Abstract
A device for moving a magnetic object in a container has two pairs of dipoles grouped around the container. Between the pairs of dipoles a pair of mutually concentrically surrounding quadrupoles is arranged. The dipoles and the quadrupoles are in the form of a Halbach cylinder. In this way, the magnetic object can be moved through the container particularly efficiently.
Claims
1: A device for moving a magnetic object (8) in a container (7), having dipoles (1-4) grouped around the container (7) and a quadrupole (5, 6), wherein the magnetic fields of the dipoles (1-4) and of the quadrupole (5, 6) can be moved relative to one another, wherein two pairs of dipoles (1-4) are arranged in different planes, at a distance from one another, and wherein two quadrupoles (5, 6) are arranged in a plane between the planes of the two dipoles (1-4).
2: The device according to claim 1, wherein magnets are arranged in Halbach cylinders in order to generate the dipoles (1-4) and the quadrupoles (5, 6), and enclose a space (18) intended for the container (7).
3: The device according to claim 1, wherein two Halbach cylinders, each having magnets for generating the dipoles (1-4) and/or the quadrupoles (5, 6), are arranged concentric to one another.
4: The device according to claim 2, wherein the Halbach cylinders, which enclose one another concentrically, can be moved relative to one another.
5: The device according to claim 2, wherein the dipoles (1-4) and quadrupoles (5, 6), which are configured as Halbach cylinders, have a drive apparatus (10), in each instance, and are mounted so as to rotate relative to one another.
6: The device according to claim 4, wherein a carriage (13) for holding the container (7) that contains the object (8) can be moved relative to the dipoles (1-4) and the quadrupoles (5, 6), and that wherein a relative movement direction of the carriage (13), relative to the dipoles (1-4) and the quadrupoles (5, 6), is arranged parallel to the axis of rotation of the Halbach cylinders.
7: The device according to claim 6, wherein the carriage (13) can be displaced parallel to the axis of rotation of the Halbach cylinders.
8: The device according to claim 1, wherein the magnetic object (8) is arranged in a probe (14) that is configured to be introduced into a human body or an animal body.
9: The device according to claim 8, wherein the probe (14) has at least one sensor (15) for capturing data.
10: The device according to claim 8, wherein an induction coil (16) is arranged in the probe (14).
11: The device according to claim 1, wherein the magnetic object (8) is configured as a permanent magnet.
Description
[0018] The invention permits numerous forms of embodiments. For further clarification of its basic principle, one of them is shown in the drawing and will be described hereinafter. The drawing shows, in
[0019] FIG. 1 a device for moving a magnetic object in a container,
[0020] FIG. 2 a sectional representation through the device, with the container in the region of the object, along the line II-II from FIG. 1,
[0021] FIG. 3 in magnification, the object from FIG. 1 in a probe,
[0022] FIG. 4 schematically, a longitudinal section through an arrangement of dipoles and quadrupoles of the device from FIG. 1, in a first orientation,
[0023] FIG. 5 the arrangement of dipoles and quadrupoles from FIG. 4 in a different orientation,
[0024] FIG. 6 a schematic representation of the geometry of Halbach cylinders.
[0025] FIG. 1 shows a device having two pairs of diploes 1-4 that enclose one another concentrically, and a pair of quadrupoles 5, 6 that enclose one another concentrically, arranged between the pairs of dipoles 1-4. The dipoles 1-4 and the quadrupoles 5, 6 enclose a space 18, in which a container 7, shown as an example as a human patient, is situated. A magnetic object 8 is situated in the plane of the quadrupoles 5, 6, within the container 7. The dipoles 1-4 and the quadrupoles 5, 6 are each configured as Halbach cylinders, having a length provided for generating magnetic fields in the container 7 to be examined, and each have gear teeth 9 for a drive apparatus 10, in each instance, of which one is shown as an example. By means of the drive apparatuses, the dipoles 1-4 and the quadrupoles can be rotated around the container. The drive apparatus 10 that is shown has an electric motor 11 having a worm-gear drive 12. In alternative embodiments, not shown, the electric motor 11 can stand in engagement with the gear teeth 9 by way of a toothed belt or a gear-wheel transmission. The container 7 lies on a carriage 13. The carriage 13 can be moved by a drive, not shown, parallel to the axis of the Halbach cylinders of the dipoles 1-4 and of the quadrupoles 5, 6, so that the object 8 always lies essentially in the center of the Halbach cylinders of the quadrupoles 5, 6. In the center, the greatest force can be transferred to the object 8 by the dipoles 1-4 and the quadrupoles 5, 6.
