JP5819688B2 - MR system safety system and MR apparatus - Google Patents

Description

  The present invention relates to a MR system safety system for detecting a person's entry into a strong magnetic field region in an MR (Magnetic Resonance) imaging room and an MR apparatus equipped with the safety system.

  Safety awareness in the use of a magnetic resonance apparatus, so-called MR apparatus, is increasing as the strength of the main magnetic field (static magnetic field) of the MR apparatus increases.

Depending on the installation location of the MR device, 5 Gauss-line (5 Gauss), which is the boundary of the off-limits area for a pacemaker wearer
It is also conceivable to place a mark on the floor so that line) can be seen visually.

  Further, Patent Document 1 proposes an MR apparatus that measures the distance between a magnetic field generating means and a measurement object using an ultrasonic wave or the like by a measurement unit and issues an alarm based on the measurement result.

JP 2005-192857 A

  However, in the MR apparatus of Patent Document 1, since the distance between the magnetic field generating means and the measured object is measured and an alarm is issued based on the measurement result, an object other than a person such as a medical instrument becomes the measured object. False detection may occur or a person hidden behind the object may not be detected, and it is not possible to accurately detect the person's entry into the strong magnetic field region in the MR imaging room.

  Under such circumstances, it is desired to provide a technique for accurately detecting a person's entry into a strong magnetic field region in the MR imaging room.

  The invention according to the first aspect provides a plurality of human sensors (sensors) provided on the ceiling or floor of an MR imaging room in which a magnetic field generating means is installed, and the MR imaging detected by the plurality of human sensors. Determining means for determining whether or not a condition for issuing an alarm is satisfied based on a position of a person in the room and information for specifying an area in which the magnetic field intensity is equal to or higher than a predetermined level in the MR imaging room; The safety system for MR apparatus provided with this.

  The invention of the second aspect provides the MR system safety system of the first aspect in which the plurality of human sensors are arranged in a grid pattern.

  The invention according to a third aspect provides the safety system for an MR apparatus according to the first aspect or the second aspect, in which the plurality of human sensors are infrared sensors.

  The invention of a fourth aspect provides the safety system for an MR apparatus according to the first aspect or the second aspect, wherein the plurality of human sensors are pressure sensors arranged on a floor.

  According to a fifth aspect of the present invention, in any one of the first to fourth aspects, the plurality of human sensors are arranged such that the installation density changes according to the distance from the magnetic field generating means. A safety system for an MR apparatus according to one aspect is provided.

  According to a sixth aspect of the invention, when it is determined that the condition is satisfied by the determination means, a display and / or a speaker provided in a gantry having the magnetic field generation means is provided. There is provided a safety system for an MR apparatus according to any one of the first to fifth aspects, further comprising alarm means for issuing an alarm.

  The seventh aspect of the invention is the first aspect of the invention further comprising alarm means for issuing an alarm to a person outside the MR imaging room when the determination means determines that the condition is satisfied. An MR device safety system according to any one of the sixth aspects is provided.

  The invention of the eighth aspect provides the safety system for an MR device according to any one of the first to seventh aspects, wherein the predetermined level is 5 gausses.

  The ninth aspect of the invention provides the MR system safety system according to any one of the first to eighth aspects, wherein the information is obtained by simulation or actual measurement. .

  According to a tenth aspect of the present invention, in any one of the first to ninth aspects, the condition includes a magnetic field strength that is a threshold value and the number of persons in the region of the magnetic field strength. A safety system for an MR apparatus according to an aspect is provided.

  The eleventh aspect of the invention provides an MR apparatus including the MR apparatus safety system according to any one of the first to tenth aspects.

  According to the invention of the above aspect, since a plurality of human sensors provided on the ceiling or floor are used for detecting the position of the person in the MR imaging room, a false detection of an object other than a person or a person hidden in the shadow And the like, and it is possible to accurately detect a person entering the strong magnetic field region in the MR imaging room.

1 is a diagram schematically showing a configuration of an MR apparatus according to an embodiment of the invention. It is a figure which shows an imaging | photography room and an operation room, and magnetic field intensity distribution. It is a flow figure of the safety monitoring processing by MR apparatus.

  Embodiments of the invention will be described below. However, this does not limit the invention.

  FIG. 1 schematically shows the configuration of an MR apparatus including the MR apparatus safety system according to the present embodiment. As shown in the figure, the MR apparatus includes a gantry 100 that is a magnet system, a cradle 500, a gantry control unit 200, and an operation console 300. The gantry 100 and the cradle 500 are installed in a photographing room 401 that is magnetically shielded. The gantry control unit 200 is installed in a control room outside the imaging room 401. The operation console 300 is installed in an operation room 403 outside the imaging room 401.

