DE102007036242A1 - Magnetic coil system for applying force to an endoscopy capsule - Google Patents

Abstract

A magnet coil system (2) comprises a three-dimensional working space (12) into which a patient (14) is at least partially insertable, a plurality of individually controllable individual coils (8) for generating at least one basic magnetic field (20) for predetermined non-contact force on a magnetically navigable, a magnetic moment (18) having endoscopy capsule (16) in the working space (12), a stabilization system (22, 24, 36) for stabilizing and homogenizing the basic magnetic field (20) for MR imaging of the patient (14) in the working space (12 ), an RF coil system (29) for generating an excitation field (33) and for receiving a resonance field (35) for MR imaging, a system controller (34) for MR imaging.

Description

The The invention relates to a magnetic coil system for applying force on an endoscopy capsule.

Such a magnetic coil system is z. B. from the DE 101 42 253 C1 known. It has a working space into which a patient is at least partially insertable. With such a system can on a z. B. also from the DE 101 42 253 C1 known, located in the working space endoscopic capsule or endocapsule without contact, in a predeterminable direction and strength of a force or torque, hereinafter always referred to for the sake of simplicity as a force exerted. Thus, a so-called capsule endoscopy (Magnetically Guided Capsule Endoscopy - MGCE) can be performed on the patient, in which the capsule in the patient is selectively and arbitrarily moved. An endocapsule usually has a camera for imaging. However, this is only a consideration of the inner surfaces of the patient, z. B. the inner intestinal wall in the gastrointestinal tract possible.

For the use of capsule endoscopy is an additional radiographic imaging of the patient in many cases Helpful to using a fluoroscopy also image information to gain from inside the patient with the MGCE invisible. This increases both the diagnostic and the therapeutic Safety. For example, an X-ray imaging on the patient be performed.

A the greatest limitations of radiology against it again is the lack of immediate therapy option, radiographic imaging of pathologies only in rare cases, z. B. directly under the skin or through a body opening are reachable. Direct access through tools such. B. Needles, from outside the patient, so minimal invasive, is only possible in rare cases.

It It is known to combine an MGCE with an X-ray imaging. This will take advantage of full imaging from the patient and a significantly increased accessibility of Pathologies united by the endocapsule.

Known is an x-ray system external to the magnet coil system to bind, z. B. in the form of an approached to the coil system C-arm.

Known is also to nest both systems, z. B. in the magnetic coil system an independent X-ray system, z. B. a CT device, integrate. X-ray source and receivers are then z. B. between or in the region of the magnet windings arranged the coil system.

such X-ray devices pose in relation to capsule endoscopy always external, not fully integrated devices, since these unlike on magnetic field based capsule endoscopy X-ray base work.

task It is the object of the present invention to provide an improved magnetic coil system and an improved method for magnetic capsule navigation specify.

The The invention is based on the recognition that an imaging from inside the patient is also suitable for MR imaging and that how the MGCE works on magnetic field basis. Idea of the invention is it therefore, that it would be beneficial to the system to MGCE so that it can be used both for capsule navigation and for MR imaging can be used, d. H. in a single system to unite an MR scanner and an MGCE.

The invention is achieved with respect to the magnetic coil system by such a three-dimensional working space, in which a patient is at least partially introduced, with a plurality of individually controllable individual coils for generating at least one basic magnetic field for specifiable non-contact force on a magnetically navigable, a magnetic torque endoscopy capsule in the workroom, such. B. from the DE 103 40 925 known. Under a magnetic moment here is z. As a permanent magnet, a magnetic coil or any other, to understand a fixed magnetic field at the Endokapsel generating element.

Contains according to the invention the magnet coil system a stabilization system for stabilization and homogenization of the basic magnetic field for MR imaging from the patient in the workroom, an RF coil system for generation an excitation field and for receiving a resonance field for MR imaging, and an equipment control for MR imaging.

The known magnet system for capsule endoscopy consists of a series of coils which generate the magnetic fields and magnetic field gradients required to apply the force to the endocapsule. Among other things, according to the invention, those fields and gradients which are required for the MR imaging are also generated. The MR magnet is z. B. constructed from the Helmholtz coils of the navigation magnet. The fields and gradients achievable with these coils are sufficient for low-end MR imaging. The other, for MR imaging still necessary components - RF coil system and system control, are supplemented according to the invention. The plant control closes here z. As a processing, Rekon Design and visualization of a obtained MR-3D image data set with a.

For The capsule endoscopy is a magnet with large magnetic Rivers and very high flux density gradients required. For MR, an extremely homogeneous magnetic flux very high temporal constancy or with very well-known temporal changes needed. Therefore, according to the Invention Stabilization system available, which is the magnet coil system for improved MR imaging. It is conceivable z. B. a System with improved over the pure capsule navigation power amplifiers for the coils of the magnetic coil system.

