CN117980765A - Local coil and magnetic resonance device with safety mechanism for preventing collision with patient - Google Patents

Abstract

The invention relates to a local coil (26) comprising at least one antenna (32), a base element (30), a holding element, a first guide means (33), a second guide means (33) and a safety means (50), wherein the at least one antenna (32) is configured for receiving radio frequency signals in the frequency range and in the power range of magnetic resonance measurements, and wherein the at least one antenna (32) is mechanically connected to the holding element (31), wherein the base element (30) is configured for holding the holding element (31) with the at least one antenna (32) in a position according to the application at a diagnostically relevant body area of a patient (15), wherein the first guide means (33) is mechanically connected to the base element (30) and the holding element (31), and wherein the second guide means (33) is configured for variably positioning the holding element (31) relative to the base element (30), and wherein the safety means (50) is configured for variably positioning the at least one antenna (32) relative to the holding element (31), wherein the safety means (33) is configured for preventing a transition from the first guide means (31) from the open position to the closed position (15) when the first guide means (33) is used for the at least one antenna (31) is closed to the closed position (15) In particular, a collision of a diagnostically relevant body region of the patient (15). The invention also relates to a magnetic resonance apparatus (10) having a local coil (26) according to the invention.

Description

Local coil and magnetic resonance device with safety mechanism for preventing collision with patient

Technical Field

The invention relates to a local coil comprising at least one antenna, a base element, a holding element, a first guiding means and a second guiding means, wherein the at least one antenna is configured for receiving radio frequency signals in the frequency range and in the power range of a magnetic resonance measurement, and wherein the at least one antenna is mechanically connected to the holding element, wherein the base element is configured for holding the holding element together with the at least one antenna in a position according to the application at a diagnostically relevant body area of a patient, wherein the first guiding means is mechanically connected to the base element and the holding element, and is configured for variably positioning the holding element relative to the base element, and wherein the second guiding means is mechanically connected to the holding element and the at least one antenna, and is configured for variably positioning the at least one antenna relative to the holding element. The invention also relates to a magnetic resonance apparatus having a local coil according to the invention.

Background

Lesions of teeth and periodontal tissue, such as caries or periodontitis, are nowadays often diagnosed by means of X-ray based imaging methods. Conventional or digital X-ray projection methods and more recently also three-dimensional X-ray methods are mainly used here. One example of a three-dimensional X-ray method is digital volume tomography, which can be used to image teeth and the face.

A major disadvantage of the X-ray method is that ionizing radiation must be used for imaging. The imaging method avoiding ionizing radiation is magnetic resonance tomography. The magnetic resonance tomography can typically achieve better soft tissue contrast than the X-ray method and support three-dimensional imaging of the examination object in accordance with the standard. Furthermore, magnetic resonance tomography can enable imaging of cysts and identification of dentin degeneration before cysts and dentin degeneration can be identified by X-ray methods. Magnetic resonance tomography is thus a potential alternative to the X-ray methods known in imaging the entire set of dental and/or jaw regions of an examination subject and in diagnosing dental lesions.

Magnetic resonance tomography is a known imaging method by means of which magnetic resonance images of the interior of an examination subject can be produced. In performing magnetic resonance imaging, the examination subject is usually positioned in a strong, static and homogeneous basic magnetic field (B0 magnetic field) of the magnetic resonance apparatus. The basic magnetic field may have a magnetic field strength of from 0.2 tesla to 7 tesla, so that the nuclear spins of the examination subject are oriented along the basic magnetic field. In order to trigger the so-called nuclear spin resonance, a radio frequency signal, a so-called excitation pulse (B1 magnetic field), is introduced into the examination subject. Each excitation pulse causes the magnetization of a particular nuclear spin of the examination object to deviate from the basic magnetic field by an amount which is also known as the flip angle. The excitation pulse may have an alternating magnetic field with the following frequency: the frequency corresponds to a larmor frequency (Larmorfrequenz) at a corresponding static magnetic field strength. The excited nuclear spins can have a rotating and decaying magnetization (nuclear spin resonance), which can be detected as magnetic resonance signals by means of a specific antenna. For spatial encoding of the nuclear spin resonances of the examination object, gradient magnetic fields can be superimposed on the basic magnetic field.

The received magnetic resonance signals are typically digitized and stored as complex values in a k-space matrix. The k-space matrix may be used as a basis for reconstructing magnetic resonance images and determining spectroscopic data. Reconstruction of magnetic resonance images is typically achieved by means of a multidimensional fourier transformation of the k-space matrix.

Since ionizing radiation is avoided, magnetic resonance tomography is particularly suitable for continuous diagnostic monitoring of dental lesions and/or dental development in the scope of longitudinal imaging studies. In longitudinal imaging studies, a plurality of imaging examinations are typically performed in order to determine the progress of a lesion or the success of a therapeutic treatment over a predetermined period of time. However, diagnostically relevant regions of the jaw region of the patient, such as the mouth, the full set of teeth, the dental arch or one tooth, provide a small volume available for generating magnetic resonance signals. Furthermore, conventional volume coils and surface coils, such as head coils and laying coils, are spaced relatively far from the jaw region of the patient. However, a large spacing increases the signal-to-noise ratio of the detected magnetic resonance signals, thereby reducing the quality of the magnetic resonance image of the patient's full set of teeth reconstructed therefrom. Furthermore, for clinical applications, it is advantageous if the coil can be positioned reproducibly and time-efficiently in close proximity to the jaw region of the patient. Safety aspects should be considered in particular due to the varying anatomy of the patient and also due to the close proximity to the patient.

Disclosure of Invention

It is therefore an object of the present invention to provide a local coil which allows recording magnetic resonance images with high quality without compromising the safety of the patient.

According to the invention, the object is achieved by the subject matter of the embodiments. Advantageous embodiments and expedient developments are the subject matter of the examples described later.

The local coil according to the invention comprises at least one antenna, a base element, a holding element, a first guiding mechanism, a second guiding mechanism and a safety mechanism.

At least one antenna is configured to receive radio frequency signals in a frequency range and a power range of the magnetic resonance measurement. The antenna may be a coupling element between electromagnetic waves guided and unguided, i.e. in free space, in the signal conductor. The at least one antenna is in particular configured for receiving electromagnetic waves in the region of the magnetic resonance frequency of the magnetic resonance active nuclei. The electromagnetic waves relevant for magnetic resonance measurement may be radio frequency signals (magnetic resonance signals) comprising frequencies between 1MHz and 500MHz, preferably between 10MHz and 300 MHz. Common magnetic resonance signals of the nuclei to be examined can have a small power of a few microwatts to a few milliwatts.

The signal conductors are preferably conductive metal wires. The wires of the signal conductors may have an oval or polygonal cross-section and are adapted to continuously transmit the above-mentioned power. It is also conceivable for the signal conductors to be embodied as conductor tracks on a circuit board and to have an approximately rectangular cross section. The signal conductors may be comprised of copper. Other conductive metals, such as gold, aluminum, etc. are also contemplated.

The local coil according to the invention may of course comprise a plurality of antennas. The antennas may be arranged spaced apart from one another, adjacent to one another or partially overlapping. The antennas may also be arranged in a grid or matrix.

