ID, password, etc.) with the user information 220C (see FIG. 3) recorded in the recording device 220. As illustrated in FIG. 8, the user information 220C is information in which the identification information of the user of the operation terminal 200 and the information indicating the user's job type divided into a plurality of levels are associated. Further, a barcode reader or a scanner may be provided in the operation terminal 200 to read the information recorded on an employee ID card or a staff ID card and use it for authentication. Biometric authentication of the user (for example, fingerprint, blood vessel pattern, iris, voiceprint, etc.) may be performed. In the magnetic resonance imaging system 10, it is possible to restrict the operations that the user can execute according to the user's level (job type) and set the role of the operation terminal according to the authentication result (described later).

[0045] [Magnet state] The processor 212 acquires magnet data (magnet information 220D in FIG. 3; first information) from the magnetic resonance imaging apparatus 100 (step S110), and determines which of a plurality of states that the magnet 110 can assume is the actual state of the magnet 110 (step S112). The processor 212 can notify the user of the acquired magnet data and the determined actual state of the magnet 110 by means of the display 202, the speaker 206, or the above-described rotating lamp or warning lamp (not shown) (step S114). The magnet data (first information) is a value of a parameter related to the magnet 110, and includes at least one of the temperature of the magnet 110 and at least one of the current applied to the magnet 110 and the voltage between the lead terminals of the magnet 110. The plurality of states that the magnet 110 can assume are a demagnetized state, a cooling state, a cooled state, an exciting state, and an excited state, and the actual state is any one of these plurality of states. Note that the demagnetized state and the cooling state may be integrated into a “cooling state”.

[0046] The above-described magnet data can be measured by the magnet temperature measurement unit 107, the ammeter 108, and the voltmeter 109. As described above with reference to FIG. 3, the value of the parameter related to the magnet 110 and the state of the magnet 110 corresponding to the value of the parameter are associated and recorded in the recording device 220 (see the example in FIG. 10, magnet information 220D), and the processor 212 can determine the actual state of the magnet 110 based on the measured data and this magnet information 220D. Note that the processor 212 may acquire parameters other than the magnet data. In this case, after the processor 212 acquires the magnet data (parameter indicating the state of the magnet 110) and determines the state of the magnet 110, the processor 212 can determine “which parameters other than the magnet data are to be acquired” according to the state of the magnet 110.

[0047] The processor 212 can obtain the values of the above parameters at determined time intervals and make judgments, and can give a notification when the actual state of the magnet 110 changes (for example, when the cooling state changes to the cooled state or when the energized state changes to the energized completed state). The processor 212 may give a notification when the state of the magnet 110 is abnormal. Also, the processor 212 can give a notification by at least one of the display 202 (display device) and the speaker 206 (audio output device).

[0048] Note that it is preferable that the processor 212 obtains the values of the parameters in real time (without time delay) and makes judgments and gives notifications about the state of the magnet 110. Also, the processor 212 can notify the remote transmission / reception unit 312A (processor 312) of the operation terminal 300 (operation terminal for service site) of the state of the magnet 110, and the remote transmission / reception unit 312A, as one aspect of the notification, can display the notified state of the magnet 110 on the display 302, output audio from the speaker 306, or output it by the above-described rotating lamp or warning lamp.

[0049] The processor 212 continues the above-described data acquisition, judgment of the state of the magnet 110, and notification until an instruction to start cooling the magnet 110 (until YES in step S120). When the magnet 110 is in a demagnetized state, the processor 212 notifies (display output, audio output) that it is in a demagnetized state.

[0050] [Actions according to the state of the magnet] Note that the processor 212 receives operations according to the actual state of the magnet 110 and transmits instructions corresponding to the received operations to the magnetic resonance imaging apparatus 100. FIG. 9 is a table showing the relationship between the state of the magnet, the information output by the processor 212, the actions requested of the user, and the operations received when the actions are executed, and this information is recorded in the recording device 220. The processor 212 determines the actions requested of the user by referring to the information in the above table recorded in the recording device 220 according to the actual state of the magnet for at least some of the multiple states that the magnet 110 can take. Note that FIG. 9 shows cases where actions are requested of the user for the cooling completed state and the exciting state, but the processor 212 may request actions of the user for all of the multiple states that the magnet 110 can take, including other states.

