JP4601978B2 - Signal transmission apparatus for medical image diagnostic system - Google Patents

Description

  The present invention relates to a signal transmission device of a medical image diagnostic system, and in particular, from a rotating unit that collects data from a subject while rotating around the subject in a medical system such as an X-ray CT scanner, The present invention relates to a signal transmission apparatus for transmitting data via a non-contact transmission channel to a fixed unit that performs the above process.

  There are various types of medical image diagnostic systems such as an X-ray CT scanner, a magnetic resonance imaging apparatus, an ultrasonic diagnostic apparatus, and a nuclear medicine diagnostic apparatus, and each system is now progressing rapidly.

  Among these, in recent X-ray CT scanners, the number of X-ray detectors is increasing from the viewpoint of shortening the inspection time and improving the inspection accuracy. As such X-ray detectors, those having four or eight detector element rows are already in practical use, and the latest detectors having 256 rows have been studied. On the other hand, the rotational speed when the pair of the X-ray detector and the X-ray tube is rotated around the subject has become very fast in combination with continuous rotation such as helical scanning. Such multi-row detection and high-speed rotation of the detector have led to a significant increase in the amount of data output from the detector.

  The gantry of the X-ray CT scanner includes a rotating part (rotating body) for rotating the above-described pair of the X-ray detector and the X-ray tube around the subject, and a fixing part (fixed body) for supporting the rotating part. ) And are provided. For this reason, it is necessary to transmit the data collected by the X-ray detector from the rotating unit side to the fixed unit side connected to the image processing apparatus via the signal transmission device.

  As described above, since a recent X-ray CT scanner accompanies a large amount of data collection, a signal transmission device from the rotating unit to the fixed unit is also required to transfer a large amount of data at a higher speed.

  Control signals such as X-ray exposure and imaging conditions are transferred from the fixed unit to the rotating unit via this signal transmission device.

  This signal transmission device includes an interface that performs processing such as serial / parallel conversion of signals on each of the rotating unit and the fixed unit, and a transmission channel (path) that connects both the interfaces. As this transmission channel, a fixed transmission means such as an electric wire or an optical fiber is used. However, in order to realize continuous rotation of the rotating unit, in recent years, optical communication, wireless communication, charge coupling, etc. The non-contact type using the method is generalized.

Patent Document 1 discloses a non-contact type signal transmission apparatus using optical communication among the above transmission methods. In order to realize higher-speed data transmission, it is a matter of course to increase the transmission speed of the transmission channel. However, as shown in Patent Document 1, a plurality of transmission channels are used to increase the transmission speed of the entire signal transmission apparatus. Can be done.
JP-A-5-253217

  However, in the signal transmission device described in the above publication, although the number of channels is increased to perform high-speed data transmission, if even one channel cannot be transmitted due to a circuit failure or failure, it is completely impossible. Data transmission becomes impossible, and photography cannot be performed. For this reason, the downtime spent for investigation and repair of a failure location etc. is generated, and the operation rate of the X-ray CT scanner is deteriorated, or the X-ray CT diagnosis is affected by work delays. It was.

  Therefore, the present invention has been made in view of the problems of the signal transmission apparatus of the conventional medical image diagnosis system described above, and there is a problem such as a failure in a multi-channel transmission path for realizing high-speed data transmission. The purpose of the present invention is to provide a signal transmission device for a medical diagnostic imaging system that avoids the occurrence of system down and reduces the impact on medical diagnostic imaging as much as possible, and further improves the reliability of the system. And

In order to achieve the above-described object, a signal transmission device of a medical image diagnostic system according to the present invention includes a rotation unit including a data collection system for collecting data related to an image of a subject, and a data processing system for processing the data In a signal transmission device of a medical image diagnostic system having a plurality of transmission channels that bidirectionally contactlessly transmit and receive a signal including the data to and from a fixed unit connected to the abnormality in the plurality of transmission channels An abnormality detecting means for detecting a state for each channel, and the signal carried by a part of the transmission channels in which the abnormal state is detected among the plurality of transmission channels by the abnormality detecting means. switching the remaining transmission channel, a transmission control means for transmitting the signal to the rest of the transmission channel in the degenerate operation mode, the And said that there were pictures.

