WO2017133876A1

WO2017133876A1 - Tomography device

Info

Publication number: WO2017133876A1
Application number: PCT/EP2017/050629
Authority: WO
Inventors: Frank Barthel; Uwe Hampel; André Bieberle
Original assignee: Helmholtz-Zentrum Dresden - Rossendorf E. V.
Priority date: 2016-02-02
Filing date: 2017-01-13
Publication date: 2017-08-10
Also published as: DE102016101787B4; DE102016101787A1

Abstract

The invention relates to a tomography device with means for generating an electron beam; a deflecting device for deflecting the electron beam; a target; a controller for controlling the deflecting device using control data such that the electron beam encounters the target at a point of incidence and the point of incidence is guided along multiple paths which run on different planes, wherein x-ray radiation is produced at the point of incidence; and multiple x-ray detectors for detecting the x-ray radiation. Each x-ray detector has a detector element, which extends over all of the planes and which comprises a scintillator material, and a light detector for detecting scintillation light and generating a detector signal, and on the basis of the control data, each detector signal is assigned to the plane on which the point of incidence of the electron beam on the target is located when the detector signal is generated.

Description

imaging device

The invention relates to a tomography ievorrichtung for electron beam X-ray computer tomography, by means of which a three-dimensional image of the internal structure of an examination object is made possible.

In the electron beam X-ray computer tomography is a in a

Vacuum chamber guided electron beam by means of an electromagnetic deflection guided over a target. The target may e.g. be an annular or ring-shaped metal target. At the impact position of the

Electron beam on the target generates X-radiation, so that by means of the substantially inertia-free electron beam a fast moving

X-ray spot can be generated. With the X-rays can be a

Examination object, e.g. a patient to be screened. The by the

Object of investigation passing through and weakened by this

X-radiation is detected by means of an X-ray detector, e.g. by means of a circular or semi-circular X-ray detector arranged with a slight axial offset from the target. Beam attenuation profiles are generated when the examination object is irradiated from different directions, and the density distribution in the irradiated sectional plane is calculated from the measured data by using tomographic image reconstruction methods. The electron beam X-ray computer tomography is e.g. used in medical diagnostics, in particular for imaging the beating heart. In process tomography, the principle of electron beam tomography may e.g. can be used to create sectional sequences of flow processes with high temporal and spatial resolution. This is possible for currents that

Contain fluid components with different radiation attenuation values, that is fluid components with different average density or average atomic number. The three-dimensional distribution of

X-ray attenuation coefficients of the flowing fluids is thereby reconstructed from a set of two-dimensional sectional images, in which by the

Electron beam orbit predetermined scan plane successively several The three-dimensional flow structure is reconstructed from the time course. Since in this case the three-dimensional

However, the flow structure is reconstructed only from a sectional sequence of two-dimensional, successively recorded in one and the same scan plane sectional images, the information gain is limited. The actual three-dimensional appearance of the flow structure can not be directly detected, and the reconstructed three-dimensional flow structure can be detected by the

actual three-dimensional flow structure differ. DE 103 56 601 A1, DE 10 2008 005 718 A1 and DE 10 2009 002 114 B4 describe arrangements for electron beam tomography, by means of which

Three-dimensional images of the internal structure of objects under investigation are possible. These arrangements require a plurality of X-ray detector arcs, which are arranged offset from one another along an axial direction, wherein each of the X-ray detector arcs consists of a plurality of individual detectors, so that these

Arrangements associated with a complex structure. DE 103 56 601 A1 also describes an arrangement for three-dimensional X-ray tomography with a single-plane linear detector, wherein by means of a stepped target

Focal spot paths are generated in a plurality of z-planes, and the x-ray radiation is generated by means of the single plane arranged at a predetermined z-position.

Linear detector is detected so that the resulting radiation levels are not parallel to each other.

Conventional electron beam X-ray computer tomographs are thus limited to the three-dimensional imaging of the internal structure of

Investigation objects, especially of temporally variable

Investigation objects, suitable and / or require a complicated structure. The invention provides an uncomplicated electron beam

X-ray computer tomograph provided by means of which in a simple manner, a three-dimensional imaging of the internal structure of a

Object of investigation is possible. According to the invention, a tomography device for electron beam X-ray tomography is provided, by means of which a three-dimensional image of the internal structure of an examination subject is made possible. The

Tomography apparatus may include a receptacle (also referred to as a receiving space) for receiving an examination object therein, the object to be imaged is accordingly positioned in the receptacle.

The tomography apparatus has means for generating an electron beam (also referred to as an electron gun), e.g. an electron gun. The tomography apparatus further includes a deflector for deflecting and guiding the electron beam. The deflection device is for

Deflection and positioning of the electron beam by means of electrical and / or magnetic fields formed. The deflection device can thus a

be electron optical deflection device, which is used to position the

Electron beam is formed by electromagnetic fields.

The tomography apparatus has a target for decelerating the electron beam to generate X-ray radiation. The target is a material provided thereon for impinging the electron beam, the electrons of the electron beam generating X-ray radiation

be slowed down. The electron beam is directed by means of the deflection device to predetermined positions on the target. In the point of impact of the

Electron beam on the target produces X-radiation, which is used to irradiate the examination subject. The target may e.g. consist of a metal or have an X-ray generating active layer of a metal, wherein the metal e.g. Tungsten can be.

The tomography apparatus further comprises a control device for controlling (i.e., driving) the deflection device. The control device is designed to control the deflection device by means of control data. The control data define the time profile of the deflection of the electron beam by the deflection device, so that by means of the control data

Deflection device caused motion control of the electron beam defined is. The control data thus also define the time course of the

Impact position of the electron beam on the target. The control device is designed to drive the deflection device based on the control data such that the electron beam (in particular the electron beam impingement point) performs the movement sequence predetermined by the control data. The control of the deflection device according to the control data may be e.g. take place by the accordingly by the control device

Control signals are transmitted to the deflection device. For transmitting the control signals, the control device may be connected to the deflection device by means of a data connection.

The control device is designed (by means of appropriate control data) for controlling the deflection device such that the electron beam is deflected by the

Control device can be directed by the deflection device to predetermined positions on the target, so that the electron beam impinges on a predetermined impact position or a predetermined impact point on the target. At the point of impact of the electron beam on the target, X-radiation is generated, which is used to irradiate the examination subject. The

Impact position of the electron beam on the target is also called the electron beam impact point, electron beam impact position, X-ray focal spot or short

Designated focal spot.

The control device is set up (by means of appropriate control data) for controlling the deflection device such that the electron beam is guided over the target in such a way that the electron beam impingement point successively describes or passes through several paths on the target. The orbits described by the electron beam impact point on the target are also referred to as

Designated focal spot paths. The control device is for controlling the

Deflection device configured such that each of the focal spot paths extends in a different plane; These levels are also called orbit planes

Designated beam paths, all of these track planes are parallel to each other. Thus, the control device for controlling the deflection by means of

Control data is formed such that the electron beam from the

Control device by means of the deflection so feasible (and the

Operating the tomography device is performed so) that the

Electron beam impact point successively along several, running in different orbits focal spot paths travels over the target, all of these orbital planes are parallel to each other and thus a common

Have normal direction (also referred to as web plane normal direction). The orbital plane normal direction designates the direction of the normal vector of the orbital planes. At the point of impact with the electron beam, X-radiation is generated, which is used to examine the object to be examined. Of the

Electron beam impact point is thus guided along multiple focal spot paths (e.g., along at least two focal spot paths or, for example, along at least three focal spot paths, e.g., along two, three, or four

Brennfleckbahnen), each of these focal lanes in another

Railway level runs.

