JP2011062434A - Transportable bed and magnetic field attraction prevention system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transportable bed and a magnetic field attraction prevention system which inexpensively prevent accidental attraction of a magnetic field during carrying a patient. <P>SOLUTION: A gas cylinder holder 29 attachably and detachably holds a ferromagnetic body. A ferromagnetic body detector 31 magnetically detects the ferromagnetic body held by the gas cylinder holder 29. A magnetic field measuring instrument 33 is provided at least at one of a top plate 11, a leg 13, and the gas cylinder holder 29 and measures magnetic field intensity. A braking mechanism 17 and a speaker 25 wait execution of a predetermined warning operation when the ferromagnetic body detector 31 detects the ferromagnetic body and the magnetic field intensity measured by the magnetic field measuring instrument 33 is lower than a predetermined value or when the ferromagnetic body detector 31 detects no ferromagnetic body. The braking mechanism 17 and the speaker 25 execute the warning operation when the ferromagnetic body detector 31 detects the ferromagnetic body and the magnetic field intensity measured by the magnetic field measuring instrument 33 is not lower than the predetermined value. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a portable bed and a magnetic field attraction prevention system for an MRI imaging room.

  2. Description of the Related Art Magnetic resonance imaging apparatuses (hereinafter referred to as MRI apparatuses) have permeated as general image diagnostic apparatuses in medical practice. A very strong magnetic field is generated in the MRI imaging room. If a ferromagnetic material is brought into the MRI radiography room, a magnetic field attraction accident may occur. Therefore, it is prohibited to bring a ferromagnetic material into the MRI imaging room. Nevertheless, ferromagnets have been brought into the MRI room, and there has been no end to accidents involving magnetic field attraction. There are many cases of magnetic field accidents related to portable beds for transporting patients. A portable medical bed is often equipped with a medical gas cylinder, which is a ferromagnetic material. Under the circumstances of transporting emergency cases using a portable bed, the basic matter of “prohibition of bringing in ferromagnetic materials” tends to be forgotten. A magnetic field attraction accident is likely to occur.

  Techniques for preventing magnetic field attraction accidents are disclosed. As a general technique for preventing a magnetic field attraction accident, for example, there is a technique in which a metal detector is installed at the entrance of the MRI radiographing room, and an alarm is sounded when a person entering the room tries to bring in a ferromagnetic material. For example, as shown in Patent Document 1 and Patent Document 2, a magnetic body detection system has been proposed as another technique for preventing a magnetic field attraction accident. This magnetic material detection system is equipped with a coil and a magnetic sensor for magnetizing a ferromagnetic material before the entrance and exit of the MRI radiography room. It is something to do.

  However, the conventional technique has the following drawbacks.

・ Because the alarm sounds frequently, switch off at medical institutions.

・ The system itself is large and expensive.

・ It is necessary to apply a magnetic field to excite the ferromagnetic material at all times or when approaching the ferromagnetic material, before the entrance door. Therefore, the system must also manage this exciting magnetic field.

・ When the distance from the ferromagnetic material to the magnetic field detector is long, it is difficult to set a threshold value for detecting the ferromagnetic material. For this reason, it is difficult to ensure a stable operation of the system.

JP 2008-17989 A JP 2007-289670 A

  An object of the present invention is to provide a portable bed and a magnetic field attraction prevention system capable of preventing the occurrence of a magnetic field attraction accident during patient transportation with an inexpensive configuration.

  The portable bed according to the first aspect of the present invention includes a top plate on which a subject is placed, a support mechanism that supports the top plate, wheels provided in the support mechanism, the top plate, and the support. A holding mechanism that is provided in at least one of the mechanisms and detachably holds the ferromagnetic material, a detection unit that magnetically detects the ferromagnetic material held by the holding mechanism, the top plate, and the support mechanism, A measurement unit that is provided in at least one of the holding mechanisms and measures the magnetic field strength, and when the ferromagnetic material is detected by the detection unit and the magnetic field strength measured by the measurement unit is not equal to or greater than a predetermined value, or the detection unit When the ferromagnetic material is not detected by the above, the system waits for execution of a predetermined warning operation, and when the ferromagnetic material is detected by the detection unit and the magnetic field intensity measured by the measurement unit is equal to or greater than the predetermined value, A warning that executes the warning action Comprising a part, a.