  The gantry 100 includes a main magnetic field coil unit 102, a gradient coil unit 106, and an RF coil unit 108. Each of these coil portions has a generally cylindrical shape and is arranged coaxially with each other. A subject 1 to be imaged is mounted on a cradle 500 in a generally cylindrical internal space (bore) of the gantry 100 and is carried in and out by a conveying means (not shown). The head of the subject 1 is accommodated in the RF coil unit 108.

  The main magnetic field coil unit 102 forms a static magnetic field in the internal space of the gantry 100. The direction of the static magnetic field is generally parallel to the direction of the body axis of the object 1. That is, a so-called horizontal magnetic field is formed. The main magnetic field coil unit 102 is configured using, for example, a superconducting coil. In addition, you may comprise using not only a superconductive coil but a normal conductive coil. Or you may form a static magnetic field using a permanent magnet, without using such a coil.

  The gantry 100 further includes a gantry display 110 and a gantry speaker 111.

  The gantry control unit 200 includes a gradient driving unit 130, an RF driving unit 140, and a data collection unit 150.

  The operation console 300 includes a sequence control unit 160, a data processing unit 170, a display unit 180, a console speaker 181, and an operation unit 190.

  A gradient driving unit 130 is connected to the gradient coil unit 106. The gradient driver 130 gives a drive signal to the gradient coil unit 106 to generate a gradient magnetic field. The gradient drive unit 130 has three drive circuits (not shown) corresponding to the three gradient coils in the gradient coil unit 106.

  An RF driving unit 140 is connected to the RF coil unit 108. The RF driving unit 140 gives a driving signal to the RF coil unit 108 and transmits an RF pulse, thereby exciting the spin in the body of the subject 1.

  A data collection unit 150 is connected to the RF coil unit 108. The data collection unit 150 takes in the received signal received by the RF coil unit 108 by sampling and collects it as digital data. The RF coil unit 108 may be installed separately for transmission and reception.

  A sequence control unit 160 is connected to the gradient drive unit 130, the RF drive unit 140, and the data collection unit 150. The sequence control unit 160 controls the gradient driving unit 130, the RF driving unit 140, and the data collection unit 150, respectively, and performs magnetic resonance signal collection.

  The sequence control unit 160 is configured using, for example, a computer. The sequence control unit 160 has a memory (not shown). The memory stores a program for the sequence control unit 160 and various data. The function of the sequence control unit 160 is realized by the computer executing a program stored in the memory.

  The output side of the data collection unit 150 is connected to the data processing unit 170. Data collected by the data collection unit 150 is input to the data processing unit 170.

  The data processing unit 170 is connected to the sequence control unit 160. The data processor 170 is above the sequence controller 160 and controls it. The function of the MR apparatus is realized by the data processing unit 170 executing a program stored in the memory.

  The data processing unit 170 reconstructs an image based on the data collected by the data collection unit 150.

  A display unit 180, a console speaker 181, and an operation unit 190 are connected to the data processing unit 170. The display unit 180 is configured by a graphic display or the like. The operation unit 190 includes a keyboard having a pointing device.

  The display unit 180 displays various types of information such as reconstructed images, patient information, imaging conditions, and alarms based on signals and data output from the data processing unit 170.

  The console speaker 181 outputs instructions, guidance, alarms, and the like by voice or sound based on signals and data output from the data processing unit 170.

  The operation unit 190 is operated by an operator and inputs various commands and information to the data processing unit 170. The operator operates the MR apparatus interactively through the display unit 180 and the operation unit 190.

  The data processing unit 170 is further connected to a gantry display 110 and a gantry speaker 111 provided in the gantry 100.

  The gantry display 110 displays necessary information such as patient information, imaging conditions, and alarms based on signals and data received from the data processing unit 170.

  The gantry speaker 111 outputs instructions, guidance, alarms, and the like by voice or sound based on signals and data output from the data processing unit 170.

  FIG. 2 shows a perspective view when the imaging room and the operation room are viewed from above, and a magnetic field intensity distribution in a predetermined horizontal plane in the imaging room.

  A plurality of human sensors 201 are arranged in a lattice pattern on the ceiling of the imaging room 301. The human sensor 201 detects, for example, the ambient temperature immediately below the sensor in near real time using infrared rays. Accordingly, it is possible to detect a person's body temperature and movement from the temperature detected by each of the human sensors 201 arranged in a grid pattern or a temporal change thereof, and to detect where the person is. .

  The arrangement interval of the human sensors 201 is, for example, about 30 cm to 100 cm, the imaging room 401 is a standard area (for example, 6 m × 8 m), and the strength of the main magnetic field is about 3 Tesla (T). For example, the arrangement interval can be about 50 cm.

