Computed tomography scanner with improved data transmission

Abstract

The computed tomography (CT) scanner gantry rotates relative to the fixed substrate of the CT scanner. During gantry rotation, digital data is transmitted from a data source via a modulator, transmission channel, and demodulator to a data receiver between the gantry and the substrate. A predistortion device located upstream of the transmission channel predistorts the transmitted signal generated by the modulator from the data source through modulation according to a predistortion rule. Only the predistorted transmitted signal is transmitted to the transmission channel. Alternatively or additionally, a postdistortion device located downstream of the transmission channel postdistorts the signal transmitted via the transmission channel according to a postdistortion rule, and only the postdistorted signal is transmitted to the demodulator. The predistortion rule and / or postdistortion rule are repeatedly reset by a setting device during gantry rotation.

Description

Technical Field

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

[0002] -The computed tomography (CT) scanner gantry rotates relative to a fixed matrix of the CT scanner.

[0003] -During the rotation of the test bench, digital data is transmitted from the data source to the data receiver between the test bench and the substrate via a modulator, transmission channel and demodulator.

[0004] This invention is also based on a computed tomography scanner.

[0005] -The computed tomography scanner has a fixed substrate and a gantry that can rotate relative to the fixed substrate.

[0006] -The computed tomography scanner has a data source, modulator, transmission channel, demodulator and data receiver, so that digital data can be transmitted from the data source to the data receiver between the table and the substrate via the modulator, transmission channel and demodulator during table rotation. Background Technology

[0007] Computed tomography (CT) scanners are generally known.

[0008] In a computed tomography (CT) scanner, an X-ray source and an X-ray detector are mounted on a gantry. The X-ray source emits X-ray radiation as the gantry rotates, and the X-ray detector detects the emitted X-ray radiation. A three-dimensional image of the subject (usually a person, especially a patient) is reconstructed from the images obtained from these images.

[0009] The applicant states that people of male or female identity are included regardless of the grammatical gender of specific personal terms (such as the term "patient" in this case).

[0010] The reconstruction of three-dimensional images is performed using an evaluation device located outside the gantry, for example, even outside the examination room equipped with a computed tomography scanner. Image data detected by an X-ray detector must be transmitted to the evaluation device during the rotation of the gantry. This is typically done via a transmission channel, through which digital data is fed from a data source (e.g., a pre-evaluation device that slightly processes the data detected by the X-ray detector) to a modulator, which modulates the digital data onto a carrier signal. The modulated carrier signal is then transmitted via the transmission channel to a demodulator. The demodulator demodulates the modulated carrier signal and transmits the determined received signal to a data receiver. In this case, the data source and modulator are located on the gantry, while the demodulator and data receiver are located on a fixed substrate. Thus, the transmission channel forms a bridge between the gantry and the fixed substrate.

[0011] With the continuous development of computed tomography (CT) scanners, the amount of data that needs to be transmitted from the data source to the data receiver is constantly increasing. Traditional data transmission devices are gradually reaching their limits. Therefore, efforts are being made to increase the data transmission rate.

[0012] In computed tomography (CT) scanners, carrier signals are typically modulated using relatively simple methods, namely phase-shift keying (PPS) or amplitude-shift keying (APS). These modulation methods are relatively robust to phase changes in the transmitted signal. Conversely, the transmittable data density is relatively low, also known as low spectral efficiency.

[0013] In the prior art, a modulation method that achieves significantly higher data density (or higher spectral efficiency), particularly quadrature amplitude modulation (QAM), is known. A purely exemplary reference can be made to the corresponding excerpt in the German Wikipedia, retrieved on August 21, 2023. Regarding quadrature amplitude modulation, there are different “extension stages,” commonly referred to as M-QAM, where M represents the number of possible values. M is typically a power of 2, often even an even power of 2. That is, the simplest “extension stage” is 4-QAM. Other “extension stages” are 16-QAM, 64-QAM, and 256-QAM. Higher “extension stages” are also known.

[0014] Quadrature amplitude modulation (QAM) allows for significantly higher data rates (within a constant bandwidth of the transmission channel). However, QAM is highly sensitive to phase changes in the transmitted signal. This is because, for proper demodulation, the phase of the signal generated by the modulator must be very clearly known at the demodulator. Even small phase shifts can cause the signal transmitted through the transmission channel to become incorrectly demodulated.

