DE102013219745A1 - An imaging device with a rotatable, positionable component and method for positioning a rotatable, positionable component of an imaging device - Google Patents

Abstract

The present invention describes an imaging device (10) with a rotatable, positionable component (50), comprising a computing and control device (44), at least one rotation means (52) for rotating the movable component (50) about a rotation axis (54) and at least one absolute rotation angle sensor (56). The at least one absolute rotation angle sensor (56) can be arranged on the rotatable component (50). The at least one absolute rotation angle sensor (56) is configured to determine an absolute rotation angle (78) with respect to an absolute rotation angle sensor axis (58) of the at least one absolute rotation angle sensor (56) and provide the absolute rotation angle (78) to the computing and control device (44). The arithmetic and control device (44) is designed to receive the absolute rotation angle (78) and a predefinable target absolute rotation angle (76) and to control the at least one rotation means (52) such that the absolute rotation angle (78) corresponds to the predefinable target absolute rotation angle (76). equivalent. Furthermore, the present invention describes a corresponding method (1) for positioning a rotatable, positionable component (50) of an imaging device.

Description

The present invention relates to an imaging device with a rotatable, positionable component. Moreover, the present invention relates to a corresponding method for positioning a rotatable, positionable component of an imaging device.

Today's imaging devices, such as X-ray systems should generally be used for a variety of recording situations. Thus, for example, an ankle fracture, just like a thorax, can be recorded with a single device, which results in the necessity that components of the imaging device, in particular in the case of an X-ray system, an X-ray source and an X-ray image detector, must be movable in almost any position. In the case of ceiling-mounted radiography systems and fluoroscopy systems, X-ray emitters and image detectors can be positioned in addition to the three translatory spatial directions, X, Y and Z, with the aid of, for example, hub motors around the three rotation angles, RTA, RVA and RHA. For detecting the angle of rotation, sensors or encoders are used directly at the output of the respective axis. Due to the mass of radiator or detector, load bearing components may deform. The deformation in turn leads to angular deviations, i. a radiator or a detector has a wrong inclination after positioning, whereby, for example, X-ray radiation does not strike the image detector completely and a patient is unnecessarily exposed to radiation. These angular deviations can currently only be reduced by complex adjustment. In the current state of the art, there is no easy way to correct deformations and associated position inaccuracies in the ceiling tripods. For example, it has been attempted with unsatisfactory success, to determine a series of measurements of a tube set, which runs in the direction of a vertical axis, on a radiator tripod, thereby introducing compensation mechanisms.

The object of the present invention is therefore to specify an imaging device with a rotatable, positionable component in which the rotatable component can be aligned more accurately than in previously known imaging devices. It is a further object of the present invention to specify a corresponding method for positioning a rotatable, positionable component of an imaging device.

The invention solves this object with an imaging device with a rotatable, positionable component having the features of the first independent patent claim and a method for positioning a rotatable, positionable component of an imaging device with the features of the second independent claim. Advantageous embodiments are described in subclaims.

A basic idea of the invention is an imaging device with a rotatable, positionable component. The imaging device comprises a computing and control device, at least one rotation means for rotating the movable component about an axis of rotation and at least one absolute rotation angle sensor. The at least one absolute rotation angle sensor can be arranged on the rotatable component. The at least one absolute rotation angle sensor is configured to determine an absolute rotation angle with respect to an absolute rotation angle sensor axis of the at least one absolute rotation angle sensor and to provide the absolute rotation angle of the calculation and control device. The arithmetic and control device is designed to counteract the absolute rotation angle and a predefinable target absolute rotation angle and to control the at least one rotation means in such a way that the absolute rotation angle corresponds to the predefinable target absolute rotation angle.

