Computed tomography scanner with improved data transmission

Abstract

During rotation of the first component of the computed tomography scanner about the rotation axis relative to the second component of the computed tomography scanner, data is transmitted between the first modem and the second modem via the first coupling element and the second coupling element. The first coupling element extends in the circumferential direction over a first angular range. The angular ranges do not intersect one another and form a complete circle around the axis of rotation when viewed over the entirety of the first coupling element. The second coupling element extends in a respective second angular range when viewed about the axis of rotation. The second angular ranges do not intersect each other and are spaced apart from each other. The second coupling elements are respectively coupled with the first coupling elements. The switching state of the switching matrix arranged between the second coupling element and the second modem is dynamically set by the setting means such that the first data is always transmitted between the same first modem and second modem.

Description

Technical Field

[0001] The invention is based on a method for operating a computed tomography scanner.

[0002] wherein during a rotation of a first component of the computed tomography scanner relative to a second component of the computed tomography scanner about a rotation axis, first data are transmitted between a plurality of first modems arranged on the first component and a plurality of second modems arranged on the second component via a plurality of first coupling elements arranged on the first component and a plurality of second coupling elements arranged on the second component,

[0003] wherein the first coupling element extends in a respective first angular range, viewed in the circumferential direction about the axis of rotation,

[0004] wherein the first angular ranges, viewed from first coupling element to first coupling element, do not intersect one another and, viewed over the entirety of the first coupling elements, form a complete circle around the axis of rotation,

[0005] wherein the second coupling element extends over a respective second angular range as viewed about the axis of rotation,

[0006] wherein the second angular ranges, viewed around the axis of rotation, do not intersect one another and are spaced apart from one another, in particular are arranged uniformly distributed around the axis of rotation,

[0007] - The second coupling elements are coupled to the first coupling elements respectively, and the second angular range of the respective second coupling element is located exactly in the first angular range of the first coupling element.

[0008] The invention is also based on a computer tomography scanner,

[0009] - wherein the computed tomography scanner comprises a first component and a second component,

[0010] - wherein the first component is rotatable relative to the second component about a rotation axis,

[0011] - a plurality of first modems are arranged on the first component, which are connected to a first coupling element arranged on the first component in terms of data, and a plurality of second modems are arranged on the second component, which are connected to a second coupling element arranged on the second component in terms of data,

[0012] wherein the first coupling element extends in a respective first angular range, viewed in the circumferential direction about the axis of rotation,

[0013] wherein the first angular ranges, viewed from first coupling element to first coupling element, do not intersect one another and, viewed over the entirety of the first coupling elements, form a complete circle around the axis of rotation,

[0014] wherein the second coupling element extends over a respective second angular range as viewed about the axis of rotation,

[0015] wherein the second angular ranges, viewed around the axis of rotation, do not intersect one another and are spaced apart from one another, in particular are arranged uniformly distributed around the axis of rotation,

[0016] - The second coupling elements are coupled to the first coupling elements respectively, and the second angular range of the respective second coupling element is located exactly in the first angular range of the first coupling element. Background Art

[0017] Computer tomography scanners are generally known.

[0018] In a computed tomography scanner, an X-ray source and an X-ray detector are arranged on a gantry (rotating part), wherein the X-ray source emits X-ray radiation during the rotation of the gantry and the X-ray detector detects the emitted X-ray radiation. A three-dimensional image of the examination object (usually a person, in particular a patient) is reconstructed from the images of the examination object (usually a person, in particular a patient) thus detected.

[0019] Applicants note that regardless of the grammatical gender of certain terms relating to individuals (such as, for example, the term "patient"), persons of both male and female identities are included.

[0020] The reconstruction of the three-dimensional image is carried out with the aid of an evaluation device which is arranged outside the gantry, for example even outside the examination room in which the computed tomography scanner is arranged. The image data detected by means of the X-ray detector must be transmitted to the evaluation device during the rotation of the gantry. This is usually carried out via a transmission channel, via which the digital data are supplied from a data source (for example a pre-evaluation device which slightly processes the data detected by the X-ray detector) to a modem which modulates the digital data onto a carrier signal. The modulated carrier signal is supplied to another modem via the transmission channel. The other modem is arranged on a substrate (fixed component). The other modem demodulates the modulated carrier signal and supplies the received signal determined in this way to a data receiver. In this case, the data source and the associated modem are arranged on the gantry, and the other modem and the data receiver are arranged on a fixed substrate. The transmission channel thus forms a bridge between the gantry and the fixed substrate.

[0021] With the continued development of computed tomography scanners, the amount of data that must be transmitted from a data source to a data receiver is increasing. Conventional types of data transmission devices are gradually reaching their limits. Therefore, attempts are being made to increase the data rate at which the data is transmitted. Summary of the invention

[0022] The object of the present invention is to provide a possibility by means of which a predetermined bandwidth for a transmission channel can increase the data rate in data transmission between a stand and a stationary base body.