  A magnetic field attraction prevention system according to a second aspect of the present invention includes a movable couch, a holding mechanism that is provided on the couch and holds the ferromagnetic material in a detachable manner, and a ferromagnetic material held by the holding mechanism. A detection unit that detects magnetically, a measurement unit that is provided on the bed and measures the magnetic field strength, a ferromagnetic material is detected by the detection unit, and the magnetic field strength measured by the measurement unit is not greater than or equal to a predetermined value When it is determined, or when it is determined that no ferromagnetic material is detected by the detection unit, a first signal is generated, and the magnetic field strength measured by the measurement unit is detected by the detection unit. When it is determined that the value is equal to or greater than a predetermined value, a determination unit that generates a second signal, and a period during which the first signal is generated, waits for execution of a predetermined warning operation, and the second signal is generated Execute the warning action And a warning unit which comprises a.

  According to the present invention, it is possible to realize a portable bed and a magnetic field attraction prevention system that can prevent occurrence of a magnetic field attraction accident during patient transportation with an inexpensive configuration.

The typical top view of the room concerning MR imaging. The top view which looked at the portable bed which concerns on embodiment of this invention from upper direction. The side view of the portable bed of FIG. The figure which shows the function structure of the portable bed of FIG. The figure which shows the ferromagnetic substance detector of an OFF state. The figure which shows the ferromagnetic material detector of an ON state. The figure which shows the determination table | surface for determining whether the warning operation for magnetic field attraction prevention is performed.

  Hereinafter, a portable bed (stretcher) and a magnetic field attraction prevention system according to an embodiment of the present invention will be described with reference to the drawings.

  The portable bed according to the present embodiment is for transporting a patient to an MRI imaging room where MR imaging is mainly performed.

  FIG. 1 is a plan view of a room related to MR imaging. As shown in FIG. 1, a medical facility where MR imaging is performed includes a gantry 100 for MR imaging, an MRI imaging room in which an MR imaging bed 200 is installed, an anterior chamber that also serves as a patient's waiting room, and a gantry 100. It has a CPU room in which a computer 300 for controlling and processing data from the gantry 100 is installed, and a console room in which a console 400 for inputting imaging conditions and displaying MRI images is installed. . In the MRI imaging room, a strong magnetic field is generated by a coil mounted on the gantry 100. In addition, a leakage magnetic field is generated in the anterior chamber adjacent to the MRI imaging room.

  The portable bed 1 is passed through the anterior room by a carry-in person such as a medical worker before being carried into the MRI imaging room. Then, the portable bed 1 is carried into the MRI radiographing room through the opening / closing door 500 that connects the MRI radiographing room and the front room.

  The portable bed 1 is equipped with a medical gas cylinder. This medical gas cylinder may be formed of a ferromagnetic material or a non-ferromagnetic material. If the portable bed 1 is transported into the MRI imaging room with the ferromagnetic gas cylinder mounted, a magnetic field attraction accident will occur. In order to prevent a magnetic field attraction accident, when transporting the portable bed 1 equipped with a gas cylinder to the MRI imaging room, it is required to check whether the gas cylinder is a ferromagnetic material.

  Despite such a check system, magnetic field accidents often occur. In particular, this often occurs when an emergency is transported to the MRI room. This is because, in the case of an emergency, a doctor or the like who moves the portable bed thinks of the patient's life first, so there is no room for checking whether the gas cylinder is a ferromagnetic material.