In a preferred embodiment, the local coil has a plurality of antennas which are designed to receive magnetic resonance signals from a diagnostically relevant body region, in particular a head region or a jaw region of a patient. At least one antenna may be mechanically connected to and carried or held by the carrying structure. It is also conceivable that at least one antenna is integrated or embedded in the carrier structure. The load bearing structure may have the following materials: the material forms a contour for providing contact protection to the patient and/or profiling a diagnostically relevant body region of the patient.

It is conceivable that the local coil according to the invention has at least one antenna which is designed to emit radio frequency signals towards the jaw region of an examination object, such as a patient. Depending on the basic magnetic field of the magnetic resonance apparatus, the radio frequency signal emitted by the at least one antenna may for example lie in the power range of a few watts to a few kw. The radio frequency signal emitted by the at least one antenna may in particular be a B1 magnetic field. The part of the local coil with the at least one antenna may be, for example, a transmitting unit of the local coil.

At least one antenna is mechanically coupled to the retaining element. The holding element may be any carrier element which is configured for holding the at least one antenna in a predetermined position relative to a diagnostically relevant body region of the patient. Preferably, the holding element is configured for positioning and/or orienting the at least one antenna in a rough manner with respect to the patient. The exact positioning and/or orientation of the at least one antenna with respect to the diagnostically relevant body region of the patient is preferably achieved by means of the second guiding mechanism.

The base element is designed to hold the holding element together with the at least one antenna in a position according to the application at a diagnostically relevant body region of the patient. The basic element is for this purpose preferably mechanically connected to a component of the magnetic resonance apparatus, such as an examination couch and/or a patient support apparatus. The base element may, for example, have a positioning unit, which is designed to position the base element and/or the holding element together with the at least one antenna relative to the magnetic resonance device and/or the patient. The basic elements may be located on opposite sides of the patient on opposite sides of or at least partially surrounding a diagnostically relevant body region of the patient in a position according to the application. Preferably, the base element is configured for reducing or minimizing a motion of a diagnostically relevant body region of the patient during the imaging examination.

The first guide mechanism is mechanically coupled to the base element and the retaining element and is configured to variably position the retaining element relative to the base element. The first guiding mechanism may comprise any mechanical principle that enables a relative movement of the holding element with respect to the basic element. Preferably, the first guiding means comprises an articulated joint, in particular a pivoting or tilting mechanism, a rail system, a linear guiding device or the like. The first guide means is preferably designed to enable a particularly simple and/or time-efficient transfer of the holding element from the open position into the closed position.

The second guide mechanism is mechanically coupled to the holding element and the at least one antenna and is configured to variably position the at least one antenna relative to the holding element. Preferably, the second guiding means is configured for enabling an accurate positioning and/or orientation of the at least one antenna with respect to the diagnostically relevant body area. The second guide means may comprise, for example, screw means, clamping means, screen means, telescopic systems, rail systems for this purpose, but may also comprise joints, hinges and/or similar mechanical principles.

In particular, the first guide mechanism and/or the second guide mechanism provide a guide for the holding element and/or the at least one antenna. This may mean that the movement of the holding element is limited to a predetermined number of spatial and/or rotational directions by means of the first guide means and/or the movement of the at least one antenna is limited by means of the second guide means. For example, by means of the first guiding mechanism, the positioning of the holding element relative to the base element may be limited to a movement of the holding element in two opposite rotational directions. Conversely, the positioning of the at least one antenna with respect to the holding element may be limited to movements along a straight line, a plane, a straight line and a plane, but may also be limited to movements along two planes, in particular two orthogonal planes.

The safety mechanism is designed to prevent collision of the at least one antenna with the patient, in particular a diagnostic-relevant body region of the patient, when the holding element is moved from the open position into the closed position by means of the first guide mechanism. Preferably, the safety mechanism is configured for limiting a relative movement of the holding element with respect to the base element and/or for performing or initiating an adjustment of the relative position of the at least one antenna with respect to the holding element. It is conceivable that the safety mechanism is designed to automatically, in particular also in the event of incorrect actuation by the user, prevent a collision of the at least one antenna with a diagnostic-relevant body region of the patient. The safety mechanism may also be designed to protect or prevent a number of scenarios in which a potential misuse of the local coil may cause a collision of at least one antenna with a diagnostically relevant body area.

Collisions may be characterized by at least one antenna coming together or being directed together with undesired contact of a body area associated with diagnosis of the patient. The collision may be premised on movement of at least one antenna toward a diagnostically relevant body region of the patient. It is particularly conceivable that the collision comprises contact, force action and/or force transmission between one of the antennas and a diagnostically relevant body region of the patient. However, the movement, contact and/or force action caused by the movement of the holding element only by means of the first guide means is to be regarded as a collision. Thus, the contact between the at least one antenna and the diagnostically relevant body region, which is established solely by the movement of the at least one antenna by means of the second guiding mechanism, is regarded as desirable and does not belong to the above definition of collision.

The open position of the holding element can be characterized by a maximum or predetermined deflection of the holding element relative to the base element by means of the first guide means. The open position may in particular be a "loading position" which enables a diagnostically relevant body region of the patient to be positioned in a relative position with respect to the base element, depending on the application. Conversely, the closed position of the holding element can be characterized by a minimum deflection of the holding element relative to the base element by means of the first guide mechanism. The closed position may in particular be an "examination position", which may be characterized by a relative position of the holding element relative to a diagnostically relevant body region of the patient during the magnetic resonance measurement, depending on the application. Transferring the holding element from the open position into the closed position may comprise, in particular, guiding the holding element and the base element together. It is conceivable to move or deflect the holding element in the direction towards the base element by means of the first guiding means when guiding together.

By providing a local coil according to the invention, the risk of collision of the at least one antenna with a diagnostic-related body region of the patient can be avoided when positioning the holding element and/or the at least one antenna in a position at the patient according to the application. Furthermore, the safety of operating the partial coil according to the invention can be increased by means of the safety mechanism according to the invention. In this way, the localization of the local coil at the diagnostically relevant body region can also be carried out in an advantageous manner by means of an inadequately qualified person.

In one embodiment of the partial coil according to the invention, the safety mechanism is designed to delimit the movement of the holding element by means of the first guide mechanism as a function of the safety position of the at least one antenna relative to the holding element when the holding element is moved from the open position into the closed position.

Preferably, the safety mechanism is configured to prevent or impede a relative movement of the holding element relative to the base element towards the base element when the relative position of the at least one antenna relative to the holding element exceeds a predetermined limit value. The movement of the limit holding element by means of the first guide means may mean: weakening, but in particular blocking or preventing, the relative movement of the holding element with respect to the base element. The predetermined limit value may be characterized, for example, by a safe position of the at least one antenna relative to the holding element. The safety position is preferably defined by a predetermined distance of a first reference point of the at least one antenna relative to a second reference point of the holding element. For example, the predetermined distance of the first reference point of the at least one antenna relative to the second reference point of the holding element may be selected such that a collision of the at least one antenna with the patient is statistically impossible or may be excluded when the holding element is transferred from the open position into the closed position.

