JP2014057896A - X-ray ct apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an X-ray CT apparatus which detects failure of an A/D conversion substrate without exposing a subject to radiation.SOLUTION: An X-ray CT apparatus has an image generating mode and a failure detection mode. In the failure detection mode, an A/D conversion control unit 104 sets a setting condition included in a control signal for an A/D conversion element 201 by sending a control signal to an A/D conversion substrate 102, and a failure determination unit 105 receives a setting condition, which has been set for the A/D conversion element 201, and prestored testing data from the A/D conversion substrate 102 and determines whether there is a failure in the A/D conversion substrate 102 by comparing the setting condition included in the control signal and the prestored test data with the setting condition and test data received from the A/D conversion substrate 102.

Description

  The present invention relates to an X-ray CT (Computed Tomography) apparatus that generates an image of a subject by irradiating the subject with X-rays, detecting X-rays transmitted through the subject, and performing image reconstruction, and a control method thereof About. More specifically, the present invention relates to an X-ray CT apparatus that detects a failure of an A / D conversion board.

  The X-ray CT apparatus is an image diagnostic apparatus that detects X-rays that have been exposed to X-rays and transmitted through the subject, and reconstructs an image in the subject from projection data that indicates the detected X-ray intensity. It plays an important role in many medical practices such as disease diagnosis, treatment and surgical planning.

  The X-ray CT apparatus has a substrate (hereinafter referred to as an A / D conversion substrate) that converts the X-ray dose measured by a detector that detects X-rays from analog data to digital data. Further, the X-ray CT apparatus has a board (hereinafter referred to as a control board) for transmitting a command from the control unit as a control signal to the A / D conversion board and controlling the A / D conversion board. Specifically, the control board sets conditions such as gain (Gain), integration time, and resolution (used bits) for the A / D conversion board. The X-ray dose data is transmitted from the detector to a system for reconstructing the image through an A / D conversion board controlled by a number control board. Usually, the X-ray CT apparatus has a plurality of A / D conversion substrates and one control substrate.

  Conventionally, a technique (for example, refer to Patent Document 1) that clearly indicates a failed detector array has been provided. However, in the X-ray CT apparatus, when a failure occurs in the A / D conversion board, it is difficult to directly detect the occurrence of the failure. Therefore, even if a failure occurs in the A / D conversion board, an abnormality is detected for the first time by imaging the subject and referring to the image data. For example, also in the technique of Patent Document 1, after the image is generated once, the position of the failure of the detector is determined. Further, in order to cope with the failure, it is necessary to replace the failed A / D conversion board after an abnormality is detected from the image data.

Japanese Patent Laying-Open No. 2005-095308

  As described above, in the conventional method for detecting a failure of the A / D conversion board, in order to determine the failure of the A / D conversion board from the generated X-ray CT image, in order to detect the failure of the A / D conversion board. The subject needs to be imaged at least once using a faulty A / D conversion board, and a normal X-ray CT image cannot be obtained with this imaging, resulting in unnecessary exposure to the subject. There was a problem that.

  The present invention has been made in view of such circumstances, and an object thereof is to provide an X-ray CT apparatus that detects a failure of an A / D conversion board without irradiating a subject with radiation.

  In order to achieve the above object, an X-ray CT apparatus according to claim 1 is set with an X-ray irradiation means for irradiating X-rays, and an X-ray detection means for detecting X-rays and converting them into electric charges. An A / D conversion board having A / D conversion means for converting analog data to digital data using setting conditions, and an A / D for transmitting a control signal for setting the setting conditions to the A / D conversion means A conversion control unit; a failure determination unit that determines a failure based on data output from the A / D conversion unit; and an image generation unit that generates an X-ray CT image based on the data converted into the digital data. , And has two operation modes of an image generation mode and a failure detection mode. In the failure detection mode, the A / D conversion control means sends the A / D conversion means to the A / D conversion means. Set the setting conditions The setting condition is input to the failure determination unit, and the A / D conversion unit stores test data in advance, and stores the setting condition set by the A / D conversion control unit in advance. Test data is read out and input to the failure determination means. The failure determination means includes setting conditions input from the A / D conversion control means and test data for determination stored in advance, and A failure of the A / D conversion board is determined by comparing setting conditions and test data input from the A / D conversion means.