[0051] [Cooling of Superconducting Magnet] [Start of Excitation after Cooling with Liquid Helium Freezing] In the conventional technology using liquid helium, the superconducting magnet was cooled only by pressure (atmospheric pressure). However, with the liquid helium freezing, it became necessary to cool the superconducting magnet with electric power instead of pressure (atmospheric pressure) to maintain the superconducting state. However, when the power supply of the superconducting magnet is turned off for maintenance or the like, the cooling stops, the magnetic field becomes zero (demagnetized state), and the temperature of the superconducting magnet rises. To return to the normal superconducting state from this state, it is necessary to first cool the superconducting magnet and then start excitation. In this embodiment, as described below, safety confirmation is performed during this excitation. Also, the user can perform excitation not only from the local operation terminal but also from a remote operation terminal (such as a service site).

[0052] [Setting of Cooling Curve] When the user instructs the operation terminal 200 to start cooling the magnet 110 (YES in step S120), the processor 212 sets a cooling curve to be used for predicting (calculating) the remaining cooling time in response to the instruction (step S130). The "cooling curve" is information showing the relationship between the time elapsed since the start of cooling the magnet 110 and the temperature of the magnet 110, which is generated based on measured values, as exemplified in FIG. 10 (cooling curve data 220B in FIG. 3). The "remaining cooling time" is the time (remaining time) required for the magnet 110 to be cooled to the cooled state. The "cooled state" is a state in which the superconducting state of the magnet 110 is maintained and the magnet 110 can start excitation. In the example of FIG. 10, the remaining cooling time 1 corresponds to the magnet temperature 1 and the remaining cooling time 2 corresponds to the magnet temperature 2 in the cooling curve C1.

[0053] FIG. 11 is a diagram showing another example of a cooling curve, and shows cooling curves C2 and C3 for refrigerators 1 and 2 (cooling devices of different types). The total cooling time (from the start of cooling to the completion of cooling) in the cooling curve C2 is the remaining cooling time 3, and the total cooling time in the cooling curve C3 is the remaining cooling time 4. FIG. 12 is a diagram showing still another example of a cooling curve, and shows a state of obtaining a cooling curve C6 at 1 year after the start of use by interpolating the cooling curve C4 at the start of use and the cooling curve C5 at 3 years after the start of use for the refrigerator 1. The total cooling times corresponding to the cooling curves C4, C5, and C6 are the remaining cooling times 5, 6, and 7, respectively.

[0054] In this way, in the magnetic resonance imaging system 10, it is preferable to store in the recording device 220 data of a plurality of cooling curves according to the type of the cooling device for cooling the magnet 110 and the secular change of the cooling device. The processor 212 preferably interpolates a plurality of cooling curves according to the type of the cooling device and the secular change of the cooling device and uses them for predicting (calculating) the remaining cooling time. By such processing, the remaining cooling time can be accurately predicted. Note that the processor 212 can newly generate a cooling curve based on the measured value of the temperature of the magnet 110 and store the data of the generated cooling curve in the recording device 220. For example, as shown in FIG. 13, a cooling curve C8 based on the measured value can be generated with respect to the cooling curve C7 (prediction curve) and stored in the recording device. The method used for generating a new cooling curve based on the measured value is not particularly limited, but for example, a machine learning method such as the non-linear least squares method can be used. The processor 212 may remove outliers included in the measured value in generating a new cooling curve.

[0055] Note that the processor 212 can display these cooling curves on the display 202 (display device).

[0056] [Calculation and Output of Remaining Cooling Time] In response to an instruction to start cooling, the processor 212 starts cooling the magnet 110 by the compressor 102 and the control unit 103 (step S140), and also acquires the magnet data described above (step S150). The processor 212 may start cooling the magnet 110 according to an operation by the user of the operation terminal 200, or may automatically start cooling without the user's operation when necessary conditions are satisfied. The processor 212 can regard the fact that the user has operated or the necessary conditions are satisfied as an "instruction to start cooling". Then, the processor 212 calculates the remaining cooling time using the cooling curve set in step S130 and the acquired magnet data, and outputs the calculated remaining cooling time (step S160). FIG. 14 is a diagram showing an example of displaying the remaining cooling time (the numerical values are examples and do not accurately reflect the cooling time of an actual magnetic resonance imaging apparatus). Not only the remaining cooling time but also the timing at which excitation can be started may be displayed. With these displays, the user can easily grasp the remaining cooling time and the timing at which excitation can be started. In addition to the remaining cooling time, the processor 212 may display (numerical display, graph display, etc.) the set cooling curve and the measured temperature of the magnet 110. With these displays, the user can accurately grasp the state of the magnet 110 and the cooling condition, etc.