In a preferred embodiment, the first guide means is mechanically coupled to the second guide means such that the holding element is prevented from moving towards the base element when a predetermined limit value is exceeded.

When the current relative position of the at least one antenna with respect to the holding element deviates from the safety position of the at least one antenna with respect to the holding element, guiding together of the holding element and the base element can be avoided in an advantageous manner by the safety mechanism according to the invention. In this way, the risk of injury to the patient when the holding element and the base element are guided together can be prevented in an advantageous manner.

In a preferred embodiment of the partial coil according to the invention, the safety mechanism has a first locking part which is designed to engage in a second locking part of the first guide mechanism and to prevent the holding element from being transferred from the open position into the closed position.

In the scope of the following description, it is assumed in a simplified manner that the second locking part is designed as a locking profile. The first locking part can thus be designed as any locking element which is designed for mechanical engagement into the locking profile in order to prevent or block a relative movement of the locking element with respect to the locking profile in at least one spatial direction. However, it is also conceivable for the first locking part to be designed as a locking profile. In this case, the second locking part may be any locking element which is configured for mechanical engagement into the locking profile in order to prevent or block a relative movement of the locking element with respect to the locking profile in at least one spatial direction.

Preferably, the locking element is designed for positive and/or force-fitting engagement into a locking profile of the first guide element in order to delimit or prevent a relative movement of the holding element with respect to the base element in at least one spatial direction. The locking element and the locking profile can be designed such that the locking element can pass through the locking profile in a first movement direction, for example in an opening movement of the holding element (i.e. a movement of the holding element in a direction opposite to the base element), whereas the locking element engages in the locking profile and prevents further movement in a second movement direction, for example in a closing movement of the holding element (i.e. a movement of the holding element towards the base element). The locking element may be supported at an elastic element, such as a mechanical spring or an elastomer. It is also conceivable that the locking element itself has an elastic material and/or can be (elastically) deformed.

The first locking part is mechanically connected to the stop element, wherein the first locking part can be mechanically separated from the second locking part of the first guide mechanism by means of the stop element in order to release the transfer of the holding element from the open position into the closed position.

The stop element may comprise means configured for changing the position, shape and/or orientation of the locking element and/or the elastic element in order to manually or automatically disengage the locking element from the locking profile of the first guiding means. The mechanism may have, in particular, a clamping mechanism, a traction mechanism, a spring mechanism, a bending mechanism and/or an adjusting mechanism, which are formed as part of the locking element and/or are mechanically coupled to the locking element. For example, the locking element can be supported on the stop element such that the locking element can be separated from the locking profile as a function of a predetermined movement and/or a predetermined force action of the stop element on the locking element. The stop element can likewise have an elastic element according to the above-described embodiment or be designed as such.

Preferably, the stop element is mechanically coupled to the second guide mechanism such that a predetermined force action and/or a predetermined movement of the stop element is caused or triggered by a relative movement of the at least one antenna with respect to the holding element.

In a further embodiment, the stop element can be actuated manually by a user and/or automatically by means of an electrical circuit. By means of the possibility of manually actuating the stop element, the blocking of the movement of the holding element towards the base element can be deliberately eliminated by the user in an advantageous manner. By actuating the stop element by means of an electrical circuit, the elimination of blocking can be automated in an advantageous manner. For example, the relative position of the at least one antenna with respect to the holding element can be monitored by means of one or more suitable sensors.

In one embodiment of the partial coil according to the invention, the first locking part is mechanically coupled to the second guide means by means of a stop element. The first locking part can be mechanically decoupled from the second locking part of the first guiding means by means of the at least one antenna being moved by means of the second guiding means into a predetermined relative position with respect to the holding element in order to release the transfer of the holding element from the open position into the closed position.

The stop element may be configured to change the position, shape and/or orientation of the locking element in order to mechanically disengage the locking element from the locking profile of the first guide mechanism. The stop element can be designed for this purpose in particular as an elastic element according to the above-described embodiment. Preferably, the stop element is mechanically coupled to the second guide mechanism such that the locking element automatically disengages the locking profile of the first guide mechanism when there is a predetermined relative position of the at least one antenna with respect to the holding element.

The locking element may be a particularly easy-to-implement and/or cost-effective solution of the safety mechanism according to the invention. Furthermore, a fail-safe and/or robust solution for preventing collision of at least one antenna with a diagnostic related body area of a patient may be provided by the locking element.

In one embodiment of the partial coil according to the invention, the safety mechanism is mechanically coupled to the first and second guide mechanism and is configured for transferring the at least one antenna into a safety position relative to the holding element using the kinetic energy (KINEMATIK) of the relative movement of the holding element relative to the base element.

The safety mechanism is preferably designed as a mechanical coupling between the first guide mechanism and the second guide mechanism. Such a mechanical coupling device may in particular comprise a transmission device with one or more transmission bodies and/or shafts. Preferably, the mechanical coupling device has a freewheel or decoupling mechanism, which is designed to limit the transfer of the at least one antenna into the safety position relative to the holding element to a closing or opening movement of the holding element. The decoupling mechanism can also be designed to displace the at least one antenna into a predetermined relative position with respect to the holding element by means of the safety mechanism during the opening movement or the closing movement.

The predetermined relative position of the at least one antenna may be characterized, for example, by a maximum deflection or a maximum spacing of the at least one antenna relative to the base element. The at least one antenna may be located in a stop or final position relative to the holding element in a direction away from the base element. However, it is also conceivable that the predetermined relative position is characterized by an allowable deflection of the at least one antenna relative to the holding element towards the base element. The permissible deflection is preferably selected such that, during the closing movement of the holding element, a collision of the at least one antenna with the diagnostically relevant body region is statistically impossible or can be ruled out. The predetermined relative position of the at least one antenna with respect to the holding element may in particular correspond to a safe position of the at least one antenna.

By providing mechanical coupling means for transferring the at least one antenna into a predetermined relative position with respect to the holding element by means of the kinetic energy of the relative movement of the holding element and the basic element, additional driving means and/or additional working steps for positioning the at least one antenna in a predetermined relative position with respect to the holding element can advantageously be saved.

In a further embodiment of the partial coil according to the invention, the second guide means has a tensioning element which is designed to be elastically deformed as a result of a relative movement of the at least one antenna with respect to the holding element toward the base element and to transmit a force to the at least one antenna which is opposite to the movement. The tensioning element may be any elastic element, such as a mechanical spring, a rubber band and/or a body made of an elastic material. The elastic material may have a synthetic or natural elastomer, such as rubber or a synthetic polymer. The tensioning element can in particular be made of plastic or metal.

The tensioning element preferably has a mechanical connection to the at least one antenna and the holding element. The tensioning element may be connected to the at least one antenna and the holding element such that the tensioning element is elastically deformed upon a relative movement of the at least one antenna with respect to the holding element towards the base element. By elastic deformation, an elastic restoring force can be formed in the tensioning element, which force is oriented counter to the direction of movement of the at least one antenna.

The safety mechanism has a first locking part which is mechanically connected to the at least one antenna and which is configured for engagement into a second locking part of the second guide mechanism and counteracts the force of the tensioning element. The first locking element and the second locking element can be implemented according to the embodiments described above.