[0023] This object is achieved by the operating method according to the invention. Advantageous embodiments of the operating method are described below.

[0024] According to the invention, an operating method of the type mentioned at the outset is designed in that the switching state of a switching matrix arranged between the second coupling element and the second modem is dynamically set by a setting device so that the first data are always transmitted between the same first modem and second modem.

[0025] The first component of the computed tomography scanner can be a fixed base of the computed tomography scanner. In this case, the second component is a rotating gantry of the computed tomography scanner. Alternatively, the first component can be a rotating gantry of the computed tomography scanner. In this case, the second component is a fixed base. Since both of these dependencies are possible, data can also be transferred from the gantry to the base or vice versa as required. Although data transfer from the gantry to the base is the usual case, transmission in the opposite transmission direction is also required.

[0026] In the context of the invention, the number of second modems corresponds to the number of first modems. The first modem and the second modem can themselves be designed as so-called backbone modems, as is known for communication systems, for example for communication between mobile radio masts. Such modems are optimized for changing signal paths and have an internal digital signal processing device consisting of an FIR filter, an equalizer and FEC (forward error correction). An example of such a modem is a chip sold by the company MaxLinear under the model BCM85110.

[0027] The number of first coupling elements is also usually consistent with the number of first modems. In contrast, the number of second coupling elements is usually greater than the number of first modems. In the optimal case, the number of said second coupling elements is exactly one greater.

[0028] The first angular ranges are usually of the same size as one another. That is, if n represents the number of first coupling elements, the first angular ranges extend in each case over a range of 360° / n.

[0029] In contrast, the extension of the second angular range can be significantly smaller. However, if the number of second coupling elements is denoted by m, the second angular range preferably extends over a maximum of 360° / nm. Due to the preferably uniform distribution, the second coupling elements are preferably spaced 360° / m apart from one another. That is to say, if (for example) n has the value 3 and m has the value 4, the second angular range preferably extends over a maximum of 360° / 12=30° and is spaced 360° / 4=90° apart from one another.

[0030] The switching matrix must associate the m second coupling elements with the n second modems. A suitable switching matrix can be formed by a parallel arrangement of n switches, each of which can connect the m inputs to one (1) output. The respective output can be permanently connected to one of the n second modems. Corresponding switches are known. Purely by way of example, reference can be made to the switch sold by the company MACOM under the model number MASW-011152.

[0031] By constantly switching the switching matrix, the jumps in the transmission performance from the first modem to the second modem can be significantly reduced. As a result, the first data can be reconstructed in a qualitatively high-quality manner. As a result, the quality of the data transmission can also be maintained during a rotation of the first component relative to the second component.

[0032] Preferably, the setting device determines the switching state of the switching matrix based on the current rotation angle of the first component relative to the second component. That is, the current rotation angle itself is known to the setting device and is used by the setting device to determine the switching state of the switching matrix. The method approach is particularly simple.

[0033] In the simplest case, the dynamic setting of the switching matrix is ​​performed by the setting device using only the rotation angle of the first component relative to the second component. Optionally, however, the setting device can also take into account at least one time derivative of the rotation angle (i.e. rotation speed, rotation acceleration, etc.) in addition to the rotation angle when determining the switching state of the switching matrix.

[0034] It is possible to measure the rotation angle in each case, that is to say to base the determination of the settings of the switching matrix on the measured rotation angle in each case. In this case, it is also possible to additionally also take into account at least one time derivative of the rotation angle in the process of determining the settings of the switching matrix.

[0035] Alternatively, it is possible to measure the rotation angle only in predetermined angular positions, for example only every 120°, every 180° or even only once per complete revolution of the first component relative to the second component. In this case, between the predetermined angular positions, the rotation angle is determined by the setting device based on operating data characterizing the rotation, in particular the rotation speed and / or the rotational acceleration, by updating the last measured rotation angle.

[0036] Preferably, the data to be transmitted is supplied to the first modem or the second modem as a complex signal, and the first modem or the second modem performs quadrature amplitude modulation of the carrier signal according to the complex signal supplied thereto. This makes it possible to maximize the data rate that can be used to transmit the first data. In particular, the present invention shows its full advantages in conjunction with quadrature amplitude modulation.

[0037] Preferably, the signals transmitted are distorted according to corresponding distortion rules by means of a distortion device arranged between the first modem and the first coupling element and / or between the second modem and the second coupling element. In this case, the corresponding distortion rule is set by the setting device according to the rotation angle of the first component relative to the second component.

