Abstract: A magnet arrangement for generating a selection magnetic field with a gradient and a field-free region in a sample volume includes: a Maxwell magnet system with two ring magnets, which are arranged in coaxial fashion and at a distance from one another on a common Z-axis extending through the sample volume, a focus field coil arrangement with at least one focus field coil pair for displacing the field-free region within the sample volume, and a drive coil for generating an MPI drive field. The magnet arrangement comprises a quadrupole magnet system with at least one quadrupole ring for generating a quadrupole magnetic field, the quadrupole magnet system being arranged coaxially with respect to the Maxwell magnet system. Using the magnet arrangement according to the invention, it is possible to switch between a selection magnet field with a field-free point and a field-free line without undesirably increasing the field gradient.

Abstract: An MPI imaging device for mapping an object to be examined in a sample volume, with a magnet arrangement which is designed to generate an MPI magnetic field with a gradient B1 and a field-free line in the sample volume, the magnet arrangement comprising a first pair of magnet rings with two magnet rings in a Halbach dipole configuration, which are arranged coaxially on a common Z axis that runs through the sample volume, wherein the magnet arrangement comprises a second pair of magnet rings with two further magnet rings in a Halbach dipole configuration, which is arranged coaxially in relation to the first pair of magnet rings, the magnet rings of both pairs being arranged rotatably with respect to one another about the Z axis. As a result, a variable MPI selection field can be generated by means of permanent magnets.

Abstract: A magnet arrangement for generating a selection magnetic field with a gradient and a field-free region in a sample volume includes: a Maxwell magnet system with two ring magnets, which are arranged in coaxial fashion and at a distance from one another on a common Z-axis extending through the sample volume, a focus field coil arrangement with at least one focus field coil pair for displacing the field-free region within the sample volume, and a drive coil for generating an MPI drive field. The magnet arrangement comprises a quadrupole magnet system with at least one quadrupole ring for generating a quadrupole magnetic field, the quadrupole magnet system being arranged coaxially with respect to the Maxwell magnet system. Using the magnet arrangement according to the invention, it is possible to switch between a selection magnet field with a field-free point and a field-free line without undesirably increasing the field gradient.

Abstract: A magnet arrangement (1) in a magnetic resonance apparatus having a permanent magnet system for generating a homogeneous magnetic field in a direction perpendicular to a z-axis in a measurement volume. The magnet system has at least two ring-shaped magnet elements (2) in a ring plane, which are arranged coaxially around the z-axis and are constructed from individual magnet segments (3) arranged next to one another in a Halbach configuration. The magnetization direction of at least two ring-shaped magnet elements deviates from the ring plane such that the component perpendicular to the ring plane varies cosinusoidally with the azimuthal angle of the respective ring-shaped magnet element. The magnetization of in each case two ring-shaped magnet elements is mirror-symmetrical with respect to one another, wherein the mirror plane is the central x-y-plane perpendicular to the z-axis. The disclosed arrangement provides a compact and lightweight permanent magnet arrangement for an MR apparatus.

Abstract: A hybrid imaging apparatus for imaging an object to be examined located in a sample volume can be operated in an MPI mode and in at least one further imaging mode and comprises a magnet arrangement embodied to generate, in the MPI mode, a magnetic field with a gradient B1 and a field-free region in the sample volume, wherein the magnet arrangement comprises a ring magnet pair with two ring magnets in a Halbach dipole configuration, which are arranged coaxially on a common Z-axis that extends through the sample volume, wherein the ring magnets are arranged so as to be twistable relative to one another about the Z-axis. Consequently, it is possible to generate magnetic fields that meet the requirements of both MRI and MPI such that the hybrid imaging apparatus can be equipped for measurements in various imaging modes, including MPI, MRI and CT.

Abstract: An MPI imaging device for mapping an object to be examined in a sample volume, with a magnet arrangement which is designed to generate an MPI magnetic field with a gradient B1 and a field-free line in the sample volume, the magnet arrangement comprising a first pair of magnet rings with two magnet rings in a Halbach dipole configuration, which are arranged coaxially on a common Z axis that runs through the sample volume, wherein the magnet arrangement comprises a second pair of magnet rings with two further magnet rings in a Halbach dipole configuration, which is arranged coaxially in relation to the first pair of magnet rings, the magnet rings of both pairs being arranged rotatably with respect to one another about the Z axis. As a result, a variable MPI selection field can be generated by means of permanent magnets.

