JP2009082331A - Magnetic resonance imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve thermal environment in a bore for disposing a subject in a magnetic resonance imaging apparatus. <P>SOLUTION: An information input section 31, an RF coil ID acquisition section 32, a temperature acquisition section 33, a humidity acquisition section 34 and a bore inner wall temperature acquisition section 35 acquire thermal environmental factors respectively. An activity amount computing section 41 computes the activity amount of the subject P based on the thermal environmental factors from an information input section 31. A clothing amount computing section 42 computes the clothing amount of the subject P based on the RF coil ID from the RF coil ID acquisition section 32. A wind speed setting section 43 sets the speed of an air flow. A PMV (Predicted Mean Vote) computing section 44 computes a PMV value based on six factors. The setting of the wind speed and the computing of the PMV are repeated till a PMV determination section 45 determines that the PMV computing value is within a tolerance. A fan control section 50 controls a fan 14 to generate the air flow of the speed when determining that the PMV computing value is within the tolerance, to the inside of the bore 20a. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a magnetic resonance imaging apparatus, and more particularly to a technique related to a thermal environment in a bore in which a subject is arranged.

  An inspection using a magnetic resonance imaging (MRI) apparatus is performed by placing the subject in a gantry hole (bore) of the gantry. Therefore, the bore is formed by a heat source in the apparatus or radiant heat from the subject itself. There is a risk that the internal temperature rises and the subject feels uncomfortable.

  In view of such a situation, contrivances have been made such as generating an air flow in the bore to prepare a thermal environment in the bore (see, for example, Patent Document 1). The thermal environment means an environmental state that affects the sense of warmth (hotness) and coolness (coldness) held by the subject of the magnetic resonance imaging apparatus.

JP-A-8-322815

  However, in the conventional magnetic resonance imaging apparatus, since the airflow generated in the bore is almost constant, the subject often feels cold due to the airflow at the beginning of the examination.

  Further, even if the thermal environment in the bore is comfortable at a certain timing during the inspection, the temperature gradually increases due to heat generated from an RF (Radio Frequency) coil as time passes, and the thermal environment deteriorates. As a result, there is a problem that the subject is uncomfortable.

  Particularly recently, the amount of high-frequency magnetic field emitted from the RF coil has increased, and therefore the necessity for improving the thermal environment in the bore has increased.

  The present invention has been made to solve the above-described problems, and provides a magnetic resonance imaging apparatus capable of improving the thermal environment in a bore where a subject is arranged. Objective.

  In order to achieve the above object, according to the first aspect of the present invention, a static magnetic field and a gradient magnetic field are applied to a subject arranged in a bore of a gantry, and a high frequency is generated by an RF coil mounted on the subject. A magnetic resonance imaging apparatus that generates a magnetic field, receives an echo signal from a nucleus in the subject corresponding to the generated high-frequency magnetic field, and forms an image of the subject based on the received echo signal An acquisition means for acquiring a thermal environment factor that affects the thermal environment in the bore; and a calculation means for calculating thermal environment information representing the thermal environment in the bore based on the acquired thermal environment factor; Changing means for changing a thermal environment in the bore based on the calculated thermal environment information.

  The invention according to claim 2 applies a static magnetic field and a gradient magnetic field to a subject arranged in a bore of a gantry, generates a high-frequency magnetic field by an RF coil mounted on the subject, A magnetic resonance imaging apparatus for receiving an echo signal from a nucleus in the subject corresponding to a generated high-frequency magnetic field and forming an image of the subject based on the received echo signal, An acquisition means for acquiring a thermal environment factor that affects the thermal environment of the machine, a calculation means for calculating thermal environment information representing the thermal environment in the bore based on the acquired thermal environment factor, and the calculated thermal environment Display means for displaying display information based on the information.

  The magnetic resonance imaging apparatus according to the present invention acquires a thermal environment factor that affects the thermal environment in the bore of the gantry in which the subject is arranged, and thermal environment information that represents the thermal environment in the bore based on the thermal environment factor Since the thermal environment in the bore is changed based on the thermal environment information, it is possible to automatically improve the thermal environment in the bore.

  In addition, the magnetic resonance imaging apparatus according to the present invention acquires a thermal environment factor that affects the thermal environment in the bore of the gantry in which the subject is placed, and based on the thermal environment factor, represents the thermal environment in the bore. Since it is configured to calculate environmental information and display display information based on this thermal environment information, the examiner can grasp the thermal environment in the bore and improve the thermal environment in the bore It is possible to take various measures.

  An example of a preferred embodiment of a magnetic resonance imaging apparatus according to the present invention will be described in detail with reference to the drawings.

<First Embodiment>
[overall structure]
FIG. 1 shows an example of the overall configuration of a magnetic resonance imaging apparatus according to the first embodiment of the present invention. A gantry 20 of the magnetic resonance imaging apparatus shown in the figure is provided with a static magnetic field magnet 1, a gradient magnetic field coil 2, and an RF coil 3.

  The gantry 20 is formed with a bore 20a in which the subject P to be examined is placed. The subject P is placed on the top plate of the bed 13 and inserted into the bore 20a. At this time, the top plate is moved by a driving mechanism (not shown) of the bed 13.

  According to the present invention, the subject P can be examined more comfortably by improving the thermal environment in the bore 20a. The gantry 20 is provided with a fan 14 for generating an air flow in the bore 20a. The operation of the fan 14 is controlled by the host computer 11.

  The static magnetic field magnet 1 is a device that generates a static magnetic field in the bore 20a, and is configured using, for example, a superconducting coil, a normal conducting coil, a permanent magnet, or the like. The static magnetic field magnet 1 is driven by a static magnetic field control device 4.

  The gradient magnetic field coil 2 is a coil that generates a gradient magnetic field in the X-axis direction, a gradient magnetic field in the Y-axis direction, and a gradient magnetic field in the Z-axis direction in the bore 20a. The gradient coil 2 is driven by an X-axis gradient magnetic field amplifier 7, a Y-axis gradient magnetic field amplifier 8, and a Z-axis gradient magnetic field amplifier 9, respectively.

  The RF coil 3 generates radio frequency (RF) pulses. This high frequency pulse causes a magnetic resonance phenomenon of the nuclei in the body of the subject P in the bore 20a. The RF coil 3 detects an echo signal generated by this magnetic resonance phenomenon. Note that transmission of RF pulses and reception of echo signals may be performed by separate transmission coils and reception coils. The RF coil 3 is driven by the transmitter 5 when magnetic resonance is excited. Further, when the RF coil 3 detects an echo signal from the subject P, the RF coil 3 transmits the detection result to the receiver 6. The RF coil 3 shown in FIG. 1 is an RF coil for imaging the head of the subject P. For example, for the chest imaging, abdominal imaging, and whole body imaging, an RF coil corresponding to the imaging region is used. Used selectively.