[0015] (See, for example, the entry already mentioned in the German Wikipedia.) It is known that by means of a post-distortion device positioned downstream of the transmission channel, the signal transmitted via the transmission channel is post-distorted according to post-distortion rules, and only the post-distorted signal is delivered to the demodulator. The post-distortion device is typically configured as a so-called matched filter. The transfer function of the filter is designed for the pulse shape formed by the modulator and allows for very good interference suppression.

[0016] By applying quadrature amplitude modulation during data transmission between the test bench and the substrate, significantly higher data rates than previously achieved can be realized. However, because data transmission occurs during test bench rotation, the runtime required for the transmitted signal fed from the modulator into the transmission channel changes until the transmitted signal reaches the demodulator. Consequently, the phase relationship between the modulator and demodulator also changes. Therefore, existing methods that apply post-distortion to the signal transmitted via the transmission channel in a matched filter cannot easily achieve the desired success. Summary of the Invention

[0017] The object of the present invention is to achieve the following feasibility, by means of which the data rate can be increased when transmitting data between a test bench and a fixed substrate for a specific bandwidth of the transmission channel.

[0018] The objective is achieved by an operating method for a computed tomography scanner according to the present invention. Advantageous designs of the operating method are described below.

[0019] According to the present invention, the operating method of the type mentioned at the beginning is designed in the following manner:

[0020] - By means of a predistortion device located upstream of the transmission channel, the transmitted signal generated by the modulator through modulation of the data stream sent from the data source to the modulator is predistorted according to the predistortion rule, and only the predistorted transmitted signal is sent to the transmission channel, and / or by means of a postdistortion device located downstream of the transmission channel, the signal transmitted via the transmission channel is postdistorted according to the postdistortion rule, and only the postdistorted signal is sent to the demodulator, and - the predistortion rule and / or the postdistortion rule are repeatedly reset by the setting device during the rotation of the test bench.

[0021] Distortion caused by the transfer function of the transmission channel in the transmitted signal can be compensated by pre-distortion, post-distortion, or (particularly preferably) a combination of pre-distortion and post-distortion. Therefore, a signal with almost no distortion in the result can be delivered to the demodulator, allowing for a high-quality, almost distortion-free reconstruction of the actual data signal. That is, matched filtering is performed in a matched filter. In this respect, the method initially corresponds to the method used in the prior art for quadrature amplitude modulation. However, to compensate for the change in runtime during rig rotation, the pre-distortion rules and / or post-distortion rules are additionally tracked more or less continuously. Thus, the quality of data transmission can be maintained even during rig rotation.

[0022] Preferably, the data source transmits the data stream as a complex signal to the modulator, and the modulator determines the transmission signal based on the transmitted complex signal through quadrature amplitude modulation of the carrier signal. This maximizes the data rate during data transmission. In particular, the present invention demonstrates its full advantages through quadrature amplitude modulation.

[0023] Preferably, the predistortion rule and / or postdistortion rule are parameterizable FIR filters (FIR = Finite Impulse Response). The filter can be reliably, robustly, and easily parameterized, or it can be dynamically parameterized.

[0024] Preferably, the setting device determines the pre-distortion rule and / or post-distortion rule based on the corresponding rotation angle of the test bench.

[0025] Preferably, the setting device considers at least one time derivative of the rotation angle in addition to the corresponding rotation angle when determining the pre-distortion rule and / or post-distortion rule.

[0026] The time derivative can be, in particular, the first time derivative (i.e., rotational velocity) and / or the second time derivative (i.e., rotational acceleration). The sign of the time derivative is especially important. For example, by considering the time derivative of the rotation angle, it is possible to compensate for the time delay between detecting or determining the corresponding rotation angle and the tracking pre-distortion rule and / or post-distortion rule.

[0027] It is feasible to measure the rotation angle separately, that is, to track the pre-distortion rule and / or post-distortion rule separately based on the measured rotation angle. In this case, it is also feasible to additionally consider at least one time derivative of the rotation angle in the process of determining the pre-distortion rule and / or post-distortion rule.

[0028] Alternatively, it is feasible to measure the rotation angle only at predetermined angular positions, such as only once every 120°, every 180°, or even only once per complete revolution of the test bench. In this case, between the predetermined angular positions, the rotation angle is determined by the setting device by updating the last measured rotation angle based on the test bench's operating data characterizing the bench's rotation, particularly the rotational speed and / or rotational acceleration.

[0029] Preferably, the setting device stores parameters for parameterizing the pre-distortion device and / or post-distortion device in a lookup table for multiple input variables, and the setting device uses the lookup table to determine the parameters.