[0057] [Discrete display, stepwise display of remaining cooling time] The remaining cooling time can be displayed discretely and / or stepwise. For example, the remaining cooling time may be displayed (on display 202) as shown in FIG. 15. In the example of this figure, the processor 212 displays the remaining cooling time (information indicating the remaining cooling time) discretely and stepwise according to the remaining cooling time. Also, as the remaining cooling time approaches zero, a small granularity is determined, and the remaining cooling time is output with the determined granularity. "Granularity" is the output unit of information, and the granularity can be made smaller as the remaining cooling time becomes shorter. Specifically, when the calculated remaining cooling time is one week or more, the processor 212 displays "week" as the granularity (unit). Similarly, when the remaining cooling time is one day or more and less than one week, "day" is displayed as the granularity, and when the remaining cooling time is less than one day, "hour" is displayed as the unit. Also, when the remaining cooling time is "more than one week and less than two weeks", the upper limit value of "about two weeks" is displayed. Furthermore, by adding the phrase "about", it is indicated that the displayed remaining cooling time is approximate. The phrase indicating approximate time may be other phrases such as "approximately", "about", "degree", etc.

[0058] FIG. 16 is a diagram showing another example of discrete display and stepwise display. In the example shown in this figure, the processor 212 rounds the numerical value of the remaining cooling time and displays an approximate time. "Rounding" the numerical value can be done, for example, by rounding, rounding up, adopting the upper limit value of the range, etc. For example, when the calculated remaining cooling time is 10 days, it can be displayed as "about two weeks". Also, in the example of FIG. 16, similar to the example of FIG. 15, as the remaining cooling time approaches zero, a small granularity is determined, and the remaining cooling time is output with the determined granularity.

[0059] FIG. 17 is a diagram showing an example of discretely displaying the remaining time on the screen. As described above, by adding the phrase "about", it is indicated that the displayed remaining cooling time is approximate.

[0060] For example, even if the difference in the remaining cooling time is 1 hour, there is not much difference between "remaining 1 week" and "remaining 1 week + 1 hour", but there is a significant difference between "remaining 1 hour" and "remaining 2 hours". Therefore, it is preferable to perform the above-described discrete display or stepped display. Such a display can be performed by recording information indicating the correspondence between the remaining cooling time and the display time, such as in FIGS. 15 and 16, in the recording device 220, and having the processor 212 refer to this information based on the calculated remaining cooling time. The same applies to the operation terminal 300. The user of the operation terminals 200 and 300 may be able to set the display granularity.

[0061] The processor 212 repeats the acquisition of the magnet data, the calculation and output of the remaining cooling time until the cooling is completed (until it becomes YES in step S170). The processor 212 can use "the temperature T < T1 continuing for a predetermined time or more" (see FIG. 18) as a requirement for the completion of cooling. When the cooling is completed (YES in step S170), the processor 212 notifies that the cooling has been completed (step S180). The notification may be a screen output as shown in FIGS. 14 and 17, or a voice output.

[0062] In the case where some abnormality is detected during the cooling or the like, the user of the operation terminals 200 and 300 can perform an operation to interrupt or cancel the cooling.

[0063] [Safety confirmation at the start of excitation] [Two-step safety confirmation: First operation] In the magnetic resonance imaging system 10 according to this embodiment, excitation is started after safety confirmation is performed after cooling is completed. This safety confirmation is preferably performed in two steps as described below. FIG. 19 is a diagram showing an example of a screen for the two-step safety confirmation. First, when the state of the magnet 110 is in a cooled state by the processing up to step S180, the processor 212 causes the display 202 to display a screen prompting the user to perform a first operation (operation for the first safety confirmation) (step S190). The (a) part of FIG. 19 is an example of a screen prompting the first operation (example of output of second information). Unless the user confirms that "there are no magnetic metals or prohibited items in the MR room (examination room)" and "there are no people in the MR room" and checks two check boxes, the "Next" button cannot be pressed. That is, checking the check boxes and pressing the "Next" button constitute the first operation. The user can perform the check and press the button with the mouse 210 (the same applies to the following safety confirmation). Instead of or in addition to the display on the display 202, a message may be output as voice (example of output of second information) from the speaker 206 to prompt the user to perform the first operation.