  The X-axis gradient magnetic field amplifier 7, the Y-axis gradient magnetic field amplifier 8, the Z-axis gradient magnetic field amplifier 9, and the transmitter 5 are driven according to a predetermined sequence by the sequence controller 10, and are respectively X-axis gradient magnetic field, Y-axis gradient magnetic field, and Z-axis. An axial gradient magnetic field and RF pulse are generated in a predetermined pulse sequence. At this time, the X-axis gradient magnetic field, the Y-axis gradient magnetic field, and the Z-axis gradient magnetic field are used as, for example, a readout gradient magnetic field, a phase encoding gradient magnetic field, and a slice gradient magnetic field, respectively.

  The host computer 11 controls the sequence controller 10 and takes in the echo signal received by the receiver 6 and applies predetermined signal processing to generate a tomographic image of the subject P and display it on the display unit 12. . The host computer 11 is provided with a console for an operator to perform various operations and information input.

[Control system configuration]
FIG. 2 is a block diagram showing details of a control system of the magnetic resonance imaging apparatus according to this embodiment.

  This magnetic resonance imaging apparatus includes an information input unit 31, an RF coil ID acquisition unit 32, a temperature acquisition unit 33, and a humidity acquisition unit 34 as acquisition means for acquiring various thermal environment factors that affect the thermal environment in the bore 20a. And the bore inner wall temperature acquisition part 35 is provided.

(Information input part)
The information input unit 31 inputs various thermal environment factors such as the height, weight, metabolic rate, SAR (specific absorption rate; specific absorption rate) of the subject P to the calculation unit 40. In the configuration shown in FIG. 2, the single information input unit 31 is provided, but two or more information input units may be provided.

  For the height and weight of the subject P, for example, an electronic medical record of the subject P is searched from an electronic medical record database in the medical institution, and values described in the electronic medical record are input. In this case, the information input unit 31 includes a communication device (such as a LAN card) that can communicate with the electronic medical record database, a microprocessor such as a CPU, and the like.

  When electronic medical record information is stored in advance in a storage device (such as a hard disk drive) of the host computer 11, the information input unit 31 includes the storage device, a microprocessor, and the like.

  In addition, the operator can manually input the height and weight of the subject P by operating the console of the host computer 11.

  As the metabolic rate, a constant value (for example, the value of the metabolic rate in a state of resting) is input. In this case, the information input unit 31 includes a storage device of the host computer 11 that stores the metabolic rate, a microprocessor, and the like. If there is information on the metabolic rate measured in the past for the subject P, this information may be input.

  The SAR represents the amount of energy absorbed by the living tissue per unit mass and unit time, and is based on the static magnetic field magnet, gradient magnetic field coil and RF coil of the magnetic resonance imaging apparatus, and further based on the imaging region. Determined in advance.

  The storage device of the host computer 11 stores in advance table information that records SAR values for each imaging region such as the head, chest, abdomen, and feet. The operator inputs an imaging region of the subject P using the console of the host computer 11. The microprocessor of the host computer 11 selects the SAR value corresponding to the inputted imaging region from the table information and inputs it to the calculation unit 40.

(RF coil ID acquisition unit)
The RF coil ID acquisition unit 32 inputs type information (RF coil ID) indicating the type of the RF coil 3 to the calculation unit 40.

  As described above, there are various types of RF coil 3 such as for head imaging, chest imaging, and abdominal imaging. Each RF coil 3 is pre-assigned with an RF coil ID consisting of a character string or the like indicating its type.

  The RF coil 3 is connected to the transmitter 5 and the receiver 6 via a connector. Information indicating the type of the RF coil 3 (such as the shape of the connection portion and a recording medium on which the RF coil ID is recorded) is provided on the RF coil 3 side of the connection portion.

On the other hand, on the transmitter 5 and / or receiver 6 side of the connection portion, reading means for reading information on the RF coil 3 side (means for converting the shape of the connection portion into a signal, reader for the storage medium) Etc.) are provided. The transmitter 5 and the receiver 6 send information read from the RF coil 3 side to the host computer 11.

  The storage device of the host computer 11 stores in advance table information that associates information provided on the RF coil 3 side with the RF coil ID. The microprocessor of the host computer 11 selects the RF coil ID corresponding to the information input from the transmitter 5 or the receiver 6 from the table information and inputs it to the calculation unit 40.

  When such a configuration is applied, the RF coil ID acquisition unit 32 includes a microprocessor and a storage device of the host computer 11 and the reading unit described above.

  In addition, when the information input from the transmitter 5 or the receiver 6 is the RF coil ID itself, the above table information is not necessary. In this case, the RF coil ID acquisition unit 32 includes the microprocessor of the host computer 11 and the reading unit described above.

  Further, the operator may manually input the RF coil ID using the console of the host computer 11. Alternatively, the RF coil ID corresponding to the imaging region may be input to the calculation unit 40 by manually inputting the imaging region of the subject P. In these cases, the RF coil ID acquisition unit 32 includes the console of the host computer 11 and a microprocessor.

  In addition, it is possible to automatically specify an imaging region based on order information of imaging performed by the magnetic resonance imaging apparatus, and to input an RF coil ID corresponding to the specified imaging region to the calculation unit 40. In this case, the RF coil ID acquisition unit 32 includes a microprocessor of the host computer 11.

(Temperature acquisition unit)
The temperature acquisition unit 33 acquires the temperature in the examination room (shield room subjected to magnetic field blocking or electromagnetic wave blocking) in which the magnetic resonance imaging apparatus is installed, in particular, the temperature in the bore 20a.

  The temperature acquisition unit 33 is constituted by, for example, a thermometer provided in the examination room, particularly in the bore 20a or in the vicinity thereof. This thermometer may be an arbitrary form of thermometer such as one using mercury, one using a thermocouple, one detecting infrared rays, or the like. The temperature acquisition unit 33 inputs the temperature detection result as a signal to the calculation unit 40.

  Further, the temperature acquisition unit 33 may be an air conditioner in a laboratory. In this case, the set temperature of the air conditioner is input to the calculation unit 40.

(Humidity acquisition unit)
The humidity acquisition unit 34 acquires the humidity in the examination room where the magnetic resonance imaging apparatus is installed, in particular, the humidity in the bore 20a.

  The humidity acquisition unit 34 is constituted by, for example, a hygrometer provided in the examination room, particularly in the bore 20a or in the vicinity thereof. The humidity acquisition unit 34 inputs the humidity detection result as a signal to the calculation unit 40.

