DE202013101097U1 - MRI Safety device means - Google Patents

Abstract

A magnetic shielding device (MSM) for preventing the penetration of metallic objects through an aperture to the open bore of an MRI device (MRD) where the magnetic field (B) is maximized; wherein said MRD is operable to generate a sweeping magnetic field (BF / L) which weakens as the distance (L) from said aperture increases; said MSM having at least one magnet with a magnetic field BMSM; said MSM being attached at a distance LMSM from said aperture of the MRD; and wherein for each distance L BMSM >> BF / L.

Description

Field of the invention

The present invention relates to safety during magnetic field related imaging procedures and, more particularly, to the protection of personnel and equipment involved in an MRI diagnosis.

Background of the invention

In general, the static magnetic fields in MRI systems can be more than about 0.5 T; Some such systems have static magnetic fields larger than 3 T. These magnetic fields will attract metallic objects in the vicinity of the static magnets. If the object is in the vicinity of the opening of the MRI, such as an opening to allow the entry of a subject to be analyzed, it may be very difficult to remove the object on the interior of the MRI. Even worse, such a magnetic hemisphere can be physically dangerous to the patient, if not fatal.

High field strength midge arrays may extend to a distance approximated by the equation X = α B ₀ , where α is a constant that depends on the size of the bore of the magnet and the magnet configuration. An unshielded 1.5 T magnet has a 1 mT hem field at a distance of -9.3 m from the center of the magnet, a 0.5 mT field at 11.5 m, and a 0.3 mT field at 14, 1 m. To reduce the extent of the magnetic fringe field, passive (such as thick metal walls near the magnet) and active (electromagnetic systems placed in the magnet housing become superconducting magnets U.S. Patent No. 5,883,558 . U.S. Patent No. 5,565,831 magnetic shielding applied. The distance of a screened hem field surrounding the MRD opening can be reduced to about 2 meters or less.

Despite the achievable reduction of the magnetic hem field boundaries, the existence of such fields leaves room for the above mentioned dangers in the MRD environment. Thus, there is a long felt need to provide an automatic and secure means of preventing loose metal objects from entering the hem area and the MRD bore and protecting patients from metallic equipment.

Summary of the invention

It is an object of the present invention to provide a system for a magnetic shielding device (MSM) for avoiding penetration of metallic objects through an aperture to the open bore of an MRI device (MRD) where the magnetic field (B) is maximized ; wherein the MRD generates a fringing magnetic field (B _{F / L} ) which weakens with increasing distance (L) from the aperture; wherein the MSM has at least one magnet with a magnetic field B _MSM ; wherein the MSM is attached at a distance L _MSM from the aperture of the MRD; where for each distance LB _MSM >> B _{F / L.}

It is another object of the present invention wherein the MSM, as defined in any of the above, is configured as an edge that at least partially surrounds the open bore.

It is another object of the present invention wherein the MSM, as defined in any of the above, comprises an array of a plurality of magnets disposed along at least a portion of the periphery of the rim.

It is another object of the present invention wherein the MSM is as defined in any of the above in connection with a horizontal patient bed or scaffold (collectively defined as "scaffold") that is configured to be reversible and reciprocal in and out of the open Maneuvering the bore along the major longitudinal axis of the same, the MSM being matched with respect to one of a group consisting of (i) to surround at least a portion of the framework, (ii) to be in association with the framework, (iii ) to be contained within or on at least part of the scaffold and a combination thereof.

It is another object of the present invention wherein the MSM comprises a plurality of magnets as defined in any of the above.

It is another object of the present invention wherein the MSM, as defined in any of the above, comprises a plurality of magnets provided in an array.

It is another object of the present invention, wherein the MSM comprises metallic objects as defined in any of the above, selected from a group consisting of medical devices, needles and surgical instruments, laboratory items, clothing, garments, footwear, iron-based materials, nickel alloys, and stainless steel of ferritic and martensitic crystal structure and any combination thereof.

It is another object of the present invention wherein the MSM, as defined in any of the above, comprises communication means thereby providing a remote connection to an MRD.

It is another object of the present invention wherein the MSM as defined in any of the above is in communication with at least one MSM in connection with an alerting device, and further wherein at least one MSM is provided in communication with a door that alerts when a metallic one Device penetrates through the door.

It is another object of the present invention wherein the MSM is as defined in any of the above in connection with an MRI Protector (GM), the GM being selected from a group consisting of (i) an MRD aperture blocking device, ( ii) a magnetic field shutter, (iii) one or more MSM and a combination thereof, wherein the alarm device is in communication with the GM when a metallic device enters through the door.