[0030] For example, for multiple grid points (Stützstelle) representing rotation angles, a lookup table contains the corresponding parameters for parameterizing the pre-distortion and / or post-distortion devices. If the corresponding rotation angle matches a grid point, the parameters stored for that grid point are used. If the corresponding rotation angle does not match any of the grid points, the parameters for the corresponding rotation angle can be determined, for example, by linear interpolation using the parameters stored for the nearest grid point. A similar approach is possible if the lookup table is not one-dimensional (using only rotation angles) but multi-dimensional (also utilizing rotation speed, etc.).

[0031] Preferably, the data stream comprises multiple data groups, each including a reference sequence and a useful sequence. In this case, the signal transmitted via the transmission channel includes a reference component and a useful component. The reference component is provided to a setting device, which determines a post-distortion rule for the useful component following the corresponding reference component. The background of this approach is that the reference sequence can be known in advance to the setting device, such that the reconstructed sequence generated after post-distortion and demodulation may need to be consistent with the reference sequence. Therefore, the setting device can track a post-distortion rule to ensure that the reconstructed sequence is as consistent as possible with the reference sequence, and uses the correspondingly tracked post-distortion rule to perform post-distortion on the useful component of the corresponding data group. The transmitted signal can be a transmitted signal that has already been post-distorted, or a transmitted signal that has not yet been post-distorted, and can also be data derived from said signal.

[0032] The objective is also achieved by a computed tomography scanner according to the invention. Advantageous designs of the computed tomography scanner are described below.

[0033] According to the present invention, the type of computed tomography scanner mentioned at the beginning is designed in the following manner:

[0034] - A predistortion device is provided upstream of the transmission channel. Using this predistortion device, the transmitted signal generated by the modulator through modulation of the data stream supplied from the data source to the modulator is predistorted according to a predistortion rule, so that only the predistorted transmitted signal is transmitted to the transmission channel. And / or a postdistortion device is provided downstream of the transmission channel. Using this postdistortion device, the signal transmitted via the transmission channel is postdistorted according to a postdistortion rule, so that only the postdistorted signal is transmitted to the demodulator.

[0035] - The computed tomography scanner has a setting device, which repeatedly resets the pre-distortion rules and / or post-distortion rules during gantry rotation.

[0036] The resulting facts and advantages correspond to the facts and advantages of the operating method according to the invention.

[0037] The advantageous design of a computed tomography scanner corresponds to the advantageous design of its operating method. The same applies to the advantages arising therefrom. Attached Figure Description

[0038] The features, characteristics, and advantages of the present invention described above, and the ways and means of achieving these features, characteristics, and advantages, become clearer and easier to understand in conjunction with the following description of embodiments, which are illustrated in detail with reference to the accompanying drawings. In this case, schematic diagrams are provided:

[0039] Figure 1 A computed tomography (CT) scanner is shown.

[0040] Figure 2 A timeline is shown.

[0041] Figure 3 Another timeline is shown.

[0042] Figure 4 The data transmission structure is shown.

[0043] Figure 5 The communication path is shown.

[0044] Figure 6 The flowchart is shown.

[0045] Figure 7 The setting device is shown.

[0046] Figure 8 The data source and modulator are shown.

[0047] Figure 9 The demodulator and data receiver are shown.

[0048] Figure 10 Show the data stream,

[0049] Figure 11 The transmitted signal is shown, and

[0050] Figure 12 The flowchart is shown. Detailed Implementation

[0051] according to Figure 1 The computed tomography scanner 1 has a fixed substrate 2. A gantry 3 is rotatably supported on the substrate 2, allowing the gantry 3 to rotate relative to the substrate 2 about a rotation axis 4. This rotatability... Figure 1As indicated by arrow 5, the gantry 3, as is commonly seen, carries an X-ray source 6 and an X-ray detector 7. The X-ray source 6 and the X-ray detector 7 are diagonally opposite each other about the rotation axis 4. In some cases, the gantry 3 also additionally carries another X-ray source 8 and another X-ray detector 9. The other X-ray source 8 and the other X-ray detector 9 are also diagonally opposite each other about the rotation axis 4. The other X-ray source 8 and the other X-ray detector 9 (wherever they are present) are typically positioned 90° off-center around the rotation axis 4 in the circumferential direction with respect to the aforementioned X-ray source 6 and the aforementioned X-ray detector 7. During rotation of the gantry 3 about the rotation axis 4, X-ray images of the object 10 to be examined, located in the area of ​​the rotation axis 4, can be detected by means of the X-ray detector 7 or X-ray detectors 7 and 9.