[0064] Note that FIG. 19 shows an example in which safety confirmation is performed by an operation (an example of the first operation) via the screen of the display 202 (display device), but the user may be able to perform safety confirmation by an operation based on voice input via the microphone 204. The operation based on voice input can be performed by uttering specific phrases (other examples of the first operation) such as, for example, "I have confirmed that there are no magnetic substances" or "I have confirmed that there are no people". Thus, the processor 212 can receive at least one of an operation via the screen of the display device and an operation based on voice input as a safety confirmation operation. In this case, it is assumed that the processor 212 has a voice recognition function.

[0065] Also, regarding the above safety confirmation, a magnetic body detection device may be provided outside or at the entrance of the examination room, etc., and this device detects magnetic bodies (for example, machines, instruments, tools used in the examination room and its surroundings, or the belongings of the subject, etc.) in the vicinity of the magnetic resonance imaging device 100 and the magnetic resonance imaging device 100, and outputs this detection result (first auxiliary information). Further, the magnetic body detection device may be provided inside the examination room. In this case, for example, a device that detects magnetic bodies based on changes in the voltage between the current lead terminals of the superconducting coil can be used. The processor 212 or the processor 312 may be provided with such a magnetic body detection function. The output may be a display output to the display 202 or an audio output to the speaker 206. When performing a display output, the name of a typical magnetic body (for example, the name of a tool such as a magnetic driver), its image, or an illustration, etc. may be displayed on the display 202, and these pieces of information may be used as auxiliary information (first auxiliary information) for confirming the presence of the magnetic body. Furthermore, a camera for photographing the magnetic resonance imaging device 100 and its vicinity may be installed, and the photographed image (second auxiliary information) may be displayed on the display 202 and used as auxiliary information (second auxiliary information) during safety confirmation. In the magnetic resonance imaging system 10, it is preferable to output at least one of these first and second auxiliary information during safety confirmation, and with these first and second auxiliary information, the user can perform safety confirmation quickly and easily.

[0066] [Two-stage safety confirmation: Second operation] In the state shown in part (a) of FIG. 19, when the user checks two check boxes, the color of the button changes as shown in part (b) of the same figure and becomes pressable (or tappable; the same applies hereinafter). When the user presses the button in this state (YES in step S200), the processor 212 causes the display 202 to display a screen (an example of output of second information) prompting the user to perform a second operation (an operation of second safety confirmation) (step S210). Specifically, the processor 212 causes the display 202 to display the screen illustrated in part (c) of FIG. 19. When the user checks the check box of "Start excitation", the color of the OK button changes as shown in part (d) of the same figure and becomes pressable by the user. That is, similar to the first operation described above, checking the check box and pressing the OK button constitute the second operation. When the user presses the OK button in this state, the processor 212 instructs the magnetic resonance imaging apparatus 100 to start excitation, and excitation is started in response to this instruction (step S230). The excitation is automatically executed along a predetermined sequence. During excitation, as shown in FIG. 20, it is preferable to display the remaining excitation time (predicted value) and the fact that entry into the examination room is prohibited. By displaying such remaining excitation time, the user can grasp the timing when the examination can start. Note that the value of the remaining excitation time shown in FIG. 20 is an example and does not accurately reflect the remaining excitation time of an actual magnetic resonance imaging apparatus. Also, the processor 212 may perform discrete display or stepwise display for the remaining excitation time in the same manner as described above for the remaining cooling time, and may change the display granularity.

[0067] According to this embodiment, by performing the two-stage safety confirmation in this way so that excitation does not start unless the user checks all items and presses the OK button, safety can be ensured and it is possible to prevent a magnetic substance from being present near the magnetic resonance imaging apparatus 100 and affecting the image quality of the magnetic resonance image.