The tomography device also has a detector device with a plurality of detectors for detecting the x-ray radiation. The detectors are also referred to as X-ray detectors or single detectors, i. In the present case, the term X-ray detector denotes a single detector for detecting X-ray radiation. Such a detector or X-ray detector is therefore also called

X-ray single detector referred. Each of the X-ray detectors has a detector element extending along the web plane normal direction across all web planes and having a scintillator material from which scintillation light is generated by scintillation of incident X-radiation thereon. The

Scintillator material is a material that emits light upon incidence of X-ray radiation, in particular light generated by scintillation. The light generated by scintillation is also called scintillation light. The scintillation light is electromagnetic radiation having a different wavelength than that

X-rays. The scintillation light can be in the visible spectral range, for example lie, but also in the ultraviolet or infrared spectral range. The

Detector elements are used to convert the X-radiation into scintillation light and are therefore also referred to as conversion elements. Each of the X-ray detectors has a light detector (also referred to as a light converter) configured to detect the scintillation light and generate a detection signal based on the detected scintillation light. The detector signal generated by the light detector of an X-ray detector simultaneously forms the detector signal of the X-ray detector and is therefore also referred to as

X-ray detector signal denotes.

Thus, each of the X-ray detectors has a light detector, which is arranged and designed such that the scintillation light generated by the conversion element of the X-ray detector can be detected by it. Such a

Light detector may e.g. be designed as a photodetector, the light detector may e.g. a photodiode, a photomultiplier, a phototransistor or photoresistor. The light detector is designed such that scintillating light incident thereon is converted into an (e.g., electrical) signal which detects the scintillation light (e.g., the intensity of the scintillation light) as a detector signal of the X-ray detector and is also referred to as a scintillation light detector.

Each of the X-ray detectors thus has a conversion element and a

A scintillation light detector, wherein the conversion element is configured to convert X-rays incident thereon to scintillation light, and wherein the scintillation light detector is configured to detect the scintillation light and generate a detection signal based on the detected scintillation light. In particular, it can be provided that each of the X-ray detectors has a single conversion element and a single scintillation light detector.

In operation of the tomography apparatus, the electron beam impact point becomes sequential along the different ones according to the control data

Focusing paths are guided, with each of the focal spot paths in another Orbital plane is located so that the X-rays are emitted successively in the different orbital planes.

The amount of the orbital planes has two outer orbital planes, namely the

Orbital plane having the smallest coordinate with respect to the web plane normal direction and the web plane having the largest coordinate with respect to the web plane normal direction, these two outer web planes are also referred to as edge planes. The conversion element of each of the X-ray detectors extends across all the orbital planes, i. each conversion element is dimensioned and arranged such that its extension along the

Web plane normal direction is at least as large as the distance between the two outer web planes along the web plane normal direction, and that it extends along the web plane normal direction at least from the first edge plane to the second edge plane.

Thus, the conversion element of each X-ray detector or single detector extends along the common orbital plane normal direction of a set of several mutually parallel trajectory planes across all these trajectory planes, i. extends at least from the web plane with the smallest coordinate with respect to the web plane normal direction to the web plane with the largest coordinate with respect to the web plane normal direction. Thus, each of the parallel track planes in the extension intersects the conversion element. In other words, the scintillation-active detector element or

Conversion element of each individual detector dimensioned and arranged so that it is cut from each web plane of the set of parallel web planes, each of the web levels passes through one of the focal lanes.

The conversion element of each of the X-ray detectors extends over all the orbital planes, so that by means of each conversion element X-radiation can be detected in each of the orbital planes and converted into a detector signal by means of the associated scintillation light detector. Thus, by means of each of the X-ray detectors X-ray radiation can be detected in each of the track planes. The Tomographievornchtung is designed so that each of them

Detector signals of the X-ray detectors based on the control data, by means of which the control of the deflection device by the control device, is assigned to one of the orbital planes, wherein the detector signals are respectively assigned to that level, which originates the signal-causing X-radiation.

The tomography device is thus designed in such a way that the assignment of the detector signals of the X-ray detectors to the individual track planes takes place via the evaluation of the deflection control implemented by the control device on the basis of the control data. This allows the means of a

Conversion element generated detector signals, which are always detected by means of one and the same scintillation light detector, are uniquely associated with the plane in which the X-ray causing them has arisen.

Each detector signal is caused by X-radiation in the plane in which the X-ray focal spot is at the time of generation of the detector signal. The conversion elements extend over all planes, so that the X-ray detectors generate a detector signal regardless of which plane the focal spot is currently in. Therefore, the detector signals can not be uniquely assigned to one of the planes on the basis of the signal-generating X-ray detector initially.

The control data defines the movement of the electron beam and the time course of the impact position of the electron beam on the target, so that based on the control data for each detector signal at the time of

Detection of the detector signal present electron beam impact position can be determined. Thus, based on the control data, each detector signal can be assigned the electron beam incident position (and thus also the orbital plane in which this electron beam incidence position is located) at the time of the signal detection.

The tomography device is accordingly designed such that each of them Detector signal of the X-ray detectors based on the control data

is assigned to that orbital plane in which the electron beam impact point is in accordance with the control data during detection of the detector signal (i.e., at the time of generation of the detector signal by the respective X-ray detector). The tomography device is thus designed in such a way that it assigns each detector signal based on the control data to the plane controlled by the electron beam during the generation of the detector signal.

During operation of the tomography device, the electron beam is thus guided one after the other along the focal spot paths in the different track planes, so that X-ray radiation is successively generated in these planes. The intended for receiving the examination object receiving space of

Tomography device is arranged in the beam path of the X-ray radiation, so that the examination object is irradiated by the X-ray radiation, wherein the X-ray radiation is weakened. The X-ray detectors are arranged such that the conversion elements (or at least one or some of the conversion elements) in the beam path of the X-ray radiation behind the

Receiving space and thus in the beam path of the weakened by the examination object X-ray are arranged so that they can be detected by the X-ray attenuated by the examination object. The X-ray radiation which has passed through the examination object is converted by means of the conversion elements of the X-ray detectors into scintillation light, which is converted into a detector signal by means of the scintillation light detectors of the X-ray detectors. Based on the control data each

Detector signal associated with that level, the signal-causing

X-rays originated.

With varying position of the electron beam impingement point within a plane, the transmission direction in which the examination object is irradiated by the X-radiation also changes. Thus, by means of the X-ray detectors for each plane, a plurality of projections of the examination object can be detected at different transmission directions. A projection characterizes the beam attenuation profile present in the respective plane for a given one Transmission direction, which is given by the totality of the signals of several or all of the X-ray detectors in the respective Durchstrahlgeometrie. The projections associated with a common plane (with different

Radiation directions) form an assigned to this level

Projection data set.