[0052] Figure 2 The rotation of platform 3 is shown as a function of time point t. According to... Figure 2 The rotation of the gantry 3 begins at time t1 to detect the X-ray image of the object 10. Specifically, the gantry 3 accelerates from time t1 to time t2, causing the rotational speed ω to reach its maximum value at time t2. Subsequently, the gantry 3 rotates at its maximum speed until time t3, and finally brakes again until the gantry comes to a standstill at time t4.

[0053] The detection of X-ray images is performed at least between time point t2 and time point t3, and often even from time point t1 until time point t4. According to Figure 3 At more or less the same time as detecting the X-ray image, the X-ray image is also transmitted from the stand 3 to the substrate 2. Figure 3 The following time periods are shown in solid lines, during which at least one data transmission occurs, and the following time periods are shown in dashed lines, during which data transmission is also possible. The transmitted data is digital.

[0054] Figure 4 The structure for data transmission between the test stand 3 and the base 2 is shown in a simplified form.

[0055] according to Figure 4 There is a data source 11. The data source 11 can be, for example, a unit that receives images from X-ray detectors 7 and 9 and (slightly) processes the images. The data source 11 is connected to multiple modulators 12. At least one modulator 12 exists. Currently, three modulators 12 exist. The modulators 12 transmit the signal SS' generated by them (see...). Figure 5 Feeded into transmission channel 17 (see also) Figure 5In the bench-side section 13 of the modulator 12, the section 13 extends over a range of approximately 360° / n, where n is the number of modulators 12. The bench-side section 13 can be configured as a waveguide or a dielectric conductor, for example. On the fixed substrate 2 side, coupling elements 14 are coupled to the bench-side section 13. The coupling elements 14 are typically uniformly distributed around the circumference. The number of coupling elements 14 is typically one greater than the number of modulators 12. The signal continues from the coupling elements 14 to the demodulator 15 and from there to the data receiver 16. There is typically a 1:1 relationship between the coupling elements 14 and the demodulator 15. The section from one of the modulators 12 to one of the demodulators 15 forms a transmission channel 17.

[0056] The data transmission was described above in conjunction with the transmission of data from the test bench 3 to the base 2. However, in principle, data transmission can also be carried out in the opposite direction. Furthermore, the section 13 can also be disposed on the side of the base 2, and the coupling element 14 can be disposed on the side of the test bench 3.

[0057] In the following text Figure 5 The communication path from data source 11 to data receiver 16 for a single transmission path will be described again.

[0058] according to Figure 5 Data is transmitted from data source 11 to data receiver 16 in the form of a data stream DS via modulator 12, its associated transmission channel 17, and demodulator 15. (See data transmission...) Figure 2 and Figure 3 This process takes place during the rotation of the test bench 3. Specifically, the data source 11 transmits the data stream DS to the corresponding modulator 12. The modulator 12 modulates the carrier signal CS according to the data stream DS. The modulated carrier signal corresponds to the transmit signal SS, and the modulator 12 should begin feeding the transmit signal SS into the transmission channel 17. However, the transmit signal SS is first fed to the predistortion device 18. The predistortion device 18 is parameterized by means of parameter PV. The parameterization of the predistortion device 18 by means of parameter PV determines the predistortion rule, and the predistortion device 18 predistorts the transmit signal SS according to the predistortion rule. The predistorted transmit signal (hereinafter referred to as SS' to distinguish it from the original transmit signal SS) is then fed into the transmission channel 17. As a result, the predistortion device 18 is thus positioned upstream of the transmission channel 17.

[0059] The signal SS' fed into transmission channel 17 is transmitted via transmission channel 17. This signal is referred to below as the transmitted signal and is designated by reference numeral TS. After transmission, the transmitted signal TS is sent to post-distortion device 19. Post-distortion device 19 is parameterized by parameter PN. By parameterizing post-distortion device 19 by parameter PN, a defined post-distortion rule is determined, and post-distortion device 19 performs post-distortion on the transmitted signal TS according to the post-distortion rule. The post-distorted transmitted signal (hereinafter designated by reference numeral TS' to distinguish it from the transmitted signal TS) is then sent to demodulator 15. As a result, post-distortion device 19 is thus located downstream of transmission channel 17.

