DE102012201850A1 - Computerized tomography scanner for image detection of three-dimensional structures in interior of enclosed bodies, such as animals or objects, particularly in medicine, has data converter, which is held by rotating ring - Google Patents

Abstract

The computerized tomography scanner (1) has an x-ray source (5) held on a rotating ring (4) in a rotatable manner, where an x-ray detector (6) is held with respect to the rotating ring for generating an x-ray image data set. An evaluation unit is provided for the evaluation and processing of the x-ray image data set in a stationary area (2). A data converter (9) is held by the rotating ring, and is arranged downstream of the x-ray detector for integration of the x-ray image data set into a data frame.

Description

The invention relates to a computer tomograph.

Imaging of three-dimensional structures within closed bodies (i.e., animals or objects) is often used in computed tomography, particularly in medicine.

For this purpose, projection images of the body region to be imaged are recorded by means of a computer tomograph at a multiplicity of different projection angles, from which a three-dimensional image (tomogram) of the body region is calculated by means of mathematical back-projection algorithms. Such a computer tomograph comprises as an image chain an X-ray source and an associated (X-ray) detector, between which the body is positioned. The image chain is rotated around the body during image acquisition.

In computed tomography, a so-called gantry is predominantly used as the holder for the image chain, that is to say the x-ray source and the x-ray detector, in which the x-ray source and the detector are accommodated in a tubular slewing ring which is mounted so as to be capable of unlimited rotation in a surrounding, stationary support frame.

Also associated with a fixed area of the computer tomograph is usually an evaluation computer in which the tomogram is calculated from the recorded projection images. Due to the unlimited degree of rotational freedom of the ring gear provided with the image chain, the image data generated by the detector can not be transmitted via a continuous cable connection to the stationary evaluation computer.

In classical computed tomography, slip ring contacts are used instead for data transmission technology coupling of the rotating turntable to the stationary area of the computer tomograph. In modern computer tomographs, the transmission of the image data from the rotating part to the stationary part takes place predominantly via a contactless data transmission path, in particular on the basis of a near-field radio transmission, since in this way a high data throughput with simultaneously low transmission error rate and thus low image noise can be achieved.

For transmission, the image data generated by the detector is packed into one or more data frames (or data packets) according to an underlying (data) transmission protocol. The packed image data are then sent via the contactless transmission interface to the evaluation computer.

Since in computed tomography recording of the projection images on the one hand, a large volume of data, but on the other hand, the resulting tomogram in real time, that is as soon as possible with or immediately after the recording of the projection images to be displayed by the processing computer is usually in a CT scanner for image data transmission uses a transmission protocol tailored specifically to this application, optimized for the highest possible data transfer rate.

Disadvantageously, specially developed transmission interfaces, in particular specially designed transmission and reception cards, are required for processing such a transmission protocol. These usually also need to be redesigned for each newly developed computed tomography model. As a result of the special cards, the image data packets transmitted by the detector can only be read out on that evaluation computer which is assigned to the computer tomograph and, in particular, has been delivered together with it.

In particular, a redistribution of these data packets to multiple computers is usually not possible. In addition, the transmission protocols currently used in computed tomography for transmission of the image data typically do not provide the ability to record the image data and to diagnose any transmission errors.

The invention has for its object to provide in a computer tomography a flexible and easy to implement way to transfer the image data generated by the detector of the rotatable slewing ring to the stationary evaluation computer.

This object is achieved by the features of claim 1. Thereafter, the computed tomography comprises a rotatable turntable, to which for generating a two-dimensional (X-ray) image data set (projection image) an X-ray source and to this in juxtaposition an (X-ray) detector are supported. The X-ray source and the detector together are also referred to below as the (X-ray) image chain. The computer tomograph can also contain several, in particular two image chains. Furthermore, the computer tomograph has an evaluation computer, which serves the evaluation and processing of the image data set. The computer tomograph further comprises a data converter for embedding the image data set generated by the detector into a data converter Data frame (also: data frame). The data converter is the data transmission technology downstream of the detector and supported on the turntable. In order to send the image data (more precisely a signal which transports the image data set packed in the data frame) from the slewing ring to the stationary area of the computer tomograph wirelessly (ie without a permanently connected line connection), the computer tomograph comprises at least a first transmission interface which is supported on the turntable is. At least one second transmission interface is arranged in the stationary area of the computed tomography apparatus in order to receive the signal transmitted by the at least one first transmission interface in a wireless manner. According to the invention, the data converter is set up to embed the image data record in the data frame in accordance with an Ethernet-based (data) transmission protocol.