The first locking part is mechanically coupled to the first guide mechanism, wherein the first locking part can be mechanically decoupled from the second locking part of the second guide mechanism by means of a predetermined relative movement of the holding element with respect to the base element, so that a deflection of the at least one antenna in a direction away from the base element by means of the tensioning element can be achieved. The mechanical coupling of the first guide means to the locking element can be designed, for example, as a stop element according to the above-described embodiments. Preferably, such a stop element is designed to separate the locking element from the locking profile of the second guide mechanism during the opening movement of the holding element, wherein the at least one antenna is transferred into the initial position by the elastic restoring force of the tensioning element.

Using the same mechanical principle, the tensioning element and the mechanical coupling device can alternatively also be configured to guide the at least one antenna back into the initial position when the closing movement of the holding element is performed, i.e. when the holding element is moved relative to the base element towards the base element.

By providing a tensioning element and a corresponding safety mechanism, it can be ensured in an advantageous manner that after an opening movement of the holding element, the at least one antenna is in the initial position. Furthermore, by means of a purely mechanical solution for the automated resetting of the at least one antenna, the additional energy requirement for electrically driven components can be avoided in an advantageous manner.

In a further embodiment of the partial coil according to the invention, the safety mechanism comprises an adjusting element which is designed to transmit a force to the at least one antenna in order to deflect the at least one antenna relative to the holding element in a direction away from the base element. The adjusting element can be connected, for example, to a pneumatic, hydraulic and/or electrical drive, which is designed to shift the adjusting element and the at least one antenna into an initial position and/or into a predetermined position relative to the holding element. The adjusting element is preferably designed to move or transport the at least one antenna along a movement path predefined by the second guide element in a direction away from the base element.

The partial coil further has a locking element which is mechanically coupled to the first guide element and is designed to transmit an interruption force to the at least one antenna via the adjusting element when the base element and the holding element are in a predetermined relative position. The locking element can be designed, for example, as a stop element such as a pin, a bolt, a locking element, a plate, but also a valve, a valve or the like. The locking element can be designed in particular for interrupting the force action of the drive on the adjusting element.

It is also conceivable that the locking element is designed to release the movement of the at least one antenna along a movement path predefined by the second guide element. The mechanical coupling between the locking element and the first guide mechanism can be designed according to the embodiments described above. Preferably, the mechanical coupling means are configured for transferring the locking element into the open position or the closed position when the holding element is guided into the closed position relative to the base element. In this case, the deflection of the at least one antenna or the force action of the adjusting element on the at least one antenna can be interrupted by the latching element being moved into the open or closed position.

In an alternative embodiment of the partial coil according to the invention, the safety mechanism comprises an adjusting element, wherein the adjusting element is designed to transmit a force to the holding element in order to delimit a relative movement of the holding element with respect to the base element and/or to deflect the holding element in a direction away from the base element. The adjusting element and the drive can be designed according to the embodiments described above. The drive can be designed in particular as a pneumatic, hydraulic or electric drive.

The partial coil further has a locking element which is mechanically coupled to the second guide element and is designed to transmit an interruption force to the holding element via the adjusting element when the at least one antenna is in a predetermined relative position to the holding element. The predetermined relative position of the at least one antenna with respect to the holding element is preferably characterized by a maximum distance of the at least one antenna with respect to the base element and/or a maximum deflection of the at least one antenna with respect to the holding element in a direction away from the base element.

In one embodiment of the partial coil according to the invention, the actuating element has a fluid connection to a pneumatic and/or hydraulic drive, wherein the locking element is designed to interrupt the fluid connection between the actuating element and the pneumatic and/or hydraulic drive. The locking element can be designed, for example, as a valve, in particular as a three-way valve.

In one embodiment, the valve is configured for interrupting the force action of the adjusting element on the at least one antenna when the holding element is in the closed position relative to the base element. The mechanical coupling between the first guide means and the valve can be embodied in particular as a servo drive for the valve. The valve can be transferred by means of the servo drive into a configuration which interrupts or opens a fluid connection with a pneumatic or hydraulic drive.

In an alternative embodiment, the valve is configured to interrupt the force action of the adjusting element on the holding element when the at least one antenna is in a predetermined relative position with respect to the holding element.

By providing the adjusting element according to the above-described embodiments, a pneumatic and/or hydraulic system, which is normally already present in the examination room of the magnetic resonance apparatus, can advantageously be used to implement the safety mechanism. Furthermore, the fluid lines, in particular of pneumatic systems, may be made of a material having a small or negligible interaction with the magnetic and/or radio frequency fields. Such a fluid line can therefore also be used in an advantageous manner in a patient receiving region or in an image recording region of a magnetic resonance apparatus without affecting the quality of the detected magnetic resonance images.

In a further embodiment of the partial coil according to the invention, the safety mechanism has an adjusting element with a drive, wherein the adjusting element is mechanically connected to the at least one antenna or the holding element, and wherein the drive is designed to deflect the at least one antenna or the holding element in a direction away from the base element by means of the adjusting element as a function of the control signal. The drive means is preferably positioned outside the patient receiving area or the image recording area of the magnetic resonance apparatus. The drive device can be connected to the adjusting element by means of a fluid line, as well as an electrical and/or mechanical coupling device. It is conceivable that the drive means are integrated into the local coil and/or the patient support device.

The safety mechanism may further comprise a control unit, which is configured to output or transmit a control signal to the drive device. It is conceivable that the control unit is configured for providing the control signal in dependence of the open and/or closed position of the holding element and the basic element. For this purpose, the control unit may have a signal connection to a sensor which is designed to determine the relative position of the holding element with respect to the base element, in particular the open and/or closed position of the holding element. In a simple example, the sensor may be designed as a switch, a contact, a relay, etc. Such a sensor is particularly suitable for determining whether the holding element is in a final position or in a stop position relative to the base element. The sensor may also comprise more complex measuring methods, such as laser distance measurement between the holding element and the base element, or comprising: the deformation of the fiber sensor upon reaching the closed and/or open position of the holding element is determined. The sensor may be adapted to determine a limited number of predetermined relative positions of the holding element with respect to the base element. However, it is likewise conceivable for the sensor to be designed to determine the relative position of the holding element with respect to the base element continuously or in discrete time steps.

In one embodiment, the control unit has a signal connection to a control unit and/or a computing unit of the magnetic resonance apparatus. It is also conceivable that the control unit corresponds to or is integrated into a control unit of the magnetic resonance apparatus. Correspondingly, the control signal may be output in dependence on a sensor of the magnetic resonance apparatus and/or a parameter of the magnetic resonance measurement. The parameters of the magnetic resonance measurement may for example comprise imaging parameters, but may also comprise any parameters characterizing the flow or progress of the magnetic resonance measurement.

By providing an electric drive and a control unit according to the invention, measures for preventing collisions of at least one antenna by means of a safety mechanism can be automated in an advantageous manner. The risk of incorrect manipulation of the local coil according to the invention by the user can thereby advantageously be reduced or completely avoided.