The so modified magnetic coil system allows a combination from capsule endoscopy and MR imaging.

The RF coil system can be designed so that it to the MGCE existing coils of the magnetic coil system uses or that these are suitably modified. The RF coil system can also a separate, so additional excitation coil for generating of the MR excitation field in the workspace. So that has to be Stimulation field not used by those exercising power Coils of the solenoid system are generated, which is optimal Design of both coil types allowed.

The In this case, the excitation coil can be a whole body coil. Such coils are already available, are for optimized MRI imaging and can be so easy in the Coil system can be integrated.

The RF coil system can be an MR receiver coil for contain the resonance field. This results in the same Advantages as above for the additional excitation coil executed.

The MR receiver coil can hereby be applied to the patient Be surface coil. This results in the same advantages as above for the whole body coil executed.

A first alternative for stabilizing the basic magnetic field, that the stabilization system additional coils, for. B. Helmholtz variants for generating the basic magnetic field can. In addition means that these coils in a known system for pure MGCE are not available and specifically for MR imaging.

A Another or additional measure for this is that the stabilization system iron absorption for the magnet coil system may contain. The solenoid coils used for the MGCE then become qualitative by upgrading with the iron mood improved so that they are also fields of better quality which are sufficient for MR imaging are homogeneous.

At least a part of the MR-imaging coils, ie the MR-magnets, can also be HTS coils. High temperature superconductors (HTS) are available for this purpose in a known manner.

In an MR scanner with a static and non-disconnectable basic field, it is always problematic to pass through a magnetic endocapsule due to the static B ₀ field gradient because this gradient is very steep and therefore the forces on the magnetic moment in the capsule are very high.

If the capsule at the time of passing through the static field gradient in the patient, the direction of force and amplitude are practically nonexistent controllable. When the patient lies in the center of the magnet and the capsule should then be fed, the capsule must be transported through the static gradient, which is technical is expensive. In contrast, if the capsule is in the homogeneity region, d. H. Work area of the magnet lying patient introduced on the other hand, must be in the following always be sure that the body region, in which is currently the capsule, in the homogeneity area of the magnet so that it does not reach the gradient area again.

Commercial MR magnets, ie MR coil systems, have a homogeneity volume of typically 20 cm to 50 cm diameter or edge length, which is generally smaller than the gastrointestinal tract of the patient. As long as only the B ₀ basic field is active, and the navigation gradient fields are turned off, an ideal capsule magnet will experience no force but only torque, as long as its momentum is not parallel to the B ₀ magnetic field. So you can use the MR gradient coils to exert forces in any direction, but the capsule direction always remains parallel to the B ₀ field.

Therefore, the necessary for MR imaging strong B ₀ field of the coil system for the MGCE can be switched off. If only the MGCE basic field or no longer exists, the introduction of the capsule magnet into the working space is facilitated. Namely, no or only a small B0 gradient at the edge of the homogeneity range must be traversed by the magnetic moment.

The solenoid system may then include a flux pump for ramping at least a portion of the MR imaging coils. The field which is stronger in relation to the MGCE and which is necessary for MR imaging is then built up after insertion or removal of the capsule into the working space, in other words rattling, and degraded again before the capsule is removed or inserted. The flux pump can remain active during MR imaging, whereby the resonance frequency is tracked analogously.

The magnetic moment of the capsule may alternatively or additionally easily, at least during MR, be removable. The Magnetic coil system can therefore be a working capsule with a, z. B. for MR imaging, deactivatable magnetic moment included.

The magnet coil system may include an endocapsule, as described, for. B. from the DE 10 2005 032 368 A1 is known. This is also called Endoratte and is equipped with an out-patient extension or tail. The magnetic moment is then movable over the extension between working capsule located in the patient and the outside space outside the patient.

Of the Extension is z. As a hollow or non-hollow cord, the endocapsule moving behind when moving. Along or in this string The magnetic moment of the capsule can be quickly and safely between the capsule and a body opening of the patient, through which the cord protrudes are transported.

The endocapsule can this one from the DE 103 36 734 A1 have known tissue anchor. Thus, the capsule is fixable in a place in the patient and remains there, even if the magnetic moment is removed.

The Material of the magnetic moment in the endocapsule can be liquid, z. B. made of a ferrofluid, be. Such a moment can at the o. g. Endoratte over its tubular extension be filled into the capsule or aspirated.