  It should be noted that the human sensor 201 increases the density by narrowing the arrangement interval at a location close to the main magnetic field center C, and decreases the density by increasing the arrangement interval at a location far from the main magnetic field center C. Good. Near the main magnetic field center C, the magnetic field strength changes abruptly, but at a location far from the main magnetic field center C, the change in magnetic field strength is gentle. Therefore, in places far from the main magnetic field center C, the installation density of the human sensors 201 can be relatively lowered to lower the detection resolution, thereby reducing the number of human sensors 201 installed and reducing the cost (cost ) Can be reduced.

  The operation console 300 further includes a magnetic field strength distribution information storage unit 202, an alarm condition setting unit 203, and an alarm determination unit 204.

  The magnetic field strength distribution information storage unit 202 stores magnetic field strength distribution information indicating the magnetic field strength distribution in the imaging room 401. This magnetic field strength distribution information is obtained by simulation or actual measurement. FIG. 2 also shows an example of the magnetic field strength distribution in the photographing room.

  The alarm condition setting unit 203 sets conditions for issuing an alarm according to the operation of the operator. Here, a plurality of alarm conditions having different severity levels are set. The alarm condition is set based on, for example, the magnetic field strength that is a threshold value, the number of people in the magnetic field strength region, and the like. In this example, the first alarm condition is when there are “two” or more people in the region R1 where the magnetic field strength is “5 gauss” or more. The second alarm condition is when there is “one person” or more in the region R2 where the magnetic field strength is “20 gauss” or more. The “5 Gauss” line is defined by the guideline as the boundary of the restricted area for the cardiac pacemaker holder. In this alarm condition, if the number of people in the area of the predetermined magnetic field intensity is set to “2” or more, an alarm will be given when someone other than the operator such as the radiographer or assistant is in the predetermined strong magnetic field area. Can be avoided, and a situation where an alarm is issued due to the presence of the operator himself can be avoided.

  The alarm determination unit 204 detects the position of a person based on the outputs of the plurality of human sensors 201 and determines whether or not the set alarm condition is satisfied by comparing with the intensity distribution indicated by the magnetic field intensity distribution information. . Thereby, it can be determined whether or not a person has entered the strong magnetic field region. This determination result is sent to the data processing unit 170.

  The data processing unit 170 controls each unit to issue an alarm when the determination result received from the alarm determination unit 204 satisfies any alarm condition set by the alarm condition setting unit 203. In this example, when the data processing unit 170 issues an alarm, in addition to the gantry display 110 and the gantry speaker 111 provided in the gantry 100 in the imaging room 401, the display unit 180 of the operation console 300 in the operation room 403. A signal is sent to the console speaker 181 to output an alarm sound or an alarm display. Thereby, it is possible to alert not only those who are in the shooting room 401 but also those who are outside the shooting room 401.

  The data processing unit 170 emits an alarm sound, an alarm sound, an alarm display, etc. according to the determination result of the alarm determination unit 204. In this example, when only the first alarm condition is satisfied, a short alarm sound “beep” is output at a low volume at intervals of 1 second, and the alarm display is turned on. When the second alarm condition is satisfied, an alarm sound is output at a large volume at intervals of 0.5 seconds, and the alarm display is blinked.

  Hereafter, the safety monitoring process by the MR apparatus according to the present embodiment will be described.

  FIG. 3 shows a flow diagram of safety monitoring processing by the MR apparatus according to the present embodiment.

  In step S <b> 1, magnetic field strength distribution information is input and stored in the magnetic field strength distribution information storage unit 202.

  In step S2, an alarm condition is set.

  In step S3, it is determined whether or not an interrupt command (command) for safety monitoring processing has been input. If it has been input, the safety monitoring process is interrupted, and if it has not been input, the process proceeds to step S4.

  In step S <b> 4, based on the output of the human sensor 201, a position where a person is present in the photographing room 401 is detected.

  In step S5, magnetic field strength distribution information is read.

  In step S6, the detected position of the person is compared with the magnetic field strength distribution to determine whether or not the alarm condition is satisfied. When any one of the alarm conditions is satisfied, it is determined that a person has entered the strong magnetic field region, and the process proceeds to step S6. When the alarm condition is not satisfied, the process returns to step S3.

  In step S7, an alarm sound, an alarm display, or the like is output according to the alarm condition that is satisfied. Then, the process returns to step S3.

  According to the MR system safety system of the present embodiment as described above, a plurality of human sensors provided on the ceiling are used for detecting the position of a person in the MR imaging room. It is possible to suppress the detection omission of a person hidden behind the object, and to accurately detect the person's entry into the strong magnetic field region in the MR imaging room and to issue an alarm.