  According to the signal transmission device of the medical image diagnostic system according to the present invention, when a signal such as data related to the collected image is transmitted between the rotating unit and the fixed unit via the multi-channel transmission channel, the transmission is performed. Even when a failure such as a failure occurs in the channel, signal transmission can be continued in the degenerate operation mode, for example. For this reason, the occurrence of system down can be avoided, the influence on delay in medical image diagnosis can be reduced as much as possible, and the reliability of the system can be further improved.

  Hereinafter, embodiments of a signal transmission device of a medical image diagnostic system according to the present invention will be described.

  In the following embodiments, a medical image diagnostic system (medical modality or simply modality) has a configuration in which an X-ray beam is irradiated toward a subject and the intensity of the X-ray transmitted through the subject is detected. An example in which an X-ray CT (Computed Tomography) scanner that reconstructs image information of the subject based on the detection information will be described.

  FIG. 1 illustrates a signal transmission apparatus of an X-ray CT scanner according to one embodiment.

  This X-ray CT scanner includes a gantry G having a mechanism for collecting X-ray transmission data from the subject P, and a data processing / control unit CU separate from the gantry G.

  The gantry G is formed with a diagnostic opening OP that passes from the front side to the back side. Inside the gantry G, a ring-shaped rotating portion RT is rotatably supported by the surrounding fixed portion FX so as to surround the opening OP. A subject P placed on a couch top (not shown) is inserted into the opening OP.

  In the rotating part RT, an X-ray tube 11 and an X-ray detector 12 are arranged at a pair of positions facing each other through the center position. The X-ray tube 11 is connected to a high voltage generator 13 installed in the rotating part RT, and is supplied with a high voltage for X-ray exposure. For this reason, the X-ray tube 11 can emit X-rays in response to such a high voltage. The exposed X-rays pass through the subject P and enter the X-ray detector 12.

  The X-ray detector 12 is configured, for example, as a two-dimensional X-ray detector of a multi-row detection element in which a plurality of detection element rows made of semiconductor solid X-ray elements are arranged in the slice direction. For this reason, each detection element of the X-ray detector 12 generates X-ray transmission data (also referred to as raw data) of an electric quantity corresponding to the incident X-ray dose.

  The rotating unit RT is further provided with a DAS (data acquisition device) 14, and X-ray transmission data detected by the X-ray detector 12 by the DAS 14 is subjected to preamplification and A / D conversion, respectively. It is subjected to a process that includes it and converted to digital data.

  The DAS 14 is sent to the signal transmission device 20 in order to pass such digital data from the rotating unit RT to the fixed unit FX. The signal transmission device 20 is provided in the fixed portion FX of the gantry G and serves as an interface with the data processing / control device CU.

  The signal transmission device 20 adopts an optical transmission method, and includes a rotation side substrate 21 installed in the rotation unit RT, a plurality of light emitting diodes (LEDs) 22 as light emitting units, and a fixed unit installed in the fixing unit FX. A side substrate 23 and a plurality of photodiodes 24 as light receiving portions are provided.

  Among these, the light emitting diode 22 and the photodiode 24 are arranged to face each other as schematically shown in FIG. For example, 80 light-emitting diodes 22 project from the circumference of the circumferential portion of the ring-shaped rotating portion (rotating body) RT at equal intervals. The light emitting diode 22 is located in any of six equal segment regions obtained by dividing the circumferential surface of the rotating portion RT along the circumferential direction. The plurality of light emitting diodes 22 belonging to each segment region are responsible for light emission of X-ray transmission data by the same detection element at the same sampling time.