[0060] Demodulator 15 demodulates the post-distorted transmitted signal TS to generate the transmitted data stream DS'. The transmitted data stream DS is then sent to data receiver 16.

[0061] As from Figure 4 As can be seen, the coupling regions of the corresponding segments 13 continuously change during the rotation of the test bench 3, where the coupling elements 14 adjacent to each other are coupled to the corresponding segments 13. Therefore, the effective length of the transmission channel 17 continuously changes during the rotation of the test bench 3. Consequently, the transmission characteristics of the transmission channel 17 also change. To maintain the overall transmission characteristics of the transmission channel 17, the pre-distortion device 18, and the post-distortion device 19 constant or at least substantially constant, a setting device 20 is provided. During the rotation of the test bench 3, the setting device 20 repeatedly resets the pre-distortion rules and / or the post-distortion rules by presetting the corresponding parameters PV and PN. This will be discussed in detail below. Figure 6 A detailed explanation is provided.

[0062] according to Figure 6 In step S1, the setting device 20 knows the corresponding rotation angle φ of the test bench 3. It is feasible to detect, i.e., measure, the rotation angle φ and transmit the corresponding measured value φ to the setting device 20. Alternatively, it is feasible to measure the corresponding rotation angle φ directly or indirectly only at predetermined angular positions of the test bench 3 (e.g., when passing a reference position), and update the last measured rotation angle φ between predetermined angular positions. In particular, updates can be made based on the operating data ω and α characterizing the rotation of the test bench 3, such as the rotational speed ω and / or rotational acceleration α.

[0063] In step S2, the setting device 20 determines the parameters PV and PN for the pre-distortion device 18 and the post-distortion device 19. This is determined based on the corresponding rotation angle φ. Optionally, as in... Figure 6As shown in the paper, at least one time derivative of the rotation angle φ, especially the first time derivative, i.e. the rotational velocity ω, can also be additionally considered, and optionally the second time derivative, i.e. the rotational acceleration α, can also be considered.

[0064] In step S3, the setting device 20 outputs the parameters PV and PN determined in step S2 to the pre-distortion device 18 and the post-distortion device 19. This resets the corresponding distortion rules.

[0065] Then, the setting device 20 returns to step S1, so that the setting device thus continuously and repeatedly performs steps S1 to S3.

[0066] The above explanation has been simplified to some extent. Therefore, it is especially unnecessary to repeat step S1 immediately after step S3. In many cases, it is sufficient to maintain the corresponding determination of parameters PV and PN made in step S3 until a specific time has elapsed or the test bench 3 continues to rotate a specific angle.

[0067] The basic principles used to determine the parameters PV and PN are explained below.

[0068] If we use H, U, and V to represent the transfer functions of transmission channel 17, predistortion device 18, and postdistortion device 19, then H' = UHV always applies, where H' is the transfer function generated by predistortion device 18, transmission channel 17, and postdistortion device 19. Ideally, the relation H' = I should also apply, where I is the unit transfer function.

[0069] Due to the rotation of the test stand 3, the transfer function H of the transmission channel 17 is variable in time. That is, at any time, the parameters PV and PN should be determined such that the aforementioned relation H' = I applies precisely or at least approximately. These parameters PV and PN are used to parameterize the predistortion device 18 and the postdistortion device 19 to determine the corresponding distortion rules and thus their transfer functions U and V.

[0070] Depending on the situation, it may be sufficient to have only the pre-distortion device 18, only the post-distortion device 19, or both distortion devices 18 and 19, but only the parameters PV and PN of one of these two distortion devices 18 and 19 are repeatedly reset. However, it is generally preferred that not only the pre-distortion device 18 but also the post-distortion device 19 be present, and that the parameters PV and PN of these two distortion devices 18 and 19 are also repeatedly reset.

[0071] The design of the pre-distortion device 18 and the post-distortion device 19 can be customized as needed. In many cases, according to... Figure 5The diagram shows that the two distortion devices 18 and 19 constitute a parameterizable FIR filter, or, in the case of only one distortion device 18 or 19, the existing distortion devices 18 and 19 constitute a parameterizable FIR filter. The parameterization of the corresponding filter is generated by the corresponding parameters PV and PN. As a result, the pre-distortion rule and / or post-distortion rule are therefore preferably parameterizable FIR filters.

[0072] The design of the setting device 20 can also be customized as needed. Therefore, for example, it is feasible for the setting device 20 to determine the parameters PV and PN by calculation using the rotation angle φ (optionally supplemented by the rotational speed ω and / or rotational acceleration α). However, as discussed below... Figure 7 The proposed design is significantly simpler.