  Moreover, the humidity acquisition part 34 may be an air conditioner (having a humidity setting function) in an examination room. In this case, the set humidity of the air conditioner is input to the calculation unit 40.

(Bore inner wall temperature acquisition unit)
The bore inner wall temperature acquisition unit 35 acquires the temperature of the inner wall of the bore 20a, that is, the wall surrounding the subject P disposed in the bore 20a.

  The bore inner wall temperature acquisition unit 35 is configured by a thermometer similar to the temperature acquisition unit 33, for example. The bore inner wall temperature acquisition unit 35 inputs the detection result of the temperature of the inner wall of the bore 20a as a signal to the calculation unit 40.

  At this time, the bore inner wall temperature acquisition unit 35 may acquire temperatures at a plurality of locations on the inner wall of the bore 20a, obtain an average value and a median value thereof, and input them to the calculation unit 40. Further, the temperature of the gantry 20 (the temperature of the static magnetic field magnet 1 and the gradient magnetic field coil 2) and the temperature in the examination room / bore 20a are detected, and the bore is determined based on the detection result and the thermal conductivity of the gantry 20 and the like. It is also possible to calculate the temperature of the inner wall of 20a.

  The temperature of the inner wall of the bore 20a acquired by the bore inner wall temperature acquisition unit 35 corresponds to the radiation temperature from the inner wall, and is used as an average radiation temperature used in the calculation of PMV described later.

[Calculation section]
The thermal environment factor as described above is input to the calculation unit 40 from the information input unit 31, the RF coil ID acquisition unit 32, the temperature acquisition unit 33, the humidity acquisition unit 34, and the bore inner wall temperature acquisition unit 35. The computing unit 40 computes thermal environment information representing the thermal environment in the bore 20a based on these thermal environment factors.

  In this embodiment, PMV (predicted mean vote) is used as the thermal environment information. PMV is based on the thermal balance equation between the human body and the environment, and is based on the amount of activity (work volume) and the amount of clothing that are factors on the human body side, and the temperature, relative humidity, average radiation temperature, and wind speed that are environmental factors. (See, for example, Japanese Patent Laid-Open No. 2000-291990).

  The calculation unit 40 includes, for example, a microprocessor and storage device of the host computer 11. The calculation unit 40 functions as an example of the “calculation unit” of the present invention.

  The calculation unit 40 includes an activity amount calculation unit 41, a clothing amount calculation unit 42, a wind speed setting unit 43, a PMV calculation unit 44, and a PMV determination unit 45.

(Activity calculation unit)
The activity amount calculation unit 41 calculates an activity amount used for calculating PMV based on information input from the information input unit 31. The activity amount calculation unit 41 includes, for example, a microprocessor of the host computer 11 and a storage device. The storage device stores various set values and arithmetic expressions used in the following calculations.

  The activity amount calculating unit 41 will be described more specifically. The information input unit 31 inputs the height, weight, metabolic rate, and SAR of the subject P to the activity amount calculation unit 41 as described above. The activity amount calculator 41 first calculates the body surface area of the subject P based on the height and weight input from the information input unit 31. This process is performed, for example, by calculating the volume of the subject P based on the general density (mass per unit volume) of the human body and calculating the body surface area based on this volume.

  Further, clinical data indicating the relationship between height and weight and body surface area may be created and stored in advance, and the body surface area may be obtained based on the clinical data. When the body surface area of the subject P has been examined in the past, this test result may be used. At this time, the body surface area value may be corrected in consideration of changes in height and weight between the past and the present.

  Further, the body surface area of the whole body of the subject P may be obtained, or the body surface area of only the part arranged in the bore 20a may be obtained. When the latter is carried out, for example, based on the moving distance when the subject P is transported into the bore 20a by the bed 13, what portion is disposed in the bore 20a with respect to the height of the subject P. Can be asked. The activity amount calculator 41 calculates the body surface area of the portion of the subject P placed in the bore 20a in consideration of the portion of the subject P placed in the bore 20a (such as the ratio to the whole body). it can.

  The height and weight of the subject P correspond to an example of “body information” of the present invention. When the body surface area of the subject P acquired by the past examination is used, the examination result of the body surface area corresponds to “body information”. The metabolic rate input from the information input unit 31 also corresponds to an example of “body information”.

  Next, the activity amount calculation unit 41 calculates the strength of the high-frequency magnetic field generated by the RF coil 3 based on the weight and SAR input from the information input unit 31. This process is performed, for example, by multiplying weight (kg) and SAR (W / kg).

  Subsequently, the activity amount calculating unit 41 calculates the strength (absorption amount) of the high-frequency magnetic field absorbed by the subject P based on the calculation result of the strength of the high-frequency magnetic field from the RF coil 3. This process is performed, for example, by subtracting a predetermined value from the calculation result of the strength of the high-frequency magnetic field. This predetermined value is the amount of high-frequency magnetic field absorbed by the magnetic resonance imaging apparatus, and is set in advance.

  Further, the activity amount calculation unit 41 calculates the metabolic rate caused by the high frequency magnetic field from the RF coil 3 based on the calculation result of the body surface area of the subject P and the calculation result of the absorption amount of the high frequency magnetic field by the subject P. Ask. This processing is obtained, for example, by dividing the absorption amount (W) of the high-frequency magnetic field by the body surface area (m ^ 2) and dividing the quotient (W / m ^ 2) by 58.2. The unit meta of the metabolic rate is defined by 1met = 58.2 (W / m ^ 2). Here, 1 met represents the amount of metabolism in the chair resting state.

  Finally, the activity amount calculating unit 41 receives the high frequency magnetic field from the RF coil 3 based on the metabolic rate input from the information input unit 31 and the calculation result of the metabolic rate caused by the high frequency magnetic field. The amount of activity of the subject P is calculated. This process is performed, for example, by adding the input metabolic rate (met) and the calculation result (met) of the metabolic rate. The activity amount calculation unit 41 inputs the obtained activity amount value to the PMV calculation unit 44.

(Clothing amount calculation unit)
The clothing amount calculation unit 42 calculates the clothing amount of the subject P based on the RF coil ID input from the RF coil ID acquisition unit 32. The amount of clothes is an index of the heat insulating properties of clothes, and the unit is clo. 1 clo corresponds to a state in which the chair is seated under conditions of an air temperature of 21.2 ° C., a relative humidity of 50%, and an airflow (wind speed) of 0.1 m / sec. Moreover, the clothing amount calculated | required by the clothing amount calculating part 42 is corresponded to an example of "clothing amount information" of this invention.

  The clothing amount calculation unit 42 includes, for example, a microprocessor of the host computer 11 and a storage device. The storage device stores setting values, table information, and arithmetic expressions used in the following calculations.

