JP2006095278A - Magnetic resonance diagnostic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic resonance diagnostic apparatus which can improve the precision of safety control regarding a partial body SAR. <P>SOLUTION: This magnetic resonance diagnostic apparatus is equipped with an inputting unit 15 which inputs information associated with the physique of a subject as well as information associated with an imaging region, a calculation unit 13 which calculates the partial body SAR associated with a partial body including the imaging region based on the inputted information on both the physique and the imaging region, and a displaying unit 14 which displays the calculated partial body SAR. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a magnetic resonance diagnostic apparatus having a safety management function based on SAR (Specific Absorption Rate).

  With respect to a magnetic resonance diagnostic apparatus (hereinafter referred to as an MRI apparatus), a radio frequency magnetic field for causing magnetic resonance is irradiated to an imaging region using a transmission high frequency coil. The resonance frequency of the high-frequency magnetic field is proportional to the static magnetic field intensity of the MRI apparatus. For example, in the case of a 1.5 T static magnetic field apparatus, the resonance frequency is 63.8 MHz. It is known that the high frequency in this frequency region causes the body temperature to rise by heating the subject. In general, in the human body, an increase in the body temperature of the trunk part is a safety problem rather than the skin temperature. In the human body, if the trunk temperature exceeds 1 ° C, a disorder may occur. The IEC standard (IEC 60601-2-33: Particular requirements for the safety of magnetic resonance equipment for medical) is defined as the SAR (Specific Absorption Rate) as the high frequency output absorbed by 1 kg of tissue as ° C. (diagnosis) and JIS standards (JIS Z 4951 “Magnetic Resonance Imaging Diagnosis Apparatus—Safety”). For example, in the normal operation mode of the IEC standard, the upper limit of the SAR value for the whole body is 2 W / kg, and the upper limit of the SAR value for the head is 3.2 W / kg.

  For example, before starting imaging, the operator inputs the patient's weight (kg) as part of patient information such as patient name, age, and sex from the console. Next, the subject is positioned in the magnet mount 2 of the MRI apparatus, and a high frequency is applied from the high frequency amplifier 3 via the transmission high frequency coil 4 to determine a high frequency condition for obtaining an optimum MR signal for the imaging region of the subject P. Take a picture using the conditions. The difference between the high-frequency output applied when determining the high-frequency condition and the high-frequency output measured in advance without the subject is the high-frequency output (W) absorbed by the subject. Dividing by the input patient weight is the whole body SAR value (W / kg). Before the start of imaging, the whole body SAR value is calculated by the MRI apparatus and displayed on the screen of the console (1). If the obtained SAR value exceeds the upper limit value of the safety standard, a warning to that effect is displayed on the console (1) screen, and the operator changes the shooting condition or switches to a higher operation mode. .

  As an example of changing the imaging condition that is normally performed, resetting may be performed so as to reduce the initially set number of multi-slices. In this case, the necessary imaging region cannot be covered by the number of multi-slices, and two or more imagings are required, resulting in a problem that the entire MRI examination time is extended. In addition to the normal operation mode, the safety standard defines the primary level management operation mode and the secondary level management operation mode. The medical standard is based on the relationship between potential risks and benefits for patients. Judgment is made. For example, in the primary level management operation mode, the upper limit of the whole body SAR value is 4 W / kg.

  The axial length of the high-frequency coil for transmission of the conventional MRI apparatus is about 50-60 cm. Apart from children, the SAR value for adults is the SAR value by dividing the high-frequency output by the total weight including the part that has not been irradiated. Is not necessarily the same as the SAR value of the body part actually irradiated. On the other hand, a pulse sequence for obtaining MR images with higher diagnostic ability requires a higher SAR value by developing a high-speed imaging method and a high magnetic field MRI apparatus.

  For this reason, the IEC standard (IEC 60601-2-33 2nd edition) revised in 2002 added the following provisions as a body partial SAR (partial body SAR).

In normal operation mode
Body part SAR = 10 (W / kg) − (8 (W / kg) × (partial body weight to be irradiated) / (patient weight))
It is stipulated. The SAR value in the range of 2 W / kg to 10 W / kg is the upper limit depending on the ratio of the patient's partial body weight and the patient's body weight that are irradiated from this equation.