[0038] The dynamic setting of the distortion rule by the setting device can also be carried out directly as a function of the rotation angle of the first component relative to the second component. Optionally, in addition to the rotation angle, at least one time derivative of the rotation angle can also be used.

[0039] This distortion can compensate for distortions of the data transmission caused by the transfer function of the corresponding transmission channel. As a result, a signal that is virtually undistorted can be recovered, so that a qualitatively high-quality reconstruction of the first data is possible. In other words, matched filtering is performed. This method approach is already known in the prior art in the case of quadrature amplitude modulation. However, in addition, the distortion rule is now tracked more or less continuously as a function of the rotation angle of the first component relative to the second component. As a result, a high quality of the data transmission can be maintained even during a rotation of the gantry.

[0040] The parameters required for setting the distortion device can be stored in a lookup table for a plurality of input variables in the setting device, for example. The input variables usually include at least the rotation angle of the first component relative to the second component, and optionally also the time derivative of the rotation angle.

[0041] Preferably, during the rotation of the first component relative to the second component, the second data is additionally transmitted between the third modem arranged on the first component and the fourth modem arranged on the second component via the first coupling element and the second coupling element. In this case, the switching matrix is ​​dynamically switched by the setting device so that the second data is always transmitted between the same third modem and the fourth modem. This can further improve the transmission rate.

[0042] Preferably, the first data and the second data are modulated onto carrier signals of different frequencies by means of the first modem to the fourth modem before being supplied to the first coupling element and the second coupling element, so that the respectively occupied frequency ranges do not intersect with each other.

[0043] The object is also achieved by a computed tomography scanner according to the invention. Advantageous embodiments of the computed tomography scanner are described below.

[0044] According to the invention, a computed tomography scanner of the type mentioned at the outset is designed as follows:

[0045] - a switching matrix is ​​arranged between the second coupling element and the second modem, and - a setting device is associated with the switching matrix, and the switching state of the switching matrix is ​​dynamically set by the setting device so that during the data transmission of first data between the first modem and the second modem during the rotation of the first component relative to the second component around the rotation axis, the first data are always transmitted between the same first modem and second modem.

[0046] The facts and advantages resulting from this correspond to those of the operating method according to the invention.

[0047] The advantageous embodiments of the computed tomography scanner correspond to the advantageous embodiments of the operating method, and the same applies to the advantages resulting therefrom. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] The characteristics, features and advantages of the present invention described above and the manner and method of achieving these characteristics, features and advantages become clearer and easier to understand in conjunction with the following description of an embodiment, which is explained in detail in conjunction with the accompanying drawings. In this case, it is shown in a schematic diagram:

[0049] Figure 1 shows a computed tomography scanner,

[0050] Figure 2 Showing a time diagram,

[0051] Figure 3 Another time diagram is shown,

[0052] Figure 4 shows the data transmission structure,

[0053] Figure 5 Showing an angle diagram,

[0054] Figure 6 Showing an angle diagram,

[0055] Figure 7 Showing an angle diagram,

[0056] Figure 8 showing a data source and a first modem,

[0057] Fig. 9 A second modem and a data receiver are shown,

[0058] Fig.10 shows the communication path,

[0059] Fig.11 Another data transmission structure is shown.

[0060] Fig.12 shows a frequency graph, and

[0061] Fig.13 Another frequency diagram is shown. DETAILED DESCRIPTION

[0062] according to Figure 1 The computed tomography scanner 1 has a fixed base body 2. The gantry 3 is rotatably supported on the base body 2, so that the gantry 3 can rotate relative to the base body 2 about a rotation axis 4. The rotatability is Figure 1 5 is indicated in the figure. The gantry 3 carries an X-ray source 6 and an X-ray detector 7, as is usually the case. The X-ray source 6 and the X-ray detector 7 are arranged diagonally opposite one another with respect to the rotation axis 4. In some cases, the gantry 3 also additionally carries a further X-ray source 8 and a further X-ray detector 9. The further X-ray source 8 and the further X-ray detector 9 are also arranged diagonally opposite one another with respect to the rotation axis 4. The further X-ray source 8 and the further X-ray detector 9 (if present) are usually arranged offset by 90° with respect to the first-mentioned X-ray source 6 and the first-mentioned X-ray detector 7, as viewed in the circumferential direction around the rotation axis 4. During the rotation of the gantry 3 about the rotation axis 4, an X-ray image of an examination object 10 arranged in the region of the rotation axis 4 can be detected by means of the X-ray detector 7 or the X-ray detectors 7, 9.

[0063] The base body 2 can be regarded as the first component for the purposes of the invention. In this case, the stand 3 is the second component for the purposes of the invention. However, the opposite relationship is also possible. The data transmission from the stand 3 to the base body 2 is explained below in conjunction with the design explained above. However, in principle, data transmission from the base body 2 to the stand 3 is also possible. What is decisive is always only the relative mobility of the two components 2, 3 relative to each other and the transmission of data from one of the two components 2, 3 to the other of the two components 2, 3.