The term "Ethernet" refers to a standard that specifies properties of software (particularly applicable data transfer protocols) and hardware (particularly, cables, distributors, network cards, etc.) for wired data networks. The contents of the "Ethernet" standard have been reviewed by the Institute of Electrical and Electronics Engineers (IEEE) under the working group designation 802.3 defined and standardized.

For the application described above, the use of the Ethernet technology according to the invention is untypical, especially since the transmission path between the rotatable slewing ring and the stationary area of a computer tomograph is not a network but a simple, direct connection between two fixed points. The Ethernet technology is not only not intended for such a purpose in itself, but - seen from the pure aspect of data transmission - also not optimally suited. In particular, ethernet-based data transmission involves a non-negligible overhead that reduces the achievable transmission rate for the payload, and is unnecessary for data transmission between the rotating and stationary portions of a CT gantry itself.

However, it is recognized that these disadvantages of ethernet-based data transmission are also outweighed in the application described above by the advantages associated with Ethernet technology. These consist in particular in the fact that the transmission protocols standardized on Ethernet are generally implemented as standard on computer systems available today, in particular on a personal computer (hereafter PC). Likewise, Ethernet-compatible communication hardware is commercially available and usually provided by default in conventional computer systems anyway. When using the commercially available communication hardware and software eliminates the need to equip a computer tomoraph and the associated evaluation computer with specially developed transmit and receive cards and associated communication software. As a result, a considerable amount of development effort is saved in the new and further development of CT systems. In addition, the exchange of communication hardware in existing CT devices is simplified. Particularly advantageous is the use of Ethernet technology in computer tomographs with multiple image chains, especially since the data streams generated by the image chains can be easily sent either via an individual data transmission path or over a common data transmission link. In particular, two or more data streams can be regularly combined by means of a simple and cost-effective Ethernet switch.

Preferably, in the context of ethernet-based data transmission as the transmission protocol, the so-called UDP / IP model is used, which - in the transport layer of the so-called OSI layer model for the transmission protocols in computer networks - from the so-called User Datagram Protocol (UDP) and - in the network layer of the OSI layer model - using the Internet Protocol (IP). Advantageously, the data frame created according to UDP / IP is very slim and thus has - compared to other ethernet-compatible transmission protocols - a high user data rate. In principle, however, other Ethernet-based transmission protocols can be used, for example the so-called TCP / IP reference model, which uses the so-called Transmission Control Protocol (TCP) in combination with IP, at the expense of a lower useful data density.

Since all Ethernet protocols have an offset-free or DC-free physical transmission layer, the protocols can be used particularly easily for contactless data transmission between the rotating part and the stationary part.

Conveniently, therefore, the signal with which the image data is transmitted between the first and the second transmission interface, and thus between the rotating part and the fixed part of the CT gantry, is coded according to the Ethernet standard for lightwave transmission, for example according to 1000BASE. SX for 850 nm lightwave transmission at a data rate of 1 gigabit per second (Gb / s).

Advantageously, the second (arranged in the stationary part of the computed tomography) transmission interface, a network data connection with at least one output connected downstream, to which the at least one evaluation unit, in particular a PC, is connected. A major advantage of ethernet-compatible transmission is that it can be connected to the computed tomography without any significant additional effort instead of a single processing computer several computers to which the data frames are alternatively or jointly addressable. This allows in particular a simplified archiving of the image data. In a particularly expedient and compact embodiment, the second transmission interface is integrated in the network data port. In particular, a conventional and commercially available Ethernet switch is used as the network data connection.

In an advantageous embodiment, the transmission interfaces are designed for bidirectional data transmission. The second transmission interface assigned to the stationary part of the computer tomograph is thus preferably also usable for transmitting data, while the first transmission interface assigned to the rotating part can also be used to receive the data. The bidirectionality of the transmission interfaces is used in this case - to send control data (more precisely a control data frame transporting control signal) from the stationary part of the computer tomograph to the turntable, for example for driving the X-ray source.

In an expedient embodiment, the transmitted image data are subjected to a "diagnosis" in the course of which the image data are checked for transmission errors. For this purpose, the data converter is preferably assigned a diagnostic unit which is set up to generate diagnostic information for the transmitted image data, by means of which it is possible to check on the receiver side whether the image data was transmitted without error. The diagnostic information is formed in particular by a checksum, which is appended to the data frame to be checked. Also for the purpose of the diagnosis, ie the transmission error detection, the use of ethernet-based transmission protocols has the great advantage that it can be used on a variety of conventional and commercially available monitoring tools for recording and verification of the transmitted signal or the transported record.