[0073] according to Figure 7 The setting device 20 has a lookup table 21. In the lookup table 21, parameters for parameterizing the pre-distortion device 18 and / or the post-distortion device 19 are stored for multiple input variables. In the simplest case, the only input variable for the lookup table 21 is the rotation angle φ. In this one-dimensional case, for example, for values ​​from 0° to 360°, the parameters PV and PN for these two distortion devices 18 and 19 can be stored in a 2° grid. The grid size can, of course, be finer or coarser. In the case of multiple input variables (e.g., rotation angle φ and angular velocity ω), the lookup table 21 is multi-dimensional. In this case, a similar implementation applies to the angular velocity ω. This also applies when the lookup table 21 is expanded with angular acceleration α (optionally added) as another input variable. In the case of the lookup table 21, the setting device 20 can use the lookup table 21 to determine the parameters PV and PN. The manner and method of using the lookup table 21 are generally known and therefore need not be described in detail.

[0074] according to Figure 8 In the diagram, data source 11 preferably transmits the data stream DS as a complex signal to modulator 12. Therefore, the data stream DS includes two sub-signals DS1 and DS2, representing the real and imaginary parts of the complex signal, respectively. In this case, modulator 12 is configured as a quadrature amplitude modulator. The modulator includes two multipliers 22 to which the cosine and sine of the carrier signal CS are transmitted. Furthermore, one sub-signal from each of the two sub-signals DS1 and DS2 is transmitted to the two multipliers 22. The signal generated by the two multipliers 22 is transmitted to adder 23, which adds the two signals to form the transmitted signal SS.

[0075] according to Figure 9In the diagram, under quadrature amplitude modulation (QAM), the demodulator 15 and data receiver 16 are correspondingly configured. Specifically, in this case, the demodulator 15 includes two multipliers 24, which provide the cosine and sine of the post-distorted transmitted signal TS' and another carrier signal CS' with the same frequency as the carrier signal CS to the two multipliers 24. These two multipliers 24 provide the real part DS1' and imaginary part DS2' of the demodulated signal DS' as output signals, where the real part DS1' and imaginary part DS2' are superimposed with corresponding high-frequency components. The corresponding high-frequency components are filtered out in corresponding low-pass filters 25, such that the real part DS1' and imaginary part DS2' of the demodulated signal DS' are provided at the output of the corresponding low-pass filter 25. The two sub-signals DS1' and DS2' are then provided to the data receiver 16.

[0076] For proper demodulation, the phase of the other carrier signal CS' must be synchronized with the phase of the carrier signal CS. In particular, this phase synchronization is achieved through the dynamic setting of the two distortion devices 18 and 19 and their distortion functions.

[0077] according to Figure 10 The data stream DS can include multiple data groups 26. This is especially applicable when the data stream DS is a complex data stream. Each data group 26 includes a reference sequence 27 and a useful sequence 28. The reference sequence 27 is fixed in advance. That is, the content of the reference sequence is known not only to the data source 11 but also to the data receiver 16. The useful sequence 28 contains the actual useful data to be transmitted, such as X-ray image data. The data groups 26 are transmitted sequentially, with the corresponding reference sequence 27 transmitted first, followed by the corresponding useful sequence 28.

[0078] Based on the order and structure of data group 26 in data stream DS, according to Figure 11 The signal TS transmitted via transmission channel 17 includes segments 29, each comprising a reference component 30 and a useful component 31. Segments 29 correspond to data groups 26, reference components 30 correspond to their respective reference sequences 27, and useful components 31 correspond to their respective useful sequences 28. The same applies (not specifically shown) to the post-distorted transmitted signal TS'.

[0079] according to Figure 11 In the diagram, reference component 30 can be transmitted to setting device 20. In this case, the parameterization of post-distortion device 19 (instead of pre-distortion device 18) described above can be combined as follows: Figure 12 Modify it as described above.

[0080] according to Figure 12In step S11, the corresponding rotation angle φ of the stage 3 is known to the setting device 20. In step S12, the setting device 20 determines the parameters PV and PN for the pre-distortion device 18 and the post-distortion device 19. In step S13, the setting device 20 outputs the determined parameters PV and PN to the pre-distortion device 18 and the post-distortion device 19. Steps S11 to S13 are related to... Figure 6 Steps S1 to S3 correspond in a 1:1 ratio. Therefore, refer to the relevant implementation scheme.