[0064] Figure 2 The rotation of the gantry 3 is shown as a function of the time point t. Figure 2 , the rotation of the gantry 3 starts at time t1 to detect the X-ray image of the inspection object. Specifically, the gantry 3 accelerates from time t1 to time t2, so that the rotation speed ω reaches the maximum value at time t2. Subsequently, the gantry 3 rotates at the maximum rotation speed until time t3, and finally brakes again until the gantry reaches a stationary state at time t4.

[0065] The X-ray image is acquired at least between time t2 and time t3, usually even from time t1 up to time t4. Figure 3 More or less simultaneously with the detection of the X-ray image, the X-ray image is also transmitted from the gantry 3 to the base body 2 . Figure 3 The solid lines show time periods during which at least data transmission takes place, and the dashed lines show time periods during which data transmission is also possible. The transmitted data are digital.

[0066] Figure 4 The structure for transmitting data between the stage 3 and the base body 2 is shown in simplified form.

[0067] according to Figure 4 , there is a data source 11. The data source 11 can be, for example, a unit that receives images from the X-ray detectors 7, 9 and (slightly) processes the images. The data source 11 is connected to a plurality of first modems 12 in terms of data. There are currently three first modems 12. The first modems 12 are connected to corresponding first coupling elements 13 in terms of data. The first coupling elements 13 extend around the rotation axis 4 in a range of 360° / n, respectively, where n is the number of first modems 12 or first coupling elements 13. The angular ranges over which the corresponding first coupling elements 13 extend do not intersect with the angular ranges over which the other first coupling elements 13 extend. The mentioned angular ranges together form a complete circle. For example, the first coupling element 13 can be configured as a dielectric conductor or a waveguide with a slit. The data source 11, the first modems 12 and the first coupling elements 13 are arranged on the gantry 3.

[0068] The first coupling element 13 is coupled to the second coupling element 14. The number of the second coupling elements 14 is usually greater than the number of the first coupling elements 13. Currently, the number of the second coupling elements 14 is 4, i.e., 1 more than the number of the first coupling elements 13. The second coupling elements 14 also extend in a corresponding angular range when viewed around the rotation axis 4. However, this angular range is significantly smaller than the angular range over which the first coupling element 13 extends. In an ideal case, the angular range is very small (only a few degrees). The angular ranges over which the second coupling elements 14 extend do not intersect in any case and are spaced apart from each other. Preferably, the angular ranges are arranged uniformly distributed around the rotation axis 4.

[0069] The second coupling element 14 is connected to the second modem 16 in terms of data via the switching matrix 15. That is, the switching matrix 15 is arranged between the second coupling element 14 and the second modem 16. The second modem 16 is in turn connected to the data receiver 17 in terms of data. The second coupling element 14 and the second modem 16 (like the switching matrix 15) are arranged on the base body 2.

[0070] The first modem 12, the first coupling element 13 and the second modem 16 are connected to each other. Figure 4 Notes a to c are provided in order to distinguish them from each other when necessary in the subsequent description. For the same reason, the second coupling element 14 is Figure 4 There are notes a to d respectively.

[0071] From the above explanation, it can be seen that the transmission of data between the first modem 12 and the second modem 16 is carried out via the first coupling element 13 and the second coupling element 14. It can also be seen that the coupling between one of the first coupling elements 13 and one of the second coupling elements 14 exists only when the angle range covered by the corresponding second coupling element 14 is within the angle range covered by the corresponding first coupling element 13. In other words, the coupling of the first coupling element and the second coupling element 13, 14 to each other changes when the gantry 3 rotates. This is described below in conjunction with Figures 5 to 7 In the process of the above description, it is assumed that: Figure 4 That is, there are a total of three first coupling elements 13, each extending over a range of 120°, and a total of four second coupling elements 14, each of which is arranged 90° offset relative to one another and each of which extends over a range of 30°.

[0072] exist Figures 5 to 7 In FIG. 1 , the rotation angles φ from 0° to 360° are plotted on the horizontal axis. For example, the rotation angle φ of 0° can correspond to Figure 4The rotational position shown in . A counterclockwise rotation should correspond to an increase in the rotation angle φ. On the vertical axis is plotted which coupling element of the second coupling element 14 the respective first coupling element 13 is coupled to. Figures 5 to 7 The coupling is shown (in this order) for the first coupling element 13a, the first coupling element 13b and the first coupling element 13c.