The conventional management method using only the whole body SAR has a problem that it cannot cope with the definition of the body part SAR and cannot provide higher diagnostic information. Furthermore, even if the length of the high frequency coil for transmission is shortened for a specific part such as the heart and the region where the high frequency is irradiated is limited, the conventional method, for example, Japanese Patent Laid-Open No. 5-317287, can cope with this. There wasn't.
JP-A-5-317287

  An object of the present invention is to improve the accuracy of safety management by a body part SAR in a magnetic resonance diagnostic apparatus.

In the first aspect of the present invention, an input unit that inputs information related to the physique of the subject together with information related to the imaging part, and a body part that includes the imaging part based on the input information related to the physique and information related to the imaging part There is provided a magnetic resonance diagnostic apparatus including a calculation unit for calculating a body part SAR (partial body SAR) and a display unit for displaying the calculated body part SAR.
In the first aspect of the present invention, an RF coil that generates an RF pulse, a calculation unit that calculates a body part SAR related to a part of the subject corresponding to a transmission range of the RF pulse unique to the RF coil, and the calculation There is provided a magnetic resonance diagnostic apparatus including a display unit for displaying a body part SAR.

  According to the present invention, the accuracy of safety management by the body part SAR can be improved in the magnetic resonance diagnostic apparatus.

Embodiments of a magnetic resonance diagnostic apparatus (MRI apparatus) according to the present invention will be described below in detail with reference to the drawings.
FIG. 1 is a block diagram showing a schematic configuration of an MRI apparatus in the present embodiment. In the cylindrical magnet stand 1, a static magnetic field magnet 2, a gradient magnetic field coil 5, and a transmission high-frequency coil 4 are provided. For convenience of explanation, it is assumed that the z axis coincides with the longitudinal direction of the cylinder, the x axis is the horizontal direction, and the y axis is the vertical direction. The static magnetic field magnet 2 is configured using, for example, a 1.5 T superconducting magnet, and forms a static magnetic field parallel to the z axis. The gradient coil 5 is disposed in the static magnetic field magnet 2 and forms a cylindrical assembly to generate an x-axis gradient field, a y-axis gradient field, and a z-axis gradient field. The shape and type of each assembly are not limited. The transmission high-frequency coil 4 is arranged inside the gradient magnetic field coil 5 and has a cylindrical shape, for example, and generates a high-frequency magnetic field. The transmission high-frequency coil 4 can be a transmission / reception combined high-frequency coil. The MR signal generated by the magnetic resonance is detected by the receiving high-frequency coil 6 arranged around the subject P. The bed has a top plate 7, and the subject P placed on the top plate 7 is inserted into an imaging space (region in which an imaging magnetic field is formed) in the magnet stand 2.

  The gradient coil 5 is connected to the controller 9 via a gradient power supply 8. Note that the gradient magnetic field power supply 8 supplies a current necessary for generating a magnetic field from the gradient magnetic field coil 5, the magnitude of the current (magnetic field strength), current supply timing (magnetic field application timing), and the like. Is controlled by a control signal from the control unit 9. The transmission high-frequency coil 4 is connected to the control unit 9 via the high-frequency amplifier 3 and the high-frequency transmission system 11. Between the transmission high-frequency coil 4 and the high-frequency amplifier 3, a power measuring instrument 17 for measuring a transmission high-frequency output is provided. The receiving high-frequency coil 6 is connected to the control unit 9 via the high-frequency receiving system 12. The high-frequency amplifier 3 is driven when transmitting a high-frequency magnetic field from the transmitting high-frequency coil 4 to the subject P, and the high-frequency receiving system 12 is driven when detecting MR signals from the subject P via the receiving high-frequency coil 6. It is what is done.

  A display unit 14, an operation unit 15, and a SAR management unit 13 are connected to the control unit 9. Physique is determined by weight and height. The partial weight of the part to be taken is almost determined from the physique. Accordingly, a standard partial weight correspondence table for weight, height, and imaging region is created in advance, and is stored in the partial weight estimation unit 16 typically configured by a ROM.

  The partial weight of the imaging region is estimated by the partial weight estimation unit 16 from the information related to the physique (weight information and height information) input from the operation unit 15 and the imaging region input from the operation unit 15.