In one embodiment, the first guide means and/or the second guide means are designed as linear guides, telescopic guides, joints, hinges or plug-in systems. The plugging system may have a plurality of components which are present in a disassembled or disassembled state separately from each other. In a preferred embodiment, the base element is mechanically connected to the patient support device by means of a positioning unit, wherein the holding element together with the at least one antenna can be guided in a substantially vertical direction or can be connected to the base element in a pluggable manner. However, the holding element can also be inserted or guided relative to the base element in a substantially horizontal direction or in a direction inclined relative to the vertical direction.

In principle, the first guide means and/or the second guide means may have any means which delimit the relative movement of the holding element with respect to the base element and/or the relative movement of the at least one antenna with respect to the holding element to one or more predetermined movement trajectories.

In a preferred embodiment of the partial coil according to the invention, the first guide means has a pivot means, wherein the holding element is pivotally supported at a maximum angle with respect to the base element by means of the pivot means.

The pivoting means may, for example, have a hinge, a joint, a swivel bearing, a slide bearing, a roller bearing and/or any other means which are designed to pivot the first element and/or the second element at an angle relative to the holding device and/or the patient support device. Preferably, the first element and/or the second element may pivot along a sagittal plane of the patient when the local coil is positioned at the patient depending on the application. It is also conceivable that the holding element can be pivoted approximately parallel to the coronal plane of the patient. The holding element and/or the at least one antenna may follow a section of an arc determined by the pivoting mechanism when pivoting. It is conceivable that the pivoting mechanism according to the above-described embodiments is comprised by and/or integrated into the basic element.

In a preferred embodiment, the pivoting mechanism has a locking element and a locking profile. According to the above embodiment, the locking element may be configured for engagement into the locking profile and preventing the holding element from pivoting in a direction towards the base element. Preferably, the locking element is mechanically coupled to the second guiding mechanism. The mechanical coupling may be designed such that the locking element is separated from the locking profile when the at least one antenna is moved into a predetermined relative position with respect to the holding element by means of the second guide mechanism.

The open position is characterized by a maximum angle between the base element and the retaining element. The maximum angle is selected such that the patient's head can be positioned unimpeded in a relative position with respect to the local coil, depending on the application.

Depending on the configuration of the magnetic resonance device and/or the patient support device, the maximum angle may be between 60 ° and 90 °, between 90 ° and 180 °, or between 180 ° and 270 °. In the case of a magnetic resonance apparatus in which the patient has a standing or sitting posture at the time of magnetic resonance measurement, the maximum angle is preferably between 60 ° and 90 °. But larger values of the maximum angle are also conceivable. In the case of a conventional magnetic resonance apparatus with an examination table, the maximum angle is preferably less than 180 °.

By providing a pivoting mechanism, the holding element can be positioned at a diagnostically relevant body region of the patient in a particularly time-efficient manner and can in turn be completely removed from the contact region of the patient with the patient support apparatus. In an advantageous manner, the time expenditure associated with positioning the local coil at a body region associated with the diagnosis of the patient as a function of the application can thereby be reduced.

In a further embodiment, the local coil according to the invention has a second antenna, wherein the second antenna is mechanically connected to the base element. The second antenna may be designed similarly to the at least one antenna. It is conceivable that the second antenna is electrically separated from or electrically connected to the at least one antenna.

The second antenna is positioned at a side of the patient facing away from the at least one antenna when the patient is positioned with respect to the base element according to the application. Preferably, the second antenna is integrated or embedded in the base element. It is also conceivable for the second antenna to be connected to the base element in a form-fitting, force-fitting and/or material-fitting manner.

In a preferred embodiment, the local coil according to the invention is designed as a head coil or a dental coil. Preferably, the basic elements of the dental coil are configured to receive the head of a patient. The second antenna may be positioned at the back side and/or at the parietal bone of the patient when the patient is positioned with respect to the base element according to the application. The local coil according to the invention can thus advantageously receive magnetic resonance signals from a larger volume, in particular from the jaw region of the patient and/or from the back region of the head of the patient.

The magnetic resonance apparatus according to the invention comprises a local coil according to the above-described embodiments. In a preferred embodiment, the local coil is mechanically connected to an examination table and/or a patient support of the magnetic resonance apparatus. The local coil may in particular have a positioning unit which is designed to position the local coil relative to the magnetic resonance apparatus and/or the patient. The local coil comprises at least one antenna, a base element, a holding element, a first guiding mechanism, a second guiding mechanism and a safety mechanism according to the above embodiments. The magnetic resonance apparatus is configured for detecting magnetic resonance data of a diagnostically relevant body region of a patient by means of local coils.

In one embodiment, the magnetic resonance system has a control unit which is connected by means of a signal connection to a drive for the adjusting element of the safety gear. Preferably, the control unit is configured to transmit information about the progress of the magnetic resonance measurement to the control unit of the drive device by means of a signal connection. However, it is also conceivable that the control unit is designed to transmit control signals to the drive. The drive means preferably form an adjusting element for transmitting the force to a holding element or at least one antenna mechanically connected to the local coil. Thus, the safety mechanism can ensure that: when the relative position of the at least one antenna deviates from a predetermined relative position of the at least one antenna with respect to the holding element, a relative positioning of the holding element towards the base element is avoided. It is also conceivable that the safety mechanism is configured for transferring the at least one antenna into a predetermined relative position with respect to the holding element when the holding element is positioned in the predetermined relative position with respect to the base element. In another example, the safety mechanism may also be configured to enable relative positioning of the at least one antenna with respect to the holding element when the holding element is positioned in a predetermined relative position with respect to the base element.

The magnetic resonance apparatus according to the invention shares the advantages of the local coil according to the invention.

Drawings

Further advantages and details emerge from the following description of embodiments with reference to the drawings. Shown in the schematic diagram:

Figure 1 shows a schematic view of an embodiment of a magnetic resonance apparatus according to the invention,

Figure 2 shows a schematic view of an embodiment of a local coil according to the invention,

Figure 3 shows one possible embodiment of a safety mechanism of a local coil according to the invention,

Figure 4 shows one possible embodiment of a safety mechanism of a local coil according to the invention,

Figure 5 shows one possible embodiment of a safety mechanism of a local coil according to the invention,

Figure 6 shows one possible embodiment of a safety mechanism of a local coil according to the invention,

Fig. 7 shows a possible embodiment of a safety mechanism of a local coil according to the invention.

Detailed Description

Fig. 1 schematically shows a possible embodiment of a magnetic resonance apparatus 10 according to the invention, which has a local coil 26 according to the invention. The magnetic resonance apparatus 10 comprises a magnet unit 11, for example with a permanent magnet, an electromagnet or a superconducting main magnet 12 for generating a strong and especially homogeneous basic magnetic field 13 (B0 magnetic field). Furthermore, the magnetic resonance apparatus 10 comprises a patient receiving area 14 for receiving a patient 15. In the present embodiment, the patient receiving area 14 is cylindrically formed and surrounded by the magnet unit 11 in the circumferential direction. However, in principle, different embodiments of the patient receiving area 14 from the illustrated example are also conceivable.