This basic concept of the invention thus describes an imaging device, for example an X-ray device, with at least one component which can be positioned at least by a rotational movement or rotational movement. The device includes a computing and control device, such as an electronic computer and at least one known rotation means, such as an electric hub motor or an electric motor with gear. With the aid of the rotation means, the movable component can be rotated or rotated about a rotation axis by a rotation angle or rotation angle. For this purpose, the computing and control device sends corresponding signals, for example in the form of an electric current to the rotating means. The device further comprises at least one absolute rotation angle sensor. The absolute rotation angle sensor is disposable or disposable on the rotatable component, and is capable of determining or measuring an absolute rotation angle with respect to an absolute rotation angle sensor axis of the at least one absolute rotation angle sensor. The absolute rotation angle sensor axis is understood to mean the axis of the absolute rotation angle sensor which moves with the absolute rotation angle sensor when the absolute rotation angle sensor moves. The absolute rotation angle can be defined by two rays, the legs of the absolute rotation angle, which lie in one plane of the space. The plane is perpendicular to the absolute rotation angle sensor axis and intersects the absolute rotation angle sensor axis in one predefinable point, the vertex of the absolute rotation angle. The first leg of the absolute rotation angle lies in the plane described, begins at the vertex and runs in a predeterminable direction associated with the rotatable, positionable component. The second leg of the absolute rotation angle also lies in the plane described, begins at the vertex and runs in a predeterminable direction associated with an inertial system of the imaging device. That is, the absolute rotation angle is determined by rotation of a local coordinate system of the rotatable positionable component and a coordinate system or reference coordinate system of the imaging apparatus assumed to be immovable. The absolute rotation angle is provided to the arithmetic and control device. The computing and control device is configured to receive, load, or receive the absolute rotation angle, for example, through a suitable interface to the absolute rotation angle sensor. Furthermore, the arithmetic and control device is able to accept a predefinable Sollabsolredotationswinkel, for example by a user input on a keyboard to then control the rotation means such that the absolute rotation angle coincides with the predetermined Sollabsolredotationswinkel. For this purpose, known methods of control engineering can be used. An advantage of the described basic idea of the imaging device according to the invention is that the considered rotation angle is measured not in a frame of reference of the rotation means, but relative to the non-moving frame of reference of the imaging device. Deformations which can lead to a distortion of a rotation angle measured in the local reference frame have no influence on the absolute rotation angle.

The computing and control device preferably comprises a mathematical position model. The mathematical position model describes the mechanical properties of the imaging device with a rotatable, positionable component and the mathematical position model additionally enters into the control of the rotation means.

Mathematical models or the creation of mathematical models are, e.g. from control engineering or from robotics, known per se. The mathematical positional model is designed to describe the mechanical properties of the rotatable positionable component imaging device, i. in particular by modeling the geometry of the imaging device and possibly also the mechanical properties, such as bending due to flexibility of mechanical components. In addition to the measured absolute rotation angle and the predefinable target absolute rotation angle, the mathematical position model additionally enters the control of the rotation means. By including the mathematical position model, the control, for example, by a control of the rotation means can be made more accurate and faster, since effects of rotational movements of the rotating means can be predicted with the tools of control technology.

In an advantageous development, the imaging device comprises three rotation means for rotating the movable component about three axes of rotation and three absolute rotation angle sensors. The three absolute rotation angle sensors are aligned differently in pairs. The three absolute rotation angle sensors are designed to determine three absolute rotation angles and to provide the absolute rotation angles of the computing and control device. The computing and control device is designed to take the absolute rotation angle and three predefinable Sollabsolredotationswinkel and to control the rotation means so that the absolute rotation angle correspond to the three predetermined Sollabsolredotationswinkeln.

In this embodiment, the movable component of the imaging device by means of three rotating means is able to perform rotations or rotational angle changes about the three axes of rotation. Preferably, the three rotation means are aligned differently in pairs in order to perform rotational movements about all three spatial axes can. For accurate positioning, the imaging device comprises three absolute rotation angle sensors, which are aligned in pairs differently, so as to be able to determine three absolute rotation angles and to provide the three absolute rotation angles of the computing and control device. The computing and control device is designed to take the three absolute rotation angles and three predefinable target absolute rotation angles and to control the three rotation means in such a way that the three absolute rotation angles correspond to the three predefinable target absolute rotation angles. Advantageously, a mathematical position model takes into account the three rotation means, and the mathematical position model is additionally included in the control of the three rotation means.

In a further advantageous embodiment, the three absolute rotation angle sensors are aligned in pairs orthogonal to each other.