By assigning each of the detector signals of the tomography device to the plane in which the electron beam point of incidence during the

If the detector signal is generated, the tomography device can thus be designed in such a way that it can generate a projection data set of the examination object assigned to this plane on the basis of the detector signals assigned to a common plane. By means of the X-ray detectors can thus for each of the levels of a record of Durchstrahlprojektionen

different projection angles are recorded.

By passing through all the orbital planes in succession, the electron beam impact point may enter from the tomography device for each of the orbital planes

Projection data set to be generated. The tomography device may thus for each of the planes for generating one of the plane associated

Projection data set to be formed so that an associated projection data set is generated by the tomography device for each of the orbital planes.

From each projection data set can in a known manner using

tomographic image reconstruction method, the inner structure of the examination subject present in the associated irradiated volume is determined without overlay, and e.g. be illustrated in the form of a tomographic image.

By an associated projection data set being detectable for each of the web levels by means of the tomography apparatus, an associated tomographic image or an associated tomographic image (eg in the form of a sectional image) can be detected for each of the web levels by means of the tomography apparatus. On the basis of the different levels associated with tomographic images, a Three-dimensional image of the internal structure of the examination object are generated. Thus, by means of the tomography device is a three-dimensional

Imaging of the internal structure of the object under examination (also referred to as 3D electron beam X-ray computed tomography).

By having each of the X-ray detectors having a conversion element extending across all of the orbital planes, X-ray radiation in each of the orbital planes can be detected by each of the X-ray detectors, so that the number of detectors required to cover the orbital planes can be minimized, with the required number the channels of the detector electronics can be kept low. As a result, the tomography device can be realized with a straightforward structure, in which case the costs for the

Detector material can be kept low. By virtue of the control data being able to be assigned to the signal-causing orbital planes, tomographic images can be generated at different positions of the examination object by means of the tomography device, so that a three-dimensional imaging of the examination subject is made possible, wherein, despite the small number of detectors, e.g. a 3D data set of individual projections of the examination object can be collected. By each X-ray detector is formed with only a single light detector, in particular, the number of required light detectors can be kept low.

According to one embodiment, each of the detector elements (also referred to as conversion elements) has, on its outer surface, a reflective coating for reflecting the scintillation light, the reflective coating covering the entire area

Outer surface of the detector element except for an exit window for the

Scintillation light acting section (also called scintillation light exit window) covered. The mirror coating is designed such that the scintillation light generated in the conversion element on the outer surface of the

Conversion element is reflected back into the interior and thus on

Leaving the conversion element is prevented. The portion of the detector element outer surface functioning as an exit window for the scintillation light is not covered by the mirroring. Due to the mirroring, the scintillation light can only at the scintillation light exit window from the

Exit conversion element. The scintillating light detector of each X-ray detector is arranged so as to exit from it through the scintillation light exit window

Conversion element of the X-ray detector emerging scintillation light can be detected. Due to the wavelength dependence of the reflectivity of mirrors, it is ensured that the X-ray radiation can enter the conversion element despite the reflective coating reflecting the scintillation light. The mirroring may e.g. be designed as a dichroic mirror (also referred to as interference mirror) or as a metal layer (for example in the form of a

Metal coating). The X-ray detectors are designed and arranged such that the conversion element of each X-ray detector extends along the Bahnebenen- normal direction over all of the orbital planes away. It can e.g.

be provided that each of the conversion elements is rod-shaped and is arranged to extend with its longitudinal direction along the web plane normal direction. In addition, each X-ray detector may be configured such that the scintillation light detector of the X-ray detector is disposed at one of the two bar ends of the bar-shaped conversion element (e.g., one of the two end faces of the conversion element constituting the longitudinal ends of the bar-shaped conversion element). In the event that the

Accordingly, the scintillation light exit window may be formed at the respective longitudinal end of the rod-shaped conversion element, e.g. at the respective end face.

According to one embodiment, the target is a hollow body with an inner circumferential surface running around a straight line or axis; such a target is also referred to below as a hollow body target. The axis around which the inner circumferential surface rotates and thus from the inner lateral surface

is enclosed below, also referred to as the inner axis or central axis designated. The inner circumferential surface of the hollow body target is also referred to as the inside of the hollow body target. It can be provided, for example, that the target is a hollow body with an inner circumferential surface in the form of the (outer) lateral surface of a straight or inclined cone or truncated cone, in particular in the form of the lateral surface of a straight or oblique circular cone or circular truncated cone. Such a target is also referred to as a funnel-shaped target. Such a target is preferably arranged such that the cone diameter of the cone or truncated cone defined by the inner circumferential surface decreases with increasing distance from the electron gun, so that the cone diameter decreases along the propagation direction of the electron beam.

The tomography device can be designed such that the electron beam can be guided by the control device by means of the deflection device (or guided in operating the tomography apparatus) such that the electron beam impinges on the target at an impact point on the inner lateral surface and the impact point successively along several, running on the inner circumferential surface of the hollow body target tracks is guided. In this case, the focal spot paths traversed by the electron beam impinging point result as sections between the inner circumferential surface of the target and the track planes, wherein the different track planes are arranged at a distance from each other along the inner axis.

According to one embodiment, the target is designed as a hollow body with an inner circumferential surface running around an inner axis, wherein the inner

Has lateral surface, the shape of the lateral surface of an oblique circular cone or oblique circular truncated cone.

Accordingly, the inner surface of the target defines an oblique circular cone or circular truncated cone with a circular cone base. The cavity target may be e.g. be arranged such that the circular cone base surface is perpendicular to the inner axis, so that the inner axis parallel to the

Normal direction of the cone base surface is (in this case, the inner axis is not parallel to the cone axis of the defined by the inner circumferential surface leaning cone or truncated cone). It can also be provided that the inner axis is parallel to the web plane normal direction; In this case, each of the focal spot lanes extends in a plane perpendicular to the inner axis, the different lane planes being spaced apart along the inner axis and the focal lobes extending as cuts between the inner surface of the target and perpendicular to the inner axis Levels arise. In this case, the orbital plane normal direction is perpendicular to the circular cone base surface, so that the web planes are parallel to the cone base surface.

According to another embodiment, the target is a hollow body with an inner surface which is rotationally symmetrical relative to an axis, in this case the axis is also referred to as the axis of symmetry. Accordingly, the target may be e.g. a rotationally symmetrical hollow body with respect to an axis of symmetry (for example, a hollow cylinder, hollow cone or hollow truncated cone). Rotationally symmetrical hollow bodies have an outer and an inner lateral surface, wherein the outer and the inner lateral surface are rotationally symmetrical with respect to the axis of symmetry. The target can in particular be designed such that the inner

Lateral surface is cone-shaped or conical and the shape of the (outer)

Has lateral surface of a straight circular cone or straight circular truncated cone.

