Abstract: The invention provides for a medical instrument (400, 500, 600, 700) comprising a magnetic resonance imaging system (404) and an external beam radiotherapy system (402) for irradiating a target zone (438) of a subject with a beam (442) of ionizing radiation within the imaging zone. The medical instrument further comprises a processor (448) for controlling the medical instrument. Execution of instructions cause the processor to: acquire (100, 200) first magnetic resonance data (458); reconstruct (102, 202) a first magnetic resonance image (460) from the first magnetic resonance data; receive (104, 204) planning data (462), wherein the planning data specifies a spatially dependent radiation dose for the target zone; register (106, 206) the planning data to the first magnetic resonance image; and calculate (108, 208) an external beam dosage plan (468) and a brachytherapy dosage plan (468) using the spatially dependent radiation dose and the first magnetic resonance image.

Abstract: The invention provides for a medical instrument (400, 500, 600, 700) comprising a magnetic resonance imaging system (404) and an external beam radiotherapy system (402) for irradiating a target zone (438) of a subject with a beam (442) of ionizing radiation within the imaging zone. The medical instrument further comprises a processor (448) for controlling the medical instrument. Execution of instructions cause the processor to: acquire (100, 200) first magnetic resonance data (458); reconstruct (102, 202) a first magnetic resonance image (460) from the first magnetic resonance data; receive (104, 204) planning data (462), wherein the planning data specifies a spatially dependent radiation dose for the target zone; register (106, 206) the planning data to the first magnetic resonance image; and calculate (108, 208) an external beam dosage plan (468) and a brachytherapy dosage plan (468) using the spatially dependent radiation dose and the first magnetic resonance image.

Abstract: In a magnetic resonance scanner, a main magnet system (10) is wound to generate a longitudinally directed main magnetic field (B0) at least in a scanning region (20). The main magnet system includes a central magnet winding region (30) wound layer-by-layer disposed between outer magnet winding regions (32, 34). A longitudinal magnetic field gradient system (12, 12?) includes a central gradient winding region (40, 40?, 42, 42?) wound to generate a main longitudinally directed magnetic field gradient disposed between outer gradient winding regions (44, 46) wound to generate a compensatory longitudinally directed magnetic field gradient having opposite polarity from the main longitudinally directed magnetic field gradient. The outer gradient winding regions are arranged to substantially null mutual inductance between the outer magnet winding regions (32, 34) and the longitudinal magnetic field gradient system (12, 12?).

Abstract: In a magnetic resonance scanner, a main magnet system (10) is wound to generate a longitudinally directed main magnetic field (B0) at least in a scanning region (20). The main magnet system includes a central magnet winding region (30) wound layer-by-layer disposed between outer magnet winding regions (32, 34). A longitudinal magnetic field gradient system (12, 12?) includes a central gradient winding region (40, 40?, 42, 42?) wound to generate a main longitudinally directed magnetic field gradient disposed between outer gradient winding regions (44, 46) wound to generate a compensatory longitudinally directed magnetic field gradient having opposite polarity from the main longitudinally directed magnetic field gradient. The outer gradient winding regions are arranged to substantially null mutual inductance between the outer magnet winding regions (32, 34) and the longitudinal magnetic field gradient system (12, 12?).

Abstract: A magnetic resonance imaging system includes main magnet (20) that produces a substantially spatially and temporally constant main magnetic field within a field of view. Magnetic field gradient coils (30) impose selected magnetic field gradients on the main magnetic field within the field of view. At least one radio frequency coil (44, 44?, 44?, 144, 154) is arranged to detect a magnetic resonance signal induced by an applied radio frequency pulse. The at least one radio frequency coil includes a radio frequency antenna (90) and electronics module (78, 78?) disposed on a substrate (72). The electronics are electrically connected with the radio frequency antenna (90). The electronics are mounted in a centered region (96) surrounded by the radio frequency antenna.

Abstract: A magnetic resonance imaging apparatus includes a main magnet (20) that surrounds an examination region (18) and generates a main magnetic field in the examination region. A magnetic field gradient system (30) is disposed outside of the main magnet. The magnetic field gradient system includes a ferromagnetic yoke (32), and a plurality of magnetic field gradient coils (34) magnetically coupled with the ferromagnetic yoke and selectively producing magnetic flux in the ferromagnetic yoke. The magnetic flux in the ferromagnetic yoke produces selected magnetic field gradients in the examination region.