[0073] The switching state of the switching matrix 15 is combined with the above Figures 5 to 7 The description is guided by the fact that the switching states are determined by the setting device 18 associated with the switching matrix 15 (see Figure 4 ) is dynamically set so that data is always transmitted between the same first modem 12 and the second modem 16. That is, the second modem 16a is always connected to the same second coupling element 14, which just obtains data from the first modem 12a via the first coupling element 13a. In a similar manner, the second modem 16b is always connected to the second coupling element 14, which just obtains data from the first modem 12b via the first coupling element 13b. And the second modem 16c is also always connected to the second coupling element 14, which just obtains data from the first modem 12c via the first coupling element 13c. In addition, the same situation applies even when communication is performed in the opposite direction.

[0074] In order to be able to determine the switching states of the switching matrix 15 and to be able to set the switching matrix 15 accordingly, the rotation angle φ of the gantry 3 must be known directly or indirectly to the setting device 18. In the simplest case, the rotation angle φ is directly supplied to the setting device 18. Optionally (whether additionally or alternatively) the rotation speed ω and / or the rotation acceleration α can also be supplied to the setting device 18. In this case, the setting device 18 can take the values ​​ω, α into account when determining or determine the rotation angle φ (for example in conjunction with a reference pulse that is output once per revolution when passing through a reference rotation position). By additionally taking into account the rotation speed ω and / or the rotation acceleration α, possible time offsets can be better taken into account.

[0075] according to Figure 8 In the figure, the data source 11 sends the data stream DS (ie, the data to be transmitted, see Fig.10) is preferably supplied to the corresponding first modem 12 as a complex signal. Therefore, the data stream DS includes two sub-signals DS1 and DS2 representing the real part and the imaginary part of the complex signal, respectively. In this case, the corresponding first modem 12 is configured as an orthogonal amplitude modulator. The first modem includes two multipliers 19, to which the cosine and sine of the carrier signal CS are supplied. In addition, one of the two sub-signals DS1 and DS2 is supplied to the two multipliers 19. The signals generated by the two multipliers 19 are supplied to an adder 20, which adds the two signals to form a transmission signal SS. The transmission signal SS is transmitted to the corresponding second modem 16 via the corresponding first coupling element 13 and the corresponding second coupling element 14.

[0076] according to Fig. 9 In the diagram in FIG. 1 , in the case of quadrature amplitude modulation, the second modem 16 and the data receiver 17 are also constructed accordingly. In particular, in this case, the corresponding second modem 16 comprises two multipliers 21, on the one hand, the transmitted signal DS' (see Fig.10 ) and the cosine and sine of another carrier signal CS' having the same frequency as the carrier signal CS are supplied to the two multipliers 21. The two multipliers 21 provide the real part DS1' and the imaginary part DS2' of the demodulated signal as output signals, and the real part DS1' and the imaginary part DS2' are superimposed with the corresponding high-frequency components. The corresponding high-frequency components are filtered out in the corresponding low-pass filter 22, so that the real part DS1' and the imaginary part DS2' of the demodulated (complex) signal are provided at the output end of the corresponding low-pass filter 22. The two sub-signals DS1', DS2' are supplied to the data receiver 17.

[0077] according to Fig.10 , data is transmitted in the form of a data stream DS from a data source 11 via one of the first modems 12, the associated first coupling element 13, and one of the second coupling elements 1415 to a corresponding second modem 16 leading to a data receiver 17. Fig.10 The switching matrix 15 is not shown together in FIG. 1 . However, it is present.

[0078] For correct demodulation, the phase of the other carrier signal CS' must be consistent with the phase of the carrier signal CS. For this purpose, according to Fig.10 , a first distortion device 23 can be arranged between the first modem 12 and the first coupling element 13. Alternatively or additionally, a second distortion device 24 can be arranged between the second coupling element 14 and the second modem 16. The distortion devices 23 and 24 can be designed in particular as FIR filters. The exact sequence during data transmission is therefore as follows:

[0079] The data source 11 transmits the data stream DS to the corresponding first modem 12. Figure 8 In the embodiment of the present invention, the data stream DS can be designed in particular as a complex signal. The first modem 12 modulates the carrier signal CS according to the data stream DS. The modulated carrier signal corresponds to the transmission signal SS, which the first modem 12 is initially intended to feed into the first coupling element 13. However, the transmission signal SS is first supplied to the first distortion device 23, which distorts the transmission signal SS according to the first distortion rule. The distorted transmission signal (which is subsequently provided with the reference numeral SS' to distinguish it from the original transmission signal SS) is then supplied to the corresponding first coupling element 13.

[0080] In a similar manner, the transmitted signal TS is first supplied to the second distortion device 24. The second distortion device 24 distorts the transmitted signal TS according to a second distortion rule. The distorted transmitted signal (which is subsequently provided with the reference numeral TS' to distinguish it from the original transmitted signal TS) is then supplied to the corresponding second modem 16. The second modem 16 demodulates the distorted transmitted signal TS', thereby generating a transmitted data stream DS'. The transmitted data stream DS' is supplied to the data receiver 16.