  The portable bed 1 according to the present embodiment is equipped with a ferromagnetic material (specifically, a ferromagnetic gas cylinder held on the portable bed), and the portable bed 1 has a magnetic field strength of a predetermined strength or more. It is automatically determined whether or not it is within the area it has. When it is determined that the ferromagnetic material is mounted and in the predetermined magnetic field strength region, the portable bed 1 performs a warning operation for preventing the ferromagnetic material from entering a region where the magnetic field strength is higher than this.

  Hereinafter, the portable bed 1 according to the present embodiment will be described in detail. FIG. 1 is a plan view of a portable bed 1 according to the present embodiment from above. FIG. 2 is a side view of the portable bed 1 of FIG.

  As shown in FIGS. 1 and 2, the portable bed 1 is equipped with a top plate 11 having a substantially rectangular shape. Here, the direction along the major axis of the top plate 11 is called the major axis direction, the direction along the minor axis of the top plate 11 is called the minor axis direction, and the direction perpendicular to the major axis direction and the minor axis direction is called the height direction. To.

  A patient is placed on the surface of the top plate 11. One end of a leg 13 is provided at each of the four corners on the back surface of the top plate 11. Each leg 13 supports the top plate 11. A wheel 15 is attached to the other end of each leg 13 so as to be rotatable around the axle. A rubber tire is typically fitted on the outside of the wheel 15. Each wheel 15 is provided with a braking mechanism 17 (brake) for suppressing the rotation of the wheel. The brake mechanism 17 is driven by receiving a drive signal from a warning mechanism drive source 19 described later.

  A support plate 21 is attached to the middle part of the four legs 13 so as to be substantially parallel to the top plate 11. The support plate 21 is provided, for example, to improve the mechanical strength of the portable bed 1. On the upper surface of the support plate 21, a warning mechanism drive source 19, a determination circuit 23, and a speaker 25 are mounted.

  A gas cylinder holder 29 for detachably holding the gas cylinder 27 is attached to the back surface of the top plate 11. The gas cylinder 29 is a pressure vessel in which a gas used for medical treatment such as oxygen is stored. The gas cylinder 29 typically has a cylindrical shape. The gas cylinder 29 may be formed of a ferromagnetic material such as iron, or may be formed of a non-ferromagnetic material such as aluminum or duralumin. The gas cylinder 29 is held by the gas cylinder holder 29 so that the major axis direction thereof and the major axis direction of the top plate 11 are parallel to each other. A ferromagnetic detector 31 is provided in the gas cylinder holder.

  The ferromagnet detector 31 magnetically detects a ferromagnet existing in the near space region. In other words, the magnetic substance that can be detected by the ferromagnetic detector 31 is a ferromagnetic substance, and the magnetic substance that is not detected by the ferromagnetic detector 31 is a non-ferromagnetic substance. A gas cylinder holder 29 is included in the neighborhood space region. The detection result is supplied to the determination circuit 23 described by the ferromagnetic detector 31. More specifically, the ferromagnetic substance detector 31 supplies a detection signal indicating that the ferromagnetic substance is detected to the determination circuit 23 during a period in which the ferromagnetic substance is detected. On the other hand, the ferromagnetic detector 31 does not supply a signal to the determination circuit 23 during a period in which no ferromagnetic material is detected. That is, the ferromagnetic detector 31 supplies a detection signal to the determination circuit 23 when the gas cylinder 27 held by the gas cylinder holder 29 is a ferromagnetic body.

  The top plate 11 and the gas cylinder holder 29 are provided with a plurality of magnetic field measuring devices (magnetic sensors) 33. Each magnetic field measuring device 33 measures the magnetic field strength at that position. The measurement result is supplied to the determination circuit 23 by the magnetic field measuring device 33. The magnetic field measuring device 33 is preferably installed at a position where the leakage magnetic field from the gantry 100 can be sensed first, regardless of the direction in which the portable bed 1 moves. For example, a plurality of magnetic field measuring devices 33 are installed on the outer periphery of the top plate 11.