By a pairwise orthogonal alignment of the three absolute rotation angle sensors can In general, angular changes in rotations about the three spatial axes are measured more accurately than in non-orthogonal orientations, since angular changes are generally manifested in larger changes in measured values.

It is proposed that the three absolute rotation angle sensors are arranged in a common housing.

An arrangement of the three absolute rotation angle sensors, which are aligned in pairs differently or in pairs orthogonal to each other, in a common housing, offers structural advantages, since only one installation location must be provided on or in the movable component of the imaging device.

With particular advantage, the three rotation means are aligned in pairs orthogonal to each other.

A pairwise orthogonal alignment of the three rotation means generally makes angle changes easier to accomplish than non-orthogonal alignments.

It has proved to be advantageous if at least one absolute rotation angle sensor comprises at least one sensor from the group of gravity sensor, magnetic sensor and gyroscope.

Gravity sensors and magnetic sensors are known per se embodiments of angle sensors, gyroscopes or gyroscopes are known rotation rate sensors, the measured variables can be converted by integration in rotation angle. A gravity sensor may be configured to measure an inclination of the gravity sensor relative to the gravitational field of the earth. A magnetic sensor can be designed to determine the orientation, and thus a rotational angle, of the magnetic sensor as a function of the magnetic field of the earth. Depending on a specific design of the geometry of the imaging device, it may be necessary to combine several of the sensor types mentioned together to form an absolute rotation angle sensor. For example, if a rotation means on which a movable component of the imaging device is arranged is aligned with its axis of rotation parallel to the acceleration vector of gravity, rotation of this rotation means in a gravity sensor located on the movable component will not cause a signal change. In the case of a magnetic sensor, on the other hand, the output of the measured rotation angle changes in this constellation.

Suitably, the movable component is an X-ray detector or a radiation source.

X-ray detectors and radiation sources of X-ray systems are often connected via linkages with a so-called tripod. In order to be able to cover a large work area, they can be moved over a wide range and are therefore subject to the deformations described above, whereby the use of one of the described imaging devices brings great advantages.

• S1) Bestimmen des Absolutrotationswinkels bezüglich der Absolutrotationswinkelsensorachse des wenigstens einen Absolutrotationswinkelsensors;
• S2) zur Verfügungstellen des Absolutrotationswinkels der Rechen- und Steuereinrichtung;
• S3) Entgegennahme des Absolutrotationswinkels und eines Sollabsolutrotationswinkels durch die Rechen- und Steuereinrichtung;
• S4) Ansteuerung des wenigstens einen Rotationsmittel derart, dass der Absolutrotationswinkel dem vorgebbaren Sollabsolutrotationswinkel entspricht.

A further basic idea of the invention is a method for positioning a rotatable, positionable component of an imaging device, comprising a computing and control device, at least one rotation means for rotating the movable component about an axis of rotation and at least one absolute rotation angle sensor, wherein the at least one absolute rotation angle sensor is rotatable Component, and wherein the at least one absolute rotation angle sensor is configured to determine an absolute rotation angle with respect to an absolute rotation angle sensor axis of the at least one absolute rotation angle sensor. The method comprises the following method steps:

• S1) determining the absolute rotation angle with respect to the absolute rotation angle sensor axis of the at least one absolute rotation angle sensor;
• S2) providing the absolute rotation angle of the arithmetic and control means;
• S3) receiving the absolute rotation angle and a target absolute rotation angle by the computing and control device;
• S4) control of the at least one rotation means such that the absolute rotation angle corresponds to the predetermined Sollabsolredotationswinkel.

The method may be performed, for example, by running a computer program that has been loaded onto the computing and control device.

In an advantageous development, the method uses one of the previously described imaging devices.

For example, it is conceivable that a mathematical position model has been loaded into the computing and control device and that in step S4 the mathematical position model is included in the control of the at least one rotation means.

A further advantageous embodiment provides that the method is carried out at least partially automatically.

Automatically executed procedures are often less error prone and execute faster than procedures requiring user input. For example, the transmission of an absolute rotation angle from an absolute rotation angle sensor to the computing and control device can be done automatically. With particular advantage, the method is fully automatic, ie without further inputs, executed after receiving a Sollabsolredotationswinkels or more Sollabsolredotationswinkel.