  According to the X-ray CT apparatus of the first aspect, the readback signal (setting condition and test data output from the A / D conversion board) from the A / D conversion board with respect to the control signal input from the board control unit is provided. By analyzing, a failure of the A / D conversion board can be detected. As a result, it is possible to detect a failure of the A / D conversion board without performing actual imaging, it is possible to quickly and easily detect a failure location of the A / D conversion board, and further, unnecessary for the subject. It is possible to reduce exposure.

1 is a block diagram of an X-ray CT apparatus according to the present invention. The schematic diagram of a detector unit. FIG. 3 is a flowchart of failure detection and image formation in the X-ray CT apparatus according to the first embodiment.

[First Embodiment]
The X-ray CT apparatus according to the first embodiment of the present invention will be described below. FIG. 1 is a block diagram showing functions of an X-ray CT apparatus according to the present invention.

  As shown in FIG. 1, the X-ray CT apparatus according to the present embodiment includes an X-ray irradiation unit 001, a detector unit 100, an image generation unit 002, a display control unit 003, a user interface 004, a mode switching unit 007, and an overall control. A control unit 008 is provided. Furthermore, the X-ray CT apparatus according to the present embodiment has two operation modes: an image generation mode and a failure detection mode. This operation mode is switched by a mode switching unit 007 described later. The user interface 004 includes a display unit 005 and an input unit 006.

  The detector unit 100 includes an X-ray detection unit 101, an A / D conversion board 102, and a control board 103. The detector unit 100 is also referred to as a DAS (Digital Acquisition System) unit. The A / D conversion board 102 includes a plurality of A / D converters 200, and the A / D converter 200 includes an A / D conversion element 201 and a readback unit 202. The A / D converter 200 corresponds to “A / D conversion means” in the present invention. The control board 103 includes an A / D conversion control unit 104 and a failure determination unit 105. Specifically, the detector unit 100 includes one control board 103 and a plurality of A / D conversion boards 102 as shown in FIG. FIG. 2 is a schematic diagram showing the configuration of the detector unit 100 in the X-ray CT apparatus according to the present invention. The control board 103 controls the operation of all the A / D conversion boards 102 mounted on the detector unit 100 and detects a failure of each A / D conversion board 102. Since the operation of the detector unit 100 is different for each mode, the detector unit 100 will be described below for each mode.

(In failure detection mode)
The A / D conversion control unit 104 refers to gain (Gain), integration time, and resolution for operating each A / D conversion element 201 mounted on the A / D conversion board 102 from the user interface 004 by the operator. Receives input of conditions. Hereinafter, these conditions may be collectively referred to as “setting conditions”. In the present embodiment, the input of the setting condition is that the operator actually inputs the target part, imaging time, dose, etc., and based on the input, the A / D conversion control unit 104 determines the gain, integration time, and This is done by calculating the resolution. Then, the A / D conversion control unit 104 transmits a control signal for setting setting conditions to the A / D conversion board 102. Transmission of a control signal from the A / D conversion control unit 104 included in the control board 103 is a signal represented by an arrow 203 in FIG. That is, a control command from one control board 103 is sequentially transmitted to a plurality of A / D conversion boards 102 as indicated by an arrow 203. The setting of setting conditions for each A / D conversion element 201 on the A / D conversion board 102 by the A / D conversion control unit 104 is called initialization. Initialization is control for operating the A / D conversion element 201 to operate under specified setting conditions. Furthermore, the A / D conversion control unit 104 outputs a control signal including the same setting condition as the control command transmitted to the A / D conversion board 102 to the failure determination unit 105. The A / D conversion control unit 104 corresponds to “A / D conversion control means” in the present invention.