The patient 15 can be positioned in the patient receiving region 14 by means of a patient support device 16 of the magnetic resonance device 10. The patient support device 16 has for this purpose an examination couch 17 which is movably embodied in the patient receiving area 14. The magnet unit 11 also has gradient coils 18 for generating magnetic gradient fields for position encoding during magnetic resonance measurement. The gradient coils 18 are operated by means of a gradient control unit 19 of the magnetic resonance apparatus 10. The magnet unit 11 may also comprise a radio frequency antenna, which in the present embodiment is configured as a body coil 20 fixedly integrated into the magnetic resonance apparatus 10. The body coil 20 is designed to excite nuclei in the basic magnetic field 13 generated by the main magnet 12. The body coil 20 is operated by a radio frequency unit 21 of the magnetic resonance apparatus 10 and emits radio frequency signals into an examination space which is substantially formed by the patient receiving region 14 of the magnetic resonance apparatus 10. The body coil 20 may also be configured to receive magnetic resonance signals.

For controlling the main magnet 12, the gradient control unit 19 and the radio frequency unit 21, the magnetic resonance apparatus 10 has a control unit 22. The control unit 22 is configured for controlling the execution of sequences, such as imaging gradient echo sequences, TSE sequences or UTE sequences. Furthermore, the control unit 22 comprises an evaluation unit 28 for evaluating digitized magnetic resonance signals detected during the magnetic resonance measurement.

Furthermore, the magnetic resonance apparatus 10 comprises a user interface 23 with a signal connection to the control unit 22. The control information, for example imaging parameters and reconstructed magnetic resonance images, can be displayed for the user on a display unit 24 of the user interface 23, for example on at least one monitor. Furthermore, the user interface 23 has an input unit 25 by means of which parameters of the magnetic resonance imaging can be entered by a user.

Furthermore, the magnetic resonance apparatus 10 has a local coil 26 which is currently positioned at the head of the patient 15 and transmits magnetic resonance signals from the volume of the jaw region to the magnetic resonance apparatus 10. The local coil 26 preferably has electrical connection lines 27 which provide signal connections to the radio frequency unit 21 and the control unit 22. The local coil 26 can however also be connected to the magnetic resonance apparatus 10 by means of a wireless signal connection. As with the body coil 20, the local coil 26 may also be configured for exciting nuclei and for receiving magnetic resonance signals. For emitting radio frequency signals, the transmitting unit of the local coil 26 is operated by the radio frequency unit 21. The local coil 26 may surround the head of the patient 15 along the longitudinal axis of the patient 15 on an outer circumference. The transmitting unit and/or the receiving unit of the local coil 26 may in particular be carried by a holding element 33, which may be positioned relative to the basic elements of the local coil 26.

The illustrated magnetic resonance apparatus 10 may of course comprise other components typically present in magnetic resonance apparatus. It is also conceivable that instead of a cylindrical configuration, the magnetic resonance apparatus 10 has a C-shaped configuration, a triangular configuration or an asymmetrical configuration of the components generating the magnetic field. The magnetic resonance apparatus 10 may in particular be a dedicated magnetic resonance apparatus 10 configured for performing magnetic resonance imaging of a jaw region of a standing or sitting patient 15.

Fig. 2 shows an embodiment of the partial coil 26 according to the invention, in which the holding element 31 is pivotably mounted relative to the base element 30 and/or the positioning unit 34. The guide mechanism 33a has a swivel bearing for this purpose. By means of a pivoting mechanism, the holding element 31 can be pivoted or tilted relative to the examination table 17 and/or the patient 15 about a pivot point, which is defined by the position or axis of the swivel bearing.

The positioning unit 34 is configured for positioning the local coil 26 relative to the patient support apparatus 16 and/or the patient 15. The positioning unit 34 may have for this purpose, for example, linear guides, rail systems and/or similar guide mechanisms. The positioning unit 34 is mechanically connected to the basic element 30, which in turn is connected to the holding element 31 by means of a guiding mechanism 33 a.

The holding element 33b has a guide mechanism 33b which enables a relative movement of the carrier structure with the antenna 32 (hereinafter only the antenna 32) with respect to the holding element 31. The guide means 33b are configured for positioning the antenna 32 along a guide axis which is oriented substantially parallel to the intersection of the sagittal and transverse planes of the patient 15 when the partial coil 26 is positioned at the jaw region of the patient 15, depending on the application, i.e. for example in the closed state of the holding element 31.

In one embodiment, the guide mechanism 33b may have a pin or bolt that is guided through the holding element 31 and mechanically connected to the antenna 32. The guide mechanism 33b is currently configured to position the antenna 32 in the Y direction when the screw 33bi is rotated. The screw or pin of the guide 33b can be guided here, for example, by a slot in the holding element 31, so that the antenna 32 can also be positioned relative to the patient 15 in the Z-direction.

In the illustrated example of fig. 2, the antenna 32 is embedded in a carrying structure that is capable of profiling the surface profile of the head of the patient 15. The carrying structure is preferably also configured to protect the patient 15 from voltages and/or exothermia caused by the antenna 32. The antenna 32 may have a plurality of antennas or signal conductors disposed adjacent to or partially overlapping one another in the carrier structure.

In one embodiment, as shown in fig. 2, the base element 30 of the dental coil 26 has a placement element. The placement element may for example be designed as a cushion or similar elastic element which fits the shape of the back side of the head of the patient 15. Preferably, the placement element has a second antenna (not shown) that is positioned at the back side of the head of the patient 15 when the patient 15 is positioned according to the application relative to the base element 30. The second antenna may be electrically connected to the antenna 32 or may be electrically separate from the antenna.

Fig. 3 shows a possible embodiment of a safety mechanism 50, which is currently integrated into the guide mechanism 33 a. The swivel bearing currently has a locking element 41 (e.g. a first locking part) which is designed to engage into a locking profile 42 (e.g. a second locking part) when the holding element 31 is moved in a closing manner, in order to prevent or interrupt the closing movement of the holding element 31, i.e. the relative movement of the holding element 31 towards the base element 30. The locking element 41 can be mechanically connected to the shaft 33ai of the shown swivel bearing for this purpose. Correspondingly, the locking profile 42 can be integrated into the holding element 31 such that it surrounds the shaft 33ai of the rotary bearing in the circumferential direction on the outer circumference. Of course, different embodiments and variants of the safety mechanism 50 are conceivable, which are not discussed in detail here. In one example, the locking profile 42 can also be embodied in the shaft 33ai, while the locking element 41 is positioned at a section of the retaining element 31 and/or the base element 30 surrounding the shaft in the circumferential direction on the outer circumference.

In the example shown, the locking element 41 is mechanically coupled to the guide mechanism 33b by means of a stop element 43. The stop element 43 may comprise, for example, a spring which is compressed or displaced into the idle position by the antenna 32 being positioned in a predetermined relative position with respect to the holding element 31. As shown in fig. 3, the locking element 41 is supported on the stop element 43 and mechanically decoupled from the locking profile 42 in the idle position. Conversely, if the antenna 32 is not in a predetermined relative position to the holding element 31, the stop element 43 is held in the holding position as currently shown and deflects the locking element 41 toward the locking profile 42. Thereby, the locking element 41 engages into the locking profile 42 and prevents a closing movement of the holding element 31 relative to the base element 30. The stop element 43 is preferably designed as a spring which can be elastically deformed during the opening movement of the holding element 31 relative to the base element 30, so that the locking element 41 can pass the respective stop points of the locking profile 42.