[0068] [Setting of notification mode according to magnet state, etc.] In addition, the processor 212 preferably sets the notification mode based on the state of the magnet 110 and the content of the action that requests the user to execute. For example, for notifications in a state where safety confirmation is required and caution is needed for the operation, such as when exciting the magnet 110, the display mode (for example, the presence, type, size of characters, symbols, graphics, icons, etc., or the color scheme of the screen, etc.) and the mode of voice output (volume, pitch, output pattern, etc.) are different from those in other states, and it is conceivable to increase the degree of attention-grabbing.

[0069] [Cancel safety confirmation] In the above-mentioned safety confirmation, when the user presses the "Cancel" button in the state shown in the (c) part of FIG. 19, the processor 212 returns to step S190 and causes the display 202 to display the screen shown in the (a) part of the figure, and prompts the user to perform the first operation again. That is, when the second operation is canceled, the processor 212 does not instruct the magnetic resonance imaging apparatus 100 to start excitation, and prompts the user to perform the first operation.

[0070] [Excitation completed] The processor 212 determines whether or not the excitation is completed (step S240). If the excitation is completed (YES in step S240), it notifies the completion of the excitation (success or failure of the excitation) by display or voice (step S250). Due to the completion (success) of the excitation, it becomes possible to image the subject with the magnetic resonance imaging apparatus 100.

[0071] In addition, when some abnormality is detected during the excitation, etc., the user of the operation terminals 200 and 300 can perform an operation to interrupt or cancel the excitation. Also, since not maintaining the low-temperature state leads to the disappearance of the magnetic field, after the inspection, power is maintained except for maintenance periods, etc., and the cooling state and the excitation state are maintained.

[0072] [Restriction of operations according to the user's occupation] [Association between the user's occupation and the operations that the user can perform] In the magnetic resonance imaging system 10 according to the first embodiment, operations that can be executed after the user logs in may be restricted according to the user's occupation (level). When such restrictions on executable operations are provided, for example, in the operation terminal 200, the identification information of the user of the operation terminal 200, the information indicating the occupations of the users divided into a plurality of levels, and the information indicating the operations that can be executed by the users belonging to each occupation are associated and stored in the storage device 160. Regarding the relationship between the user identification information and the user level and occupation, for example, the association can be made as shown in FIG. 8. Also, the operations that can be executed by the users belonging to each occupation can be defined, for example, as shown in the table of FIG. 21. These pieces of information can be recorded in the recording device 220 as user information 220C and specific operation information 220E (see FIG. 3).

[0073] In the example shown in the (a) part of FIG. 21, the user levels are divided by "whether a safety confirmation operation can be performed" and "whether an excitation start operation can be performed". In the example of the same part, it is assumed that a user who cannot perform a safety confirmation operation cannot perform an excitation start operation either. As a result, the users are divided into three levels (upper / middle / lower). Specifically, a user belonging to level 1 (the first level) has the authority to perform the safety confirmation operation of the magnetic resonance imaging device 100 and the excitation start operation of the magnet 110 included in the magnetic resonance imaging device 100. A user belonging to level 2 (the second level) lower than level 1 has the authority to perform a safety confirmation operation but does not have the authority to perform an excitation start operation. A user belonging to level 3 (the third level) lower than level 2 does not have the authority to perform a safety confirmation operation or an excitation start operation.

[0074] In contrast, in the example shown in the (b) part of FIG. 21, among the users of "Level 3", users of a specific occupation (users belonging to the "specific level"; in this example, nurses) are classified so that they can check the remaining cooling time (an example of "information indicating the state of the magnet"). This is assuming a case where it is necessary to check the state of the magnetic resonance imaging apparatus 100 depending on the occupation. For example, it is conceivable that a user of a specific occupation receives an order for the examination content from a doctor and arranges an operation schedule according to the start date of using the magnetic resonance imaging system 10. Note that such "users of a specific occupation" may be able to check not only the remaining cooling time but also other states of the magnet 110 (any one of the demagnetized state, cooling state, cooled state, exciting state, and excited state).

[0075] In the example shown in FIG. 21, although there is no restriction on the cooling start operation depending on the occupation, restrictions may be provided in the same way as other operations.