The tomography device can be designed in such a way that the electron beam can be guided by the control device by means of the deflection device such that the electron beam strikes the target at an impact point on the rotationally symmetrical inner lateral surface and the impact point successively along several, running on the inner circumferential surface of the target circular paths is performed. Each of the

Circular paths extends in a plane which is perpendicular to the axis of symmetry of the rotationally symmetrical inner circumferential surface, wherein the different

Circular path planes along the axis of symmetry are each arranged at a distance from each other.

Accordingly, the traversed by the electron beam impact point Circular paths as sections between the rotationally symmetrical inner lateral surface of the target and planes perpendicular to the axis of symmetry of the inner

Are lateral surface, so that the normal direction of the web planes is parallel to the axis of symmetry. The orbits traversed by the focal spot are thus concentric with the axis of symmetry (i.e., the centers of the orbits are all on the axis of symmetry) so that the orbits are also concentric

to each other.

The defined by the inner circumferential surface of the hollow body target cavity is also referred to as the target interior. The tomography device can thus be designed in such a way that the electron beam is directed towards the inner

The outer surface of the target is directed so that the X-ray radiation is emitted from the inner circumferential surface into the target interior (for example, toward the axis of symmetry) and transilluminates the target interior. The receiving space provided therein for receiving the examination object can accordingly be arranged in the target interior.

It can be provided that the X-ray detectors (which are also known as

Röntgeneinzeldetektoren be designated) to form a

X-ray detector arches are arranged in a row. Accordingly, it may be provided that the tomography device comprises a detector arc having a plurality of X-ray single detectors, i. X-ray detectors in the form of

Single detectors having. It can be provided that the X-ray detectors form an X-ray detector arc along a circular line section (so-called partially circular detector arc) or along a circular line

(so-called fully circular detector arc) are arranged in a row. The detector arc can be arranged such that the center of the

Detector arc (i.e., the center of curvature of the circle) lies on the inner axis so that the detector arc is concentric with the inner axis. When the cavity target is formed with an inner circumferential surface which is rotationally symmetrical with respect to an axis of symmetry, it is possible, e.g.

be provided that the center of the detector arc lies on the axis of symmetry of the rotationally symmetrical inner circumferential surface of the cavity target, so that the detector arc is arranged concentrically to the axis of symmetry of the inner circumferential surface.

It can be provided in particular that the conversion elements of

X-ray detectors along the circular line section or the circular line

are arranged in a row, wherein the conversion elements are rod-shaped as described above and are arranged to extend with its longitudinal direction along the web plane normal direction, and wherein the

Scintillation light detectors are each arranged at one of the two longitudinal ends of the rod-shaped conversion elements.

The X-ray detector arc can be arranged inside or outside the target interior. The X-radiation is emitted from the inner surface of the target into the target interior. When the detector arc is located outside the target interior, the target is for the X-radiation

permeable, so that at least a part of the incident thereon

X-ray passes through the target. When the detector arc is arranged within the target interior, it may likewise be provided that the target is made permeable to the x-radiation (in this case, however, this is not absolutely necessary).

Thus, in one embodiment, the target is designed to be transmissive to x-ray radiation (e.g., by targeting the target)

is formed correspondingly small thickness or material thickness). The target may e.g. be formed such that the intensity of the X-ray radiation as it passes through the target by at most 50% (for example, at most 25%, preferably at most 10%) is reduced.

The tomography device may have a target carrier body, wherein the target is applied in the form of a coating or x-ray generation layer on the target carrier body. It can be provided, for example, that the hollow body target is applied with its outer lateral surface in contact with the target carrier body. It may be provided, for example, that the target as (eg rotationally symmetrical) hollow body with an inner and an outer

Formed lateral surface, wherein the target is applied with its outer lateral surface contacting on the target carrier body. In this case, the target can be formed with a thin layer thickness, wherein the target carrier body can serve to stabilize the target.

By means of the target carrier body, the target can be used in particular as for

X-ray transmissive target be formed by the target is applied as a coating with such a thin layer thickness on the target carrier body, that the coating is transparent to the X-radiation. In this case, the target carrier body is also for the X-radiation

permeable and may e.g. made of a material having a lower atomic number than the target. According to one embodiment, the tomography device has a diaphragm for spatially limiting the X-ray radiation, wherein the diaphragm has one or more through openings for the passage of the X-radiation at the level of each of the track planes, and the diaphragm at the height between the track planes respectively shielding sections (in shape from

Material sections, e.g. in the form of material webs) for shielding the

X-radiation has. The panel thus has, along the Bahnebenen- normal direction alternately through openings and Abschirmabschnitte, wherein in each orbit plane one or more passage openings are arranged and wherein between the track planes in each case a shielding section is arranged. The diaphragm can also be designed such that a shielding section is arranged on each side of each passage opening along the normal direction.

The diaphragm is arranged in the beam path of the X-ray radiation between the target and the detector device in such a way that it emits light emitted at the target

X-rays only after passing through the aperture meets the X-ray detectors. By means of the aperture, the opening angle or the divergence of the

X-rays are reduced, so that the aperture acts as a kind of limiter for the X-ray radiation, whereby a higher image quality is possible. When the target is designed as a hollow-body target with an inner circumferential surface running around an inner axis, it is possible to form the diaphragm in a circular or annular manner around the inner axis and to arrange it concentrically with respect to the inner axis. Accordingly, the annular aperture may be arranged such that its ring axis coincides with the inner axis.

When forming the target as a hollow body target with respect to a

Symmetry axis rotationally symmetrical inner circumferential surface may e.g.

be provided to form the aperture circular or annular around the axis of symmetry circumferentially and concentric with the axis of symmetry (and thus also to the rotationally symmetrical inner lateral surface) to arrange. That Accordingly, the annular aperture is arranged such that its ring axis with the

Symmetry axis of the rotationally symmetrical inner lateral surface of the target coincides. The annular aperture is also referred to as ring aperture.

By the annular diaphragm is arranged concentrically to the inner axis, from her the target interior and thus also the formed therein

Enclosed around recording room, so regardless of the

Circumferential position of the X-ray focal spot a dazzling effect is ensured.

The ring shield may be located inside or outside the target interior. It can e.g. Provision is made for the detector arc to be arranged outside the target interior and for the annular diaphragm to be arranged on a circumference between the target hollow body and the detector arc outside the target interior (the target being permeable to the x-ray radiation). According to one embodiment, the diaphragm is annular and arranged outside the target concentric to the inner axis, wherein the detector arc is arranged outside the diaphragm concentric with the inner axis (the target is transparent to the X-ray radiation). According to one

Embodiment with a hollow body target with respect to a

Symmetryeachse rotationally symmetrical inner lateral surface is thus formed the aperture circular and outside the target concentric to the Symmetryeachse arranged, wherein the detector arc is arranged outside the diaphragm concentric with the axis of symmetry (wherein the target for the

X-radiation is permeable). As another example, it may be provided that the detector arc is located outside of the target interior and the annulus is located within the target interior (the target being transmissive to the x-ray radiation). In this embodiment, the aperture of the X-ray radiation is passed through twice before impinging on the detector arc, whereby a higher imaging quality can be made possible.

In one embodiment, the detector element is each of the

X-ray detectors (complete) of scintillator material, i. of a material from which scintillation light is generated by scintillation of incident X-ray radiation thereon.