  On the other hand, for example, six photodiodes 24 are arranged at equal intervals along the circumferential surface facing the rotating portion RT in the fixed portion FX facing the periphery of the rotating portion RT. The six photodiodes 24 are assigned to transmission channels = 6 channels, respectively. Therefore, light emission corresponding to the same X transmission data (digital amount) is performed in each segment area, and this light is received by one photodiode 24 facing the segment area. Although the rotating portion RT rotates, the same X-ray transmission data can be transmitted to each photodiode 24 while each photodiode 24 faces the same segment region. When the rotational movement of the rotating portion RT advances and each photodiode 24 faces the adjacent segment area, the next X-ray transmission data can be transmitted to each photodiode 24 from the light emitting diode 22 belonging to the segment area.

  In addition, the reference symbol 22 of the signal transmission device 20 in FIG. 1 collectively indicates a plurality of light emitting diodes 22 (diode group) located in each segment region of the rotating unit RT as described above. Each reference numeral 24 indicates the six photodiodes 24 described above, that is, six light receiving channels.

  Further, although not shown in FIG. 2, a control channel is provided for transmitting signals (such as X-ray exposure and signal transmission control means) from the fixed portion FX to the rotating portion RT. If the control channel is a non-contact type, the control channel is configured by a light emitting diode 26 provided in the fixed portion FX and a photodiode 27 provided in the rotating portion RT, and is provided by using a part of the divided region of FIG. It is done. The control channel may be a contact type. In that case, it is configured as a slip ring having a stator and a slider, and the slip ring is installed in a state of being juxtaposed to a data transmission channel of an optical transmission system.

  The rotation side substrate 21 and the fixed side substrate 23 of the signal transmission device 20 are, for example, integrated into an IC. Among these, the rotation side substrate 21 includes a first switch 21A, parallel / serial (P / S) converters 21B1 to 21Bn for the number of transmission channels, a second switch 21C, and a control circuit 21D. ing.

  The first switch 21A switches the parallel X-ray transmission data (digital quantity) sent from the DAS 14 to each of six data transmission channels in response to a switching control signal given separately. ing. The six sets of light emitting diodes (groups) 22 for the six channels described above are connected to the six terminals on the output side of the first switch 21A.

  As a result, the X-ray transmission data output from the DAS 14 in accordance with the switching operation of the first switch 21A is distributed to the parallel / serial (P / S) converters 21B1 to 21Bn for six channels. At the time of distribution, a check signal such as a check bit is added to each data as an example of a transmission state check.

  For this reason, each of the parallel-serial (P / S) converters 21B1 to 21Bn performs parallel-serial (P / S) conversion of the X-ray transmission data to which the check signal is added, and each set of light emitting diodes as a serial signal. Send to (group) 22. Therefore, each group of light emitting diodes (group) 22 emits X-ray transmission data as an optical signal for each group (that is, for each transmission channel).

  Further, the photodiode 27 serving as the control channel is connected to the second switch 21C. The second switch 21C has two output terminals for switching, and the two output terminals are connected to the control circuit 21D and a required unit, respectively. When the output of the second switch 21C is switched to the required unit, the tube voltage and the tube for scan control from the fixed unit FX side to the data collection system of the rotating unit RT, as in the conventional device. Control signals such as current, scan speed, and slice pitch are connected to the X-ray detector 12, the high voltage generator 13, and the like. On the other hand, when the second switch 21C switches its output to the control circuit 21D side, the control circuit 21D has an abnormality notification signal indicating whether or not an abnormality has occurred in the data transmission channel. Given.

  The control circuit 21D decodes the abnormality notification signal sent from the fixed unit FX side via the control channel, and when this abnormality notification signal notifies the occurrence of some abnormality of the data transmission channel, The first switch 21A, the X-ray detector 12 and the like are controlled to execute data transmission in the degenerate operation mode.

  On the other hand, the six-channel photodiodes 24 provided on the fixed portion FX side receive optical signals emitted from the respective pairs of light-emitting diodes (groups) 22 arranged to face each other and convert them into electrical signals. Thereby, the X-ray transmission data is transmitted from the rotating unit RT to the fixed unit FX for each channel via the optical signal.