In an alternative embodiment of the invention, the method is repeatedly executed until a checked termination criterion is met.

This feature describes an embodiment in which one of the previously described methods is repeated, i. a rotatable component of an imaging device is repeatedly positioned until an abort criterion that is checked at each repetition is met. An abort criterion can be understood to mean, for example, the pressing of a button by an operator or the achievement of a predefinable repeat counter reading.

The embodiments described in more detail below represent preferred embodiments of the present invention.

Further advantageous developments will become apparent from the following figures, including description. Show it:

1 exemplary and schematic of an imaging device with two rotatable positionable components according to the prior art;

2 by way of example and schematically a part of an imaging device with a rotatable and positionable component;

3 by way of example and schematically a part of an imaging device with a rotatable about three axes and positionable component;

4 exemplary and symbolic a housing with three absolute rotation angle sensors;

5 by way of example and schematically a part of an imaging device with a rotatable about three axes and positionable component in a second layer;

6 by way of example a flow diagram of a method according to the invention for positioning a rotatable, positionable component of an imaging device.

1 shows by way of example and schematically an imaging device 10 ' with two rotatable, positionable components 20 ' , here an X-ray image detector, and 30 ' , here a radiation source, according to the prior art. The imaging device 10 ' , and in particular a positioning of the components 20 ' and 30 ' is done by a computing and control device 44 , for example, a first rotating means 52 controls and thereby the component 20 ' around a first axis of rotation 54 around a first rotation angle 68 rotates. Due to gravity, indicated by a vector 42 the gravitational acceleration "g", deforms a support arm 64 a ceiling stand, here a Detektortragarm a ceiling stand, and a boom arranged thereon 60 so that's the component 20 ' tending further than by the first angle of rotation 68 is predetermined. This means that even with knowledge of the first rotation angle 68 , the angle of inclination of the components 20 ' in terms of the reference system 40 the imaging device 10 ' , is indefinite. Through a complex measurement of the deformation of the support arm 64 of the ceiling stand and the jib 60 could be the actual tilt angle or the first absolute rotation angle of the components 20 ' in terms of the reference system 40 the imaging device 10 ' be determined.

In 2 is exemplary and schematically a part of an imaging device 10 with a rotatable and positionable component 50 and a computing and control device 44 , here a computer. The part of the device shown 10 includes a support arm 64 a ceiling stand, on which a boom 60 and the rotatable and positionable component 50 is arranged. With the help of a first rotation means 52 , here an electric hub motor, can be the moving component 50 around a first axis of rotation 54 around a first rotation angle 68 of the first rotating means 52 be rotated or rotated. For this purpose, the computing and control device sends 44 corresponding signals, for example in the form of an electric current to the first rotating means 52 , The device 10 further comprises a first absolute rotation angle sensor 56 , The first absolute rotation angle sensor 56 is on the rotatable component 50 arranged and he is capable of a first absolute rotation angle 78 with respect to a first absolute rotation angle sensor axis 58 of the first absolute rotation angle sensor 56 to be determined or measured. Below the first absolute rotation angle sensor axis 58 becomes the axis of the first absolute rotation angle sensor 56 understood in a movement of the first absolute rotation angle sensor 56 with the first absolute rotation angle sensor 56 emotional. The first absolute rotation angle 78 can by two beams, the legs of the first absolute rotation angle 78 , which lie in a plane of the room, can be defined. The plane is perpendicular to the first absolute rotation angle sensor axis 58 and intersects the first absolute rotation angle sensor axis 58 in a predeterminable point, the vertex of the first absolute rotation angle 78 , The first leg of the first absolute rotation angle 78 lies in the described plane, begins at the vertex and runs in a predefinable, with the rotatable, positionable component 50 linked direction, here parallel to the square base of the rotatable positionable component 50 ie in a local coordinate system 40 ' the rotatable, positionable component 50 , The second leg of the first absolute rotation angle 78 also lies in the described plane, starts at the apex and runs in a predeterminable, with an inertial system 40 the imaging device 10 linked, direction, here parallel to a vector 42 of gravity. This means the first absolute rotation angle 78 is determined by a rotation of a local coordinate system of the rotatable positionable component 50 and an assumed immovable coordinate system or reference coordinate system of the imaging device 10 , The first absolute rotation angle 78 becomes the computing and control device 44 made available. The computing and control device 44 is designed, for example, by a corresponding interface, the first absolute rotation angle 78 to receive, to load or to receive. Next is the computing and control device 44 capable of a prescribable first Sollabsolredotationswinkel 76 to receive, for example, by a user input on a keyboard, then the first rotation means 52 in such a way that the first absolute rotation angle 78 with the predefinable first Sollabsolredotationswinkel 76 matches. For this purpose, known methods of control engineering can be used. An advantage of the described embodiment is that the considered rotation angle, ie the first absolute rotation angle 78 not in a frame of reference of the first rotation means 52 as the local coordinate system 40 ' , is measured, but relative to the stationary reference frame 40 the imaging device. Deformations that can lead to a falsification of a measured in the local reference frame rotation angle, indicated in the embodiment by the curved support arm 64 the ceiling tripod, which is also in the direction of the double arrow 62 is movable, and the curved boom 60 , do not affect the first absolute rotation angle 78 , The deformation of the support arm 64 of the ceiling stand and the jib 60 lead to a stronger inclination of the rotatable component 50 , which by regulation to the first Sollabsolredotationswinkel 76 can be compensated.