According to another embodiment, each of the detector elements along the web plane normal direction alternately comprises sections with scintillator material and sections without scintillator material. Such designed in sandwich construction detector elements are also referred to as alternating detector elements or alternating conversion elements.

The sections of scintillator material are also referred to as scintillation sections. Each of the scintillation sections has scintillator material. It can e.g. be provided that the scintillation sections completely off

Scintillator material exist. Alternatively, it can be provided that the

Scintillation sections consist only partly of scintillator material, e.g.

in that each scintillation section has an outer layer or surface layer of scintillator material.

The sections without scintillator material are not scintillating and are also referred to as passive sections. The passive sections are made of a material which is transparent or optically clear to the scintillation light. The passive sections thus consist of a Lichtleitmatehal, of which in the

Scintillation sections generated scintillation light forwarded or

is passed through. The light-guiding material may e.g. have a lower atomic number than the scintillator material.

It can e.g. be provided that each of the detector elements at the level of each of the track planes has a (scintillation-active) scintillation section and at the level between the track planes one (not scintillation active)

Passive section has. According to this embodiment, each of the

Detector elements along the Bahnenbenen-normal direction alternately

Scintillation sections and passive sections in such a way that in each track plane, a scintillation section is arranged and between the track planes each a passive section is arranged. Accordingly, the X-ray radiation detected by the detector elements can be spatially limited to the extent of the scintillation sections along the web plane normal direction by means of the detector elements, so that, as it were, an aperture effect can be achieved by means of the detector element itself.

According to another embodiment, it is provided that each of the

Detector elements at the level of each of the orbital planes has a (non-scintillation-active) passive section and at height between the track planes each having a scintillation section. According to this embodiment, each of the

Detector elements along the Bahnenbenen-normal direction alternately

Scintillation sections and passive sections in such a way that in each track plane, a passive section is arranged and between the track planes one each

Scintillatinsabschnitt is arranged. According to this embodiment, moreover, each detector element can be designed in such a way that a scintillation section is arranged on both sides of each passive section along the web plane normal direction.

It can be provided, for example, that the target is designed as a cavity target with an inner circumferential surface running around an inner axis, wherein the X-ray detectors form a fully circular detector arc are arranged, which is arranged concentrically to the inner axis within the defined by the inner circumferential surface target interior, and wherein each of the detector elements at the level of each of the orbital planes has a (non-scintillation active) passive portion and at height between the orbital planes each having a scintillation section. It can be provided, for example, that the target is designed as a cavity target with an axis of rotation symmetrical with respect to an inner circumferential surface for impinging the electron beam thereon, wherein the X-ray detectors to form a fully circular

Detector arc are arranged, which is arranged concentric with the axis of symmetry within the defined by the inner circumferential surface target interior, and wherein each of the detector elements at the level of each of the orbital planes has a (non-scintillation active) passive section and at height between the

Bahnenbenen each having a scintillation section. The receiving space provided for accommodating the examination subject is located within the cavity defined by the fully circular detector arc.

According to this embodiment, the X-ray radiation from the inner

Jacket surface emitted into the target interior inside. Before reaching the receiving space (or the examination object received therein), the X-radiation passes through the detector arc, wherein the X-ray radiation is transmitted within a web plane of the arranged at the level of this orbital plane passive sections of the detector elements, but greatly weakened by the adjacent scintillation sections (da These scintillation sections, the X-rays in scintillation light

is converted). As a result, the X-radiation before reaching the

Spatially limited examination object, whereby the image quality can be improved. Subsequently, the spatially delimited

X-ray radiation, the examination object and the radiation weakened by the examination subject strikes again on the detector arc, wherein it is detected by the present-day X-ray detectors. By means of the detecting alternating detector elements, as already explained above, the detected X-ray radiation is spatially limited again to the extent of the scintillation sections along the plane of the normal plane of the web, whereby the imaging quality is improved again can be improved. In this embodiment, the X-ray radiation used for imaging does not run exactly in the respective orbital plane, but in a (small) angle thereto. The tomography device may include a vacuum chamber within which the electron beam is guided. The tomography device may be so

be formed such that the electron beam is guided in the vacuum chamber, wherein the target is disposed within the vacuum chamber. In addition, it can be provided that the means for generating the electron beam and / or the deflection device and / or the X-ray detectors and / or the diaphragm are arranged within the vacuum chamber.

The invention is illustrated below with reference to embodiments with reference to the accompanying figures, wherein the same or similar features are provided with the same reference numerals; Here are shown schematically:

Figure 1 is a side sectional view of a tomography device according to an embodiment;

Figure 2 is a sectional view of the tomography device of Figure 1 in

Top view; and

Figure 3 is a side sectional view of a tomography device according to another embodiment.

Figures 1 and 2 show schematically a tomography device 1 according to one embodiment. The tomography device 1 has a receiving space 3, in which an examination object 5 to be imaged is accommodated. The

Tomography device 1 comprises means 7 for generating an electron beam 9 and an electron-optical deflection device 11 for deflecting the

Electron beam 9 on.

The tomography device 1 also has a target 13. The target 13 is designed as a hollow body with an inner circumferential surface 15, wherein the inner

Lateral surface 15 is rotationally symmetrical with respect to the symmetry axis 17. The inner lateral surface 15 is also referred to as the inner side 15 of the target 13. The target 13 is rotationally symmetrical (with respect to the axis of symmetry 17)

Hollow truncated cone formed (also referred to as a funnel-shaped target). The symmetry axis 17 runs parallel to the z-axis of the Cartesian xyz coordinate system shown in the figures. The formed by the target 13

Hollow truncated cone tapers in the negative z direction, i. the diameter of the hollow truncated cone formed by the target 13 decreases with increasing distance from the electron gun 9. The target 13 may e.g. optionally be applied in the form of a coating on a target carrier body 19. The inner circumferential surface 15 of the target 13 also defines a target interior

designated cavity, within which the receiving space 3 is arranged.

The tomography device 1 also has a control device 21, which is connected to the deflection device 11 and is designed to control the deflection device 11 by means of control data. The deflection device 11 is of the

Control device 21 is controlled by means of appropriate control signals such that the electron beam 9 impinges on a hit point 23 on the target 13, and that the impact point 23 successively describes a plurality of webs in different planes on the target 13. The point of incidence 23 of the electron beam on the target 13 is also referred to as an X-ray focal spot, the paths traversed by the impact point 23 are also referred to as focal spot paths. Of the

Electron beam 9 is guided within a vacuum in a vacuum chamber 24.

The control device 21 is designed to drive the deflection device 11 by means of corresponding control data in such a way that the electron beam 9 impinges on an impact point 23 on the inner circumferential surface 15 of the target 13 and the impact point 23 is guided successively along a plurality of circular paths (also referred to as circular paths). which run on the rotationally symmetrical inner lateral surface 15. The movement of the electron beam impingement point 23 along circular paths is illustrated in FIG. 1 by the circular arrow 30. Each of the circular paths is located in another, perpendicular to the z-direction (and thus also perpendicular to the axis of symmetry 17) extending plane. All these planes have the z-direction as a common normal direction and are along This normal direction is arranged at a distance from each other. In Figure 1, four levels 25, 27, 29 and 31 are exemplified, so that the

Impact point 23 is guided in succession along four circular paths, wherein according to Figure 1, the impact point 23 is located in the plane 27.