  The first to sixth channel photodiodes 24 are connected to the fixed-side substrate 23 for each channel. The fixed-side substrate 23 includes serial / parallel converters 23A1 to 23An that perform serial / parallel (S / P) conversion, corresponding to the number of data transmission channels, a first switch 23B, and an abnormality. A detection circuit 23C and a second switch 23D are provided.

  Among these, the serial / parallel converters 23A1 to 23An convert serial X-ray transmission data individually given for each channel from the first to sixth channel photodiodes 24 into parallel data. Therefore, the first switch 23B sequentially selects and selects the output signals of the serial / parallel converters 23A1 to 23An at regular intervals, and sends the parallel X-ray transmission data to the data processing / control unit CU. For this reason, this apparatus CU reconstructs an X-ray CT image based on the X-ray transmission data.

  The abnormality detection circuit 23C determines whether or not X-ray transmission data passing through the first switch 23B, that is, data transmitted from the rotating unit RT to the fixed unit FX for each channel by the optical transmission method has been normally transmitted. For example, monitoring is performed based on a check signal. When the abnormality detection circuit 23C detects an abnormality in the transmission state in any of the data transmission channels, the abnormality detection circuit 23C outputs an abnormality detection signal that identifies the data transmission channel that has fallen into the abnormal state. This abnormality detection signal is sent to the second switch 23D.

  The second switch 23D uses the two input signals as control signals indicating various conditions relating to the X-ray scan given from the above-described abnormality detection signal and the data processing / control unit CU, and both at a minute constant time. Are selected alternately. For this reason, the second switch 23 </ b> D can alternately send the abnormality detection signal and the control signal to the light emitting diode 26. The light emitting diode 26 blinks in response to a given signal, so that the signal content can be transmitted as an optical signal to the photodiode 27 in a non-contact manner.

  As shown in FIG. 1, the signal transmission device 20 has six data transmission channels. With these six channels, the optimum and maximum transmission capacity for transmission of X-ray transmission data from the rotating unit RT to the fixed unit FX is provided. Suppose that it is demonstrating (refer Fig.3 (a)).

  In this normal transmission state, it is assumed that an abnormal transmission state such as signal loss or disconnection occurs in one or more of the six channels for some reason. For example, assume that an abnormality has occurred in the sixth channel (see FIG. 3B).

  The abnormality detection circuit 23C of the fixed-side substrate 23 and the control circuit 21D of the rotation-side substrate 21 always execute the process shown in FIG. 4 at a constant minute time Δt. Therefore, the occurrence of such an abnormal state is automatically detected by the abnormality detection circuit 23C of the fixed side substrate 23 based on the check signal (FIG. 4, step S1). The abnormality detection circuit 23C creates an abnormality detection signal that identifies the data transmission channel in an abnormal state, and outputs this to the second switch 23D. Therefore, the abnormality detection signal is transmitted from the fixed unit FX to the rotating unit RT via the control channel including the light emitting diode 26 and the photodiode 27 and reaches the rotating side substrate 21. In the rotation side substrate 21, the abnormality detection signal is sent to the control circuit 21D via the second switch 21C.

  For this reason, the control circuit 21D sets the contents of the degenerate operation mode (mode in which the level of the scan specification is lowered) of the signal transmission device 20 corresponding to the abnormal state indicated by the abnormality detection signal based on a predetermined algorithm (FIG. 4, Step S3).

  An example of the degenerate operation mode is as follows. In the present example, since the sixth channel becomes abnormal and cannot be used, the remaining first to fifth channels are responsible for transmission of X-ray transmission data. However, in this degenerate operation mode, data transmission cannot be performed at the maximum transmission speed of the apparatus, and therefore control is performed to change to scan conditions that can be realized at the maximum speed that can be exhibited by the data transmission channels for five channels.