  The subject P is subjected to an inspection in a state in which predetermined inspection clothes are worn and the RF coil 3 is further attached. The clothing amount calculation unit 42 stores in advance table information in which the value of the clothing amount corresponding to the type of the RF coil 3 is recorded. This table information is created, for example, by actually measuring the amount of clothes for various RF coils 3. In addition, the clothing amount calculation unit 42 stores in advance a clothing amount value for the examination clothing.

  For example, the clothing amount calculation unit 42 selects a clothing amount value corresponding to the RF coil ID input from the RF coil ID acquisition unit 32 from the above table information, and the selected clothing amount value and the examination clothing. The amount of clothing (clo) of the subject P is obtained by adding together the value of the amount of clothing. The clothing amount calculation unit 42 inputs the obtained clothing amount to the PMV calculation unit 44.

(Wind speed setting part)
In order to calculate PMV, as described above, six thermal environment factors are required: activity amount, clothing amount, temperature, relative humidity, average radiation temperature, and wind speed. The five thermal environmental factors of activity amount, clothing amount, temperature, relative humidity, and average radiation temperature are information input unit 31, RF coil ID acquisition unit 32, temperature acquisition unit 33, humidity acquisition unit 34, and bore inner wall temperature acquisition unit 35. Can be obtained from the input content.

  On the other hand, since this magnetic resonance imaging apparatus is intended to improve the thermal environment in the bore 20a by adjusting the wind speed of the airflow in the bore 20a, it is necessary to obtain a suitable value for the wind speed of the airflow. The wind speed setting unit 43 operates to set the value of the wind speed of the airflow used for calculating the PMV and input the value to the PMV calculation unit 44.

  Further, as described later, the wind speed setting unit 43 receives feedback of the determination result from the PMV determination unit 45, changes the setting value of the wind speed, and operates to input to the PMV calculation unit 44. In addition, when the fan 14 is operating, the wind speed setting unit 43 acts to input the value of the wind speed of the airflow generated in the bore 20 a by the fan 14 to the PMV calculation unit 44.

(PMV calculation unit)
The PMV calculation unit 44 includes an activity amount input from the activity amount calculation unit 41, a clothing amount input from the clothing amount calculation unit 42, a temperature input from the temperature acquisition unit 33, and a relative humidity input from the humidity acquisition unit 34. The PMV value is calculated based on the average radiation temperature input from the bore inner wall temperature acquisition unit 35 and the wind speed of the airflow input from the wind speed setting unit 43.

  The calculation of the value of PMV by the PMV calculation unit 44 can be performed by a standard method (ISO7730 Thermal comfort by P.O.Funger McGraw-Hill Book Company 1972); see, for example, Japanese Patent Laid-Open No. 2000-291990 . ). The PMV calculation unit 44 inputs the calculated PMV value to the PMV determination unit 45.

(PMV judgment part)
The PMV determination unit 45 determines whether or not the PMV value calculated by the PMV calculation unit 44 is included in a predetermined range.

  PMV is considered to be a comfortable thermal environment in the range of -0.5 to 0.5. Therefore, in this embodiment, a range of −0.5 to 0.5 is set as the predetermined range. This range is sometimes referred to as “allowable range”. It is also possible to set an allowable range other than the range of −0.5 to 0.5 as appropriate.

  The PMV determination unit 45 determines whether or not the PMV value calculated by the PMV calculation unit 44 is included in the allowable range. When the PMV value is not included in the allowable range, the PMV determination unit 45 determines whether the calculated PMV value is larger or smaller than the allowable range, and calculates the calculated PMV value and the allowable range. Calculate the difference.

  For example, when the calculated PMV value is 0.7, the PMV determination unit 45 determines (1) that the value 0.7 is not included in the allowable range of −0.5 to 0.5, (2) It is determined that the value 0.7 is larger than the allowable range, and (3) the difference (absolute value) between the value 0.7 and the allowable range | 0.7−0.5 = 0. 2 | is calculated.

  In the calculation of (3), a difference from an arbitrary value (target value) within an allowable range may be obtained. For example, when the target value is 0, the calculation of (3) is | 0.7-0 | = 0.7.

  It is also possible to perform (2) and (3) at a time, for example, by obtaining a displacement amount of the calculated PMV value with respect to the target value. For example, when the calculated value of PMV is 0.7, the amount of displacement with respect to the target value (0) is 0.7-0 = + 0.7. When the calculated PMV value is −0.7, the displacement amount with respect to the target value (0) is −0.7−0 = −0.7. “±” of the calculation result of the displacement amount represents a magnitude relationship with the target value (allowable range).

  When the PMV determination unit 45 determines that the calculated PMV value is included in the allowable range, the PMV determination unit 45 acquires the set value of the wind speed at this time from the wind speed setting unit 43 and inputs it to the fan control unit 50.

  On the other hand, when it is determined that the calculated PMV value is not included in the allowable range, the PMV calculation unit 44 determines the determination result of the magnitude relationship between the calculated PMV value and the allowable range ((2 in the above specific example). ) And the calculation result of the difference between the calculated PMV value and the allowable range (the calculation result of (3) of the above specific example) are input to the wind speed setting unit 43.

  At this time, the calculated PMV value may be input to the wind speed setting unit 43 as necessary. Moreover, you may make it input into the wind speed setting part 43 other factors (activity amount, the amount of clothes, temperature, relative humidity, average radiation temperature) used for the calculation of PMV as needed.

  The wind speed setting unit 43 changes the set value of the wind speed of the airflow based on the determination result and the calculation result input from the PMV determination unit 45 and inputs them to the PMV calculation unit 44. The wind speed setting unit 43, the PMV calculation unit 44, and the PMV determination unit 45 repeat such feedback processing until the PMV determination unit 45 determines that “the calculated PMV value is included in the allowable range”. To do.

(Fan control unit)
The fan control unit 50 controls the fan 14 based on the value of the wind speed of the airflow input from the PMV determination unit 45, thereby generating an airflow of this wind speed in the bore 20a.

  A specific example of the fan control unit 50 will be described. For example, the fan control unit 50 stores in advance information indicating the relationship between the rotational speed of the blades (not shown) of the fan 14 that is rotationally driven by a driving device such as a motor and the generated wind speed. Then, based on this information, the fan control unit 50 obtains the rotation speed of the fan 14 blades corresponding to the wind speed value input from the PMV determination unit 45 and rotates the fan 14 blades at this rotation speed. To control the drive device.

  Here, the fan 14 provided with a blade | wing and a drive device functions as an example of the "air flow generation means" of this invention. The fan control unit 50 functions as an example of the “control unit” of the present invention. Further, the fan 14 and the fan control unit 50 function as an example of the “changing unit” of the present invention.