[0081] In step S14, the setting device 20 receives the corresponding reference component 30. In step S15, the setting device 20 determines the corresponding reconstructed sequence 32 by demodulating the reference component 30. In step S16, the setting device 20 corrects the parameter PN used by the post-distortion device 19. The correction is made so that the reconstructed sequence 32 is as close as possible to the reference sequence 27, ideally completely identical to it. Steps S15 and S16 can be performed iteratively as needed until the parameter PN is fully optimized or at least optimized to a sufficient extent. In step S17, the setting device 20 outputs the corrected parameter PN to the post-distortion device 19. As a result, steps S14 to S17 cause the setting device 20 to track the post-distortion rule according to the corresponding reference component 30. According to the post-distortion rule thus corrected, the corresponding useful component 31 is demodulated by means of the demodulator 15.

[0082] In step S18, the setting device 20 checks whether the parameter PV used for the predistortion device 18 needs to be redefined. This check may include, for example, a time process or sweep exceeding a specific angular range or a predetermined angle. If the check in step S18 determines that the parameter PV used for the predistortion device 18 does not need to be redefined, then the setting device 20 returns to step S14, thus performing steps S14 to S17 multiple times sequentially. Conversely, if the check in step S18 determines that the parameter PV used for the predistortion device 18 needs to be redefined, then the setting device 20 returns to step S11, thus performing steps S11 to S13 again.

[0083] Figure 12 The method is based on the transmitted signal TS, i.e., the transmitted signal before post-distortion. However, it is equally feasible to perform the process using the transmitted signal TS' after post-distortion. Figure 12 The method and approach. In this case, step S15 can be omitted.

[0084] In summary, the present invention therefore relates to the following facts:

[0085] The gantry 3 of the computed tomography (CT) scanner rotates relative to the fixed substrate 2 of the CT scanner. During the rotation of the gantry 3, digital data is transmitted from the data source 11 to the data receiver 16 between the gantry 3 and the substrate 2 via the modulator 12, the transmission channel 17, and the demodulator 15. A predistortion device 18, located upstream of the transmission channel 17, predistorts the transmit signal SS generated by the modulator 12 through modulation of the data stream DS sent from the data source 11 to the modulator 12 according to a predistortion rule. Only the predistorted transmit signal SS' is transmitted to the transmission channel 17. Alternatively or additionally, a postdistortion device 19, located downstream of the transmission channel 17, postdistorts the signal TS transmitted via the transmission channel 17 according to a postdistortion rule, and only the postdistorted signal TS' is transmitted to the demodulator 15. The predistortion rule and / or the postdistortion rule are repeatedly reset by the setting device 20 during the rotation of the gantry 3.

[0086] This invention has many advantages. In particular, it enables a relatively simple yet robust data transmission, by means of which high transmission rates in the gigabits per second range can be achieved.

[0087] Although the invention has been described in detail with reference to preferred embodiments, the invention is not limited to the disclosed examples and other variations can be derived by those skilled in the art without departing from the scope of protection of the invention.

Claims

1. A method for operating a computed tomography scanner, - wherein the computed tomography scanner platform (3) is rotated relative to the fixed substrate (2) of the computed tomography scanner. - During the rotation of the test stand (3), digital data is transmitted from the data source (11) to the data receiver (16) via the modulator (12), the transmission channel (17) and the demodulator (15) between the test stand (3) and the substrate (2). - Wherein, by means of a predistortion device (18) disposed upstream of the transmission channel (17), the transmit signal (SS) generated by the modulator (12) by modulating the data stream (DS) sent from the data source (11) to the modulator (12) according to the predistortion rule is predistorted, and only the predistorted transmit signal (SS') is transmitted to the transmission channel (17), and / or by means of a postdistortion device (19) disposed downstream of the transmission channel (17), the signal (TS) transmitted via the transmission channel (17) according to the postdistortion rule is postdistorted, and only the postdistorted signal (TS') is transmitted to the demodulator (15), and - During the rotation of the test bench (3), the pre-distortion rules and / or the post-distortion rules are repeatedly reset by the setting device (20).

2. The operating method according to claim 1, Its features are, The data source (11) transmits the data stream (DS) as a complex signal to the modulator (12), and the modulator (12) determines the transmitted signal (SS) based on the complex signal transmitted to the modulator through quadrature amplitude modulation of the carrier signal (CS).

3. The operating method according to claim 1 or 2, Its features are, The pre-distortion rule and / or the post-distortion rule are parameterizable FIR filters.