  An example of the degenerate operation mode is to reduce the rotation speed of the rotating unit RT (X-ray tube 11 and X-ray detector 12). For example, the scan speed per rotation, which was the scan speed before the occurrence of an abnormality, cannot be set to 0.5 seconds, but a slow scan speed of 0.75 seconds or more is set to reduce the data transmission amount. . Another degenerate operation mode is to reduce the number of detection element rows used in the X-ray detector 12 from 16 rows to 8 rows, from 4 rows to 2 rows, and the like.

  However, if there is room in the data transmission channel when the maximum transmission speed of the device is realized, even in this degenerate operation mode, speed control is performed to increase the transmission speed of each channel, and an error occurs. The transmission capability of the previous device may be maintained as much as possible.

  Therefore, the control circuit 21D controls, for example, the first switch 21A, the X-ray detector 12 and the like according to the set degenerate operation mode to execute data transmission in the degenerate operation mode (step S4). If necessary, a signal indicating the set degenerate operation mode is sent to a controller on the fixed unit FX side using a part of the data transmission channel, and a gantry drive control unit (not shown) installed in the fixed unit FX is installed. The operation of the top panel drive control unit is controlled based on the degenerate operation mode.

  As a result, as shown in FIG. 3B, even when an abnormality occurs in some of the plurality of data transmission channels, the abnormality is automatically detected, and the remaining data transmission channels are detected according to the detection result. Can be used to continue data transmission in the degenerate operation mode.

  Therefore, it is not necessary to stop the X-ray scan in most cases when a part of the data transmission channel fails. That is, even during such a failure, the scan can be continued and the occurrence of system downtime can be prevented. A decrease in system availability can be minimized.

  Note that the above-described 6-channel data transmission is merely an example, and the present invention can be implemented regardless of the number of channels as long as it is a multi-channel data transmission. Further, as described above, the mode of the degenerate operation mode is not limited to the adjustment of the rotation speed of the rotating unit RT and the number of detection element arrays to be used, but other factors are adjusted to allow an acceptable decrease in data transmission capability. May be realized.

  Other embodiments will be described with reference to FIGS.

  In FIG. 5, contrary to the above-described embodiment, a plurality of signal transmission channels based on a non-contact transmission method such as an optical transmission method and a radio wave transmission method are constructed for signal transmission from the fixed portion FX to the rotating portion RT. An example is shown. Here, the case of 2 channels is illustrated.

  In the embodiment shown in FIG. 5, only one of the two channels (first channel) is used in the normal use state, and the remaining channels (second channel) are set as spare channels. (See FIG. 5A). That is, this spare signal transmission channel is not used in a normal state and is installed as a redundant system.

  In this signal transmission channel, a signal transmission abnormality is automatically detected on the signal receiver side (rotation unit RT side) in the same manner as described above, and automatically switched from the first channel to the spare second channel. (See FIG. 5B). This switching uses any one of a plurality of data transmission channels to return an abnormality detection signal to the fixed portion FX side, and to the switches 30 and 31 incorporated in the rotation side substrate and the fixed side substrate respectively, This can be done by switching to a channel.

  As a result, even if the normally used signal transmission channel from the fixed portion FX to the rotating portion RT fails, it can be immediately switched to the spare channel. Therefore, it is possible to avoid the occurrence of down time during which the system cannot be operated in the X-ray CT scanner.

  In addition, you may implement the structure of the signal transmission channel which concerns on embodiment mentioned above to the rotation part RT from the fixing | fixed part FX of embodiment shown in FIG. The configuration of the signal transmission channel according to this modification may be implemented for the data transmission channel from the rotating unit RT to the fixed unit FX in the embodiment shown in FIG.

  The embodiment shown in FIG. 6 relates to another example of a contactless communication method. That is, this mode shows an example in which a plurality of charge-coupled data transmission channels are constructed, and the degenerate operation described in the above-described embodiments (FIGS. 1 to 4) can be performed on this data transmission channel.