  The A / D conversion board 102 includes a plurality of A / D converters 200 as shown in FIG. Each A / D converter 200 includes an A / D conversion element 201 and a readback unit 202. Furthermore, the A / D converter 200 has a storage area such as a memory. The A / D converter 200 stores test data output in the failure detection mode in advance. The test data is simple data such as continuous numeric data such as “1, 2, 3, 4, 5”. Further, the A / D converters 200 mounted on one A / D conversion board 102 are all connected by a daisy chain as shown in FIG. That is, the first A / D converter 200 in the daisy chain receives the control signal from the A / D conversion control unit 104 and sequentially outputs a control command to the next A / D converter 200 in the daisy chain. The A / D converter 200 at the end of the daisy chain is configured to output a control command to the failure determination unit 105.

  As described above, the A / D converter 200 includes the A / D conversion element 201 and the read back unit 202. The A / D conversion element 201 receives a control signal including setting conditions from the A / D conversion control unit 104. The A / D conversion element 201 operates with gain, integration time, and resolution based on the setting conditions input from the A / D conversion control unit 104. The A / D conversion element 201 corresponds to the “A / D conversion element” in the present invention. Then, the read back unit 202 reads the gain, the integration time, and the resolution, which are conditions under which the A / D conversion element 201 operates. Then, the readback unit 202 adds the test data stored in the A / D converter 200 on which it is mounted to the read setting condition, and outputs the test data to the next A / D converter 200 in the daisy chain. Then, after sequentially repeating this output on the daisy chain, the read back unit 202 of the last A / D converter 200 in the daisy chain outputs data obtained by adding test data to the control signal to the failure determination unit 105. The read back portion 202 corresponds to the “read back portion” in the present invention. An output from the last A / D converter 200 of the daisy chain included in the A / D conversion board 102 is a signal represented by an arrow 204 in FIG. That is, a signal is output as indicated by an arrow 204 from each A / D conversion board 102 of the plurality of A / D conversion boards 102 on the detector unit 100 toward one control board 103 in order.

  Here, the output when the A / D converter 200 is normal and when it fails is described. When the A / D converter 200 is operating normally, the setting condition included in the control signal is set as it is, so that the same setting condition as the input setting condition is output. On the other hand, when the A / D converter 200 is out of order, a setting condition different from the setting condition included in the control signal may be set in the A / D conversion element 201. A setting condition different from the set condition is output. Further, when the above-described data “1, 2, 3, 4, 5” is used as the test data, if the A / D converter 200 is operating normally, the read back unit 202 receives “1, 2, 2, Data of “3, 4, 5” is output. On the other hand, when the A / D converter 200 is out of order, data different from the original test data is output. The different data refers to data such as “1, 2, 3, 5” in which intermediate data is missing. Further, the A / D converter 200 may be out of order and cannot output. In this case, the fact that the setting conditions and test data are not output corresponds to the output of data different from the input setting conditions and test data.

  The failure determination unit 105 has a storage area such as a memory. The failure determination unit 105 stores in advance the same test data as the test data stored in advance in the A / D converter 200 in its own storage area.