  When the ferromagnetic gas cylinder 27 is mounted on the gas cylinder holder 29, the leakage magnetic flux from the gantry 100 is concentrated on the gas cylinder 27. The magnetic field generated by magnetizing the ferromagnetic gas cylinder 27 having a substantially rod shape attenuates in proportion to the 1/3 power of the distance. Therefore, a strong magnetic field acts on the gas cylinder holder 29 installed in the vicinity of the ferromagnetic gas cylinder 27 as compared with other positions on the portable bed 1. Accordingly, if the ferromagnetic detector 31 and the magnetic field measuring device 33 are installed in the gas cylinder holder 29, the magnetic field can be sensed more sensitively (highly sensitive) than other positions (for example, a top plate). Therefore, the ferromagnetic detector 31 is preferably installed on the gas cylinder holder 29. The magnetic field measuring device 33 needs to sense the magnetic field with higher sensitivity than the ferromagnetic material detector 31. Therefore, it is preferable that at least one magnetic field measuring device 33 is installed on the gas cylinder holder 29 at the end portion in the major axis direction of the gas cylinder 27 having a substantially rod shape.

  Considering the detection accuracy of the ferromagnetic material by the ferromagnetic material detector 31 and the magnetic field measurement accuracy by the magnetic field measuring device 33, all the members constituting the portable bed 1 (excluding the gas cylinder 27) are made of a ferromagnetic material. Preferably it is not formed. The member constituting the portable bed 1 is preferably a non-ferromagnetic material such as aluminum or duralumin.

  As described above, the portable bed 1 according to the present embodiment has a gas cylinder holder 29, the ferromagnetic material detector 31, the magnetic field measuring device 33, the determination circuit 23, the warning mechanism drive source 19, and the warning mechanism in a normal movable bed. (Braking mechanism 17 and speaker 25 etc.) are provided.

  Hereinafter, an operation example of the portable bed 1 according to the present embodiment will be described with reference to FIG. FIG. 4 is a diagram illustrating a functional configuration of the portable bed 1 according to the present embodiment. As shown in FIG. 4, the portable bed 1 includes a ferromagnetic material detector 31, a magnetic field measuring device 33, a determination circuit 23, a warning mechanism drive source 19, and a warning mechanism (such as the braking mechanism 17 and the speaker 25). Yes. The determination circuit 23, the warning mechanism drive source 19, and the warning mechanism constitute a warning unit.

  The ferromagnet detector 31 has, for example, a switch that can be switched ON / OFF by interaction with a magnetic field by a ferromagnet. FIG. 5 is a diagram showing the ferromagnetic detector 31 in the OFF state, and FIG. 6 is a diagram showing the ferromagnetic detector 31 in the ON state. As shown in FIGS. 5 and 6, the ferromagnetic detector 31 is installed in the vicinity of the gas cylinder holder 29. The ferromagnetic detector 31 includes a power supply 311, a switch 313, and a signal generation element 315. The power supply 311, the switch 313, and the signal generation element 315 are wired by a conducting wire 317 and constitute a circuit. A power supply 311 supplies current to the circuit. The switch 313 is constituted by a permanent magnet, for example. The permanent magnet generates a stable magnetic field without receiving external energy supply. Thus, the ferromagnetic detector 31 has a simple and inexpensive circuit configuration.

  As shown in FIG. 5, when the ferromagnetic material is not mounted on the gas cylinder holder 29, the switch 313 is stationary at the OFF position. When the switch is located at the OFF position, the circuit is cut off and no current is supplied from the power supply 311 to the signal generation element 315. When no current is supplied, the signal generation element 315 does not generate a detection signal. That is, when no ferromagnetic material is mounted on the gas cylinder holder 29, the ferromagnetic material detector 31 is in an OFF state (inactive). During the inactive state, the ferromagnetic detector 31 does not generate a detection signal.