[Usage form]
A usage pattern of the magnetic resonance imaging apparatus having the above configuration will be described. The flowchart shown in FIG. 3 represents an example of a usage pattern of the magnetic resonance imaging apparatus.

  First, the subject P is placed on the bed 13, and at least a part of the subject P including the imaging region is placed in the bore 20a to start imaging (S1).

  The information input unit 31, the RF coil ID acquisition unit 32, the temperature acquisition unit 33, the humidity acquisition unit 34, and the bore inner wall temperature acquisition unit 35 each acquire the above-mentioned thermal environment factor and input it to the calculation unit 40 (S2). .

  The activity amount calculation unit 41 calculates the activity amount of the subject P based on the thermal environment factor input from the information input unit 31, and inputs the activity amount to the PMV calculation unit 44 (S3).

  Also, the clothing amount calculation unit 42 calculates the amount of clothing of the subject P based on the RF coil ID input from the RF coil ID acquisition unit 32 and inputs it to the PMV calculation unit 44 (S4). Note that the order of execution of the activity amount calculation process and the clothing amount calculation process is arbitrary (may be executed simultaneously).

  The wind speed setting unit 43 inputs the value of the wind speed of the airflow to the PMV calculation unit 44 (S5). The PMV calculation unit 44 includes an activity amount input from the activity amount calculation unit 41, a clothing amount input from the clothing amount calculation unit 42, a temperature input from the temperature acquisition unit 33, and a relative humidity input from the humidity acquisition unit 34. Based on the temperature (average radiation temperature) input from the bore inner wall temperature acquisition unit 35 and the wind speed input from the wind speed setting unit 43, the PMV value is calculated and input to the PMV determination unit 45 (S6).

  The PMV determination unit 45 determines whether or not the calculated PMV value is included in an allowable range (here, a range of −0.5 to 0.5) (S7).

  When it is determined that the calculated PMV value is included in the allowable range (S7; Y), the PMV determination unit 45 acquires the value of the wind speed at this time from the wind speed setting unit 43, and the fan control unit 50 (S8).

  The fan control unit 50 controls the fan 14 based on the wind speed value input from the PMV determination unit 45, thereby generating an air current of this wind speed in the bore 20a (S9). The process in this case ends here.

  On the other hand, when it is determined in step S7 that the calculated PMV value (calculated value) is not included in the allowable range (S7; N), the PMV determination unit 45 determines whether the calculated value of PMV and the allowable range are the same. The magnitude relationship and the difference are obtained and input to the wind speed setting unit 43 together with the PMV value and other factors (S10).

  The wind speed setting unit 43 sets a new wind speed value based on the input content from the PMV determination unit 45 and inputs it to the PMV calculation unit 44 (S11). At this time, the PMV determination unit 45 performs, for example, the following process to set a new wind speed value.

  First, the wind speed setting unit 43 indicates the degree of influence of the wind speed value on the change in the PMV value, that is, how much the PMV value changes when the wind speed value is changed at an arbitrary PMV value. (Table information and graph information) are stored in advance. This information (referred to as wind speed-PMV related information) can be created by simulating the amount of change in the PMV value when the wind speed value is changed using the PMV arithmetic expression. .

  The wind speed setting unit 43 refers to the wind speed-PMV related information, obtains a new wind speed value corresponding to the input information from the PMV determination unit 45, and inputs the new wind speed value to the PMV determination unit 45. At this time, the wind speed setting unit 43 sets the new PMV value based on the new wind speed value to an arbitrary value within the allowable range (for example, −0.5, −0.25, 0, 0.25, 0.5). Etc.) to set a new wind speed value. Here, when the calculated value of PMV is larger (smaller) than the allowable range, that is, when the inside of the bore 20a is warmer (cooler) than a comfortable thermal state, the wind speed value larger (smaller) than the previous set value. Can be set.

  The PMV calculation unit 44 calculates the value of PMV using the new wind speed value input from the wind speed setting unit 43 (S6). At this time, a new thermal environment factor may be acquired by the temperature acquisition unit 33, the humidity acquisition unit 34, and the bore inner wall temperature acquisition unit 35, and the value of the PMV may be calculated using the new thermal environment factor.

  Steps S6 to S11 are repeated until it is determined in step S7 that “PMV value is included in the allowable range” (S7; Y). The operation after such a determination is the same as steps S8 and S9 described above. The description of the usage pattern of the magnetic resonance imaging apparatus based on the flowchart of FIG.

  The usage pattern described above is for adjusting the thermal environment in the bore 20a at the start of photographing. In general, imaging by a magnetic resonance imaging apparatus requires several tens of minutes depending on the imaging region. The magnetic resonance imaging apparatus according to this embodiment can adjust the thermal environment in the bore 20a during imaging by, for example, periodically performing the same operation as that shown in FIG.

  The operation during the photographing will be described. First, the temperature acquisition unit 33, the humidity acquisition unit 34, and the bore inner wall temperature acquisition unit 35 acquire the respective thermal environment factors and input them to the PMV calculation unit 44 (S2). Further, the wind speed setting unit 43 inputs the wind speed of the airflow currently generated by the fan 14 to the PMV calculation unit 44. The PMV calculation unit 44 calculates the value of PMV based on these pieces of information (S6). The subsequent processing is the same as in the above usage pattern.

[Action / Effect]
The operation and effect of the magnetic resonance imaging apparatus as described above will be described.

  The magnetic resonance imaging apparatus according to this embodiment acquires a thermal environment factor that affects the thermal environment in the bore 20a, and calculates thermal environment information (PMV) that represents the thermal environment in the bore 20a based on the thermal environment factor. At the same time, the thermal environment in the bore 20a is changed by generating an air flow having a suitable wind speed in the bore 20a based on the thermal environment information. Therefore, according to this magnetic resonance imaging apparatus, it is possible to improve the thermal environment in the bore 20a where the subject P is disposed.

  In particular, this magnetic resonance imaging apparatus operates so as to calculate the wind speed of an air current such that the value of PMV is included in a predetermined allowable range and generate an air current of this wind speed. As described above, this allowable range is set to a range corresponding to a comfortable thermal environment. Therefore, according to this magnetic resonance imaging apparatus, it is possible to improve the thermal environment in the bore 20a.

  Further, according to this magnetic resonance imaging apparatus, the activity amount of the subject P is calculated based on the strength of the high-frequency magnetic field from the RF coil 3, and the thermal environment in the bore 20a is calculated based on the PMV value based on the calculation result. Therefore, the thermal environment in the bore 20a can be improved according to the type of the RF coil 3.