3 shows by way of example and schematically a part of an imaging device 10 with one, on a support arm 64 a ceiling stand and a jib 60 arranged, rotatable and positionable component 50 that are around three axes 54 . 54 ' and 54 '' is rotatable and positionable. The three axes 54 . 54 ' and 54 '' are each rotation angle 68 . 68 ' and 68 '' assigned. Exemplary is a first rotation means 52 represented that the movable component 50 around the first axis of rotation 54 around the first rotation angle 68 of the first rotating means 52 turns or rotates. Three absolute rotation angle sensors arranged in pairs orthogonal to each other 56 . 56 ' and 56 '' measure three absolute rotation angles 78 . 78 ' and 78 '' whose vertices point to three absolute rotation angle sensor axes 58 . 58 ' and 58 '' lie. The three absolute rotation angles 78 . 78 ' and 78 '' are related to a resting reference coordinate system, indicated by a Cartesian coordinate system 40 , measured. For measuring the three absolute rotation angles 78 . 78 ' and 78 '' include the three absolute rotation angle sensors 56 . 56 ' and 56 '' Gravity sensors giving a tilt against a vector 42 to measure gravity. The three absolute rotation angles 78 . 78 ' and 78 '' become a computing and control device 44 made available. The computing and control device 44 is designed for the three absolute rotation angles 78 . 78 ' and 78 '' and to accept three presettable target absolute rotation angles and to control the three rotation means such that the three absolute rotation angles 78 . 78 ' and 78 '' correspond to the three predetermined Sollabsolredotationswinkeln. For this purpose, algorithms known from control engineering can be used, which are in the computing and control device 44 be processed.

In 4 is exemplary and symbolic a housing 74 which includes three absolute rotation angle sensors (not shown) inside. The three absolute rotation angle sensors are designed to have three absolute rotation angles 78 . 78 ' and 78 '' with respect to an inertial system, indicated by a Cartesian coordinate system 40 whose Z-axis is antiparallel to an acceleration vector 42 Gravity is aimed to measure. For this purpose, at least one of the absolute rotation angle sensors comprises at least one sensor from the group of gravity sensor, magnetic sensor and gyroscope.