  The SAR management unit 13 includes a partial weight estimated by the partial weight estimation unit 16, a transmission high-frequency output measured in the presence of the subject P by pre-transmission of a high-frequency pulse (RF pulse) by the power meter 17, Based on the number of high-frequency pulses of the pulse sequence set via the unit 15 and the like, the body part SAR regarding the imaging region is calculated.

  Further, the SAR management unit 13 calculates the upper limit value of the body part SAR regarding the imaging part based on the partial weight estimated by the partial weight estimation part 16 from the imaging part and the weight input from the operation unit 15. In addition, the SAR management unit 13 compares the body part SAR with the upper limit value.

  Note that the SAR management unit 13 uses the information related to the physique (weight information and height information) input from the operation unit 15, the imaging region input from the operation unit 15, and the power meter 17 without obtaining the partial weight. Based on the transmission high-frequency output measured in the presence of the subject P by pre-transmission of high-frequency pulses (RF pulses) and the number of high-frequency pulses of the pulse sequence set via the operation unit 15, the body related to the imaging region The partial SAR may be obtained directly. A correspondence table of the body part SAR with respect to the weight, height, imaging region, transmission high-frequency output, and number of high-frequency pulses is created in advance and is typically provided in the ROM.

  The SAR management unit 13 causes the display unit 14 to display a comparison result between the body part SAR and the upper limit value. The display unit 14 displays the MR image of the subject P, imaging conditions, the whole or body part SAR, the comparison result between the SAR and the upper limit value, and reduces the SAR when the calculated SAR value exceeds the upper limit value. The recommended changes to the shooting conditions are displayed. Recommended changes to the imaging conditions include a decrease in the number of multi-slices due to the pulse sequence, an increase in slice thickness due to the pulse sequence, and a change in the pulse sequence.

  Hereinafter, the SAR management operation in the present embodiment will be described with reference to FIG. The operator inputs patient information, imaging conditions, and safety management mode from the operation unit 15 before starting imaging (S11). Patient information includes patient name, age, gender, and physique information. The physique information includes patient weight and height. In some cases, these pieces of information are already input at the time of examination reservation. If the body weight and height are also described in the medical record etc., the values are entered as they are from the keyboard of the operation unit 15, but if there is no such information, a weight scale, a height scale, etc. before starting the MR examination The value is measured and the value is input from the keyboard of the operation unit 15. Alternatively, a plurality of standard models having different physiques may be prepared, and an engineer may select a single standard model that approximates the subject from the plurality of standard models, thereby replacing the input of weight and height.

  The imaging conditions include the imaging site, the type of pulse sequence, the number of multi-slices, the slice thickness, and the like. These may be specified at the time of an examination request from a patient doctor, may be determined at each facility, or may be determined by a doctor at the time of imaging. The operator inputs necessary shooting conditions according to the situation. The safety management mode includes options of a normal operation mode, a primary level management operation mode, and a secondary level management operation mode, which are different in the method for calculating the upper limit value of the SAR, and one of these modes is selected.

  After these input operations (S11) are completed, the subject P is placed on the couch top 7 of the bed, inserted into the magnet mount 1, and positioned for imaging. In general, the center of the imaging region is aligned with the center of the magnet mount 1. Under the control of the control unit 9, an optimum condition for the transmission high-frequency pulse (RF pulse) is searched at the position set before the start of imaging. A plurality of RF pulses having different time integration values are intermittently applied to the subject P, and an MR signal from the subject P is received via the receiving high-frequency coil 6 every time the RF pulse is applied (S12). A time integral value of the RF pulse corresponding to the MR signal having the highest intensity generated in a state where the magnetization spin is tilted to the flip angle closest to 90 ° is selected as the optimum condition. Further, the transmission high-frequency output is measured by the power meter 17 every time the RF pulse is applied (S13). The transmission high frequency output measured when applying the RF pulse corresponding to the MR signal having the highest intensity is selected.