[0076] As described above, in the magnetic resonance imaging system 10 according to the present embodiment, safety can be improved by restricting the operations that can be performed according to the occupation of the user. Note that the operation terminal 300 can similarly restrict the operations that can be performed according to the occupation of the user.

[0077] [Safety confirmation and excitation according to the occupation of the user] FIG. 22 is a flowchart in the case of performing safety confirmation and excitation according to the occupation of the user. The processing until the safety confirmation operation is performed in step S200 is the same as that in FIGS. 6 and 7, and the same processing is performed at the same step numbers as in FIGS. 6 and 7.

[0078] In the flowchart of FIG. 22, the processor 212 determines whether the user who performed the first operation has the authority for the first safety confirmation (confirmation of the absence of a magnetic body and the absence of a person) (step S202). The processor 212 can refer to the tables of FIGS. 8 and 21 described above to determine the presence or absence of the authority for the safety confirmation operation (one aspect of the "specific operation"). When the user does not have the authority for the first safety confirmation (NO in step S202), the processor 212 does not accept the operation that the user tried to execute and performs the first safety confirmation corresponding process (step S204). "Not accepting the operation" includes, for example, being unable to check the checkbox in the state of FIG. 19 or being unable to press (or tap) the OK button. After executing the first safety confirmation corresponding process in step S204, the process returns to step S200.

[0079] [First Safety Confirmation Corresponding Process] The processor 212 outputs at least one of information indicating that the user does not have the authority to execute the first safety confirmation operation (specific operation) (safety confirmation information 1) and information prompting the upper-level user to execute the first safety confirmation operation (safety confirmation information 2) (step S204). The (a) part of FIG. 23 is a diagram showing an output example of the first safety confirmation corresponding process (an example of outputting both pieces of the above information). In the same part, a situation is assumed where "Hanako Minami-Aoyama" (a nurse), who is a user at level 3, tries to execute the first safety confirmation operation (specific operation). The processor 212 can display and output the above information on the screen (display 202) of the operation terminal (operation terminal 200; first terminal device) used by the unauthorized user, but it may also output the information as sound via the speaker 206.

[0080] When the user clicks or taps "Request operation" on the same part, an information output request is sent from the processor 212 to the processor 312 (the processor of the operation terminal (here, the operation terminal 300; the second terminal device) used by the upper user). In response, the processor 312 outputs (which may be a display output or an audio output) the information (safety confirmation information 2) illustrated in the (b) part of FIG. 23. Note that the processor 212 may output (display on the screen, audio output) a message to a mobile terminal (smartphone, tablet terminal; one aspect of the second terminal device) carried by the upper user instead of the operation terminal 300.

[0081] In the state shown in the (b) part of FIG. 23, when the upper user clicks or taps "Confirm safety", a screen as shown in FIG. 19 is displayed on the operation terminal 300 or the mobile terminal, and the first safety confirmation becomes possible.

[0082] Note that in FIG. 23, the case where an unauthorized user uses the operation terminal 200 and the upper user uses the operation terminal 300 is described, but this relationship may be reversed. Also, in FIG. 23, the case where an unauthorized user tries to execute a specific operation is described, but the screen (see FIG. 19) for performing safety confirmation and excitation according to the user level may not be displayed so that a user without permission cannot even try to execute a specific operation.

[0083] [Second safety confirmation corresponding process] Similar to the operation restriction during the above-described first safety confirmation, similar processing can also be performed for the operation restriction (steps S222, S224; second safety confirmation corresponding process) during the second safety confirmation (confirmation of excitation start).

[0084] [Role sharing of operation terminal] In the magnetic resonance imaging system 10 according to the present embodiment, the above-described safety check may be performed by only one of the operation terminals 200 and 300, or may be performed by both. When performing the safety check with both operation terminals, one of the operation terminals 200 and 300 (for example, the operation terminal 200 which is a local operation terminal) is used as an operation terminal dedicated to the first operation (first terminal device), and the other (for example, the operation terminal 300 which is a service site operation terminal) can be used as an operation terminal capable of performing the first operation and the second operation (second terminal device). For example, it is conceivable that a level 2 user (technician) performs the first safety check with the operation terminal 200, and a level 1 user (chief technician) performs the second safety check (monitoring of the first safety check and) with the operation terminal 300. In this case, the operation terminal 200 is the first terminal device, and the operation terminal 300 is the second terminal device. When performing such a role sharing, the screen for the second operation (confirmation and operation of the start of excitation) may not be displayed on the operation terminal 200.