[0081] The distortion means 23, 24 can be parameterized by means of parameters PV, PN. The parameter PV determines the first distortion rule. In a similar manner, the parameter PN determines the second distortion rule.

[0082] As already mentioned, data transmission takes place during the rotation of the gantry 3. Therefore, the area of ​​the respective first coupling element 13 at which the respective adjacent second coupling element 14 is coupled to the respective first coupling element 13 changes continuously during the data transmission. Therefore, during the rotation of the gantry 3, the effective length of the transmission channel from the respective first modem 12 to the respective second modem 16 changes continuously. Therefore, the transmission characteristics of the transmission channel also change. Fig.10 The significance and purpose of the method approach is to keep the transmission characteristics of the first distortion device 23, the transmission channel and the second distortion device 24 as a whole constant or at least substantially constant by correspondingly setting the distortion devices 23, 24 or correspondingly presetting the parameters PV, PN.

[0083] In order to keep constant, it is necessary to dynamically set the parameters PV and PN during the rotation of the gantry 3. Fig.10 As can be seen in FIG. 1 , in particular, it can be done by a setting device 18. The setting can be done in particular as a function of the rotation angle φ, optionally with additional consideration of the rotation speed ω and / or the rotation acceleration α. ​​The corresponding embodiments for setting the switching matrix 15 can be applied in an analogous manner.

[0084] Determining the corresponding settings for the switching matrix 15 is relatively simple. In contrast, determining the parameters PV, PN can be significantly more complex and must also be performed more frequently. Therefore, preferably a lookup table is stored in the setting device 18, in which the parameters PV, PN are stored for specific values ​​of the rotation angle φ, optionally also additionally for specific values ​​of the rotation speed ω and / or the rotation acceleration α. ​​The use of the lookup table ensures real-time performance in a simple manner.

[0085] The basic principle for determining the parameters PV, PN is explained below.

[0086] If the transfer functions of the transmission channel, the first distortion device 23 and the second distortion device 24 are represented by H, U and V, then H'=UHV always applies, where H' is the resulting transfer function of the first distortion device 23, the transmission channel and the second distortion device 24. Ideally, the relationship H'=I should continue to apply, where I is the unit transfer function.

[0087] Due to the rotation of the gantry 3, the transfer function H of the transmission channel is variable in time. That is, the parameters PV, PN, which are used to parameterize the two distortion devices 23, 24 and thus determine the corresponding distortion rules and thus their transfer functions U, V, should be determined at any time so that the mentioned relationship H'=I applies exactly or at least approximately.

[0088] Depending on the situation, either only the first distortion device 23 or the second distortion device 24 is present or, although both distortion devices 23, 24 are present, it is sufficient to always reset the parameters PV, PN of only one of the two distortion devices 23, 24. However, it is generally preferred that not only are both distortion devices 23, 24 present, but also the parameters PV, PN of both distortion devices 23, 24 are always reset.

[0089] Fig.11 Show Figure 4 The data transmission structure is modified. Fig.11, a plurality of third modems 25 are arranged on the gantry 3. The number of the third modems 25 usually corresponds to the number of the first modems 12. The third modems 25 are connected to the first coupling element 13 in terms of data. In a similar manner, a plurality of fourth modems 26 are arranged on the base body 2. The number of the fourth modems 26 corresponds to the number of the third modems 25. The fourth modem 26 is connected to the second coupling element 14 in terms of data via the switching matrix 15. Analogously to the method approach in the case of the first modem and the second modem 12, 16, during the rotation of the gantry 3, the switching matrix 15 is dynamically switched by the setting device 18 so that other data is always transmitted between the same third modem 25 and the fourth modem 26. That is, data transmission is always carried out between the third modem 25a and the fourth modem 26a, between the third modem 25b and the fourth modem 26b, and between the third modem 25c and the fourth modem 26c. Therefore, during the rotation of the gantry 3, another additional communication can be realized in a completely similar manner via the first coupling element 13 and the second coupling element 14. The communication can take place in the same direction as the data transmission between the first modem 12 and the second modem 16, namely from the third modem 25 to the fourth modem 26. However, it is also possible to carry out data transmission in the other direction, so that data transmission in the opposite direction takes place simultaneously.