  Subsequent to S12 and S13, the partial body weight is estimated from the body weight, height, and imaging part input from the operation unit 15 (S14). Actually, the partial weight associated with the weight, height, and imaging region input from the operation unit 15 is supplied from the partial weight estimation unit 16 to the SAR management unit 13. In S15, the upper limit value of the body part SAR of the imaging region is calculated based on the weight input from the operation unit 15 and the estimated partial weight according to the safety management mode selected in S11. Calculated by the unit 13. Further, the SAR management unit 13 searches in the presence of the high frequency output measured in the absence of the subject in which the subject P is not inserted in the gantry 1 and the subject in which the subject P is inserted in the gantry 1 in advance. The difference between the transmitted RF pulse and the transmitted high-frequency output is calculated as the absorbed energy of the subject by the application of a single 90 ° high-frequency pulse. The absorption energy by the application of a single 90 ° high-frequency pulse, the number of 90 ° high-frequency pulses in the pulse sequence specified in S11, the number of 180 ° high-frequency pulses, and the number of other high-frequency pulses are added to the subject. The absorbed energy is calculated by the SAR management unit 13 (S16). By dividing the total absorbed energy by the estimated partial body weight, the SAR management unit 13 calculates the body part SAR corresponding to the imaging part (S17).

  In the above description, the partial body weight of the imaging region is estimated, and the body part SAR is calculated from the partial body weight. However, the body part SAR is not the imaging region but is included in the range in which the RF pulse is substantially transmitted (transmission range). The body part SAR may be calculated by estimating the weight of the part of the specimen and dividing the total absorbed energy by the weight of the part. As a range in which the RF pulse is substantially transmitted, typically, in a spatial distribution of the high-frequency electric field strength with respect to the body axis Z inherent to the transmission coil 4 shown in FIG. For example, it is set to a range given by a half width. Note that typically, the transmission range of the RF pulse is wider than the range in which the image is reconstructed.

  In the SAR management unit 13, the body part SAR calculated in S17 is compared with the upper limit value calculated in S15 (S18). When the body part SAR is less than the upper limit value (YES), the control unit 9 causes the display unit 14 to display the body part SAR calculated in S17, the upper limit value calculated in S15, and the photographing permission message ( In step S19, the operation unit 15 waits for an input of a pulse sequence execution trigger. When a pulse sequence execution trigger is input from the operation unit 15, the pulse sequence of S11 is executed with the optimized high frequency pulse (S20).

  When the body part SAR is equal to or exceeds the upper limit value (NO), the control unit 9 causes the display unit 14 to display the body part SAR calculated in S17, the upper limit value calculated in S15, the photographing prohibition message, and the pulse. A sequence change guide is displayed (S21). The pulse sequence change guide includes changing the pulse sequence itself to another type of pulse sequence, reducing the number of multi-slices, and increasing the slice thickness. When the pulse sequence is changed via the operation unit 15 (S22), the body part SAR is recalculated (corrected) by the same calculation method as S17 according to the changed pulse sequence (S23).

  S21 to S23 are repeated until the body part SAR corrected in S23 becomes less than the upper limit value.

Hereinafter, a method for obtaining the SAR value in the present embodiment will be described in detail. First, the definition of the SAR and the upper limit value thereof in the safety standard of the MRI apparatus will be described by taking IEC 60601-2-33 2nd Edition as an example. The SAR is a high-frequency output per unit mass absorbed by the subject, and its unit is [W / kg]. The SAR is divided into a whole body SAR, a body part SAR, a head SAR, and a local SAR according to the imaging region. The whole body SAR is used for photographing the whole body, the head SAR is used for photographing the head, and the local SAR is used for photographing a small area of the body using a transmission / reception surface coil. Is the average value. The body part SAR is an item included from the IEC standard second edition, and is an average value over the weight of the body part exposed to the transmitting high-frequency coil. For example, in the normal operation mode, these upper limit values are the whole body SAR upper limit value 2 W / kg, the head SAR upper limit value 3.2 W / kg, the local SAR upper limit value is 10 W / kg for the head and trunk, and 20 W / kg for the extremities. kg, body part SAR upper limit is
10-8 x (partial weight / weight of subject) [W / kg]
It is.

  As the operation mode, in addition to the normal operation mode, a primary level management operation mode and a secondary level management operation mode are defined, and an SAR upper limit value is defined for each. These upper limit values are intended to suppress the temperature rise of the trunk and the crystalline lens with a small cooling effect due to blood flow to 1 ° C. or less by heating with high frequency. When a high frequency is applied to the whole body, the whole body SAR value can be obtained by dividing the absorbed high frequency output by the body weight of the subject, and when a high frequency is applied only to the head, the head weight is calculated for the human body. The head SAR value can be obtained by estimating from the standard data and dividing the high frequency output by the head weight. The head weight is almost constant for adults and is relatively easy to estimate. On the other hand, it is difficult to estimate the body part SAR value only by weight information.