The data converter is furthermore advantageously assigned an additional data unit which is set up to embed additional data (additional data) beyond the pure image data into the data frame sent to the stationary part of the computer tomograph. In particular, these additional data are actual values of acquisition parameters, such as the orientation of the X-ray beam in space or the dose of the X-ray beam.

Embodiments will be explained in more detail with reference to a drawing. Show:

1 a schematic representation of a computer tomograph with a rotatable turntable, with a data transmission device between the turntable and a fixed area of the computed tomography and with an evaluation unit,

2 schematically shows an embodiment of the data transmission device, and

3 in illustration according to 2 a further embodiment of the data transmission device.

Corresponding parts are always provided with the same reference numerals in all figures.

In 1 is a computer tomograph 1 shown. The computer tomograph 1 includes a fixed area 2 , a fixed area 2 associated frame 3 a gantry, and one in the frame 3 rotatably positioned circular slewing ring 4 the gantry. The computer tomograph includes as image chain 1 an X-ray source 5 and an (X-ray) detector 6 , which in juxtaposition to each other on the turntable 4 are held. Furthermore, the computer tomograph includes 1 a data transmission device 7 and a connected to this evaluation unit in the form of a personal computer (hereafter: PC 8th ).

The data transmission device 7 serves to transmit the with the detector 6 captured two-dimensional (X-ray) image data sets (projection images) to the PC 8th , By means of the PC 8th a three-dimensional image (tomogram) is generated from these projection images.

The data transmission device 7 includes a data converter 9 , a first (transmission) interface 10 , a second (transmission) interface 11 and a network data port 12 , The data converter 9 and the first interface 10 are over a data line 13 with the detector 6 connected and each on the turntable 4 supported. To transfer data between the first interface 10 and the - on the stationary frame 2 supported, second interface 11 ensure is between the first interface 10 and the second interface 11 a contactless, optoelectronic transmission path 14 educated. The network data port 12 is with the second interface 11 again via a data line 15 connected.

The computer 8th is with the network data deadline 12 via a connecting cable 16a connected. At the network data deadline 12 are optional additional connecting cables 16b and 16c connectable to the connection of further evaluation units that serve to store, output or otherwise further processing the image data.

The data converter 9 is set up to embed each projection image in one or more data frames. The or each data frame is constructed in accordance with an Ethernet-based (data) transmission protocol, namely according to the UDP / IP model.

The through the data converter 9 Created data frame is then using the interface 10 encoded in an optical transmission signal to the interface 11 transmitted from there via the data line 15 to the PC 8th and / or at least one of the optionally connected further evaluation units.

An embodiment of the data transmission device 7 of the computer tomograph 1 is in 2 shown in more detail. It can be seen that between the detector 6 and the data converter 9 a readout electronics 17 is arranged. This readout electronics 17 is set up the detector 6 to read out the image data set and to the data converter 9 to hand over. Furthermore, according to 2 additional components, namely a diagnostic data unit 19 and an additional data unit 21 each via a port 23a . 23b respectively. 23c to the data converter 9 connected.

The diagnostic data unit 19 is provided for the provision of a diagnostic data set in the PC 8th to check the data frame is evaluable for transmission errors. The diagnostic data set is a simple version of the diagnostic unit 19 by a checksum, in particular a cyclic redundancy value (CRC value).

The additional data unit 21 passes to the data converter 9 an additional data record which serves additional information for the evaluation, processing and / or interpretation of the image data record. The additional information includes in particular technical recording parameters such as the rotational position of the turntable 3 and thus the X-ray source, the radiation dose of the X-ray source 5 X-ray generated, the tube voltage and the tube current of the X-ray source, etc. This additional information is from the data converter 9 packed together with the associated image data in the data frame.

Next to the PC 8th is in the example according to 2 another PC 24 intended. The PCs 8th and 24 are each with a (network) port 26a and 26b via an associated connection cable 16a respectively. 16b with the network connection 12 connected. About the respective port 26a respectively. 26b The transmitted data frames are parallel from both PCs 8th and 24 receive. The PCs 8th and 24 serve, for example, a parallel image data processing. Alternatively, the PC 24 also serve to record the image data.