[0090] In order to realize the two data transmissions via the corresponding first coupling element 13, before being supplied to the first coupling element and the second coupling element 13, 14, the corresponding data are modulated onto carrier signals of different frequencies by means of the corresponding modems 12, 25 or 12, 26, so that the respectively occupied frequency ranges do not intersect with each other. Fig.12 1 , the pairing of one of the first modems 12 and one of the second modems 16 is shown by way of example on the one hand, and the pairing of one of the third modems 25 and one of the fourth modems 26 is shown on the other hand. It can be seen that the frequency f used for data transmission between the corresponding first modem 12 and the corresponding second modem 16 does not intersect with the frequency f used for data transmission between the corresponding third modem 25 and the corresponding fourth modem 26.

[0091] according to Fig.13 It is even possible to transmit data simultaneously in both directions via these two pairs of modems 12 , 16 , 25 , 26 , as long as the basic condition that the respectively occupied frequency ranges do not intersect one another is maintained.

[0092] In summary, the present invention therefore relates to the following facts:

[0093] During the rotation of the first component 3 of the computed tomography scanner 1 relative to the second component 2 of the computed tomography scanner 1 about the rotation axis 4, data is transmitted between the first modem 12 arranged on the first component 3 and the second modem 16 arranged on the second component 2 via the first coupling element 13 arranged on the first component 3 and the second coupling element 14 arranged on the second component 2. The first coupling element 13 extends in a corresponding first angular range around the rotation axis 4 when viewed in the circumferential direction. The angular ranges do not intersect with each other when viewed from first coupling element 13 to first coupling element 13, and form a complete circle around the rotation axis 4 when viewed over the entirety of the first coupling element 13. The second coupling element 14 extends in a corresponding second angular range when viewed around the rotation axis 4. The second angular ranges do not intersect with each other when viewed around the rotation axis 4 and are spaced apart from each other. Therefore, the second coupling elements 14 are respectively coupled to the first coupling elements 13, and the second angular range of the corresponding second coupling element 14 is exactly in the first angular range of the first coupling element 13. The switching state of the switching matrix 15 provided between the second coupling element 14 and the second modem 16 is dynamically set by the setting device 18 so that the first data is always transmitted between the same first modem 12 and second modem 16 .

[0094] The invention has many advantages. In particular, a relatively simple and nevertheless robust data transmission is achieved, by means of which high transmission rates in the multi-gigabit per second range can be achieved. The measures according to the invention are also easily suitable for retrofitting in already existing computed tomography scanners that are not yet according to the invention.

[0095] Although the present invention has been described in detail through preferred embodiments, the present invention is not limited to the disclosed examples and other variations can be derived therefrom by those skilled in the art without departing from the scope of protection of the present invention.

Claims

1. A method for operating a computed tomography scanner (1), - wherein during a rotation of a first part (3) of the computed tomography scanner (1) relative to a second part (2) of the computed tomography scanner (1) about a rotation axis (4), first data are transmitted between a plurality of first modems (12) arranged on the first part (3) and a plurality of second modems (16) arranged on the second part (2) via a plurality of first coupling elements (13) arranged on the first part (3) and a plurality of second coupling elements (14) arranged on the second part (2), - wherein the first coupling element (13) extends in a respective first angular range, viewed in a circumferential direction about the rotation axis (4), - wherein the first angular ranges do not intersect one another when viewed from first coupling element (13) to first coupling element (13) and form a complete circle around the rotation axis (4) when viewed over the entirety of the first coupling element (13), - wherein the second coupling element (14) extends over a respective second angular range, viewed about the rotation axis (4), - the second angular ranges, viewed around the rotation axis (4), do not intersect one another and are spaced apart from one another, in particular are arranged uniformly distributed around the rotation axis (4), - the second coupling element (14) is coupled to the first coupling element (13) respectively, and the second angular range of the corresponding second coupling element (14) is exactly in the first angular range of the first coupling element (13), and - wherein the switching state of a switching matrix (15) arranged between the second coupling element (14) and the second modem (16) is dynamically set by a setting device (18) so that the first data is always transmitted between the same first modem and second modem (12, 16).

2. The operating method according to claim 1, It is characterized in that The setting device (18) determines the switching state of the switching matrix (15) according to the rotation angle (φ) of the first component (3) relative to the second component (2).

3. The operating method according to claim 2, It is characterized in that The setting device (18) takes into account at least one time derivative of the rotation angle (φ) in addition to the corresponding rotation angle (φ) when determining the switching state of the switching matrix (15).

4. The operating method according to claim 1, 2 or 3, It is characterized in that Data to be transmitted are supplied as a complex signal to the first modem or the second modem (12, 16), and the first modem or the second modem (12, 16) performs quadrature amplitude modulation of a carrier signal (TS) according to the complex signal supplied thereto.

5. The operating method according to any one of the preceding claims, It is characterized in that By means of a distortion device (23, 24) arranged between the first modem (12) and the first coupling element (13) and / or between the second modem (16) and the second coupling element (14), the respectively transmitted signals are distorted according to corresponding distortion rules, and the setting device (18) sets the corresponding distortion rules according to the rotation angle (φ) of the first component (3) relative to the second component (2).