  Further, according to the magnetic resonance imaging apparatus, the amount of activity of the subject P is calculated based on the physical information including the height and weight of the subject P, and the bore 20a is calculated based on the PMV value based on the calculation result. Since the thermal environment can be changed, there is an advantage that the thermal environment in the bore 20a can be improved according to the physique of the subject P and the like.

  Further, according to the magnetic resonance imaging apparatus according to this embodiment, since the thermal environment in the bore 20a can be automatically adjusted, there is an advantage that the examiner can concentrate on the imaging work.

[Modification]
A modification of the magnetic resonance imaging apparatus according to this embodiment will be described.

  FIG. 4 shows an example of the configuration of a control system of a modification of the imaging apparatus according to this embodiment. The calculation unit 40 of the magnetic resonance imaging apparatus shown in the figure is provided with a wind speed calculation unit 46 instead of the wind speed setting unit 43, the PMV calculation unit 44, and the PMV determination unit 45 of the above embodiment.

  The wind speed calculation unit 46 calculates the activity amount calculation result of the subject P based on the thermal environment factor acquired by the information input unit 31 and the calculation of the clothing amount based on the RF coil ID acquired by the RF coil ID acquisition unit 32. The result and the thermal environment factor respectively acquired by the temperature acquisition unit 33, the humidity acquisition unit 34, and the bore inner wall temperature acquisition unit 35 are input.

  The wind speed calculation unit 46 calculates the wind speed value of the airflow such that the PMV value is included in the allowable range based on these pieces of information. This calculation process will be described. An arithmetic expression of PMV is assumed to be f (x1, x2, x3, x4, x5, x6). Here, x1 = activity amount, x2 = clothing amount, x3 = temperature, x4 = relative humidity, x5 = average radiation temperature, and x6 = wind speed. Assuming that the target value of PMV is α, the wind speed calculation unit 46 has f (x1, x2, x3, x4, x5, x6) = f (x6) in a state where each of x1, x2, x3, x4, and x5 is known. ) = 6 so that α = α. At this time, an arithmetic method such as an approximate expression or simulation may be used.

  The wind speed calculation unit 46 inputs the obtained wind speed value to the fan control unit 50. The fan control unit 50 controls the fan 14 based on the value of the wind speed input from the wind speed calculation unit 46 to generate an air flow having the calculated wind speed in the bore 20a.

  According to such a modification, since the thermal environment in the bore 20a can be changed by generating an air flow having a suitable wind speed based on the thermal environment information (PMV) in the bore 20a, the bore in which the subject P is disposed. It is possible to improve the thermal environment within 20a.

  In the above embodiment, the thermal environment is improved by changing the wind speed among the six thermal environment factors used for calculating the PMV. For example, the temperature of the examination room (especially in the bore 20a) is improved. It is also possible to change the thermal environment factors other than the wind speed, such as humidity and relative humidity, so as to improve the thermal environment.

  When changing the temperature, a temperature changing device such as an air conditioner, a heater or a cooler for changing the temperature in the examination room (particularly in the bore 20a) is provided in the magnetic resonance imaging apparatus. Further, an information input unit 31, an RF coil ID acquisition unit 32, a humidity acquisition unit 34, and a bore inner wall temperature acquisition unit 35 are provided as acquisition means for acquiring a thermal environment factor. Further, an arbitrary wind speed detection device is obtained as means for acquiring the wind speed of the airflow in the bore 20a. As described in the above embodiment, the wind speed may be obtained from the rotational speed of the fan 14. The host computer 11 calculates the activity amount of the subject P based on the thermal environment factor acquired by the information input unit 31 (activity amount calculation unit 41) and the RF coil acquired by the RF coil ID acquisition unit 32 Based on the ID, the clothing amount of the subject P is computed (clothing amount computation unit 42). Then, the host computer 11 obtains the temperature at which the PMV value is included in the allowable range (calculation unit 40), and controls the temperature changing device (in particular, the examination room (in particular) The temperature inside the bore 20a is set to the temperature.

  When the humidity is changed, a humidity changing device such as an air conditioner, a dehumidifier or a humidifier for changing the humidity in the examination room (particularly in the bore 20a) is provided in the magnetic resonance imaging apparatus. Further, an information input unit 31, an RF coil ID acquisition unit 32, a temperature acquisition unit 33, and a bore inner wall temperature acquisition unit 35 are provided as acquisition means for acquiring a thermal environment factor. The host computer 11 calculates the amount of activity of the subject P based on the thermal environment factor acquired by the information input unit 31, and based on the RF coil ID acquired by the RF coil ID acquisition unit 32, the subject computer The amount of P clothes is calculated. Then, the host computer 11 obtains the humidity (relative humidity) such that the PMV value falls within the allowable range in the same manner as in the above-described embodiments and modifications, and controls the humidity changing device to control the inside of the examination room (in particular, the bore). 20a) is set to the humidity.

  When both the temperature and the humidity are changed, both the temperature changing device and the humidity changing device are provided in the magnetic resonance imaging apparatus. As an acquisition means, an information input unit 31, an RF coil ID acquisition unit 32, and a bore inner wall temperature acquisition unit 35 are provided. The host computer 11 obtains both values of temperature and humidity by, for example, appropriately setting the temperature and humidity and simulating the value of PMV. Then, the host computer 11 controls the temperature changing device and the humidity changing device to set the temperature and the humidity in the examination room (particularly in the bore 20a).

  According to such a modification, the temperature and humidity in the bore 20a can be changed to a suitable temperature and humidity based on the thermal environment information (PMV), so that the inside of the bore 20a in which the subject P is placed is arranged. It is possible to improve the thermal environment. The above temperature changing device and / or humidity changing device functions as an example of the “temperature / humidity changing means” of the present invention. The host computer 11 functions as an example of the “control unit” of the present invention.

  In the above embodiment, the allowable range (target value) of PMV that is uniformly applied to each subject may be changed for each subject. For example, it is possible to change the tolerance range and target value according to gender, such as setting the tolerance range and target value for women higher than those for men in consideration of the fact that many women are cold.

  Also, if the subject is hot, the tolerance range or target value should be set low, and if the subject is cold, the tolerance range or target value should be changed. Is also possible.

  In the above embodiment, the air flow is generated by the fan 14, but the “air flow generating means” of the present invention has a mechanism capable of generating an air flow in the bore 20a. The configuration is arbitrary.

  In the above embodiment, PMV is used as the thermal environment information, but other indicators such as ET and SET may be used. Here, ET (new effective temperature) is an indoor body sensation index called a new effective temperature, and SET (standard new effective temperature) is an indoor body sensation index called a standard new effective temperature.