  In this embodiment, since a plurality of human sensors are arranged, the position of a person can be detected with high spatial resolution.

  In this embodiment, since an infrared sensor is used as the human sensor, an object whose temperature is significantly lower or higher than the human body temperature is not erroneously detected.

  In the present embodiment, since the magnetic field strength distribution information is obtained by simulation or actual measurement, the accuracy in determining whether or not the alarm condition is satisfied is very high.

  As mentioned above, although embodiment of invention was described, various deformation | transformation is possible for embodiment of invention in the range which does not deviate from the meaning of invention.

  For example, as the human sensor 201, an infrared sensor that detects temperature, an optical sensor that detects light shielding, an ultrasonic sensor that detects reflected waves of ultrasonic waves, and the like can be used. The human sensor 201 can be arranged not only on the ceiling but also on the floor. When arranged on the floor, a pressure sensor for detecting pressure can be used as the human sensor 201.

  Further, for example, the plurality of human sensors 201 may be arranged not only in a lattice shape but also in other modes such as a honeycomb shape or a concentric shape.

  In addition, for example, an alarm lamp composed of an LED lamp or the like may be separately provided inside and outside the photographing room 401, and this alarm lamp may be turned on when performing an alarm.

  Also, for example, when issuing an alarm, the form of the alarm may be changed according to the magnetic field strength of the region where the person is approaching so that the magnetic field strength of the region where the person is approaching can be sensed. Good.

  Further, for example, when a normal state or an alarm is issued, each magnetic field strength and the number of persons existing in the magnetic field strength region may be displayed in association with each other on the display unit 180 or the gantry display 110. .

  Further, for example, a map in which the magnetic field strength distribution in the photographing room and the position where the person is present may be displayed in a normal state or when an alarm is issued.

  Further, for example, when an alarm is issued, an alarm signal may be transmitted wirelessly to a portable terminal carried by the camera technician in charge to display alarm information on the portable terminal, or an alarm may be generated by sound or vibration.

  Also, for example, a 3-axis magnetic sensor is installed outside and inside the imaging room, and changes in the magnetic field inside the imaging room are observed to determine whether a person with a magnetic body enters or exists in the imaging room 401. An alarm may be issued depending on the situation.

  Also, for example, the safety system may be configured completely independently of the MR device.

1 Target 100 Gantry 102 Main magnetic field coil section (magnetic field generating means)
106 Gradient coil section 108 RF coil section 110 Gantry display (alarm means)
111 Gantry speaker (alarm means)
130 Gradient drive unit 140 RF drive unit 150 Data collection unit 160 Sequence control unit 170 Data processing unit (alarm means)
180 Display section (alarm means)
181 Console speaker (alarm means)
190 Operation unit 200 Gantry control unit 201 Human sensor 202 Magnetic field intensity distribution information storage unit 203 Alarm condition setting unit 204 Alarm determination unit (determination means)
300 Operation console 401 Shooting room 403 Operation room 500 Cradle

Claims (8)

A plurality of human sensors provided on the ceiling or floor of the MR imaging room in which the magnetic field generating means is installed;
Based on the position of the person in the MR imaging room detected by the plurality of human sensors and the information specifying the region where the magnetic field strength is equal to or higher than a predetermined level in the MR imaging room, a condition for issuing an alarm is satisfied. whether it is provided with a determination means,
The MR system safety system in which the plurality of human sensors are arranged such that the installation density thereof changes according to the distance from the magnetic field generation means . A plurality of human sensors provided on the ceiling or floor of the MR imaging room in which the magnetic field generating means is installed;
Based on the position of the person in the MR imaging room detected by the plurality of human sensors and the information specifying the region where the magnetic field strength is equal to or higher than a predetermined level in the MR imaging room, a condition for issuing an alarm is satisfied. whether it is provided with a determination means,
The MR system safety system , wherein the condition includes a threshold magnetic field strength and the number of persons in the magnetic field strength region . The MR system safety system according to claim 1 or 2 , wherein the plurality of human sensors are arranged in a grid pattern. The MR system safety system according to any one of claims 1 to 3, wherein the plurality of human sensors are infrared sensors. The MR system safety system according to any one of claims 1 to 3, wherein the plurality of human sensors are pressure sensors arranged on a floor.   6. The apparatus according to claim 1, further comprising alarm means for issuing an alarm via a display and / or a speaker provided in a gantry having the magnetic field generation means when the determination means determines that the condition is satisfied. The safety system for MR apparatus as described in any one of these.   7. The apparatus according to claim 1, further comprising an alarm unit that issues an alarm to a person outside the MR imaging room when the determination unit determines that the condition is satisfied. Safety system for MR equipment. An MR apparatus comprising the safety system for an MR apparatus according to any one of claims 1 to 7 .

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