Preferably, the data transmission device 7 bidirectional, in particular also for data transmission of control data records from the PC 8th to the X-ray source 5 used. The X-ray source 5 is here with the first interface 10 via a data line 13 connected. A control unit for generating the control data sets for the X-ray source 5 is in the PC 8th integrated.

In a further embodiment of the data transmission device 7 are the second interface 11 and the network data port 12 in one component, a so-called Ethernet switch 28 , integrated ( 3 ). The Ethernet switch 28 is designed for a star-shaped distribution of the data frame arriving on a connection or of the signal transporting it to all available connections. In the embodiment according to 3 is still on the turntable 4 held first interface 10 double available to allow parallel signal transmission. The Ethernet switch 28 has two fiber optic connections 30 on, one of which with an associated interface 10 corresponds. The Ethernet switch 28 is at the same time to transform the optical transmission signal into an electromagnetic signal for the ethernet-compliant wired forwarding of the data frames to the PCs 8th and 24 designed.

The object of the invention is not limited to the embodiments described above. Rather, other embodiments of the invention may be derived by those skilled in the art from the foregoing description. In particular, the individual features of the invention described with reference to the various exemplary embodiments and their design variants can also be combined with one another in a different manner.

LIST OF REFERENCE NUMBERS

1

CT Scanner

2

fixed area

3

frame

4

slewing ring

5

X-ray

6

(X-ray) detector

7

Data communications equipment

8th

PC

9

Data converter

10

first (transmission) interface

11

second (transmission) interface

12

Network data connection

13

data line

14

contactless transmission path

15

data line

16a-16c

connecting cable

17

readout electronics

19

Diagnostic data unit

21

Additional data unit

23a-23c

port

24

PC

26a, 26b

 (Network) port

28

Ethernet switch

30

Fiber optic connector

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited non-patent literature

• (IEEE) under the working group designation 802.3 [0013]

Claims (7)

Computer tomograph ( 1 ), - with one on a rotatable slewing ring ( 4 ) held X-ray source ( 5 ) and an opposite this on the turntable ( 4 ) held X-ray detector ( 6 ) for generating an X-ray image data set, - with at least one evaluation unit ( 8th . 24 ) for evaluating and processing the X-ray image data set in a fixed area ( 2 ) of the computer tomograph ( 1 ), - with one on the turntable ( 4 ) and the X-ray detector ( 6 ) downstream data converter ( 9 ) for embedding the X-ray image data set in a data frame, - with at least one first on the turntable ( 4 ) supported transmission interface ( 10 ) for the contactless transmission of a signal carrying the data frame, and - with at least one second transmission interface ( 11 ) located in the fixed area ( 2 ) of the computer tomograph ( 1 ) for non-contact reception of the signal from the first transmission interface ( 10 ), the data converter ( 9 ) is arranged such that the X-ray image data set is embedded in the data frame according to an Ethernet-based data transmission protocol. Computer tomograph ( 1 ) according to claim 1, wherein the contactless transmission signal between the first and second transmission interfaces ( 10 . 11 ) is coded by a standardized according to an Ethernet standard for lightwave transmission coding. Computer tomograph ( 1 ) according to claim 1 or 2, wherein the second transmission interface ( 11 at least one network data port ( 12 )) for a connection of the or each evaluation unit ( 8th . 24 ) and wherein by means of the or each evaluation unit ( 8th . 24 ) the data frame is readable. Computer tomograph ( 1 ) according to claim 3, wherein the second transmission interface ( 11 ) in the network data port ( 12 ) is integrated. Computer tomograph ( 1 ) according to one of claims 1 to 4, wherein the second transmission interface ( 11 ) for sending a control data frame from a control unit to the X-ray source ( 5 ) transporting signal, and the first transmission interface ( 10 ) are usable for receiving the signal carrying the control data frame. Computer tomograph ( 1 ) according to one of claims 1 to 5, wherein the data converter ( 9 ) a first unit ( 19 ) is assigned to generate a diagnostic data record and wherein the diagnostic data record in the or each evaluation unit ( 8th . 24 ) for checking the contactless transmission of the data frame of the X-ray image data transporting signal is evaluated. Computer tomograph ( 1 ) according to one of claims 1 to 6, wherein the data converter ( 9 ) a second unit ( 21 ) is assigned to generate an additional data record and wherein in the additional data record information for an evaluation of the X-ray image data set in the or each evaluation unit ( 8th . 24 ) are included.

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