Regarding of the method, the object of the invention is achieved by a method for magnetic capsule navigation in a patient, that with the aid of a magnetic coil system according to one of the claims 1 to 9 MR imaging based works in MR imaging and Exercising power on the working capsule in temporal change respectively.

The by means of the magnetic coil system according to the invention described, quality reduced Namely, MR imaging can not usually be done simultaneously to be used with capsule endoscopy, especially if the capsule is over has a permanent magnet, as this by the MR imaging would be changed in his position and which also interferes with MRI imaging.

It can therefore by MR imaging z. B. a review diagnostic assumptions or an examination of critical Areas or identification and marking of pathological Areas before inserting the capsule. The regions concerned You can then use the following capsule navigation be explored closer. Also, an MR based confirmation or outcome control after a successful diagnosis or therapy, So capsule navigation, take place.

By the possibility integrated into the magnetic coil system MR imaging also makes better use and thereby cost savings with respect to the solenoid system, when this, z. B. in everyday clinical practice, used alone for MR imaging as long as it is not needed for capsule navigation.

The magnetic moment of the endocapsule, as mentioned, for. B. during MR imaging, removed from the workspace become.

is the endocapsule, as described above, an endoratte, the magnetic Moment removed over the extension, so with the fields critical field strength filled working space away, become.

For the two operating modes MGCE and MR imaging of the coil system will i. d. R. uses a common coordinate system. In one 3D image data set of the MR imaging can then coordinate marker, ie bookmarks, be generated. These mark places or regions in the MR data set, a later optical viewing and / or a biopsy or therapy by endoscopy or MGCE require. These bookmarks can then be during the subsequent endoscopy or MGCE directly from the endoscope or the endocapsule are approached.

Out A 3D MR image data set can be used to generate a virtual endoscopy be, for. B. along a path covered by a working capsule has or will cover. If the o. G. Transfer bookmarks to this, can during the MGCE using a combination of virtual Be navigated endoscopy and real endoscopy.

Vice versa may target targets during endoscopy or MGCE, surfaces or volumes are defined as 3D bookmarks, the z. B. after removing the capsule or the magnetic moment from the Body of the patient or workspace then specifically by means MR imaging can be detected.

For a further description of the invention will be made to the embodiments referred to the drawing. It shows, in a schematic outline sketch:

1 a magnetic coil system for MR imaging-based magnetic capsule navigation.

1 shows a magnetic coil system 2 , which consists of two subsystems, namely a navigation system 4 and an MR system 6 for magnetic resonance imaging. The navigation system 4 corresponds essentially to that from the DE 103 40 925 B3 known magnet coil system of fourteen controllable individual coils, of which in 1 exemplarily the two coils 8a , b are shown in the form of Helmholtz coils. The navigation system 4 includes with its housing 10 a workroom 12 in which a patient 14 is introduced. In the patient 14 is one, z. B. from the DE 101 42 253 C1 known endocapsule 16 , The endocapsule 16 contains a magnet as a magnetic element or moment 18 in the form of a permanent magnet.

The navigation system 4 generated with its coils 8a , b a homogeneous basic magnetic field 20 in the workroom 12 , The basic magnetic field 20 used together with a gradient field, not shown, the targeted force or torque on the magnet 18 and with it the endocapsule 16 to this in any predetermined direction in the patient 14 to move translationally as well as rotationally.

The well-known navigation system 4 is according to the invention to the MR system 6 extended, which two HTS field coils 22a , b and two HTS screen coils 24a , b includes. The field coils 22a , b and shielding coils 24a , b are each of a thermal shielding 26 surrounded and serve to stabilize the basic magnetic field 20 to serve as a basic magnetic field for MR imaging. So together they form a stabilization system 28 for the basic magnetic field 20 ,

The MR system 6 further comprises an RF coil system 29 consisting of an excitation coil 30 to excite magnetic resonance in the patient 14 through an excitation field 33 ; and a receiver coil 32 for receiving the magnetic resonance field 35 , in the example one on the patient 14 coatable surface coil. coil system 29 , Field coils 22a , b and shielding coils 24a , b are with a plant control 34 which controls the MR imaging, as well as the signal processing, image display, etc. accomplished.

In an alternative embodiment, the navigation system 4 with respect to its coils 8a , b designed according to high quality to the basic field 20 high quality and therefore suitable for MR imaging. The MR system 6 then contains no field coils 22a , b and shielding coils 24a , b. The plant control 34 is directly with the coils 8a , b connected. The quality increase in the coils 8a , b is due to an attached to this iron mood 36 accomplished, which thus the stabilization system for homogenization of the basic magnetic field 20 represents.