  The failure determination unit 105 receives input of gain, integration time, resolution, and test data set by the A / D converter 200 from the last A / D converter 200 in the daisy chain on the A / D conversion board 102. . Furthermore, the failure determination unit 105 receives an input of a control signal for setting the setting condition transmitted to the A / D conversion board 102 from the A / D conversion control unit 104. Then, the failure determination unit 105 includes a gain, an integration time, and a resolution input from the A / D converter 200, and a gain, an integration time, and a setting condition included in the control signal input from the A / D conversion control unit 104. And compare the resolution. When the gain, integration time, and resolution input from the A / D converter 200 are different from the gain, integration time, and resolution of the setting conditions input from the A / D conversion control unit 104, the failure determination unit 105 Determines that the A / D converter 200 has failed. This is because it can be determined that the A / D converter 200 has failed when the A / D converter 200 has set a condition different from the received setting condition. The failure determination unit 105 compares the test data input from the A / D converter 200 with the test data stored by itself. When the test data input from the A / D converter 200 is different from the test data stored by itself, the failure determination unit 105 determines that the A / D converter 200 has failed. For example, when the test data is a continuous number “1, 2, 3, 4, 5” and the A / D converter 200 is faulty, the data input from the A / D converter 200 is “1, When data is missing, such as “2, 3, 5”, the original test data is different from the input data, and the A / D converter 200 is faulty. Can be judged. This failure determination unit 105 corresponds to “failure determination means” in the present invention.

  The A / D conversion control unit 104 and the failure determination unit 105 are equipped with all the A / D conversion boards 102 (for example, 12 A / D conversion boards 102 mounted on the detector unit 100). If so, all the 12 A / D conversion boards 102) are performed.

  When the failure determination unit 105 detects a failure of the A / D converter 200, the failure control unit 105 displays information that the A / D conversion board 102 including the failed A / D converter 200 is broken, which will be described later. Send to 003. Here, in the present embodiment, since the A / D conversion board 102 needs to be replaced when the mounted A / D converter 200 is faulty, the faulty A / D conversion board 102 has to be replaced. Information is being output. However, since the failure determination unit 105 can determine which A / D converter 200 has output different test data, it can detect which A / D converter 200 has failed. Therefore, the failure determination unit 105 may be configured to output information on the failed A / D converter 200.

  In the above description, the failure determination unit 105 outputs information on the failed A / D conversion board 102 to the display control unit 003 for display on the display unit 005. Any other notification may be used as long as the notification can be recognized. For example, information on the failed A / D conversion board 102 may be output to a service center or the like at a remote location using wireless communication or the like. As a result, the failure information is directly transmitted to a technician who repairs the X-ray CT apparatus in the service center, so that it is possible to deal with the failure of the A / D conversion board 102 more quickly.

(In image generation mode)
The X-ray detection unit 101 includes a scintillator and a photodiode. The scintillator absorbs X-rays that have passed through the subject and generates fluorescence. The photodiode receives the fluorescence generated by the scintillator and converts it into electric charge. The X-ray detection unit 101 outputs the generated charge to the A / D conversion substrate 102.

  The A / D conversion control unit 104 outputs the setting conditions including the gain, integration time, and resolution input from the input unit 006 by the operator to the A / D conversion board 102.

  The A / D conversion element 201 included in the A / D converter 200 mounted on the A / D conversion board 102 receives the control signal input from the A / D conversion control unit 104, and is included in the control signal. Operates according to conditions. The A / D conversion board 102 receives charge input from the X-ray detection unit 101. The A / D conversion element 201 performs processing on the input electric charge, which is analog data, based on the set gain, integration time, and resolution, and converts it into digital data. The A / D conversion element 201 outputs the generated digital data to the image generation unit 002.

  Next, functional units other than the detector unit 100 will be described.

  The X-ray irradiation unit 001 includes an inverter, a target, a high voltage transformer, a filament, and the like. The X-ray irradiation unit 001 generates X-rays by applying a high voltage generated by an inverter and a high-voltage transformer between the filament and the target, and causing electrons jumping out of the filament to collide with the target. Then, the X-ray irradiation unit 001 irradiates the subject with the generated X-rays. This X-ray irradiation unit 001 corresponds to the “X-ray irradiation means” in the present invention.