[0085] Further, without fixing which of the operation terminals 200 and 300 is the first terminal device and the second terminal device, the roles may be interchanged according to the level (occupation type) of the user. For example, it is conceivable to set roles for the operation terminals 200 and 300 according to the ID and occupation type of the logged-in user.

[0086] [Effects of the Embodiment] As described above, according to the first embodiment, not only professional service personnel with advanced knowledge and technology but also general users can correctly understand the state of the magnet. In addition, since actions such as safety checks are required, the user can easily understand what to do and can surely perform appropriate operations.

[0087] [Others] Note that the present invention is not limited to the above-described embodiment, and various modifications are possible. [Description of Reference Numerals]

[0088] 10 Magnetic resonance imaging system 100 Magnetic resonance imaging apparatus 101 Refrigerator 102 Compressor 103 Control unit 104 Pressure measurement unit 106 Shield temperature measurement unit 107 Magnet temperature measurement unit 108 Ammeter 109 Voltmeter 110 Magnet 120 Bed device 200 Operation terminal 202 Display 212 Processor 212A Arithmetic unit 212B Remote transceiver 300 Operation terminal 302 Display 312 Processor 312A Remote transceiver 312B Analysis unit Each step of the operation method S100 - S250

Claims

1. An operation terminal of a magnetic resonance imaging apparatus, comprising: The processor, acquiring information indicating a temperature of a magnet provided in a magnetic resonance imaging apparatus from the magnetic resonance imaging apparatus; Calculating a remaining cooling time, which is the time required for the magnet to be cooled to a cooling completion state, based on the acquired information; outputting information indicating the remaining cooling time; Operation terminal.

2. a non-transitory and tangible recording medium for recording cooling curve data showing a relationship between a time from when cooling of the magnet is started and a temperature of the magnet, the cooling curve data being generated based on actual measurements; The operation terminal according to claim 1 , wherein the processor calculates the time by referring to the recorded data of the cooling curve.

3. the recording medium records, as the cooling curve data, a plurality of cooling curve data corresponding to a type of a cooling device that cools the magnet and aging of the cooling device; The operation terminal according to claim 2 , wherein the processor uses the data of the plurality of cooling curves to calculate the remaining cooling time by interpolating the data of the plurality of cooling curves depending on the type of the cooling device and aging of the cooling device.

4. The operation terminal according to claim 2 or 3, wherein the processor generates new cooling curve data showing the relationship between the cooling time of the magnet and the temperature of the magnet based on the actual measured temperature of the magnet, and records the generated cooling curve data on the recording medium.

5. The operation terminal according to claim 2 or 3, wherein the processor causes a display device to display data of the cooling curve.

6. 4. The operation terminal according to claim 1, wherein the cooling completion state is a state in which the superconducting state of the magnet is maintained and excitation of the magnet can be started.

7. The operation terminal according to claim 1 , wherein the processor outputs the information by at least one of a display output and an audio output.

8. The operation terminal according to claim 1 , wherein the processor outputs the information discretely depending on the remaining cooling time.

9. The operation terminal according to claim 1 , wherein the processor determines a gradually smaller granularity for the information according to the remaining cooling time, and outputs the information at the determined granularity.

10. A method for operating an operation terminal of a magnetic resonance imaging apparatus, comprising: The operation terminal includes a processor, The processor, acquiring information indicating a temperature of a magnet provided in a magnetic resonance imaging apparatus from the magnetic resonance imaging apparatus; Calculating a remaining cooling time, which is the time required for the magnet to be cooled to a cooling completion state, based on the acquired information; outputting information indicating the remaining cooling time; How it works.

11. An operation terminal according to any one of claims 1 to 3; The magnetic resonance imaging device; A magnetic resonance imaging system comprising:

12. A cooling device for cooling the magnet; A thermometer for measuring the temperature of the magnet; Further equipped with 12. The magnetic resonance imaging system according to claim 11, wherein the magnet is a superconducting magnet for generating a static magnetic field.

Images