6. The operating method according to any one of the preceding claims, It is characterized in that During the rotation of the first component (3) relative to the second component (2), second data are additionally transmitted between a third modem (25) arranged on the first component (3) and a fourth modem (26) arranged on the second component (2) via the first coupling element and the second coupling element (13, 14), and the switching matrix (15) is dynamically switched by the setting device (18) so that the second data is always transmitted between the same third modem and fourth modem (25, 26).

7. The operating method according to claim 6, It is characterized in that Before being supplied to the first coupling element and the second coupling element (13, 14), the first data and the second data are modulated onto carrier signals of different frequencies (f) by means of the first to fourth modems (12, 16, 25, 26) so that the respectively occupied frequency ranges do not intersect with each other.

8. A computer tomography scanner, - wherein the computed tomography scanner comprises a first component and a second component (3, 2), - wherein the first component (3) is rotatable relative to the second component (2) about an axis of rotation (4), - wherein a plurality of first modems (12) are arranged on the first component (3), the first modems (12) being connected to a first coupling element (13) arranged on the first component (3) in terms of data, and a plurality of second modems (16) are arranged on the second component (2), the second modems (16) being connected to a second coupling element (14) arranged on the second component (2) in terms of data, - wherein the first coupling element (13) extends in a respective first angular range, viewed in a circumferential direction about the rotation axis (4), - wherein the first angular ranges do not intersect one another when viewed from first coupling element (13) to first coupling element (13) and form a complete circle around the rotation axis (4) when viewed over the entirety of the first coupling element (13), - wherein the second coupling element (14) extends over a respective second angular range, viewed about the rotation axis (4), - the second angular ranges, viewed around the rotation axis (4), do not intersect one another and are spaced apart from one another, in particular are arranged uniformly distributed around the rotation axis (4), - the second coupling element (14) is coupled to the first coupling element (13) respectively, and the second angular range of the corresponding second coupling element (14) is exactly in the first angular range of the first coupling element (13), and - wherein a switching matrix (15) is arranged between the second coupling element (14) and the second modem (16), and - wherein the switching matrix (15) is associated with a setting device (18), and the switching state of the switching matrix (15) is dynamically set by the setting device (18) so that during data transmission of first data between the first modem and the second modem (12, 16) during rotation of the first component (3) relative to the second component (2) around the rotation axis (4), the first data is always transmitted between the same first modem and second modem (12, 16).

9. The computer tomography scanner according to claim 8, It is characterized in that The setting device (18) determines the switching state of the switching matrix (15) according to the rotation angle (φ) of the first component (3) relative to the second component (2).

10. The computer tomography scanner according to claim 9, It is characterized in that The setting device (18) takes into account at least one time derivative of the rotation angle (φ) in addition to the corresponding rotation angle (φ) when determining the switching state of the switching matrix (15).

11. The computer tomography scanner according to claim 8, 9 or 10, It is characterized in that Data to be transmitted are supplied to the first modem or the second modem (12, 16) as a complex signal, and the first modem or the second modem (12, 16) is designed as a quadrature amplitude modulator which performs quadrature amplitude modulation of a carrier signal (TS) as a function of the complex signal supplied thereto.

12. The computer tomography scanner according to any one of claims 8 to 11, It is characterized in that Distortion devices (23, 24) are provided between the first modem (12) and the first coupling element (13) and / or between the second modem (16) and the second coupling element (14), by means of which the signals transmitted respectively are distorted according to corresponding distortion rules, and the setting device (18) sets the corresponding distortion rules according to the rotation angle (φ) of the first component (3) relative to the second component (2).

13. The computer tomography scanner according to any one of claims 8 to 12, It is characterized in that A plurality of third modems (25) are arranged on the first component (3), the third modems (25) being connected to the first coupling element (13) in terms of data, and a plurality of fourth modems (26) are arranged on the second component (2), the fourth modems (26) being connected to the second coupling element (14) in terms of data via the switching matrix (15), so that during the rotation of the first component (3) relative to the second component (2), second data are additionally transmitted between the third modems (25) and the fourth modems (26) via the first coupling element and the second coupling element (13, 14), and the switching matrix (15) is dynamically switched by the setting device (18), so that during the data transmission of the second data during the rotation of the first component (3) relative to the second component (2), the second data are always transmitted between the same third modems and fourth modems (25, 26).

14. The computer tomography scanner according to claim 13, It is characterized in that The first data and the second data are modulated onto carrier signals of different frequencies (f) by means of the first to fourth modems (12, 16, 25, 26) before being supplied to the first coupling element and the second coupling element (13, 14), so that the respectively occupied frequency ranges do not intersect with each other.

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