  As shown in FIG. 6, when the ferromagnetic body (ferromagnetic gas cylinder 27) is mounted on the gas cylinder holder 29, the switch 313 is moved from the OFF position to the ON position by the interaction of the magnetic field with the ferromagnetic body. Is done. When the switch 313 is located at the ON position, the circuit is electrically connected, and current is supplied from the power supply 311 to the signal generation element 315. When a current is supplied, the signal generation element 315 repeatedly generates a detection signal indicating that a ferromagnetic material has been detected at regular intervals. The generated detection signal is supplied to the determination circuit 23 wirelessly by the signal generation element 315, for example. That is, when a ferromagnetic body (ferromagnetic gas cylinder 27) is mounted on the gas cylinder holder 29, the ferromagnetic body detector 31 is in an ON state (active). During the active state, the ferromagnetic detector 31 generates a detection signal.

  The magnetic field measuring device 33 measures the magnetic field intensity at the position and supplies the measurement result to the determination circuit 23 wirelessly. As the magnetic field measuring device 33, any existing measuring device for measuring the magnetic field strength can be applied. As the magnetic field measuring device 33, for example, a Hall element magnetometer that measures the magnetic field strength using the Hall effect is applied. As described above, a plurality of magnetic field measuring devices 33 are installed on the portable bed 1. The measurement results obtained by the magnetic field measuring devices 33 are individually supplied to the determination circuit 23.

  The determination circuit 23 is mounted on the support plate 21, for example. The determination circuit 23 automatically determines whether or not the ferromagnetic material is mounted and the portable bed 1 is in a region having a magnetic field strength equal to or higher than a predetermined strength. Actually, whether the determination circuit 23 causes the warning mechanism drive source 25 to perform a warning operation for preventing magnetic field attraction based on the detection result from the ferromagnetic material detector 31 and the measurement result from the magnetic field measuring device 33. Determine whether or not.

  The detection result from the ferromagnetic material detector 31 is classified by the determination circuit 23 into “with ferromagnetic material” and “without ferromagnetic material”. “With ferromagnetic material” and “without ferromagnetic material” can be determined by whether or not a detection signal is supplied from the ferromagnetic detector 31. That is, the determination circuit 23 determines that “there is a ferromagnetic material” during a period in which the detection signal is supplied from the ferromagnetic material detector 31 (that is, a time period in which the ferromagnetic material detector 31 is in an active state). During a period in which no detection signal is supplied from the detector 31 (that is, a period in which the ferromagnetic detector 31 is in an inactive state), it is determined that “no ferromagnetic material”. On the other hand, the measurement result from the magnetic field measuring device 33 is classified by the determination circuit 23 into “the magnetic field strength is equal to or lower than the threshold value” and “the magnetic field strength is equal to or higher than the threshold value”. The threshold value can be set in advance by the user. For example, the threshold value may be set between 1 gauss and 5 gauss. “Magnetic field strength is below threshold” and “magnetic field strength is above threshold” are determined for each magnetic field measuring device 33. The determination circuit 23 monitors the measurement result from each magnetic field measuring device 33 and determines that “the magnetic field strength is equal to or greater than the threshold” if there is one or more magnetic field measurers 33 that measure the magnetic field strength equal to or greater than the threshold. If there is no magnetic field measuring device 33 for measuring the magnetic field strength, it is determined that “the magnetic field strength is equal to or less than the threshold value”. As described above, since the magnetic field measuring device 33 is installed at a position where the magnetic field can be detected with high sensitivity, it is easy to determine the threshold value. Therefore, the determination circuit 23 can determine “the magnetic field strength is equal to or lower than the threshold value” and “the magnetic field strength is equal to or higher than the threshold value” with relatively stable accuracy.