Fig. 4 shows an embodiment of the partial coil 26 according to the invention, wherein the guide means 33b have tensioning elements 44. The tensioning element 44 is currently implemented as a mechanical spring connected to the manual adjustment portion 33bi and to the surface of the holding element 31. The manual adjustment portion 33bi is mechanically connected to the antenna 32 and is configured to move the antenna 32 relative to the holding member 31. Upon relative movement of the antenna 32 toward the base member 30 by means of the manual adjustment portion 33bi, the tensioning member 44 is compressed and applies a force against the base member 30 to the manual adjustment portion 33bi in conjunction with the antenna 32.

The guide means 33b currently comprise a substantially cylindrical bore with a locking profile 42 (e.g. a second locking member) on the inside. The safety mechanism 50 has a locking element 41 (e.g. a first locking part) which is configured for engagement into the locking profile 42 and prevents movement of the manual adjustment portion 33bi and the antenna 32 in a direction away from the base element 30. This may simplify the positioning of the antenna 32 in the position of the patient 15 at the jaw area according to the application for the user, since the manual adjustment portion 33bi has already been locked in the stride preset by the locking profile 42 when guiding the antenna 32 towards the patient 15.

As shown in fig. 3, the locking element can be supported on a spring, which is designed to deflect the locking element 41 toward the locking profile 42. The safety mechanism 50 also has a locking element 43, which is mounted so as to be movable in the cylindrical bore and is designed to mechanically disengage the locking element 41 from the locking profile 42. The stop element 43 may be mechanically connected to a manual switch or lever which allows a user to manually manipulate the stop element 43 in order to move the antenna 32 relative to the holding element 31 in a direction away from the base element 30. Preferably, however, the stop element 43 is mechanically coupled to the guide mechanism 33 a. The mechanical coupling between the stop element 43 and the guide mechanism 33a can be designed such that, when the holding element 31 is moved relative to the base element 30 into a position facing away from the patient support device (i.e. the open position), the stop element 43 is deflected towards the locking element 41 and mechanically separates said locking element from the locking profile 42.

Fig. 5 shows an embodiment of the partial coil 26 according to the invention, wherein the safety mechanism 50 has an adjusting element 45 embodied as a pressure spring together with the drive 46. The drive 46 may be designed as a pneumatic drive as shown, but may also be designed as an electric or hydraulic drive. The adjusting element 45 is configured to transmit a force to the manual adjusting portion 33bi of the guide mechanism 33 b. Currently, the force is oriented in a direction opposite to the base element 30 and/or the patient 15, so that movement of the antenna 32 in a direction towards the base element 30 by means of the guiding mechanism 33b becomes difficult or prevented. The pneumatic drive 46 has a signal connection to the sensor 60 of the magnetic resonance apparatus 10 and/or to the control unit 22. In one embodiment, the pneumatic drive 46 or a control unit (not shown) of the pneumatic drive 46 is designed to detect a signal comprising information about a predetermined relative position of the holding element 31 relative to the base element 30 by means of the signal connection. The information about the predetermined relative position of the holding element 31 with respect to the base element 30 may comprise, for example, information about the arrival of the final position, the current relative position of the holding element 31 with respect to the base element 30 and/or information about the end of the magnetic resonance measurement. The sensor 60 may be implemented, for example, as a pitch sensor, incremental encoder, position encoder, contactor, or the like. Preferably, the sensor 60 is configured for determining whether the holding element 31 is in a predetermined relative position with respect to the base element 30 (and/or whether a corresponding arrangement of the guide means 33a is present).

In another embodiment, the signal connection to the control unit 22 and/or the sensor 60 may be omitted. In this case, the drive device 46 has a locking element 48 which is designed to inhibit the fluid connection 47 with the adjusting element 45 when the holding element 31 is in a predetermined relative position with respect to the base element 30. The locking element 48 can be designed, for example, as a valve.

The guide mechanism 33a is

In an alternative embodiment, the adjusting element 45 is designed to shift the antenna 32 into the initial position or into a predetermined relative position with respect to the holding element 31. For this purpose, the adjusting element 45 can in particular also be integrated in a cylindrical bore of the holding element 31 and transmit a rotational and/or translational movement to the adjusting portion 33 bi. The drive 46 is preferably designed as an electromotive drive which positions the antenna 32 as a function of information about the predetermined relative position of the holding element 31 relative to the base element 30. It is also conceivable to dispense with the implementation of the locking element 48. In this case, the adjusting element 45 and the drive 46 can be designed to automatically shift the antenna 32 into a predetermined relative position with respect to the holding element 31 as a function of the signals of the sensor 60 and/or the control unit 22. It is also conceivable that the adjusting element 45 and the drive device 46 are configured for positioning the antenna 32 relative to the holding element 31 by the user, either automatically or via a remote control.

Fig. 6 shows a further possible embodiment of the partial coil 26 according to the invention, wherein the safety mechanism 50 comprises an adjusting element 45. The adjusting element 45 is currently embodied as a pressure spring, which is acted upon by the drive 46. The pressure is preferably so high that manual transfer of the holding element 31 into the closed position is prevented.

The drive device 46 has a signal connection to the sensor 60 and/or to the control unit 22 of the magnetic resonance apparatus 10. The sensor 60 may be embodied, for example, as a distance sensor, an incremental encoder, a position encoder, a contactor, etc., which is designed to determine whether the antenna 32 is in a predetermined relative position with respect to the holding element 31 (and/or whether a corresponding arrangement of the guide means 33b is present). In the presence of such a predetermined position of the antenna 32 relative to the holding element 31, the sensor 60 transmits a signal to the drive device 46. The drive is correspondingly designed to adjust the force acting on the pressure spring in the presence of such a signal of the sensor 60, so that the holding element 31 can be manually moved into the closed position. The drive means may for example constitute a valve for opening to a bypass (see fig. 5) or to manipulate the pressure in the line of the fluid connection 47. It is also conceivable that the drive device 46 has a signal connection to the control unit 22 of the magnetic resonance apparatus 10 instead of the sensor 60 or in addition to the sensor 60. In this case, the drive device 46 can be configured, corresponding to the above-described embodiment, to adjust the force action on the pressure spring as a function of the progression of the magnetic resonance measurement.

Of course, the drive 46 in fig. 6 can also be embodied as an electromotive drive, which is designed to limit the relative movement of the holding element 31 with respect to the base element 30 as a function of a predetermined relative position of the antenna 32 with respect to the holding element 31. It is also conceivable to automatically implement the opening and/or closing movement of the holding element 31 by means of the drive 46. For example, the opening and/or closing of the holding element 31 relative to the base element 30 can be effected as a function of the signals of the sensor 60 and/or the control unit 22, but a relative movement of the antenna 32 into a safety position (which excludes injury to the patient) can also be effected.