At the impact point 23 of the electron beam 9 on the target 13 is formed

X-ray radiation 32, which is emitted fan-shaped from the point of impact 23 into the target interior (illustrated schematically in FIG. 1 by the two marginal rays of the radiation fan 32). The X-ray radiation 32 passes through the receiving space 3 arranged within the target interior and the examination object 5 received therein.

In the embodiment of Figures 1 and 2, the target 13 for the

X-ray radiation 32 formed permeable. The target 13 may e.g. be formed with such a small Schicktdicke that the intensity of the

X-ray radiation 32 when passing through the target 13 by at most 50% (for example, at most 25%, preferably at most 10%) is reduced. In the presence of a target carrier body 19, this is made of a material with a lower

Nuclear charge number as the target 13, wherein the target carrier body 19 is also formed permeable to the X-ray radiation 32.

The tomography device 1 has a detector device 33. The

Detector device 33 has a plurality of X-ray detectors 35. The

X-ray detectors 35 are in the form of individual detectors 35 and are therefore also referred to as X-ray single detectors 35.

Each of the X-ray detectors 35 has a detector element 37 which extends along the normal direction of the web planes 25, 27, 29, 31 across all these web planes. Each of the detector elements 37 has scintillator material, ie, material from which X-radiation incident thereon is generated by scintillation scintillation light. Since X-ray radiation is converted into scintillation light by the detector elements 37, the detector elements 37 are also referred to as conversion elements 37. In the embodiment of Figure 1, each the detector elements 37 entirely of scintillator material.

Each detector element 37 extends along the orbital plane normal direction (z-direction) across all orbital planes 25, 27, 29, 31, i. extends at least from the web plane 31 with the smallest z-coordinate to the

Orbital plane 25 with the largest z-coordinate (in this case extend the

Detector elements 37 even beyond the two outer track planes 31 and 25). Each detector element 37 is thus dimensioned and arranged such that its extent along the web plane normal direction (z direction) is at least as great as the distance between the two outer web planes 25 and 31 along the web plane normal direction (z direction), and that's it

extends at least from the first edge plane 31 to the second edge plane 25. Furthermore, each of the X-ray detectors 35 has a light detector 39 configured to detect the scintillation light and generate a detection signal based on the detected scintillation light. The light detectors 39 are also referred to as scintillation light detectors 39. Present are the

Light detectors 39 e.g. Photodiodes.

In the present case, each of the detector elements 37 is rod-shaped and arranged with its longitudinal direction along the normal direction of the web planes 25, 27, 29, 31 (ie along the z-direction) running. Each of the rod-shaped

Detector elements 37 has an end face at each of its two longitudinal ends. The scintillation light detector 39 of each X-ray detector 35 is arranged on one of the two longitudinal ends of the associated detector element 37, as an example on the end face of the detector element 37 facing away from the electron beam 9.

Each of the detector elements 37 has on its outer surface a reflective coating 41, which is designed to reflect the scintillation light, wherein the

Mirroring 41, the outer surface of the detector element 37 to one as

Exit window for the scintillation light acting section covered. In the present case, the reflective coating 41 of each detector element element 37 covers its outer surface on the electron beam 9 facing away from the end face, on which the

Scintillation light detector 39 is arranged. The mirror coating 41 may e.g. be formed in the form of a reflective coating (e.g., as a dichroic mirror or as a metal coating).

The X-ray detectors 35 are to form a fully circular

Detector arc 43 arranged along a circular line juxtaposed, wherein the detector arc 43 is disposed outside of the target 13 concentric with the axis of symmetry 17. The detector arc 43 is thus arranged around the target 13 circumferentially concentric with the axis of symmetry 17 and the target 13.

The tomography device 1 has a circular aperture 45. The aperture 45 has at the level of each of the levels 25, 27, 29, 31 a passage opening or

Passage opening 47 for the passage of the X-ray radiation 32. The aperture 45 also has at height between the levels 25, 27, 29, 31 each one

Shielding portion 49 for shielding the X-ray radiation 32. In addition, the aperture 45 is formed such that each passage opening 47 along the

Bahnenbenen-normal direction is bounded on both sides by a shield 49. The circular aperture 45 is arranged extending on a circumference between the target 13 and the detector arc 43, concentric with the axis of symmetry 17 or the target 13, so that the annular aperture 45 is arranged outside the target 13 concentric with the axis of symmetry 17 and the Detector arc 43 outside the aperture 45 concentric with the

Symmetryeachse 17 is arranged.

FIG. 2 shows a schematic sectional view of the tomography apparatus 1 according to FIG. 1 in a plan view, wherein in particular the arrangement of the

Detector arc 43 and the annular aperture 45 is concentric with the axis of symmetry 17 of the inner circumferential surface 15 of the target 13 can be seen. FIG. 2 shows by way of example a circular path 51 (here as an example the circular path running in plane 27) of the electron beam impingement point 23. At the electron beam impingement point 23, X-ray radiation 32 is emitted fan-shaped, wherein in FIG. 2 the two marginal rays of the radiation fan 32 are schematically illustrated. The electron beam 9 strikes the target 13 in each case in one of the planes 25, 27, 29, 31, with x-ray radiation 32 being emitted into the target interior and thus also into the receiving space 3 at the electron beam impingement point 23. The

X-ray radiation 32 radiates through the receiving space 3 and in it

recorded examination object 5, wherein the X-ray radiation 32 is weakened. Subsequently, the radiation passes through the examination object 5

X-ray 32 has passed through the portion of the X-ray transmissive target 13, opposite the electron-beam impingement point 23.

Subsequently, the X-ray radiation 32 impinges successively on the diaphragm 45 and the detector arc 43. Before the X-ray radiation 32 strikes the detector arc 43, it is spatially limited by the diaphragm 45 to the extent of the passage openings 47 along the z-direction.

The incident on the detector sheet 43 X-ray radiation 32 is incident on the

Conversion elements 37 of the X-ray detectors 35 and is of these in

Scintillation light converted. The scintillation light is detected by the scintillation light detectors 39 and converted into a detector signal.

The control device 21 is designed to control the deflection device 11 on the basis of control data, the control data defining the time profile of the deflection of the electron beam 9 by the deflection device 11 and thus also the time profile of the impact position 23 of the electron beam on the target 13. The control data thus define, in particular, in which of the planes 25, 27, 29, 31 the electron beam impingement point 23 becomes one

predetermined time is. As an example, the control data may be a

Target coordinate function z (t) include, which describes the controlled by the deflection device 11 coordinate z of the electron beam impact point 23 as a function of time t.