  FIG. 7 is a diagram illustrating a determination table for determining whether or not to perform a warning operation for preventing magnetic field attraction. As shown in FIG. 7, when “there is a ferromagnet” and “the magnetic field strength is equal to or less than a threshold value”, when “there is no ferromagnet” and “the magnetic field strength is equal to or less than a threshold”, or “no ferromagnet” and “ If the magnetic field strength is equal to or greater than the threshold value, the determination circuit 23 determines not to perform the warning operation. If it is determined not to execute the warning operation, the determination circuit 23 supplies a non-execution signal to the warning mechanism drive source 25. On the other hand, only when “there is a ferromagnetic material” and “the magnetic field strength is equal to or greater than the threshold value”, the determination circuit 23 determines to execute the warning operation. If it is determined that the warning operation is to be executed, the determination circuit 23 supplies an execution signal to the warning mechanism drive source 19. That is, the determination circuit 23 has a logical product circuit that calculates the logical product of the detection result and the measurement result.

  The warning mechanism drive source 19 is mounted on the support plate 21, for example. The warning mechanism drive source 19 waits for the drive signal to be supplied to the warning mechanism while the non-execution signal is supplied from the determination circuit 23. The warning mechanism drive source 19 supplies a drive signal to a warning mechanism such as the braking mechanism 17 or the speaker 25 during a period when the execution signal is supplied from the determination circuit 23.

  Warning mechanisms such as the brake mechanism 17 and the speaker 25 wait for execution of a warning operation for preventing magnetic field attraction while a drive signal is not supplied from the warning mechanism drive source 19. While the drive signal is supplied from the warning mechanism drive source 19, the warning mechanisms such as the braking mechanism 17 and the speaker 25 perform a warning operation. Specifically, the brake mechanism 17 receives the supply of the drive signal from the warning mechanism drive source 19 and presses the wheel 15 to suppress and stop the rotation of the wheel 15. The speaker 25 receives a drive signal from the warning mechanism drive source 19 and outputs a warning sound such as a predetermined message or alarm. The message may be, for example, “Ferromagnetic material is installed”. By performing such a warning operation, it is possible to prevent the portable bed 1 from being transported to a region with a stronger magnetic field strength. In other words, it is possible to notify the carrier that the ferromagnetic material is mounted on the portable bed 1.

  The warning mechanism does not need to include both the braking mechanism 17 and the speaker 25, and may be either one. Further, the warning mechanism is not limited to the braking mechanism 17 and the speaker 25. For example, a ring retaining ring 35 embedded in the boundary between the strong magnetic field region and the non-strong magnetic field region on the floor of the MRI radiography room may be used. The strong magnetic field region is a region having a magnetic field strength of a level slightly higher than a threshold value (a value between 1 gauss and 5 gauss) used for the measurement result from the magnetic field measuring device 33, for example, 10 gauss or more. is there. The loop ring 35 is raised from the floor to the outside in response to the drive signal supplied from the warning mechanism drive source 19. The portable bed 1 can no longer be transported to the strong magnetic field region by lifting the ring stopper 35. Further, the warning mechanism may be a light emitting device such as an LED (light-emitting diode) or a lamp.

  In the above configuration, the determination circuit 23 is mounted on the portable bed 1. However, the present embodiment is not limited to this. For example, the function of the determination circuit 23 may be incorporated in a computer installed in a CPU room, a console room, a front room, or the like. In this case, the computer and the portable bed 1 constitute a magnetic field attraction prevention system. The detection result from the ferromagnetic detector 31 provided on the portable bed 1 of the magnetic field attraction prevention system and the measurement result from the magnetic field measurement device 33 may be transmitted wirelessly to the computer of the magnetic field attraction prevention system. .

  As described above, the portable bed 1 and the magnetic field attraction prevention system automatically determine whether or not the portable bed 1 is equipped with a ferromagnetic material and the portable bed 1 is in a region having a magnetic field strength higher than a predetermined strength. Judgment. When it is determined that the ferromagnetic material is mounted and in the predetermined magnetic field strength region, the portable bed 1 performs a warning operation for preventing the ferromagnetic material from entering a region where the magnetic field strength is higher than this. As described above, the portable bed 1 is provided with an active magnetic field accident prevention function.