Abstract: A hybrid imaging apparatus for imaging an object to be examined located in a sample volume can be operated in an MPI mode and in at least one further imaging mode and comprises a magnet arrangement embodied to generate, in the MPI mode, a magnetic field with a gradient B1 and a field-free region in the sample volume, wherein the magnet arrangement comprises a ring magnet pair with two ring magnets in a Halbach dipole configuration, which are arranged coaxially on a common Z-axis that extends through the sample volume, wherein the ring magnets are arranged so as to be twistable relative to one another about the Z-axis. Consequently, it is possible to generate magnetic fields that meet the requirements of both MRI and MPI such that the hybrid imaging apparatus can be equipped for measurements in various imaging modes, including MPI, MRI and CT.

Abstract: A magnet arrangement having a hollow-cylindrical magnet element that has an axial length Lz,M and an inner radius Rin, is constructed from magnet segments arranged concentrically around the z-axis, and has a Halbach magnetization. At least one ring-shaped magnet element has a notched, hollow-cylindrical cutout extending circumferentially around the z-axis symmetrically with respect to the plane z=0, the axial extent Lz,A of the cutout being less than the axial length Lz,M of the magnet element. The cutout has a radial depth TA and an axial length Lz,A<Lz,M between the z-positions z=?zA to z=+zA. The radial depth TA and the axial length Lz,A of the cutout are to ensure that the remaining inhomogeneity of the homogenous magnetic field B0 in a predefined measurement volume having an axial plateau length LP in the center of the magnet arrangement does not exceed 10 ppm.

Abstract: A magnet arrangement having a hollow-cylindrical magnet element that has an axial length Lz,M and an inner radius Rin, is constructed from magnet segments arranged concentrically around the z-axis, and has a Halbach magnetization. At least one ring-shaped magnet element has a notched, hollow-cylindrical cutout extending circumferentially around the z-axis symmetrically with respect to the plane z=0, the axial extent Lz,A of the cutout being less than the axial length Lz,M of the magnet element. The cutout has a radial depth TA and an axial length Lz,A<Lz,M between the z-positions z=?zA to z=+zA. The radial depth TA and the axial length Lz,A of the cutout are to ensure that the remaining inhomogeneity of the homogenous magnetic field B0 in a predefined measurement volume having an axial plateau length LP in the center of the magnet arrangement does not exceed 10 ppm.

Abstract: A magnet arrangement (1) having a permanent magnet system with at least two ring-shaped magnet elements (2) which are made of individual magnet segments (3), are arranged cylindrically symmetrically and stacked on one another in the z direction and/or concentrically, and arranged such that the magnetization directions of the individual segments in the rings extend parallel in an x-y plane. The magnet elements align relative to one another in the z direction and have a Halbach magnetization Before final mounting in the magnetic resonance apparatus, the magnet elements are prefabricated as solid structures and their respective magnet segments are fixed undisplaceably relative to one another. But the magnet elements are displaceable relative to one another in the x-y plane, and are mounted rotatably and/or tiltably relative to one another.

Abstract: A magnet arrangement (1) in a magnetic resonance apparatus having a permanent magnet system for generating a homogeneous magnetic field in a direction perpendicular to a z-axis in a measurement volume. The magnet system has at least two ring-shaped magnet elements (2) in a ring plane, which are arranged coaxially around the z-axis and are constructed from individual magnet segments (3) arranged next to one another in a Halbach configuration. The magnetization direction of at least two ring-shaped magnet elements deviates from the ring plane such that the component perpendicular to the ring plane varies cosinusoidally with the azimuthal angle of the respective ring-shaped magnet element. The magnetization of in each case two ring-shaped magnet elements is mirror-symmetrical with respect to one another, wherein the mirror plane is the central x-y-plane perpendicular to the z-axis. The disclosed arrangement provides a compact and lightweight permanent magnet arrangement for an MR apparatus.

Abstract: A superconducting magnet coil arrangement has a high-temperature superconductor (HTS) coil section (1a,1b,1c) in the form of a solenoid that is wound with an HTS tape conductor, and also has a field-shaping device comprising at least two field-shaping elements (2a,2b,2c). At least one respective field-shaping element is arranged adjoining each of the two axial ends of the HTS coil section, the field-shaping elements being configured in such a way that they reduce the field angle of the magnetic field generated by the magnet coil arrangement with respect to the axial direction in the region of the HTS coil section by at least 1.5°.

Abstract: A device for alternating examination of a measurement object (170) by means of MPI and MRI with two magnetic field-generating elements is presented. The device is characterized by a main magnet coil system with two coaxial partial coil systems (100a1, 100a2; 100b2, 100b1) arranged mirror-symmetrically relative to a central plane running perpendicularly to the z-axis through the first volume under investigation (162). The volumes under investigation are superimposed. A polarity reversal device (190) reverses the polarity of the current through a partial coil system and the main magnet coil system generates a homogeneous magnetic field of at least sixth order in the first volume under investigation when the partial coil systems have identical polarity, and a spatially strongly varying magnetic field profile in the second volume under investigation when the polarities are opposite. Repositioning of the measurement object is thereby simplified or can even be eliminated.