It is another object of the present invention wherein the MSM is as defined in any of the above in communication with a metal detector.

It is another object of the present invention wherein the MSM is portable as defined in any of the above.

It is another object of the present invention to provide an MRD comprising one or more magnetic MSMs for avoiding penetration of metallic objects through an aperture toward the bore of said MRD where the magnetic field (B) is maximized; wherein the MRD generates a sweeping magnetic field (B _{F / L} ) which weakens as the distance (L) from said aperture increases; wherein the MSM has at least one magnet with a magnetic field B _MSM ; wherein the MSM is attached at a distance L _MSM from the aperture of the MRD; and further wherein for each distance LB _MSM >> B _{F / L.}

It is another object of the present invention wherein the MRD, as defined in any of the above, comprises an MSM configured as a rim that at least partially surrounds the open bore.

It is another object of the present invention wherein the MRD includes an array of a plurality of magnets disposed along at least a portion of the periphery of the rim.

It is another object of the present invention, wherein the MRD as defined in any of the above, additionally comprises a horizontal patient bed or scaffold configured to be reversibly and reciprocally in and out of the open bore along the major longitudinal axis of the same maneuvering, wherein the MSM is adapted with respect to one of a group consisting of (i) to surround at least a portion of the framework, (ii) to be in association with the framework, (iii) within or at least to be included in a part of the framework and a combination thereof.

It is another object of the present invention wherein the MRD comprises an MSM as defined in any of the above and the MSM comprises a plurality of magnets.

It is another object of the present invention wherein the MRD as defined in any of the above includes an MSM, wherein in the aforementioned MSM the plurality of magnets are provided in an array.

It is another object of the present invention wherein the MRD is defined as in any of the above wherein the metallic objects are selected from a group consisting of medical devices, needles and surgical instruments, laboratory items, apparel, garments, footwear, iron-based materials, nickel alloys, and stainless steel of ferritic and martensitic crystal structure and any combination thereof.

It is another object of the present invention wherein the MRD as defined in any of the above is in remote connection with an MSD as defined above.

It is another object of the present invention wherein the MRD as defined in any of the above includes an alerting device in communication with at least one MSM, wherein at least one MSM is provided in communication with a door that alerts when a metallic device passes through the door penetrates.

It is another object of the present invention, wherein the MRD, as defined in any of the above, further comprises an MRI guard (GM), the GM being selected from a group consisting of (i) an MRD aperture blocking device, (ii) a magnetic field shutter, (iii) one or more MSM and a combination thereof, wherein the alarm device is in communication with the GM when a metallic device enters through the door.

It is another object of the present invention wherein the MRD is as defined in any of the above in communication with an MSM that is in communication with a metal detector.

It is another object of the present invention wherein the MRD is defined as in any of the above wherein the MSM is portable.

Brief description of the figures

In order to better understand the invention and its implementation in practice, a plurality of embodiments will now be described, by way of non-limiting example only, with reference to the accompanying drawings, in which: FIG

1 (see upper figure) is a schematic cross section (side view) of an MRI apparatus 110 illustrating an open hole with a volume of interest 103 has where applied in maximum magnetic field, and an MSM 200 next to the aperture of the hole; the lower graph shows the strength of the magnetic field as a function of the distance between the center of the VOI ( 103 where the maximum magnetic field is applied, 104 ) and a theoretical line provided by the hole ( 102 where there is a much less penetrating magnetic field, namely the magnetic field outside the magnet itself, 105 ) and the external environment surrounding the MRD ( 106 where zero magnetic field is applied, 107 );

2a to 2f illustrate schematic front views of some MSMs according to several embodiments of the invention;

3 and 4 illustrate schematic perspective views of other embodiments of the invention; an MRD ( 110 ) in conjunction with a scaffold ( 300 ), where patients ( 1 ) are placed within the MRD prior to their imaging; an MSM ( 200 ) is in connection with the scaffold;

5 a door 400 to an MRD 110 and / or an MRD housing, the door being in communication with an MSM 200 is; and

6 an MRD 101 which is in communication with a portable or otherwise mobile MSM that may be configured at more than one predetermined location.

Detailed Description of the Preferred Embodiments

The following description is provided throughout for all the chapters of the present invention so as to enable any person skilled in the art to use the invention, and sets forth the best modes contemplated by the invention for carrying out the invention. Various modifications will, however, be apparent to those skilled in the art, as the generic principles of the present invention are defined to specifically provide a means and method for preventing penetration of metallic objects through an aperture to the open bore of an MRI apparatus.

The term "metallic objects" hereinafter refers to any metal that generates a magnetic field in response to an applied magnetic field, such as ferromagnetic and ferrimagnetic metals.