  This embodiment specializes in preventing magnetic field attraction accidents at medical sites, especially magnetic field attraction accidents due to ferromagnetic gas cylinders during emergency patient transport. For this reason, the mechanism (for example, the ferromagnetic substance detector 31, the magnetic field measuring device 33, and the determination circuit 23) for preventing magnetic field attraction accidents is small-scale, and all can be mounted on the portable bed 1. In other words, the mechanism for preventing magnetic field attraction accidents does not deviate from the size of the portable bed 1 and does not need to have a large size as in the prior art. Therefore, the ferromagnetic material detector 31 and the magnetic field measuring device 33 can be installed at a position where the magnetic field generated by the ferromagnetic material is easily detected with high sensitivity, for example, in the gas cylinder holder 29. For this reason, this embodiment can prevent a magnetic field attraction accident with stable operation and accuracy. Moreover, since the magnetic field attraction accident prevention mechanism has a simple configuration, it can be manufactured at a relatively low cost.

  Thus, the portable bed 1 and the magnetic field attraction prevention system according to the present embodiment can prevent the occurrence of a magnetic field attraction accident during patient transportation with an inexpensive configuration.

  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 constituent elements 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.

  As described above, according to the present invention, it is possible to realize a portable bed and a magnetic field attraction prevention system that can prevent the occurrence of a magnetic field attraction accident during patient transportation at low cost.

  DESCRIPTION OF SYMBOLS 1 ... Portable bed, 11 ... Top plate, 13 ... Leg, 15 ... Wheel, 17 ... Braking mechanism, 19 ... Warning mechanism drive source, 21 ... Support plate, 23 ... Judgment circuit, 25 ... Speaker, 27 ... Gas cylinder, 29 ... gas cylinder holder, 31 ... ferromagnetic substance detector, 33 ... magnetic field measuring instrument.

Claims (5)

A top plate on which the subject is placed;
A support mechanism for supporting the top plate;
Wheels provided in the support mechanism;
A holding mechanism that is provided on at least one of the top plate and the support mechanism and removably holds a ferromagnetic material;
A detection unit for magnetically detecting the ferromagnetic material held by the holding mechanism;
A measurement unit that is provided on at least one of the top plate, the support mechanism, and the holding mechanism, and measures the magnetic field strength;
When a ferromagnetic material is detected by the detection unit and the magnetic field intensity measured by the measurement unit is not equal to or higher than a predetermined value, or when the ferromagnetic material is not detected by the detection unit, execution of a predetermined warning operation is awaited. A warning unit that executes the warning operation when a ferromagnetic material is detected by the detection unit and the magnetic field intensity measured by the measurement unit is equal to or greater than the predetermined value;
A portable sleeper comprising: A speaker provided on at least one of the top plate and the support mechanism;
The warning unit outputs a warning sound through the speaker as the warning operation.
The portable bed according to claim 1. A braking mechanism for suppressing rotation of the wheel provided in the support mechanism;
The warning unit drives the braking mechanism as the warning operation.
The portable bed according to claim 1. The warning unit drives, as the warning operation, a ring stopper embedded in the boundary between the strong magnetic field region and the non-strong magnetic field region on the floor of the MRI imaging room.
The portable bed according to claim 1. A movable bed,
A holding mechanism provided on the bed and detachably holding the ferromagnetic material;
A detection unit for magnetically detecting the ferromagnetic material held by the holding mechanism;
A measurement unit provided on the bed for measuring magnetic field strength;
A first signal when a ferromagnetic material is detected by the detection unit and when it is determined that the magnetic field intensity measured by the measurement unit is not equal to or greater than a predetermined value, or when it is determined that no ferromagnetic material is detected by the detection unit. A determination unit that generates a second signal when a ferromagnetic material is detected by the detection unit and the magnetic field intensity measured by the measurement unit is greater than or equal to the predetermined value;
A warning unit that waits for execution of a predetermined warning operation during a period in which the first signal is generated, and executes the warning operation when the second signal is generated;
Magnetic field attraction prevention system comprising:

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