[0026] FIG. 2 shows a sectional representation through the device having the container 7 from FIG. 1, along the line II-II. The movements of the carriage 13 and of the dipoles 1-4 and of the quadrupoles 5, 6 are indicated with arrows in FIGS. 1 and 2. For example, the magnetic object 8 is arranged in an endoscopic probe 14 and is moved through the container 7 using the magnetic fields of the dipoles 1-4 and of the quadrupoles 5, 6, as well as the movement of the carriage 13.
[0027] FIG. 3 shows, on a larger scale, the object 8 from FIGS. 1 and 2 arranged in the probe 14. The object 8 is a preferably spherical permanent magnet or magnetizable material. The probe 14 furthermore contains a sensor 15 and an induction coil 16. In an embodiment that is not shown, the probe 14 can furthermore contain a medical tool, for example for a biopsy, for thermal treatment, or the like.
[0028] FIG. 4 schematically shows a longitudinal section through the arrangement of the dipoles 1-4 and of the quadrupoles 5, 6 shown in FIG. 1. Arrows shown in the dipoles 1-4 and the quadrupoles 5, 6 represent the magnetic orientation there. The arrows shown in the center and marked with F represent the resulting magnetic force vectors in the planes x, y, and z. The arrows marked with B represent the magnetic flux density. In the orientation shown, the magnetic object 8 is oriented in the x direction, and moved and accelerated in the central xy plane by means of rotation of the two quadrupoles 5, 6.
[0029] FIG. 5 schematically shows a different orientation, as compared to FIG. 4, of the dipoles 1-4 and the quadrupoles 5, 6 shown in FIG. 1. By means of a corresponding rotation, the two quadrupoles 5, 6 have been brought into a compensation position relative to one another, so that no movement of the object 8 in the xy plane takes place. The dipoles 1-4 have been rotated into an opposite orientation. In this way, a magnetic field gradient is generated along the z direction, and thereby the object 8 is moved in this direction.
[0030] FIG. 6 shows, for clarification, a schematic representation of the geometry of Halbach cylinders: a) shows the dipoles 1-4 described in FIGS. 1 to 5: The homogeneous magnetic field is generated by means of a ring-shaped cylinder composed of permanent magnet material. In this regard, the arrows 17 shown in the cylinder 1 indicate the magnetization of this material, which changes continuously over the entire circumference. However, the arrows 17 can also be formed by individual magnets. The amount (intensity) of the magnetic field is represented by means of shading of a space 18 that surrounds the cylinder. The container 7 with the object 8, shown in FIGS. 1 to 5, is arranged in the space 18. Here, the field is homogeneous. The direction of the magnetic field is additionally represented by flow lines 19 marked with arrows. b) shows the quadrupoles 5, 6 shown in FIGS. 1 to 5 in the same representation as a). c) and d) now show the B.sub.x and B.sub.y component of the magnetic field in b). The black and white arrows now show the intensity and direction of the magnetic field, however (no flow lines). The different intensity of the magnetic field is shown with the shading in a/b and c/d.
[0031] The further technological background of the dipoles 1-4 and of the quadrupoles 5, 6 as well as the field gradients produced with them is described in detail in DE 10 2016 014 192 A1, so that reference is made to this document with regard to the disclosure.