It will be up now 1 With reference to FIG. 1 (see upper figure), a schematic cross section (side view) of an MRI apparatus is shown 110 illustrating an open hole with a volume of interest 103 has, where in maximum magnetic field is applied. The hole has an aperture 102 through which the patient is examined. 1 further illustrates (see lower graph) the strength of the magnetic field as a function of the distance between the center of the VOI ( 103 where the maximum magnetic field is applied, 104 ) and a theoretical line provided by the hole ( 102 where a much less penetrating magnetic field, namely the magnetic field outside the magnet itself, is applied) and the external environment surrounding the MRD ( 106 where zero magnetic field is applied, 107 ). 1 further illustrates, in accordance with an embodiment of the invention, an annular magnetic shielding element (MSM, 200 ) located in the outer part of the MRD adjacent to the edge of the opening 102 the bore is arranged. The magnetic strength of the MSM ( 101 , see lower curve) is effectively higher than the magnetic midge fields (ibid. 105 ) of the MRD. Metallic implements that happen to be next to the opening 102 are therefore magnetically safe toward the MSM 200 pulled instead of being magnetically attracted to the aperture 102 towards the magnet of the MRD located within the bore.

It is still going on 1 Reference is made, which shows an example of the invention: The magnetic shielding device (MSM, 200 ) is particularly adapted to the dangerous penetration of metallic objects such as surgical tools, medical devices and sharp instruments through an aperture 102 towards the open bore of an MRI device (MRD, 110 ), Where 103 the magnetic field (B, 104 ) is to be avoided. The MRD includes a skirting magnetic field (B _{F / L} , 105 ), with increasing distance (L, x-axis of the curve) from the aperture 102 becomes weaker. The MSM 200 comprises at least one magnet with a magnetic field B _MSM 101 , The MSM is attached at a distance L _MSM from said VOI of the MRD, outside the MED; For example, here is the distance between the aperture and the MSM about zero; where for each distance LB _MSM >> B _{F / L.}

It will now be referred to 2a to 2f , which illustrate schematic front views of some embodiments of the invention. 2a shows a configuration of an MSM 200 , which as an example an upper magnet 201 and / or a lower magnet 202 includes. 2 B shows another configuration of an MSM 200 comprising a plurality of magnets 201 . 202 etc. 2 B shows another configuration of an MSM 200 comprising one or more continuously shaped magnets 201 , 2 B shows another configuration of an MSM 200 namely, a door-like MSM comprising one or more magnets 201 . 202 outside the aperture 102 the bore are arranged. 2e and 2f still present other configurations of MSM in a still non-limiting way 200 Here, an annular MSM is provided over or at least partially around a framework of the MRD, a horizontal bed, and the like.

It will be up now 3 Reference is made schematically illustrating a perspective view of another embodiment of the invention. An MRD 110 in conjunction with a scaffold 300 where patients are placed before imaging within the MRD. According to this embodiment of the invention, an MSM 200 in conjunction with said framework, e.g. B. with respect to the aperture 102 positioned the MRD. The magnetic strength of the MSM is effectively stronger 101 as the sweeping magnetic field in its place 107 and significantly weaker than that in the VOI 104 applied magnetic field. In addition, the magnetic field curve of the MSM 101 very sharp. A top view of the magnetic framework 300 is at view 300A given

It will be up now 4 Reference is made schematically illustrating a perspective view of another embodiment of the invention. An MRD 110 in conjunction with a scaffold 300 another type. According to this embodiment of the invention, as described above, an MSM 200 in conjunction with said framework, e.g. B. with respect to the aperture 102 positioned the MRD. As shown separately in a schematic plan view, the framework comprises 300D a magnetic border 300B on the circumference of a non-magnetic part of the framework 300C , The magnetic strength of the MSM is effectively stronger 101 as the lapping magnetic field in its place ( 105 - 107 ) and significantly weaker than that in the VOI 104 applied magnetic field. The magnetic field curve of the MSM 101 has a wide shape.

It will be up now 5 Reference is made schematically illustrating a perspective view of another embodiment of the invention. A door 400 to an MRD 110 and / or a housing of the MRD is in communication with an MSM 200 , The patient to be imaged is instructed to pass the said MSM before approaching the MRD-adjacent environment. The magnetic field 101 inside the door 400 is significantly larger than the magnetic hem field 107 At this place.