  Note that the modification described above can also be applied as appropriate to the magnetic resonance imaging apparatus of the second embodiment described below.

<Second Embodiment>
In the first embodiment, the magnetic resonance imaging apparatus capable of automatically adjusting the thermal environment in the bore has been described. In the second embodiment, a configuration will be described in which the examiner manually adjusts the thermal environment in the bore.

  Note that the configurations of the first and second embodiments are not mutually exclusive, and it is possible to configure a magnetic resonance imaging apparatus including both. In that case, it is desirable that the automatic adjustment according to the first embodiment or the manual adjustment according to the second embodiment can be selectively executed.

[Constitution]
The magnetic resonance imaging apparatus according to this embodiment has the same overall configuration as that of the first embodiment (see FIG. 1). FIG. 5 shows an example of the configuration of the control system of the magnetic resonance imaging apparatus according to this embodiment. Note that components similar to those in the first embodiment are denoted by the same reference numerals.

  The magnetic resonance imaging apparatus shown in FIG. 5 has the same information input unit 31, RF coil ID acquisition unit 32, temperature acquisition unit 33, humidity acquisition unit 34, and bore inner wall temperature acquisition unit as those in the first embodiment (see FIG. 2). 35, a calculation unit 40 and a fan control unit 50 are provided. In addition, the wind speed setting part 43 of the calculating part 40 is unnecessary.

  The fan control unit 50 of this embodiment turns on / off the operation of the fan 14. When the wind speed of the airflow generated by the fan 14 can be changed, the fan control unit 50 controls the wind speed. In addition, the fan control unit 50 inputs the value of the wind pressure of the airflow generated by the fan 14 to the PMV calculation unit 44. At this time, the fan control unit 50 calculates the wind pressure based on the rotational speed of the blades of the fan 14 as described in the first embodiment.

  The magnetic resonance imaging apparatus according to this embodiment includes the display unit 12 and the display control unit 60 shown in FIG.

  The display unit 12 includes an arbitrary display device such as an LCD (Liquid Crystal Display) or a CRT (Cathode Ray Tube) display. The display unit 12 functions as an example of the “display unit” of the present invention.

  The display control unit 60 functions to display various screens and images on the display unit 12 and includes, for example, a microprocessor of the host computer 11. The display control unit 60 functions as an example of the “control unit” of the present invention.

[Usage form]
A usage pattern of the magnetic resonance imaging apparatus according to this embodiment will be described. The flowchart shown in FIG. 6 represents an example of a usage pattern of the magnetic resonance imaging apparatus.

  First, the subject P is placed on the bed 13 and placed in the bore 20a, and imaging of the subject P is started (S21).

  The information input unit 31, the RF coil ID acquisition unit 32, the temperature acquisition unit 33, the humidity acquisition unit 34, and the bore inner wall temperature acquisition unit 35 acquire the respective thermal environment factors and calculate the same as in the first embodiment. 40. Moreover, the fan control part 50 acquires the wind pressure (thermal environment factor) of the airflow currently generated by the fan 14, and inputs it into the calculating part 40 (S22).

  Here, the fan 14 generates an air flow in response to power-on of the magnetic resonance imaging apparatus or an operation by the examiner. When the fan 14 is not operating, the fan control unit 50 inputs, for example, wind pressure = 0 to the calculation unit 40.

  The activity amount calculation unit 41 calculates the activity amount of the subject P based on the thermal environment factor input from the information input unit 31, and inputs the activity amount to the PMV calculation unit 44 (S23).

  Further, the clothing amount calculation unit 42 calculates the clothing amount of the subject P based on the RF coil ID input from the RF coil ID acquisition unit 32, and inputs it to the PMV calculation unit 44 (S24).

  The PMV calculation unit 44 calculates the value of PMV based on the input six thermal environment factors, and inputs the value to the PMV determination unit 45 (S25).

  The PMV determination unit 45 determines whether or not the calculated PMV value is included in the allowable range, and inputs the determination result to the display control unit 60 (S26).

  The display control unit 60 causes the display unit 12 to display information (display information) such as a message or an image representing the determination result input from the PMV determination unit 45 (S27).

  As the display information, for example, text information such as “the inside of the bore is hot” or “the temperature inside the bore is falling” is displayed. Further, the calculated value of the PMV by the PMV calculating unit 44 can be displayed as display information, or the PMV value can be taken on the horizontal axis or the vertical axis, and the calculated value can be displayed on this axis.

  Note that when only the calculated value of PMV is displayed as display information, the PMV determination unit 45 is unnecessary. In this case, the PMV calculation unit 44 functions to directly input the PMV calculation value to the display control unit 60.

  This is the end of the description of the usage pattern of the magnetic resonance imaging apparatus based on the flowchart of FIG.

  Also in this embodiment, display information indicating the thermal environment in the bore 20a at an arbitrary timing during photographing can be displayed by periodically performing the same operation as in FIG. 6, for example.

[Action / Effect]
The magnetic resonance imaging apparatus according to this embodiment acquires a thermal environment factor that affects the thermal environment in the bore 20a, and calculates thermal environment information (PMV) that represents the thermal environment in the bore 20a based on the thermal environment factor. In addition, the display information based on the thermal environment information is displayed.

  Therefore, the examiner can grasp the thermal environment in the bore 20a in which the subject P is arranged by visually recognizing the display information, and adjust the temperature, humidity, and wind speed with an air conditioner in the examination room. By taking various measures, it is possible to improve the thermal environment in the bore 20a.

  Further, according to the magnetic resonance imaging apparatus, the activity amount of the subject P is calculated based on the strength of the high-frequency magnetic field from the RF coil 3, and the display information is displayed based on the PMV value based on the calculation result. Therefore, there is also an advantage that the thermal environment in the bore 20a can be improved according to the type of the RF coil 3.

  Further, according to the magnetic resonance imaging apparatus, the activity amount of the subject P is calculated based on the physical information including the height and weight of the subject P, and the display information is displayed based on the PMV value based on the calculation result. Therefore, there is also an advantage that the thermal environment in the bore 20a can be improved according to the physique of the subject P.

[Modification]
FIG. 7 shows an example of a modification of the magnetic resonance imaging apparatus according to this embodiment. The magnetic resonance imaging apparatus shown in the figure includes an operation unit 70 in addition to the configuration shown in FIG.

  The operation unit 70 is operated by an examiner to change the wind speed of the airflow generated by the fan 14, and is configured by a console (not shown) of the host computer 11, for example. The console includes an operation device and an input device such as a keyboard, a mouse, a trackball, and a joystick. The operation unit 70 functions as an example of the “operation means” in the present invention.