  In the present embodiment, not only the body weight but also the imaging part (for example, the chest, abdomen, lower abdomen, thigh, etc.) and the partial weight of the body part irradiated with high frequency from the height of the subject are used together with the standard data of the human body. The body part SAR value is estimated from this. Naturally, an error is expected in the estimated value, so it is also necessary to set the upper limit value lower on the safe side. Thus, as explained above, in the normal imaging mode, the upper limit value of whole body SAR when high frequency is irradiated to the whole body is 2 W / kg, but for example, when high frequency is irradiated to a half of the body weight. , Irradiation up to 6 W / kg is allowed for safety against the same high frequency. Thereby, it is possible to obtain high diagnostic information by faster imaging, shortening of imaging time by increasing the number of multi-slices, and collection of diffusion images with high b values. The current high-frequency coil for transmission is about 60cm long, and adults except for short subjects such as children and children are unlikely to be exposed to high-frequency radiation at once, and the body part SAR is applied. It is considered realistic to do. Of course, when the height is low and the chest and abdomen are selected as an imaging region, the MRI apparatus side may apply the whole body SAR.

There are the following methods as height data to be input.
1) Enter the height from the keyboard of the operation unit 15 as a numerical value.
2) Select an appropriate range from a plurality of height ranges shown on the input screen of the operation unit 15 (for example, selection with a height range button every 10 cm such as 150 to 159 cm, 160 to 169 cm,...) .
3) Input electronically from the patient database at the facility.
There are the following methods as means for measuring the height in the MR room.
1) Measure with a height meter.
2) A scale (height measuring ruler) 20 is attached to the door of the MR room, and the height is visually measured when the patient enters the room. (Figure 3)
3) The scale 20 is affixed on the surface of the couch top 7, and the height is visually measured when setting the patient as a couch. (Fig. 4)
As a method of selecting an imaging region, as shown in FIG. 5, the target imaging region is selected from the imaging region selection diagram displayed on the screen of the display unit 14. Similarly, the pulse sequence is selected including related parameters on the console screen or switch.

  The SAR value obtained from the above weight, height, imaging region and the absorbed high-frequency output is displayed on the console screen before the start of imaging with the selected pulse sequence (type of whole body, body part, head). Part, extremity) and the SAR value, and if the SAR value exceeds the upper limit value of the safety standard, the fact is displayed, and the recommended change contents of each parameter for relaxing the SAR value are displayed. . Specifically, the number of multi-slices is reduced to increase the number of imaging, the slice thickness is increased, or another pulse sequence is selected. When a wide area is covered with a series of imaging such as whole body imaging or lower limb imaging, the maximum value of the body part SAR obtained for each imaging area is displayed.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

It is a block diagram which shows schematic structure of the MRI apparatus in this embodiment. It is a figure which shows the flow of the SAR management operation | movement in this embodiment. It is a figure which shows the scale of the MR chamber door in this embodiment. It is a figure which shows the scale of the bed part in this embodiment. It is a figure which shows the selection screen of the imaging | photography site | part concerning this embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Magnet stand, 2 ... Static magnetic field magnet, 5 ... Gradient magnetic field coil, 4 ... Transmission high frequency coil, 6 ... Reception high frequency coil, 7 ... Top plate, 8 ... Gradient magnetic field power supply, 9 ... Control part, 3 ... High frequency Amplifier 11, high frequency transmission system, 17 power meter, 12 high frequency reception system, 14 display unit, 15 operation unit, 13 SAR management unit, 16 partial weight estimation unit.

Claims (28)