5 shows by way of example and schematically a part of an imaging device 10 in a second location. At the imaging device 10 is on a support arm 64 a ceiling stand and a jib 60 a rotatable and positionable component 50 around three axes, for example around a first axis of rotation 54 , rotatable and positionable, arranged. Exemplary is a first absolute rotation angle sensor 56 which is due to the rotatable component 50 is arranged, shown. He is capable of a first absolute rotation angle 78 with respect to a first absolute rotation angle sensor axis 58 of the first absolute rotation angle sensor 56 in an inertial system, indicated by a Cartesian coordinate system 40 whose Z-axis is antiparallel to an acceleration vector 42 gravity is determined to determine. The determined absolute rotation angle 78 and a predefinable Sollabsolredotationswinkel be a computing and control device 44 to hand over. The computing and control device 44 is designed to be the first rotating means 52 in such a way that the first absolute rotation angle 78 coincides with the predetermined first Sollabsolredotationswinkel. Accordingly, the two other absolute rotation angles can be measured and the computing and control device 44 be passed, which receives two more Sollabsolredotationswinkel and by controlling further rotation means the rotatable and positionable component 50 rotated accordingly.

• S1) Bestimmen eines Absolutrotationswinkels bezüglich einer Absolutrotationswinkelsensorachse des wenigstens einen Absolutrotationswinkelsensors;
• S2) zur Verfügungstellen des Absolutrotationswinkels der Rechen- und Steuereinrichtung;
• S3) Entgegennahme des Absolutrotationswinkels und eines Sollabsolutrotationswinkels durch die Rechen- und Steuereinrichtung;
• S4) Ansteuerung des wenigstens einen Rotationsmittel derart, dass der Absolutrotationswinkel dem vorgebbaren Sollabsolutrotationswinkel entspricht;
• S5) Abfrage eines Abbruchkriteriums und falls das Abbruchkriterium erfüllt ist, „J“, beenden, „ENDE“, des Verfahrens, ansonsten, „N“, Sprung zu Verfahrensschritt S1.

6 shows an example of a flowchart of a method according to the invention 1 for positioning a rotatable, positionable component of an imaging device. The procedure 1 includes the method steps S1 to S5. It starts, "START", with method step S1 and ends, "END", after method step S5. The individual process steps are:

• S1) determining an absolute rotation angle with respect to an absolute rotation angle sensor axis of the at least one absolute rotation angle sensor;
• S2) providing the absolute rotation angle of the arithmetic and control means;
• S3) receiving the absolute rotation angle and a target absolute rotation angle by the computing and control device;
• S4) control of the at least one rotation means in such a way that the absolute rotation angle corresponds to the predefinable target absolute rotation angle;
• S5) Query of an abort criterion and if the abort criterion is met, "J", terminate, "END", of the method, otherwise, "N", jump to step S1.

In summary, further embodiments and advantages of the invention will be described. The invention proposes, inter alia, an imaging device in which, for example, an X-ray source and an X-ray image detector are each equipped with a plurality of rotation means for positioning X-ray emitter and X-ray image detector, and with an angle sensor for measuring absolute angles of rotation of the three spatial axes. These measured absolute values are compared, for example, with the aid of a computer program with angles to be controlled. In the event of deviations, the corresponding axes are automatically corrected.

By using angle sensors in the detector or spotlight, the actual angles can be determined. Based on the values, the axes of rotation can be corrected later.

By precisely adjusting the angle, it is possible to effectively reduce or prevent oblique radiation of the radiator onto the detector and thus improve the image quality. As a result, the non-imaging radiation dose can be reduced.

A conventional rotation angle detection via rotary encoders, which are arranged directly at the output of the rotation means, can be omitted, and the rotatable, positionable component can be positioned via the angle sensors. This results in a cost savings.

Elaborate models that try to anticipate deformations can be partially or completely eliminated.

Claims (12)