Fig. 7 shows an embodiment of the local coil 26 according to the invention according to fig. 4. The stop element 43 currently has a joint 43a which is mechanically coupled to the stop element 43 according to fig. 4. In the opening movement of the holding element 31, the tab 43a is guided against the stop element 51 and moves in the direction of rotation R relative to the holding element 31. The movement or tilting of the joint 43a causes a deflection of the stop element 43, whereby the locking element 41 is mechanically decoupled from the locking profile 42, and the manual adjustment portion 33bi is moved by means of the tensioning element 44 in a direction away from the base element 30. The safety mechanism 50 can of course also be realized such that the mechanical separation of the locking element 41 from the locking profile 42 is realized by a closing movement of the holding element 31.

While the details of the present invention have been illustrated and described in detail by the preferred embodiments, the present invention is not limited by the disclosed examples and other variations may be derived by those skilled in the art without departing from the scope of the present invention.

Claims (14)

1. A local coil (26) comprising at least one antenna (32), a base element (30), a holding element (31), a first guiding mechanism (33), a second guiding mechanism (33) and a safety mechanism (50), wherein the at least one antenna (32) is configured for receiving radio frequency signals in the frequency range and in the power range of a magnetic resonance measurement, and wherein the at least one antenna (32) is mechanically connected with the holding element (31), wherein the base element (30) is configured for holding the holding element (31) together with the at least one antenna (32) in a position according to the application at a diagnostically relevant body area of a patient (15), wherein the first guiding mechanism (33) is mechanically connected with the base element (30) and the holding element (31) and is configured for variably positioning the holding element (31) relative to the base element (30), and wherein the second guiding mechanism (33) is mechanically connected with the holding element (31) and the at least one antenna (32) and is configured for variably positioning the holding element (31) relative to the at least one antenna (31),

Characterized in that the safety mechanism (50) is designed to prevent the at least one antenna (32) from colliding with the patient (15), in particular a diagnostically relevant body region of the patient (15), when the holding element (31) is transferred from the open position into the closed position by means of the first guide mechanism (33).

2. The local coil (26) according to claim 1, wherein the safety mechanism (50) is configured for limiting a movement of the holding element (31) by means of the first guide mechanism (33) as a function of a safety position of the at least one antenna (32) relative to the holding element (31) when the holding element (31) is transferred from the open position into the closed position.

3. The partial coil (26) according to claim 2, wherein the safety mechanism (50) has a first locking part (41, 42) which is designed to engage into a second locking part (41, 42) of the first guide mechanism (33) and prevent the holding element (31) from being transferred from the open position into the closed position, wherein the first locking part (41, 42) is mechanically connected with a stop element (43), and wherein the first locking part (41, 42) can be separated manually or automatically by means of the stop element (43) from the second locking part (41, 42) of the first guide mechanism (33) in order to release the transfer of the holding element (31) from the open position into the closed position.

4. A partial coil (26) according to claim 3, wherein the first locking part (41, 42) is mechanically coupled with the second guide mechanism (33) by means of the stop element (43), and wherein the first locking part (41, 42) is separable from the second locking part (41, 42) of the first guide mechanism (33) by means of the second guide mechanism (33) into a predetermined relative position with respect to the holding element (31) by means of the at least one antenna (32) in order to release the transfer of the holding element (31) from the open position into the closed position.

5. The local coil (26) according to claim 1, wherein the safety mechanism (50) is mechanically coupled with the first guide mechanism (33) and the second guide mechanism (33), and the safety mechanism (50) is configured for transferring the at least one antenna (32) into a safety position using kinetic energy of a relative movement of the holding element (31) with respect to the base element (30).

6. The local coil (26) according to claim 5, wherein the second guide mechanism (33) has a tensioning element (44) which is designed to be elastically deformed as a result of a relative movement of the at least one antenna (32) with respect to the holding element (31) toward the base element (30) and to transmit a force opposite to the movement to the at least one antenna (32), wherein the safety mechanism (50) has a first locking part (41, 42) which is mechanically connected to the at least one antenna (32) and which is designed to engage in a second locking part (41, 42) of the second guide mechanism (33) and to counteract a force of the tensioning element (44), wherein the first locking part (41, 42) is mechanically coupled to the first guide mechanism (33) and wherein the first locking part (41, 42) can be separated from the second guide mechanism (33) by means of a predetermined relative movement of the holding element (31) with respect to the base element (30) in order to be deflected in at least one direction (32) by means of the second locking part (41, 42).

7. The local coil (26) according to claim 1, wherein the safety mechanism (50) comprises an adjustment element (45) configured for transmitting a force to the at least one antenna (32) for deflecting the at least one antenna (32) relative to the holding element (31) in a direction away from the base element (30), wherein the local coil (26) further has a locking element (48) mechanically coupled with the first guiding element and configured for interrupting the transmission of the force to the at least one antenna (32) through the adjustment element (45) when the base element (30) and the holding element are in a predetermined relative position.

8. The local coil (26) according to claim 1 or 2, wherein the safety mechanism (50) comprises an adjustment element (45), wherein the adjustment element (45) is configured for transmitting a force to the holding element (31) in order to delimit a relative movement of the holding element (31) with respect to the base element (30) and/or to deflect the holding element (31) in a direction away from the base element (30), wherein the local coil (26) further has a locking element (48) which is mechanically coupled with the second guide element and is configured for interrupting the transmission of the force to the holding element (31) through the adjustment element (45) when the at least one antenna (32) is in a predetermined relative position with respect to the holding element (31).

9. Local coil (26) according to one of claims 7 or 8, wherein the adjusting element (45) has a fluid connection (47) with a pneumatic and/or hydraulic drive (46), and wherein the locking element (48) is configured for interrupting the fluid connection (47) between the adjusting element (45) and the pneumatic and/or hydraulic drive (46).

10. Local coil (26) according to claim 1, wherein the safety mechanism (50) has an adjusting element (45) with a drive (46), wherein the adjusting element (45) is mechanically connected to the at least one antenna (32) or the holding element (31), and wherein the drive (46) is designed to deflect the at least one antenna (32) or the holding element (31) in a direction away from the base element (30) by means of the adjusting element (45) as a function of a control signal.

11. Local coil (26) according to one of the preceding claims, wherein the first guide means (33) and/or the second guide means (33) are designed as linear guides, telescopic guides, joints, hinges or plug-in systems.

12. The local coil (26) according to claim 11, wherein the first guide mechanism (33) has a pivoting mechanism, and wherein the holding element (31) is pivotably supported by means of the pivoting mechanism at a maximum angle relative to the base element (30), wherein the open position is characterized by the maximum angle between the base element (30) and the holding element (31), and wherein the maximum angle is selected such that the head of the patient (15) can be positioned unimpeded in a relative position relative to the local coil (26) depending on the application.

13. The local coil (26) according to any one of the preceding claims, wherein the local coil (26) further has a second antenna (32), wherein the second antenna (32) is mechanically connected with the base element (30), and wherein the second antenna (32) is positioned at a side of the patient (15) facing away from the at least one antenna (32) when the patient (15) is positioned as applied with respect to the base element (30).

14. A magnetic resonance apparatus (10) comprising a local coil (26) according to any one of the preceding claims, wherein the magnetic resonance apparatus (10) is configured for detecting magnetic resonance data of a diagnostically relevant body region of a patient (15) by means of the local coil (26).