  As shown in FIG. 6, a charge-coupled three-channel data transmission channel 40 is configured. Each data transmission channel 40 </ b> A (˜40C) has a substrate attached to the outer peripheral surface of the ring body 41, and a counter electrode is provided in a non-contact manner at a predetermined position facing the outer peripheral surface of the ring body 41. Therefore, non-contact data transmission / reception can be performed between the electrode on the substrate and the counter electrode depending on the presence or absence of charges. As a result, data having the same content can be transmitted and received at any position on the outer peripheral surface of the ring body 41 at a high speed of, for example, 64 Mbps.

  In the three data transmission channels 40 (40A to 40C), as in the first embodiment described above, when an abnormality in data transmission is detected, for example, in the third channel on the fixed portion RT side, the remaining first and Data transmission in the degenerate operation mode can be continued on the data transmission channel of the second channel. This also avoids downtime due to abnormal data transmission in some channels, and is effective in maintaining the system operation rate and improving reliability.

The functional block diagram centering on the signal transmission apparatus of the X-ray CT scanner as a medical image diagnostic system which concerns on one Embodiment of this invention. The figure explaining the positional relationship of the light emitting diode and photodiode which were provided in the rotation part and the fixed part corresponding to a data transmission channel. The figure which illustrates the normal time and the abnormal time of a some data transmission channel. The schematic flowchart explaining the abnormality detection of a data transmission channel, and its subsequent response. The figure which illustrates the normal time and the abnormal time of a some signal transmission channel based on other embodiment of this invention. The perspective view explaining the outline of a plurality of data transmission channels concerning other embodiments of the present invention.

Explanation of symbols

FX fixed portion RT rotating portion G mount P subject CU data processing / control device 11 X-ray tube 12 X-ray detector 14 DAS
21 Rotation side substrate 21A, 21C Switch 21B P / S converter 21D Control circuit 22 Light emitting diode 23 Fixed side substrate 23A S / P converter 23B, 23D Switch 23C Abnormality detection circuit 24 Photodiode 30, 31 Switch 40 Data transmission channel

Claims (6)

A signal including at least the data is not bidirectionally contacted between a rotating unit having a data collection system for collecting data related to the image of the subject and a fixed unit connected to the data processing system for processing the data. In a signal transmission device of a medical diagnostic imaging system having a plurality of transmission channels for transmitting and receiving at
An abnormality detecting means for detecting an abnormal state of the plurality of transmission channels for each channel;
The signal carried by a part of the plurality of transmission channels in which the abnormal state is detected by the abnormality detection means is switched to the remaining transmission channels of the plurality of transmission channels, and the remaining transmission channels And a transmission control means for transmitting the signal in a degenerate operation mode . The degenerate operation mode is an operation mode in which signals are transmitted to the remaining transmission channels at a transmission rate lower than the maximum transmission rate when the plurality of transmission channels transmit the signal. The signal transmission apparatus of the medical image diagnostic system according to claim 1 . Wherein the plurality of transmission channels, according to claim 1 or 2, characterized in that it comprises a plurality of transmission channels for transmitting data collected by the data acquisition system of the rotating part to the stationary part from the rotary part Signal transmission device for medical image diagnosis system in Japan. The plurality of transmission channels include a plurality of transmission channels for transmitting control signals necessary for the rotation operation of the rotation unit and the collection operation of the data collection system from the fixed unit to the rotation unit. The signal transmission apparatus of the medical image diagnostic system according to claim 1 or 2 . A plurality of transmission channels for transmitting the control signal from the fixed unit to the rotating unit are used for a normal use transmission channel set to be used in a normal state and when the abnormal state is detected. With a pre-used transmission channel set to
5. The medical device according to claim 4 , wherein the switching means is means for switching transmission of the control signal to the transmission channel for preliminary use when an abnormal state is detected in the transmission channel for normal use. Signal transmission device for diagnostic imaging system. The medical image diagnostic system is an X-ray CT scanner, the plurality of transmission channels optical communication, wireless communication, or any one of claims 1-5, characterized in that it comprises a transmission means by the communication charge coupling system The signal transmission apparatus of the medical image diagnostic system according to item.

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