It will be up now 6 Reference is made schematically illustrating a perspective view of another embodiment of the invention. The MRD 101 is in communication with a portable or otherwise movable MSM that may be configured at more than one predetermined location. In one example of the invention, the MSM is in place near the bore hole (eg, at the aperture of the bore or adjacent to the aperture) of the MED 200A located along the scaffolding 300 the MRD locally 200b or at a respective remote location 200c near the end of the scaffolding. In one embodiment of the invention, the MSM is reversibly reciprocated by means of a telescoping mechanical device, by one or more levers or translating means, or in any other suitable device.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• US 5883558 [0003]
• US 5565831 [0003]

Claims (24)

A magnetic shielding device (MSM) for preventing the penetration of metallic objects through an aperture to the open bore of an MRI device (MRD) where the magnetic field (B) is maximized; said MRD being operable to generate a fringing magnetic field (B _{F / L} ) which weakens as the distance (L) from said aperture increases; said MSM having at least one magnet with a magnetic field B _MSM ; wherein said MSM is attached at a distance L _MSM from said aperture of the MRD; and where for each distance LB _MSM >> B _{F / L.} The MSM of claim 1, wherein said MSM is configured as an edge that at least partially surrounds said open bore. The MSM of claim 1, wherein said MSM comprises an array of a plurality of magnets disposed along at least a portion of the periphery of said rim. The MSM of claim 1, wherein said MSM is in communication with a scaffold configured to maneuver reversibly and reciprocally in and out of said open bore along the major longitudinal axis of the same, said MSM being adapted for one of a group consisting of (i) to surround at least part of said framework, (ii) to be in association with said framework, (iii) to be contained within or on at least part of said framework, and Combination of it. The MSM of claim 2, wherein said MSM comprises a plurality of magnets. The MSM of claim 1, wherein said plurality of magnets are provided in an array. The MSM of claim 1, wherein said metallic objects are selected from a group consisting of medical devices, needles and surgical instruments, laboratory articles, apparel, garments, footwear, iron-based materials, nickel alloys, and ferritic and martensitic crystal stainless steel and any combination thereof. The MSM of claim 1, comprising communication means thereby providing remote connection to an MRD. The MSM of claim 1, wherein said MSM is in communication with an alerting device in communication with at least one MSM, and further wherein at least one MSM is provided in communication with a door that alerts when a metallic device enters through said door. The MSM of claim 1, wherein said MSM is in conjunction with an MRI protector (GM), said GM being selected from a group consisting of (i) an MRD aperture blocking device, (ii) a magnetic field shutter, (iii) one or more MSMs and a combination thereof, said alarming device in communication with said GM when a metallic device enters through said door. The MSM of claim 1, wherein said MSM is in communication with a metal detector. The MSM of claim 1, wherein said MSM is portable. A magnetic resonance device (MRD) comprising one or more magnetic shielding devices (MSMs) for preventing the penetration of metallic objects through an aperture to the open bore of said MRD where the magnetic field (B) is maximized; said MRD being operable to generate a fringing magnetic field (B _{F / L} ) which weakens as the distance (L) from said aperture increases; said MSM having at least one magnet with a magnetic field B _MSM ; wherein said MSM is attached at a distance L _MSM from said aperture of the MRD; and further wherein for each distance LB _MSM >> B _{F / L.} The MRD of claim 13, wherein said MSM is configured as an edge that at least partially surrounds said open bore. The MRD of claim 13, wherein said MSM comprises an array of a plurality of magnets disposed along at least a portion of the periphery of said rim. The MRD of claim 13, further comprising a framework configured to reversibly and reciprocally maneuver in and out of said open bore along a major longitudinal axis of the same, said MSM being adapted for one of a group consisting of: i) to surround at least part of said scaffold, (ii) to be located in connection with said scaffold, (iii) to be contained within or on at least part of said scaffold, and a combination thereof. The MRD of claim 13, wherein said MSM comprises a plurality of magnets. The MRD of claim 13, wherein said plurality of magnets are provided in an array. The MRD of claim 13, wherein said metallic objects are selected from a group consisting of medical devices, needles and surgical instruments, laboratory items, clothing, garments, footwear, iron-based materials, nickel alloys, and ferritic and martensitic crystal stainless steel and any combination thereof. An MRD system wherein said MRD is in remote communication with an MSM as defined in claim 1. The MRD system of claim 20, comprising an alerting device in communication with at least one MSM, wherein at least one MSM is provided in communication with a door that alerts when a metallic device enters through said door. The MRD system of claim 21, further comprising an MRI guard (GM), said GM selected from a group consisting of (i) an MRD aperture blocking device, (ii) a magnetic field shutter, (iii) one or more MSM and a combination thereof, said alarming device in communication with said GM when a metallic device enters through said door. The MRD of claim 13, wherein said MSM is in communication with a metal detector. The MRD of claim 13, wherein said MSM is portable.

Images