Abstract: A magnetic field gradient coil includes upper and lower sections (40, 42) that define a coil bore (44) therebetween. The upper section (40) has an arcuate curvature (Cupper) transverse to a longitudinal direction and a length (Lupper) in the longitudinal direction that is smaller than a longitudinal length (Llower) of the lower section (42). Gradient coil windings (70, 72, 74, 76, 102, 104, 112, 114) impose one or more transverse magnetic field gradients on a static magnetic field generally oriented in the longitudinal direction. The windings are supported by the upper and lower sections (40, 42) of the coils support. The windings supported by the upper section (40) are longitudinally limited in distribution to the longitudinal length (Lupper) of the upper section (40), which is shorter than its diameter. The windings supported by the lower section (42) are longitudinally distributed across substantially the length (Llower) of the lower section (42).

Abstract: A magnetic resonance imaging apparatus includes a main magnet (20) that surrounds an examination region (18) and generates a main magnetic field in the examination region. A magnetic field gradient system (30) is disposed outside of the main magnet. The magnetic field gradient system includes a ferromagnetic yoke (32), and a plurality of magnetic field gradient coils (34) magnetically coupled with the ferromagnetic yoke and selectively producing magnetic flux in the ferromagnetic yoke. The magnetic flux in the ferromagnetic yoke produces selected magnetic field gradients in the examination region.

Abstract: A magnetic field gradient coil includes upper and lower sections (40, 42) that define a coil bore (44) therebetween. The upper section (40) has an arcuate curvature (Cupper)transverse to a longitudinal direction and a length (Lupper)in the longitudinal direction that is smaller than a longitudinal length (Llower) of the lower section (42). Gradient coil windings (70, 72, 74, 76, 102, 104, 112, 114) impose one or more transverse magnetic field gradients on a static magnetic field generally oriented in the longitudinal direction. The coil windings are supported by both the upper and lower sections (40, 42) of the coils support. The coil windings supported by the upper section (40) are longitudinally limited in distribution to the longitudinal length (Lupper) of the upper section (40), which is shorter than its diameter. The coil windings supported by the lower section (42) are longitudinally distributed across substantially the longitudinal length. (LioWer) of the lower section (42).

Abstract: A magnetic resonance imaging apparatus includes a first magnetic field coil (30) and a second magnetic field coil (32). A power supply (40, 42) energizes the first magnetic field coil (30) and selectively energizes the second magnetic field coil (32) to selectively generate a first magnetic field defining a first selectable field of view (FOV1) that is elongated in a first direction and a second magnetic field defining a second selectable field of view (FOV2) that is elongated in a second direction different from the first direction.

Abstract: The invention relates to a cooling method for cooling a superconducting coil assembly in a MR apparatus, wherein the superconducting coil assembly 10 is cooled using a cooling agent 41, 42 which is in thermal contact with the superconducting coil assembly in a cooling chamber 20, the cooling agent being cooled by a refrigerator 50. The method comprises the steps of transferring (S2) cooling agent from the cooling chamber to a cooling agent storage when a predetermined temperature is exceeded in at least a part of the cooling agent in the cooling chamber, and returning (S4) cooling agent from the cooling agent storage to the cooling chamber when the temperature of at least a part of the cooling agent in the cooling chamber is equal to or less than the predetermined temperature. The invention also relates to a cooling device for performing the cooling method and to an MR apparatus with such a cooling device.

Abstract: The invention relates to a magnetic resonance imaging (MRI) system (1) comprising an examination volume (11) in which a patient to be examined can be accommodated, a main magnet system (3) for generating a magnetic field having a main field portion (17) in the examination volume with a substantially constant magnetic field strength (B0), and a gradient magnet system (13) for generating gradients of the main field portion. The MRI system further comprises a damping member (25, 27) which is mounted to a part (5) of the MRI system susceptible to vibrations relative to the magnetic field during operation. Said damping member comprises an electrically conductive member (29, 35, 37) which is present in the magnetic field and in which eddy currents are generated as a result of said vibrations.

Abstract: The invention relates to a gradient coil arrangement for the generation of a gradient magnetic field for an MR arrangement with at least two gradient coils arranged on a cylinder surface with a substantially circular cross section. In order to enable adjustment of gradient fields extending as linearly as possible in the area of an object to be examined without having to modify the entire mechanical structure of the MR arrangement and without having to increase the power required to feed the gradient coil arrangement, it is proposed according to the invention to configure the gradient coils so as to be asymmetrical in relation to a central plane lying horizontally through the longitudinal axis of the cylinder.