  The image generation unit 002 performs sensitivity correction, X-ray intensity correction, and the like on the data input from the A / D conversion board 102. Then, the image generation unit 002 reconstructs the data that has been subjected to the above-described processing, and generates image data. Further, the image generation unit 002 performs various image processing on the image data in accordance with the operator's instruction input from the input unit 006. For example, the image generation unit 002 performs volume rendering processing, MPR processing, or the like to generate three-dimensional image data or MPR image data (arbitrary slice image data) and outputs the generated data to the display control unit 003. This image generation unit 002 corresponds to the “image generation means” in the present invention.

  In the failure detection mode, when a failure has occurred in the A / D conversion board 102, the display control unit 003 inputs information on the A / D conversion board 102 in which the failure has occurred from the failure determination unit 105. receive. Then, the display control unit 003 causes the display unit 005 to display the information of the input A / D conversion board 102 in which the failure has occurred.

  In the image generation mode, the display control unit 003 receives image data input from the image generation unit 002. Then, the display control unit 003 displays an X-ray CT image on the display unit 005 based on the input image data.

  When the X-ray diagnostic apparatus is turned on, the mode switching unit 007 first switches to the failure detection mode. When no failure is detected by the failure determination unit 105, the mode switching unit 007 switches to the image generation mode. Further, when the setting condition of the A / D converter 200 is changed during the operation in the image generation mode (for example, after photographing a predetermined range in the treatment plan, the setting condition of the A / D converter 200 is changed to further change the setting condition) The mode switching unit 007 switches to the failure detection mode in response to an instruction to change the setting condition from the overall control unit 008. Then, when no failure is detected in all the A / D converters 200 in the failure determination unit 105, the mode is switched to the image generation mode.

  The overall control unit 008 controls the operation timing of each functional unit and exchanges information between the functional units.

  Furthermore, the overall control unit 008 has a storage area such as a memory or a hard disk. The overall control unit 008 stores in advance the treatment plan input from the input unit 006 by the operator. Further, the overall control unit 008 acquires position information of X-ray irradiation toward the subject. The overall control unit 008 refers to the stored treatment plan, and transmits an instruction to change the setting condition to the mode switching unit 007 when the X-ray irradiation position reaches the position where the setting condition is changed.

  When a failure is detected, the overall control unit 008 stops the operation of the X-ray CT apparatus after the failure determination of all the A / D converters 200 is completed.

  Next, with reference to FIG. 3, the flow of operation of failure detection and image formation in the X-ray CT apparatus according to the present embodiment will be described. Here, FIG. 3 is a flowchart of failure detection and image formation in the X-ray CT apparatus according to the present embodiment.

  Step S001: The operator turns on the X-ray CT apparatus.

  Step S002: The mode switching unit 007 switches the X-ray CT apparatus to the failure detection mode.

  Step S003: The A / D conversion control unit 104 outputs the set conditions including the input gain, integration time, and resolution to the A / D conversion board 102, and the A / D conversion element 201 of the A / D converter 200 is output. Operate under the set conditions. At this time, the A / D conversion control unit 104 outputs the setting condition input also to the failure determination unit 105.

  Step S004: The read-back unit 202 of the A / D converter 200 sends test data to the next A in the daisy chain together with setting conditions including gain, integration time, and resolution, which are conditions under which the A / D conversion element 201 operates. Output to the / D converter 200, and the last A / D converter 200 in the daisy chain outputs to the failure determination unit 105.

  Step S005: The failure determination unit 105 compares the setting condition input from the A / D conversion control unit 104 with the setting condition input from the A / D converter 200, and compares the test data stored in advance with the A / D The test data input from the D converter 200 is compared.

  Step S006: The failure determination unit 105 matches the setting condition input from the A / D conversion control unit 104 with the setting condition input from the A / D converter 200, and the test data stored in advance and the A / D It is determined whether the test data input from D converter 200 matches. If one or both of the data do not match, it is determined that the A / D conversion board 102 on which the A / D converter 200 is mounted has failed, and the process proceeds to step S007. If both data match, it is determined that there is no failure in the A / D conversion board 102, and the process proceeds to step S008.