Imaging device ( 10 ) with a rotatable, positionable component ( 50 ), comprising a computing and control device ( 44 ), at least one rotating agent ( 52 ) for rotation of the movable component ( 50 ) about a rotation axis ( 54 ) and at least one absolute rotation angle sensor ( 56 ), wherein the at least one absolute rotation angle sensor ( 56 ) on the rotatable component ( 50 ) and wherein the at least one absolute rotation angle sensor ( 56 ) is designed to provide an absolute rotation angle ( 78 ) with respect to an absolute rotation angle sensor axis ( 58 ) of the at least one absolute rotation angle sensor ( 56 ) and the absolute rotation angle ( 78 ) of the computing and control device ( 44 ), and wherein the computing and control device ( 44 ) is adapted to the absolute rotation angle ( 78 ) and a predefinable Sollabsolredotationswinkel ( 76 ) and the at least one rotation means ( 52 ) so that the absolute rotation angle ( 78 ) the predefinable Sollabsolredotationswinkel ( 76 ) corresponds. Imaging device ( 10 ) according to claim 1, wherein the computing and control device ( 44 ) comprises a mathematical position model, which mathematical position model the mechanical properties of the imaging device ( 10 ) with a rotatable, positionable component ( 50 ) and where the mathematical Position model additionally in the control of the rotation means ( 52 ) received. Imaging device ( 10 ) according to claim 1 or claim 2, wherein the imaging device ( 10 ) three rotating means for rotating the movable component ( 50 ) around three axes of rotation ( 54 . 54 ' . 54 '' ) and three absolute rotation angle sensors ( 56 . 56 ' . 56 '' ), wherein the three absolute rotation angle sensors ( 56 . 56 ' . 56 '' ) are aligned in pairs differently and wherein the three absolute rotation angle sensors ( 56 . 56 ' . 56 '' ) are designed to have three absolute rotation angles ( 78 . 78 ' . 78 '' ) and the absolute rotation angles ( 78 . 78 ' . 78 '' ) of the computing and control device ( 44 ), and wherein the computing and control device ( 44 ) is adapted to the absolute rotation angles ( 78 . 78 ' . 78 '' ) and three presettable Sollabsolredotationswinkel and take the rotation means ( 52 ) so that the absolute rotation angles ( 78 . 78 ' . 78 '' ) correspond to the three predefinable Sollabsolredotationswinkeln. Imaging device ( 10 ) according to claim 3, wherein the three absolute rotation angle sensors ( 56 . 56 ' . 56 '' ) are aligned in pairs orthogonal to each other. Imaging device ( 10 ) according to claim 3 or claim 4, wherein the three absolute rotation angle sensors ( 56 . 56 ' . 56 '' ) in a common housing ( 74 ) are arranged. Imaging device ( 10 ) according to one of claims 3 to 5, wherein the three rotation means are aligned in pairs orthogonal to each other. Imaging device ( 10 ) according to one of the preceding claims, wherein at least one absolute rotation angle sensor ( 56 . 56 ' . 56 '' ) comprises at least one sensor from the group of gravity sensor, magnetic sensor and gyroscope. Imaging device ( 10 ) according to one of the preceding claims, wherein the movable component is an X-ray detector ( 20 ) or a radiation source ( 30 ). Procedure ( 1 ) for positioning a rotatable, positionable component ( 50 ) of an imaging device, comprising a computing and control device ( 44 ), at least one rotating agent ( 52 ) for rotation of the movable component ( 50 ) about a rotation axis ( 54 ) and at least one absolute rotation angle sensor ( 56 ), wherein the at least one absolute rotation angle sensor ( 56 ) on the rotatable component ( 50 ) and wherein the at least one absolute rotation angle sensor ( 56 ) is designed to provide an absolute rotation angle ( 78 ) with respect to an absolute rotation angle sensor axis ( 58 ) of the at least one absolute rotation angle sensor ( 56 ), comprising the following method steps: S1) determining an absolute rotation angle ( 78 ) with respect to an absolute rotation angle sensor axis ( 58 ) of the at least one absolute rotation angle sensor ( 56 ); S2) providing the absolute rotation angle ( 78 ) of the computing and control device ( 44 ); S3) acceptance of the absolute rotation angle ( 78 ) and a target absolute rotation angle ( 76 ) by the computing and control device ( 44 ); S4) activation of the at least one rotation means ( 52 ) such that the absolute rotation angle ( 78 ) the predefinable Sollabsolredotationswinkel ( 76 ) corresponds. Procedure ( 1 ) according to claim 9, wherein the method ( 1 ) an imaging device ( 10 ) used according to one of claims 2 to 8. Procedure ( 1 ) according to claim 9 or claim 10, wherein the process ( 1 ) is performed at least partially automatically. Procedure ( 1 ) according to one of claims 9 to 11, wherein the method ( 1 ) is repeatedly executed until a checked termination criterion (S5) is met.

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