4. The operating method according to claim 1 or 2, Its features are, The setting device (20) determines the pre-distortion rule and / or the post-distortion rule based on the corresponding rotation angle (φ) of the platform (3).

5. The operating method according to claim 4, Its features are, In determining the pre-distortion rule and / or the post-distortion rule, the setting device (20) considers at least one time derivative of the rotation angle (φ) in addition to the corresponding rotation angle (φ).

6. The operating method according to claim 4, Its features are, The rotation angle (φ) is measured individually or only at predetermined angular positions, and the rotation angle (φ) is determined between the predetermined angular positions by updating the last measured rotation angle (φ) based on the operating data characterizing the rotation of the test bench (3).

7. The operating method according to claim 6, Its features are, The operating data are rotational speed (ω) and / or rotational acceleration (α).

8. The operating method according to claim 1 or 2, Its features are, In the setting device (20), parameters for parameterizing the pre-distortion device (18) and / or the post-distortion device (19) are stored in a lookup table (21) for multiple input variables, and the setting device (20) determines the parameters using the lookup table (21).

9. The operating method according to claim 1 or 2, Its features are, The data stream (DS) includes multiple data groups (26), each of which includes a reference sequence (27) and a useful sequence (28), such that the signal (TS, TS') transmitted via the transmission channel (17) includes a reference component (30) and a useful component (31), the reference component (30) is transmitted to the setting device (20), and the setting device (20) tracks the post-distortion rule for the useful component (31) that follows the corresponding reference component (30) according to the corresponding reference component (30).

10. A computed tomography scanner, - The computed tomography scanner described therein has a fixed substrate (2) and a gantry (3) that can rotate relative to the fixed substrate (2). - The computed tomography scanner wherein the computed tomography scanner has a data source (11), a modulator (12), a transmission channel (17), a demodulator (15), and a data receiver (16) such that, during rotation of the gantry (3), digital data can be transmitted between the gantry (3) and the substrate (2) from the data source (11) via the modulator (12), the transmission channel (17), and the demodulator (15) to the data receiver (16). - A predistortion device (18) is provided upstream of the transmission channel (17) to predistort the transmit signal (SS) generated by the modulator (12) from the data stream (DS) transmitted from the data source (11) to the modulator (12) according to a predistortion rule, so that only the predistorted transmit signal (SS') is transmitted to the transmission channel (17), and / or a postdistortion device (19) is provided downstream of the transmission channel (17) to postdistort the signal (TS) transmitted via the transmission channel (17) according to a postdistortion rule, so that only the postdistorted signal (TS') is transmitted to the demodulator (15), and - The computed tomography scanner wherein the computed tomography scanner has a setting device (20) that repeatedly resets the pre-distortion rules and / or the post-distortion rules during rotation of the gantry (3).

11. The computed tomography scanner according to claim 10, Its features are, The modulator (12) is configured as a quadrature amplitude modulator, which determines the transmitted signal (SS) based on the complex signal supplied to it by the data source (11) according to the quadrature amplitude modulation.

12. The computed tomography scanner according to claim 10 or 11, Its features are, The pre-distortion device (18) and / or the post-distortion device (19) are configured as a parameterizable FIR filter.

13. The computed tomography scanner according to claim 10 or 11, Its features are, The setting device (20) determines the pre-distortion rule and / or the post-distortion rule based on the corresponding rotation angle (φ) of the platform (3).

14. The computed tomography scanner according to claim 13, Its features are, In determining the pre-distortion rule and / or the post-distortion rule, the setting device (20) considers at least one time derivative of the rotation angle (φ) in addition to the corresponding rotation angle (φ).

15. The computed tomography scanner according to claim 10 or 11, Its features are, The setting device (20) has a lookup table (21) in which parameters for parameterizing the pre-distortion device (18) and / or the post-distortion device (19) are stored for a plurality of input variables, and the setting device (20) uses the lookup table (21) to determine the parameters.

16. The computed tomography scanner according to claim 10 or 11, Its features are, The data stream (DS) includes multiple data groups (26), each of which includes a reference sequence (27) and a useful sequence (28), such that the signal (TS, TS') transmitted via the transmission channel (17) includes a reference component (30) and a useful component (31), the reference component (30) is transmitted to the setting device (20), and the setting device (20) tracks the post-distortion rule for the useful component (31) that follows the corresponding reference component (30) according to the corresponding reference component (30).

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