  The examiner appropriately changes the wind speed of the air flow generated by the fan 14 by operating the operation unit 70 based on the display information displayed on the display unit 12. Thereby, the thermal environment in the bore 20a can be improved.

  In this modification, the wind speed of the airflow in the bore 20a is changed. However, by changing the temperature and humidity in the bore 20a by the temperature changing device and the humidity changing device of the first embodiment. It is also possible to configure so as to improve the thermal environment.

  In the above embodiment, display information based on the thermal environment information (PMV) in the bore 20a is displayed, but it is configured to output any notification information based on the thermal environment information in the bore. Is also possible. As an output mode of the notification information, for example, voice information such as a beep sound or a voice message can be output when the PMV is out of the allowable range.

  In the above embodiment, the PMV is calculated using the wind speed of the airflow generated by the fan 14 as the thermal environment factor. However, in a magnetic resonance imaging apparatus not equipped with a fan, the PMV is calculated with the wind speed = 0. Display information can be displayed.

1 is a schematic diagram illustrating an example of the overall configuration of a preferred embodiment of a magnetic resonance imaging apparatus according to the present invention. It is a schematic block diagram showing an example of the structure of the control system of suitable embodiment of the magnetic resonance imaging apparatus concerning this invention. It is a flowchart showing an example of the usage pattern of suitable embodiment of the magnetic resonance imaging apparatus concerning this invention. It is a schematic block diagram showing an example of the structure of the control system in the modification of suitable embodiment of the magnetic resonance imaging apparatus concerning this invention. It is a schematic block diagram showing an example of the structure of the control system of suitable embodiment of the magnetic resonance imaging apparatus concerning this invention. It is a flowchart showing an example of the usage pattern of suitable embodiment of the magnetic resonance imaging apparatus concerning this invention. It is a schematic block diagram showing an example of the structure of the control system in the modification of suitable embodiment of the magnetic resonance imaging apparatus concerning this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Static magnetic field magnet 2 Gradient magnetic field coil 3 RF coil 11 Host computer 12 Display part 14 Fan 20 Gantry 20a Bore 31 Information input part 32 RF coil ID acquisition part 33 Temperature acquisition part 34 Humidity acquisition part 35 Bore inner wall temperature acquisition part 40 Calculation part 41 activity amount calculation unit 42 clothing amount calculation unit 43 wind speed setting unit 44 PMV calculation unit 45 PMV determination unit 46 wind speed calculation unit 50 fan control unit 60 display control unit 70 operation unit P subject

Claims (10)

Applying a static magnetic field and a gradient magnetic field to a subject arranged in a bore of a gantry, generating a high-frequency magnetic field by an RF coil mounted on the subject, and the subject corresponding to the generated high-frequency magnetic field A magnetic resonance imaging apparatus for receiving an echo signal from an inner nucleus and forming an image of the subject based on the received echo signal,
An acquisition means for acquiring a thermal environment factor that affects the thermal environment in the bore;
Calculation means for calculating thermal environment information representing the thermal environment in the bore based on the acquired thermal environment factor;
Changing means for changing the thermal environment in the bore based on the calculated thermal environment information;
A magnetic resonance imaging apparatus comprising: Applying a static magnetic field and a gradient magnetic field to a subject arranged in a bore of a gantry, generating a high-frequency magnetic field by an RF coil mounted on the subject, and the subject corresponding to the generated high-frequency magnetic field A magnetic resonance imaging apparatus for receiving an echo signal from an inner nucleus and forming an image of the subject based on the received echo signal,
An acquisition means for acquiring a thermal environment factor that affects the thermal environment in the bore;
Calculation means for calculating thermal environment information representing the thermal environment in the bore based on the acquired thermal environment factor;
Display means for displaying display information based on the calculated thermal environment information;
A magnetic resonance imaging apparatus comprising: Operating means for changing a thermal environment in the bore based on the display information displayed on the display means;
Changing means for changing a thermal environment in the bore based on an operation on the operating means;
The magnetic resonance imaging apparatus according to claim 2, further comprising: The changing means includes airflow generating means for generating an airflow in the bore, and control means for changing a thermal environment in the bore by controlling a wind speed of the airflow generated by the airflow generating means.
The magnetic resonance imaging apparatus according to claim 1, wherein the magnetic resonance imaging apparatus is a magnetic resonance imaging apparatus. The calculation means calculates a value of PMV (predicted mean vote) as the thermal environment information based on the thermal environment factor acquired by the acquisition means, and the calculated PMV value is included in a predetermined range. Calculate the wind speed of the airflow,
The control means controls the airflow generation means so as to generate an airflow of the calculated wind speed;
The magnetic resonance imaging apparatus according to claim 4. The changing means includes temperature / humidity changing means for changing the temperature and / or humidity in the bore, and control means for changing the thermal environment in the bore by controlling the temperature / humidity changing means.
The magnetic resonance imaging apparatus according to claim 1, wherein the magnetic resonance imaging apparatus is a magnetic resonance imaging apparatus. The calculation means calculates a value of PMV as the thermal environment information based on the thermal environment factor acquired by the acquisition means, and a temperature and / or a value at which the calculated PMV value is included in a predetermined range. Or calculate the humidity,
The control means controls the temperature / humidity changing means so that the calculated temperature and / or humidity is set in the bore.
The magnetic resonance imaging apparatus according to claim 6. The acquisition means acquires, as the thermal environment factor, physical information of the subject and a value of a SAR (specific absorption rate) corresponding to the imaging region of the subject,
The calculation means calculates the strength of the high-frequency magnetic field generated by the RF coil based on the acquired physical information and the value of SAR, and calculates the thermal environment information based on the calculated strength of the high-frequency magnetic field. Calculate,
The magnetic resonance imaging apparatus according to claim 1, wherein the magnetic resonance imaging apparatus is a magnetic resonance imaging apparatus. The acquisition means acquires the subject's height, weight and metabolic rate as the physical information,
The calculation means calculates the intensity of the high-frequency magnetic field based on the acquired weight and the value of the SAR, calculates the body surface area of the subject based on the acquired height and weight, and the calculation The activity amount of the subject is calculated based on the intensity and body surface area of the radio frequency magnetic field and the acquired metabolic amount, and the value of PMV as the thermal environment information is calculated based on the calculated activity amount To
The magnetic resonance imaging apparatus according to claim 8. The acquisition means acquires type information indicating the type of the RF coil mounted on the subject,
The calculation means calculates the amount of clothing information of the subject based on the acquired type information, and calculates the value of PMV as the thermal environment information based on the determined amount of clothing information.
The magnetic resonance imaging apparatus according to claim 1, wherein the magnetic resonance imaging apparatus is a magnetic resonance imaging apparatus.

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