The tomography device 1 is formed such that each of them of the X-ray detectors 35 generated detector signals based on the control data of those of the levels 25, 27, 29, 31 is assigned, in which the impact point 23 of the electron beam 9 during the generation of the respective detector signal is located. As an example, in the present case, that of the planes 25, 27, 29, 31 in which the electron beam impingement point 23 is at a given time t can be determined from the inverse function of the target coordinate function z (t) (this inverse function assigns each time t) This time present coordinate z of the electron beam Aufnreffposition 23, and thus also at this time of the electron beam 9 driven web plane).

The tomography device 1 may be e.g. an evaluation device, which is connected to the detector device 33 and is designed such that from each of the generated by the X-ray detectors 35 detector signals based on the control data of those of the levels 25, 27, 29, 31 is assigned, in which the impact point 23 of the electron beam 9 at the time of generation of the respective detector signal. The evaluation device may e.g. be integrally formed with the control device 21.

The electron beam impact point 23 travels along the

Circular paths in the planes 25, 27, 29, 31, wherein X-radiation is formed, by means of which the examination object 5 is irradiated. For each of the planes 25, 27, 29, 31, tomography apparatus 1 uses the X-ray detector arc 43 to generate a data set of transmission projections of the examination object 5 at different transmission directions or from different ones

Projection angles recorded. The projection data sets assigned to the different planes 25, 27, 29, 31 enable a three-dimensional image of the internal structure of the examination object 5.

FIG. 3 illustrates a tomography device 1 'according to a further embodiment. The tomography device 1 'has no aperture and also differs in the design and arrangement of the target 13 and the X-ray detectors 35 of the tomography device 1 according to Figures 1 and 2. Otherwise correspond to the structure and operation of the Tomograph ievorrichtung V of Figure 3 to those of the tomography device 1 according to Figures 1 and 2, so reference is made in this regard to the explanations with reference to Figures 1 and 2. The tomography apparatus 1 'has a hollow body target 13 with an inner circumferential surface 15 rotationally symmetrical with respect to an axis of symmetry 17, the inner lateral surface 15 being conical or conical and the shape of the outer lateral surface of a straight circular cone or circular truncated cone

equivalent. The symmetry axis 17 runs parallel to the z-axis of the xyz coordinate system shown in the figures. Unlike the

Tomography device 1 according to Figure 1, the target 13 of the

Tomography device V according to Figure 3 is not designed to be transparent to the X-ray radiation 32. In the tomography device 1 ', analogously to the tomography device 1, the control device 21 for driving the deflection device 11 by means of

corresponding control data is formed such that the electron beam 9 impinges on an impingement point 23 on the inner circumferential surface 15 of the target 13 and the impact point 23 is guided successively along a plurality of circular paths which extend on the rotationally symmetrical inner lateral surface 15. Each of the

Circular paths lie in another, perpendicular to the z-direction (and thus also perpendicular to the axis of symmetry 17) extending plane. All these levels 25, 27, 29, 31 have the z-direction as a common normal direction and are arranged along this normal direction in each case at a distance from each other. At the impact point 23 of the electron beam 9 on the target 13 is formed

X-ray radiation 32 which is emitted from the impact point 23 into the target interior.

The tomography device 1 'has a detector device 33 with a plurality of X-ray detectors 35. Each of the X-ray detectors 35 has one

Detector element 37 (also referred to as conversion element 37) extending along the normal direction of the web planes 25, 27, 29, 31 over all these

Bahnenbenen extends across. The X-ray detectors 35 of the Tomograph ievorrichtung V are formed such that the detector element 37 of each of the X-ray detectors 35 along the web plane normal direction (z-direction) alternately sections 53 with scintillator and sections 55 without scintillator material. The portions 53 of scintillator material are also referred to as scintillation portions 53. The sections 55 without scintillator material are also referred to as passive sections 55. In FIG. 3, the

Scintillation sections 53 shown with a different hatching than the

Passive sections 55. The scintillation sections 53 may be e.g. completely made of scintillator material or having an outer coating of scintillator material. Each detector element 37 has a passive section 55 at the level of each of the track planes 25, 27, 29, 31, and a scintillation section 55 at the level between the track planes. The detector elements 37 are also designed such that each passive section 55 along the Bahnebenen- normal direction is bounded on both sides by a Szintillationsabschnitt 53.

Furthermore, each of the X-ray detectors 35 has a scintillation light detector 39 configured to detect the scintillation light and generate a detection signal based on the detected scintillation light. Analogous to Figure 1, in the embodiment of Figure 3, each of the detector elements 37 is rod-shaped and arranged with its longitudinal direction along the normal direction of the web planes 25, 27, 29, 31 (ie, along the z-direction) running. The scintillation light detector 39 of each X-ray detector 35 is arranged on one of the two longitudinal ends of the associated detector element 37, as an example on the end face of the detector element 37 facing away from the electron beam 9. Also according to the embodiment of FIG. 3, each of the detector elements 37 has a mirror coating on its outer surface 41 for reflecting the scintillation light, wherein the reflective coating 41 covers the outer surface of the detector element 37 except for a section acting as an exit window for the scintillation light.

In the present case, the reflective coating 41 of each detector element element 37 covers it

Outer surface except for the electron beam 9 facing away from the end face on which the scintillation light detector 39 is arranged. In the embodiment according to FIG. 3, the x-ray detectors 35 are arranged in a row along a circular line, forming a fully circular detector arc 43, the detector arc 43 being arranged inside the target 13 concentrically with the axis of symmetry 17. The detector arc 43 is thus arranged concentrically with the inner lateral surface 15 within the target inner space defined by the inner lateral surface 15. The recording room 3 of the

Tomography device V is disposed within the interior defined by the detector sheet 43. The electron beam 9 strikes the target 13 in each case in one of the planes 25, 27, 29, 31, with x-ray radiation 32 being emitted into the target interior space at the electron beam impingement point 23. Before reaching the receiving space 3 (and the object to be examined 5) received therein passes through the

X-ray radiation 32, the detector sheet 43, wherein the X-ray radiation 32 within a web plane 25, 27, 29, 31 of the arranged at the level of this orbital plane passive sections 55 of the detector elements 37 is transmitted substantially unattenuated, but of the two sides of it

adjacent scintillation sections 53 is greatly weakened, whereby the X-ray radiation 32 is spatially limited before reaching the examination object 5. Subsequently, the thus spatially limited X-ray radiation 32 irradiates the examination subject 5 and the radiation, which is weakened by the examination subject, strikes again the detector arc 43, being detected by the X-ray detectors 35 on this side. By means of the detecting detector elements 37, the detected x-ray radiation is spatially focused on the extent of the

Scintillation sections 53 along the Bahnebenen-normal direction (z-direction) limited. According to this embodiment, the one used for imaging runs

X-ray radiation 32 not exactly in the respective orbital plane 25, 27, 29, 31, but in a (small) angle thereto. The X-ray radiation 32 strikes the scintillation sections 53 of the detector elements 37 arranged adjacent to the respective plane and is converted by these into scintillation light. The scintillation light is detected by the scintillation light detectors 39 and into a detector signal

transformed. Also in the embodiment according to FIG. 3, the control device 21 is set up to control the deflection device 11 on the basis of control data, the control data representing the time profile of the deflection of the electron beam 9 by the deflection device 11 and thus also the time course of the impact position 23 of the electron beam on the target 13 define. The control data thus define in particular in which of the planes 25, 27, 29, 31 the electron beam impingement point 23 is located at a predetermined time. As an example, the

Control data include a target coordinate function z (t), which describes the controlled by the deflection device 11 coordinate z of the electron beam impact point 23 as a function of time t.