Abstract: A magnet arrangement (1) having a permanent magnet system with at least two ring-shaped magnet elements (2) which are made of individual magnet segments (3), are arranged cylindrically symmetrically and stacked on one another in the z direction and/or concentrically, and arranged such that the magnetization directions of the individual segments in the rings extend parallel in an x-y plane. The magnet elements align relative to one another in the z direction and have a Halbach magnetization Before final mounting in the magnetic resonance apparatus, the magnet elements are prefabricated as solid structures and their respective magnet segments are fixed undisplaceably relative to one another. But the magnet elements are displaceable relative to one another in the x-y plane, and are mounted rotatably and/or tiltably relative to one another.

Abstract: An arrangement for setting the spatial profile of a magnetic field in a working volume of a main field magnet (2), in particular a superconducting main field magnet, of a magnetic resonance installation. The main field magnet is arranged in a cryostat (1) and the spatial profile is set by a passive shim apparatus (3) with magnetic field forming elements which are arranged within the cryostat during operation and which have cryogenic temperatures. The magnetic resonance installation contains a room temperature tube (4), in which the sample volume is situated during operation. The passive shim apparatus is introduced into or removed from the cold region of the cryostat via a vacuum lock (5), without needing to ventilate the cold region of the cryostat. This provides a relatively simple, cost effective, and time-efficient method to carry out a stable field homogenization using a passive shim apparatus.

Abstract: Device for alternating examination of a measurement object (103) by means of MPI and MRI within a magnetic system is characterized in that the magnetic system has a specified magnetic field profile, which is not temporally variable during the alternating examination, and both magnetic field generating elements (101,102; 201,202; 801a,801b,811,812) generate a magnetic field portion, in the first examination region (104) and in the second examination region (105), which is essential for the MRI operation and for the MPI operation, and in that there is a transport apparatus (106) by means of which the measurement object can be moved out of the first examination region and into the second examination region and/or vice versa. The total space requirement for both modalities is thus reduced and the complexity of an integrally designed hybrid system is minimized.

Abstract: A superconducting magnet coil arrangement has a high-temperature superconductor (HTS) coil section (1a,1b,1c) in the form of a solenoid that is wound with an HTS tape conductor, and also has a field-shaping device comprising at least two field-shaping elements (2a,2b,2c). At least one respective field-shaping element is arranged adjoining each of the two axial ends of the HTS coil section, the field-shaping elements being configured in such a way that they reduce the field angle of the magnetic field generated by the magnet coil arrangement with respect to the axial direction in the region of the HTS coil section by at least 1.5°.

Abstract: An arrangement for setting the spatial profile of a magnetic field in a working volume of a main field magnet (2), in particular a superconducting main field magnet, of a magnetic resonance installation. The main field magnet is arranged in a cryostat (1) and the spatial profile is set by a passive shim apparatus (3) with magnetic field forming elements which are arranged within the cryostat during operation and which have cryogenic temperatures. The magnetic resonance installation contains a room temperature tube (4), in which the sample volume is situated during operation. The passive shim apparatus is introduced into or removed from the cold region of the cryostat via a vacuum lock (5), without needing to ventilate the cold region of the cryostat. This provides a relatively simple, cost effective, and time-efficient method to carry out a stable field homogenization using a passive shim apparatus.

Abstract: A device for alternating examination of a measurement object (170) by means of MPI and MRI with two magnetic field-generating elements is presented. The device is characterized by a main magnet coil system with two coaxial partial coil systems (100a1, 100a2; 100b2, 100b1) arranged mirror-symmetrically relative to a central plane running perpendicularly to the z-axis through the first volume under investigation (162). The volumes under investigation are superimposed. A polarity reversal device (190) reverses the polarity of the current through a partial coil system and the main magnet coil system generates a homogeneous magnetic field of at least sixth order in the first volume under investigation when the partial coil systems have identical polarity, and a spatially strongly varying magnetic field profile in the second volume under investigation when the polarities are opposite. Repositioning of the measurement object is thereby simplified or can even be eliminated.

Abstract: Device for alternating examination of a measurement object (103) by means of MPI and MRI within a magnetic system is characterized in that the magnetic system has a specified magnetic field profile, which is not temporally variable during the alternating examination, and both magnetic field generating elements (101,102; 201,202; 801a,801b,811,812) generate a magnetic field portion, in the first examination region (104) and in the second examination region (105), which is essential for the MRI operation and for the MPI operation, and in that there is a transport apparatus (106) by means of which the measurement object can be moved out of the first examination region and into the second examination region and/or vice versa. The total space requirement for both modalities is thus reduced and the complexity of an integrally designed hybrid system is minimized.