  Step S007: The failure determination unit 105 outputs information on the failed A / D conversion board 102 to the display control unit 003, and the display control unit 003 displays information on the failed A / D conversion board 102. Displayed on the part 005.

  Step S008: The control board 103 determines whether or not all the A / D conversion boards 102 have been checked. If not, the process returns to step S003. If completed, the process proceeds to step S009.

  Step S009: The overall control unit 008 determines whether a failure has occurred in any of the A / D conversion boards 102. If a failure has occurred, the image generation is terminated. If no failure has occurred, the process proceeds to step S010.

  Step S010: The mode switching unit 007 switches the mode of the X-ray CT apparatus to the image generation mode.

  Step S011: The X-ray irradiation unit 001 emits X-rays toward the subject.

  Step S012: The detector unit 100 detects X-rays transmitted through the subject, converts them into digital data based on setting conditions such as gain, integration time, and resolution, and outputs them to the image generation unit 002.

  Step S013: The image generation unit 002 acquires digital data from the detector unit 100, generates X-ray CT image data, and outputs the generated X-ray CT image data to the display control unit 003.

  Step S014: The display control unit 003 displays an X-ray CT image on the display unit 005.

  Step S015: The overall control unit 008 determines whether or not imaging has been completed based on a treatment plan previously input from the operator and stored. When the imaging is finished, the image generation is finished. If imaging has not ended, the process proceeds to step S016.

  Step S016: The overall control unit 008 determines whether or not to change the setting condition of the A / D converter 200 based on the treatment plan previously input and stored by the operator. When changing the setting conditions of the A / D converter 200, the process returns to step S002. If the setting conditions of the A / D converter 200 are not changed, the process returns to step S011.

  As described above, the X-ray CT apparatus according to the present embodiment receives the setting conditions and test data output from the A / D converter when the setting conditions are set for the A / D converter. In this configuration, the failure is determined by comparing the setting condition and test data with the setting condition and test data stored in advance transmitted by the A / D conversion control unit. As a result, it is possible to detect a failure of the A / D converter without actually performing imaging, so it is possible to detect a failure of the A / D converter quickly and easily. In addition, unnecessary exposure to the subject can be reduced.

[Second Embodiment]
The X-ray CT apparatus according to the second embodiment of the present invention will be described below. The X-ray CT apparatus according to the present embodiment is different from the first embodiment in that the X-ray CT apparatus is configured to constantly monitor the failure of the A / D converter. The functional configuration of the X-ray CT apparatus according to the present embodiment is also represented by the block in FIG. In the following description, functional units having the same reference numerals as those in the first embodiment are assumed to have the same functions unless otherwise specified.

  It is assumed that the X-ray CT apparatus according to this embodiment is always turned on.

  The A / D conversion control unit 104 has a timer inside. Furthermore, the A / D conversion control unit 104 stores a time interval for checking a failure of the A / D converter 200 in advance. When the operator does not input setting conditions including gain, integration time, and resolution from the input unit 006 with the power on, the A / D conversion control unit 104 stores the sense of time stored therein. Every time, a control command indicating that the setting condition is not input, that is, a control command not setting the setting condition is transmitted to the A / D conversion board 102. Specifically, an instruction not to set a setting condition may set a setting condition for canceling all the settings.

  The A / D converter 200 mounted on the A / D conversion board 102 receives a control command that the setting condition is not input. Then, in accordance with the received control command, setting that the setting condition is not set for the A / D conversion element 201 of the A / D converter 200, that is, setting of the setting condition that cancels all the setting conditions is performed. The read back unit 202 of the A / D converter 200 reads out the setting conditions set in the A / D conversion element 201 (here, the setting conditions for canceling all settings), and the read setting conditions and test data. Are sequentially output to the next A / D converter 200 in the daisy chain, and the last A / D converter 200 in the daisy chain is further output to the failure determination unit 105. At this time, if the A / D converter 200 is operating correctly, a setting condition for canceling all the setting conditions is output.