The tomography device V is designed (eg by means of the control device 21, which can also function as an evaluation device) such that each of the detector signals generated by the X-ray detectors 35 is assigned to those of the planes 25, 27, 29, 31 based on the control data which is the impact point 23 of the electron beam 9 during the generation of the respective detector signal. As an example, in the present case, that of the planes 25, 27, 29, 31 in which the electron beam impingement point 23 is at a given time t can be determined from the inverse function of the target coordinate function z (t) (this inverse function assigns each time t) this time present coordinate z of the electron beam impact position 23, and thus to the time at this time of the electron beam 9 driven web plane).

For each of the levels 25, 27, 29, 31, a data set of transmission projections of the examination object 5 is acquired by the tomography device 1 'by means of the X-ray detector arc 43 at different transmission directions or from different projection angles. The projection data sets assigned to the different planes 25, 27, 29, 31 enable a three-dimensional image of the internal structure of the examination object 5.

In the embodiments according to FIGS. 1 to 3, the target is a cavity target with an inner circumferential surface 15 which is rotationally symmetrical with respect to the inner axis 17 which acts as the axis of symmetry. Alternatively, at these embodiments, instead of the cavity target with the rotationally symmetrical inner lateral surface, a cavity target with an inner lateral surface 15 revolving around an inner axis 17 can be provided such that the inner lateral surface 15 has the shape of the lateral surface of an oblique circular cone or oblique circular truncated cone, eg tapered in negative z-direction. According to this alternative, the inner circumferential surface 15 of the target defines an oblique circular cone or circular truncated cone with a circular one

Cone base. According to this alternative embodiment, it can be provided, in particular, that the cavity target is arranged such that the

Cone base is perpendicular to the inner axis 17, so that the normal direction of the cone base surface is parallel to the inner axis 17. Since the Bahnebenen- normal direction is also parallel to the inner axis 17, in this case, the track planes are parallel to the cone base, wherein the traversed by the electron beam incidence Brennflckbahnen be as cuts between the obliquely conical inner surface of the target and perpendicular to the

Inner axis 17 extending track planes arise.

List of reference numbers used

1, V Tomography device

3 recording nests for recording an examination object

5 examination object

7 means for generating an electron beam

9 electron beam

11 deflection device

13 target

15 inside / inner surface of the target

17 inner axis / symmetry axis

19 target carrier body

21 control device

23 Impact position of the electron beam on the target / focal spot

24 vacuum chamber

25, 27, 29, 31 levels / track planes in which the focal lanes run

30 movement of the electron beam

32 X-ray radiation

33 detector device

35 x-ray detector / single detector

37 detector element / conversion element

39 light detector / scintillation light detector

41 mirroring

43 detector arc

45 aperture

47 aperture of the aperture

49 Shield section of the panel

51 circular path of the electron beam impact point

53 Section with Scintillator Material / Scintillation Section

55 Section without Scintillator Material / Passive Section

Claims

claims

1 . An electron beam x-ray computer tomography tomography device for imaging the internal structure of an examination subject (5), comprising: - means (7) for generating an electron beam (9),

a deflection device (11) for deflecting the electron beam (9),

a target (13) for decelerating the electron beam (9) to produce X-radiation (32),

a control device (21) which is designed to control the deflection device (11) by means of control data such that the electron beam (9) can be guided by the control device (21) by means of the deflection device (11) in such a way that the electron beam (9) is guided at one Impact point (23) impinges on the target and the impact point is guided successively along a plurality, in different planes (25, 27, 29, 31) extending tracks, wherein the planes are parallel to each other and along a common normal direction (z) at a distance to each other are arranged, wherein at the impact point (23) X-ray radiation (32) for

Radiography of the examination object (5) is created

a detector device (33) with a plurality of individual detectors (35) for

Detecting the x-ray radiation (32), each of the individual detectors (35) having a detector element (37) extending along the normal direction (z) across all the planes (25, 27, 29, 31) and having scintillator material, of which with incident X-radiation (32) by scintillation

Scintillation light is generated, and wherein each of the individual detectors (35) has a single light detector (39) for detecting the scintillation light and generating a detector signal based on the detected scintillation light, wherein

- The tomography device is designed such that from each of them detector signal based on the control data that of the planes (25, 27, 29, 31) is assigned, in which the point of incidence (23) of the electron beam (9) during the generation of the detector signal is located ,

2. Tomography device according to claim 1, wherein the detector element (37) of each of the individual detectors (35) on its outer surface a reflective coating (41) for reflecting the scintillation light, wherein the mirror coating (41) Exterior surface of the detector element (37) covers except for acting as an exit window for scintillation light section.

3. Tomography device according to claim 1 or 2, wherein the target (13) is a hollow body with an about an axis (17) encircling inner lateral surface (15).

4. Tomography device according to claim 3, wherein the inner circumferential surface (15) of the target (13) has the shape of the lateral surface of an oblique circular cone or oblique circular truncated cone.

5. Tomography device according to claim 3, wherein the target (13) is a hollow body with respect to the axis (17) rotationally symmetrical inner lateral surface (15).

6. Tomography device according to one of claims 1 to 5, wherein the

Single detectors (35) are arranged to form a detector arc (43) along a circular line or a circular line section strung together.

7. A tomographic device according to any one of claims 1 to 6, further comprising a diaphragm (45) for spatially limiting the X-radiation (32), wherein the

Aperture (45) at the level of each of the levels (25, 27, 29, 31) one or more

Through openings (47) for passing through the X-ray radiation (32), and wherein the diaphragm (45) at the level between the planes (25, 27, 29, 31) each having a shielding portion (49) for shielding the X-radiation (32).

8. A tomography device according to claims 6 and 7, when dependent on any one of claims 3 to 5, wherein the diaphragm (45) is annular and outside of the target (13) concentric with the axis (17) is arranged, and wherein the detector arc (43) is arranged outside the diaphragm (45) concentric with the axis (17).

9. Tomography device according to one of claims 1 to 8, wherein the

Detector element (37) of each of the individual detectors (35) completely out of the Scintillator material exists.

10. Tomography device according to one of claims 1 to 8, wherein the

Detector element (37) of each of the individual detectors (35) along the normal direction (z) of the planes (25, 27, 29, 31) alternately sections (53) with Szintillatormaterial and sections (55) without Szintillatormaterial.

11. Tomographic device according to claim 10, wherein the detector element (37) of each of the individual detectors (35) at the level of each of the planes (25, 27, 29, 31) has a portion (55) without scintillator material and at the level between the planes (25, 27, 29, 31) each having a portion (53) with scintillator material.

A tomography device according to claim 10 or 11, when dependent on claim 6 and any one of claims 3 to 5, wherein the inner surface (15) of the target (13) defines a target interior and the detector arc (43) within the target interior is arranged concentrically to the axis (17).