In an alternative embodiment, the plant control comprises 34 a river pump 38 , This energizes the field coils 22a , b and shielding coils 24a , b such that they are rammed only for MR imaging to this purpose, the basic magnetic field 20 to stabilize. During the MGCE are the field coils 22a , b and shielding coils 24a , b then not ratted or not energized.

In an alternative embodiment, the endocapsule contains 16 an extension 40 So, is one of the DE 10 2005 032 368 A1 known Endoratte. The extension 40 then passes through a body opening 42 of the patient 14 into the outer space 43 and serves to transport the endocapsule in this embodiment 16 removable magnet 18 ,

For this purpose, the magnet 18 in a first embodiment, one with a ferrofluid 44 be fillable hollow body. The ferrofluid 44 is then over the tubular extension 40 for navigation or exercise of force or movement of the endocapsule 16 pumped into this. For magnetic resonance imaging, the ferrofluid 44 removed again.

In a second embodiment, the magnet 18 continue to be a permanent magnet, but along the extension 40 , this time in the form of a cord, is transported from the endocapsule to the outside.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 10142253 C1 [0002, 0002, 0044]
• - DE 10340925 [0011]
• DE 102005032368 A1 [0029, 0050]
• - DE 10336734 A1 [0031]
• - DE 10340925 B3 [0044]

Claims (15)

Magnetic coil system ( 2 ) with a three-dimensional work space ( 12 ) into which a patient ( 14 ) is at least partially introduced, with a plurality of individually controllable individual coils ( 8th ) for generating at least one basic magnetic field ( 20 ) for the specifiable non-contact application of force to a magnetically navigable, a magnetic moment ( 18 ) endoscopy capsule ( 16 ) in the workroom ( 12 ), characterized by - a stabilization system ( 22 . 24 . 36 ) for the stabilization and homogenization of the basic magnetic field ( 20 ) for MR imaging of the patient ( 14 ) in the workroom ( 12 ), - an RF coil system ( 29 ) for generating an excitation field ( 33 ) and for receiving a resonance field ( 35 ) for MR imaging, - a system control ( 34 ) for MR imaging. Magnetic coil system ( 2 ) according to claim 1, wherein the RF coil system ( 29 ) an excitation coil ( 30 ) for generating an MR excitation field ( 33 ) in the workroom ( 12 ) contains. Magnetic coil system ( 2 ) according to claim 2, wherein the excitation coil ( 30 ) is a whole body coil. Magnetic coil system ( 2 ) according to one of the preceding claims, in which the RF coil system ( 29 ) an MR receiver coil ( 32 ) for receiving the resonance field ( 35 ) contains. Magnetic coil system ( 2 ) according to claim 4, wherein the MR receiver coil ( 32 ) one on the patient ( 14 ) can be applied surface coil. Magnetic coil system ( 2 ) according to one of the preceding claims, in which the stabilization system ( 22 . 24 . 36 ) additional coils ( 22 . 24 ) for generating the basic magnetic field ( 20 ) contains. Magnetic coil system ( 2 ) according to one of the preceding claims, in which the stabilization system ( 22 . 24 . 36 ) an iron mood ( 36 ) for the magnet coil system ( 2 ) contains. Magnetic coil system ( 2 ) according to one of the preceding claims, in which at least a part of the MR-imaging coils ( 8th . 22 . 24 ) HTS coils are. Magnetic coil system ( 2 ) according to one of the preceding claims, with a flow pump ( 38 ) for ramping at least part of the MR imaging coils ( 8th . 22 . 24 ). Magnetic coil system ( 2 ) according to one of the preceding claims, with an endoscopy capsule ( 16 ) with a deactivatable magnetic moment ( 18 ). Magnetic coil system ( 2 ) according to claim 10, wherein the endoscopy capsule ( 16 ) an endoratte with one in the outer space ( 43 ) extending extension ( 40 ), where the magnetic moment ( 18 ) over the extension ( 40 ) between endoscopy capsule ( 16 ) and outdoor space ( 43 ) is movable. Magnetic coil system ( 2 ) according to claim 11, with an over the extension ( 40 ) transportable, the magnetic moment ( 18 ) generating ferrofluid ( 44 ). Method for magnetic capsule navigation in a patient ( 14 ) by means of a magnetic coil system ( 2 ) according to one of the claims 1 to 9, which is performed MR imaging-based, and in the MR imaging and force application to the endoscopy capsule ( 16 ) in temporal change. Method according to Claim 13, in which the magnetic moment ( 18 ) of the endoscopy capsule ( 16 ) during MR imaging from the workspace ( 12 ) Will get removed. The method of claim 14, wherein the endoscopy capsule ( 16 ) an endoratte with extension ( 40 ), where the magnetic moment ( 18 ) over the extension ( 40 ) Will get removed.