  The failure determination unit 105 receives an input of setting conditions for canceling all settings from the A / D conversion control unit 104. Further, the failure determination unit 105 receives the set setting conditions and test data input from the A / D converter 200. The failure determination unit 105 compares the setting condition for canceling all the settings with the setting condition set by the A / D converter 200 and the setting condition for canceling all the settings. If the set setting condition input from the A / D converter 200 and the setting condition for canceling all the settings do not match, it is determined that the A / D converter 200 has failed. Further, failure determination unit 105 compares test data input from A / D converter 200 with test data stored in advance. The failure determination unit 105 determines that the A / D converter 200 has failed when the test data input from the A / D converter 200 and the test data stored in advance do not match.

  Here, in the above description, the operations of the A / D conversion board 102, the A / D conversion control unit 104, and the failure determination unit 105 in a state where the setting condition is not input have been described. When the operator inputs the setting condition from the input unit 006, the same operation as that of the first embodiment is performed.

  As described above, the X-ray CT apparatus according to the present embodiment is configured to detect a failure of the A / D conversion board even in a state where the setting condition is not input from the operator. As a result, it is possible to detect the failure of the A / D conversion board even when it is not actually time to take an image, and it is possible to deal with the failure of the A / D conversion board more quickly, and to It is possible to further improve the efficiency of diagnosis.

001 X-ray irradiation unit 002 Image generation unit 003 Display control unit 004 User interface 005 Display unit 006 Input unit 007 Mode switching unit 008 Overall control unit 100 Detector unit 101 X-ray detection unit 102 A / D conversion board 103 Control board 104 A / D conversion control unit 105 Failure determination unit 200 A / D converter 201 A / D conversion element 202 Readback unit

Claims (4)

X-ray irradiation means for irradiating X-rays;
X-ray detection means for detecting X-rays and converting them into electric charges;
An A / D conversion board having A / D conversion means for converting analog data to digital data using the set conditions;
A / D conversion control means for transmitting a control signal for setting the setting condition to the A / D conversion means;
Failure determination means for performing failure determination based on data output from the A / D conversion means;
An X-ray CT apparatus comprising image generation means for generating an X-ray CT image based on the data converted into the digital data,
It has two operation modes, image generation mode and failure detection mode,
In the failure detection mode,
The A / D conversion control means sets the setting condition to the A / D conversion means, and inputs the setting condition to the failure determination means,
The A / D conversion means stores test data in advance, the setting condition set by the A / D conversion control means and the test data stored in advance are read out, and the failure determination Entered into the means,
The failure determination means includes setting conditions input from the A / D conversion control means and test data for determination stored in advance, and setting conditions and test data input from the A / D conversion means. An X-ray CT apparatus characterized in that a failure of the A / D conversion board is determined by comparison. A plurality of the A / D conversion means are arranged on an A / D conversion board,
An A / D conversion element that receives the control signal and operates according to a setting condition included in the control signal;
A read-back unit that reads the setting conditions set in the A / D conversion element and outputs test data stored in advance together with the read setting conditions;
Further, the A / D conversion elements are connected in a daisy chain on the A / D conversion board, and the read back unit reads the set conditions and the test data that are read out next in the daisy chain. The A / D conversion means at the end of the daisy chain outputs the read setting condition and the test data to the failure determination means,
The X-ray CT apparatus according to claim 1. A plurality of the A / D conversion substrates are arranged,
In the failure detection mode,
The A / D conversion control means sequentially transmits a control signal to each of the A / D conversion boards,
The failure determination means sequentially receives data from each of the A / D conversion boards and sequentially determines a failure of each A / D conversion board.
The X-ray CT apparatus according to claim 2.   4. The X-ray CT apparatus according to claim 1, wherein the A / D conversion means can be controlled by a serial signal.

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