An input unit for inputting information on the physique of the subject and information on the imaging region;
A calculation unit for calculating a body part SAR relating to a body part including the imaging part based on the input information relating to the physique and information relating to the imaging part;
A magnetic resonance diagnostic apparatus comprising: a display unit that displays the calculated body part SAR. The magnetic resonance diagnostic apparatus according to claim 1, wherein the information related to the physique includes a weight of the subject. The magnetic resonance diagnostic apparatus according to claim 2, wherein the information related to the physique includes a height of the subject. The magnetic resonance diagnostic apparatus according to claim 1, wherein the calculation unit includes an estimation unit that estimates a partial weight of a body part including the imaging region based on the input information regarding the physique and information regarding the imaging region. The magnetic resonance diagnostic apparatus according to claim 4, wherein the estimation unit that estimates the partial body weight includes a storage unit that stores a correspondence table of standard partial body weights with respect to the physique and the imaging region. The estimation unit for estimating the partial weight is a whole body SAR instead of the body part SAR when the height of the subject is equal to or less than the axial length of the transmission high-frequency coil and the input imaging region is a chest or abdomen. The magnetic resonance diagnostic apparatus according to claim 1, wherein 2. The magnetic resonance according to claim 1, wherein the calculation unit that calculates the body part SAR selects a maximum value among the plurality of body part SARs related to the plurality of parts when performing a series of imaging while dividing the wide area into a plurality of times. Diagnostic device. 2. The magnetic resonance diagnostic apparatus according to claim 1, wherein the calculation unit that calculates the body part SAR calculates the body part SAR for each imaging region when performing a series of imaging while dividing the wide region into a plurality of times. The magnetic resonance diagnostic apparatus according to claim 4, wherein the calculation unit includes a determination unit that determines a body part SAR upper limit value based on the estimated partial body weight and the input information related to the physique. The magnetic resonance diagnostic apparatus according to claim 9, wherein the calculation unit includes a comparison unit that compares the calculated body part SAR with the determined body part SAR upper limit value. The magnetic resonance diagnostic apparatus according to claim 10, wherein the display unit displays a message according to a comparison result between the calculated body part SAR and the determined body part SAR upper limit value. When the calculated body part SAR exceeds the upper limit value, the display unit displays a recommended change of the imaging condition together with a message indicating that the calculated body part SAR exceeds the upper limit value. The magnetic resonance diagnostic apparatus according to claim 11. The magnetic resonance diagnostic apparatus according to claim 12, wherein the recommended change content includes a decrease in the number of multi-slices by the pulse sequence. The magnetic resonance diagnostic apparatus according to claim 12, wherein the recommended change content includes an increase in slice thickness due to the pulse sequence. The magnetic resonance diagnostic apparatus according to claim 12, wherein the recommended change content includes a change in the pulse sequence. The magnetic resonance diagnostic apparatus according to claim 9, wherein the display unit displays the determined body part SAR upper limit value together with the calculated body part SAR. The magnetic resonance diagnostic apparatus according to claim 1, wherein the input unit inputs selection of an arbitrary standard model from a plurality of standard models having different physiques as the physique. Means for measuring the transmission high-frequency output to the subject;
Means for controlling a pulse sequence applied to the subject;
The magnetic resonance diagnostic apparatus according to claim 1, wherein the calculation unit that calculates the body part SAR calculates the body part SAR based on the transmission high-frequency output and a pulse sequence together with the part weight. The magnetic resonance diagnostic apparatus according to claim 1, wherein the information related to the physique of the subject is received from an external patient database. The magnetic resonance diagnostic apparatus according to claim 3, wherein the weight and height of the subject are input as numerical values. The magnetic resonance diagnostic apparatus according to claim 3, wherein the weight and height of the subject are selected from a plurality of height ranges. The magnetic resonance diagnostic apparatus according to claim 1, wherein the imaging region is selected from a plurality of region ranges. The magnetic resonance diagnostic apparatus according to claim 1, further comprising a scale attached to a bed portion on which the subject is placed. The magnetic resonance diagnostic apparatus according to claim 1, further comprising a scale attached near an entrance of the MR imaging room. An RF coil for generating RF pulses;
A calculation unit for calculating a body part SAR relating to a part of the subject corresponding to a transmission range of the RF pulse specific to the RF coil;
A magnetic resonance diagnostic apparatus comprising: a display unit that displays the calculated body part SAR. 26. The magnetic resonance diagnostic apparatus according to claim 25, wherein the transmission range of the RF pulse is set to a range that exceeds a predetermined intensity in a spatial distribution with respect to a coil central axis of a high-frequency electric field intensity unique to the RF coil. 26. The magnetic resonance diagnostic apparatus according to claim 25, wherein the transmission range of the RF pulse is set to a half-value width in a spatial distribution with respect to the coil central axis of the high-frequency electric field strength unique to the RF coil. 26. The magnetic resonance diagnostic apparatus according to claim 25, wherein a transmission range of the RF pulse is wider than a range in which an image is reconstructed.

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