Abstract: The invention relates to an MR apparatus (1) having an examination volume (6) of the open type such that the examination volume (6) is also accessible laterally, having main coil devices (2) for producing a main magnetic field that are disposed on two opposite sides of the examination volume (6), having at least one high-frequency coil device (5) for exciting the proton precession and having at least one two-part gradient coil device (4), disposed on opposite sides of the examination volume (6), for the positional coding of the excitation of the proton precession. The dynamic Lorentz forces have hitherto resulted in a high oscillation level. It is an object of the invention to provide an MR apparatus (1) that has only a low oscillation level.

Abstract: The invention relates to an open magnetic resonance imaging (MRI) magnet system (1) for use in a medical imaging system. The open MRI magnet system has two main coil units which are accomodated, at some distance from each other, in a first housing (2) and in a second housing (3), respectively. Between the two housings, an imaging volume (6) is present wherein a patient to be examined is placed. A gradient coil unit (9, 10) facing the imaging volume is present near a side of each of the two housings. Functional connections of the gradient coil units (9, 10), such as electrical power supply lines (13, 14) and cooling channels (15, 16) are provided in a central passage (4, 5) which is present in each of the two housings. As a result, these functional connections do not reduce the space in the imaging volume available for the patient.

Abstract: The invention relates to an MR method in which the nuclear magnetization is enhanced under the influence of a first steady magnetic field and a second steady magnetic field acts on the nuclei previously influenced by the first magnetic field. According to the invention, the two magnetic fields overlap in time and enclose an angle other than 0° relative to one another, the angle preferably amounting to 90°. The enhanced nuclear magnetization is then sustained after the activation of the first steady magnetic field while the direction of the nuclear magnetization is determined by the second steady magnetic field. The use of two mutually perpendicular magnetic fields is advantageous notably for Overhauser imaging methods, because it enables the use of mutually perpendicular RF fields for the ESR saturation and the MR excitation, thus uncoupling the coils generating such RF fields from one another.

Abstract: A magnetic resonance device has a main field magnet system which generates a steady magnetic field in an examination zone. The main field magnet system includes a yoke structure which consists of two yoke plates and a yoke wall interconnecting the two yoke plates, a pole block which is arranged inside the yoke device, and below an examination zone, and a coil which is arranged within the yoke system and above the examination zone. In order to ensure that a patient present in the examination zone can also undergo further treatments and is freely accessible during an MR examination, the inner space of the coil as well as the space between the coil and the examination zone remains free from components of the magnet system, the coil being constructed so as to be ring-shaped and encloses the examination zone essentially in such a manner that the patient is freely accessible from above and from the sides.

Abstract: The apparatus comprises a magnet system which is rotationally symmetrically arranged about a central axis (9) and which comprises a superconducting inner coil system (1) for generating a steady magnetic field in a measurement space (5) within the magnet system, and also comprises an outer coil system (7) which is arranged so as to be coaxial with the inner coil system and which is electrically connected in series therewith in order to shield the environment from the magnetic field generated by the inner coil system. The magnet system can be bridged by of a superconducting persistent current switch (33) and comprises a superconducting shunt (37) which bridges a pan of the magnet system which is situated between first and second connection points (39, 41).

Abstract: An extremely efficient magnet system having a comparatively large angle of aperture can be obtained for magnetic resonance imaging by a reduction of fields of all orders in a common approach affecting active and passive as well as positive and negative oriented coil elements. Passive soft-magnetic ring segments are arranged in two pairs and located within a plurality of larger diameter active magnetic coils. The active coils include a central coil and outer coils wherein the outer coils are smaller than the central coil. The coils are in a helium Dewar vessel and arranged such that the system has an aperture of about 90.degree.. The central active coil may have a larger radius than the smaller outer coils.

Abstract: A magnet system for generating a uniform magnetic field in an examination zone (5) in an accommodation space of magnetic resonance apparatus is formed by a first, approximately cylindrical electromagnetic coil system (1) which encloses the examination zone and which is symmetrically arranged relative to a symmetry axis (9) and relative to a asymmetry plane (11) extending perpendicularly to the symmetry axis, and a second, approximately cylindrical electromagnetic coil system (7) which is arranged so as to be symmetrical relative to the symmetry axis and relative to the symmetry plane and which is arranged so as to be concentric with the first coil system, the magnetic dipole moments of the first and the second coil system being oppositely directed and substantially equal.