JP2014050497A - Data collection device for radiation detection device and x-ray ct apparatus using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently collect signals from a radiation detector, and to efficiently transfer a large amount of digital data.SOLUTION: In a data collection device 7, data collection control means 23 changes over data storage means 27 by memory changeover means 28 based on a data collection trigger signal that is a signal becoming a trigger to start data collection. Specifically, the data collection control means 23 changes over the data storage means 27 by the memory changeover means 28 in each data collection trigger signal. When performing X-ray measurement at even intervals at the time of photography, the data collection trigger signal is transmitted to the data collection device 7 from an upper device at even intervals. The data collection device 7 collects digital data corresponding to m×n elements in synchronization with the received data collection trigger signal. At this time, a memory changeover signal that is a signal for changing over the memory changeover means 28 is inverted in each reception of the data collection trigger signal, and connection between a memory a and a memory b, and the memory changeover means 28 is changed over.

Description

  The present invention relates to a data collection apparatus for a radiation detection apparatus that collects signals from a plurality of radiation detection elements that detect radiation such as X-rays and γ-rays, and an X-ray CT apparatus using the same.

  Generally, a radiation detection apparatus of an X-ray CT apparatus has a radiation detector and a data collection device. The radiation detector has a plurality of radiation detection elements arranged in an arc shape. Each radiation detection element converts incident radiation into an electrical signal. The data collection device receives all the electrical signals output from the radiation detection elements, converts them from analog signals to digital signals, and transfers them to the host device as digital data.

  In recent years, multi-slice and high-speed rotation scans are becoming mainstream in X-ray CT apparatuses, and in order to meet these needs, data acquisition apparatuses are required to collect and transfer data at high speed and high efficiency. ing.

  For example, when an X-ray CT apparatus equipped with a radiation detector of 256 slices × 900 channels is measured 1000 times during one scan, digital data of about 500 Mbytes is generated. As described above, in order to seamlessly perform image processing using a large amount of digital data generated at the time of shooting, it is necessary for the data collection device to perform data collection and transfer with high efficiency.

  In a conventional data acquisition apparatus of an X-ray CT apparatus, data acquisition speed is improved by temporarily storing AD-converted serial data in a memory and transferring the serial data to a host apparatus via a parallel bus (for example, Patent Document 1). reference).

  In another conventional X-ray CT apparatus, two buffer memories are provided in a processing apparatus that processes a signal from an X-ray detector. These buffer memories are alternately switched for each transfer unit, and when one is connected to the system bus and receives data, the other transfers data to the magnetic disk (see, for example, Patent Document 2). .

JP 7-327972 A JP-A-8-103441

  However, in the data collection device of Patent Document 1, if a large amount of data processing is performed at a short measurement interval, the data storage processing to the memory and the data reading processing from the memory overlap, and high speed and large amount of data collection / transfer It was difficult to follow. In addition, since all wiring paths from the AD converter to the memory are serial connections, the number of AD converter connections and the number of memories required for the data acquisition device are determined by the upper limit of the maximum number of input signals of the memory. Sufficient consideration has not been given to manufacturing costs and data collection efficiency when configuring the collection device.

  Further, in the X-ray CT apparatus of Patent Document 2, the memory for receiving data and the memory for transferring data are switched every predetermined amount of data (for example, data for 10 views). In the X-ray CT apparatus, the data to be transferred to the image processing apparatus at a time becomes large, and smooth image processing cannot be performed unless the specifications of the image diagnostic apparatus are increased.

  The present invention has been made to solve the above-described problems, and is a radiation detection apparatus capable of efficiently collecting signals from a radiation detector and efficiently transferring a large amount of digital data. An object of the present invention is to obtain an X-ray CT apparatus using the data acquisition apparatus.

  A data collection device for a radiation detection apparatus according to the present invention includes an AD conversion unit that converts an analog signal from a radiation detector into a digital signal, and a serial / parallel device that converts digital data serially output from the AD conversion unit into parallel. Conversion means, data collection switching means for selectively switching collection of digital data output from the serial / parallel conversion means, a plurality of data storage means for temporarily storing digital data, and data for storing and reading digital data A data collection device main body having a memory switching means for switching the storage means and a data transfer means for transferring the digital data read from the data storage means to the host device, and a data collection control means for controlling the data collection device main body, The data collection control means provides a trigger for starting data collection. Based on the data collection trigger signal is a signal serving, for switching the data storage means by the memory switching means.

  The data collection device of the radiation detection apparatus of the present invention can efficiently collect signals from the radiation detector and efficiently transfer a large amount of digital data.

It is a block diagram which shows the X-ray CT apparatus by Embodiment 1 of this invention. It is a circuit diagram which shows the detail of the radiation detector of FIG. 1, and a data acquisition device. It is explanatory drawing which shows the 1st example of the digital data collection method by the data collection device of FIG. It is explanatory drawing which shows the 2nd example of the digital data collection method by the data collection device of FIG. 3 is a timing chart showing a method for storing and reading data by the data collection device of FIG. 2. It is a timing chart which shows the storage and reading method of the data of the data collection device by Embodiment 2 of this invention. It is a timing chart which shows the storage and reading method of the data of the data collection device by Embodiment 3 of this invention.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.
Embodiment 1 FIG.
1 is a block diagram showing an X-ray CT apparatus according to Embodiment 1 of the present invention. In the figure, the X-ray CT apparatus has a scan gantry unit 1 and a console 2. The scan gantry unit 1 includes a rotating disk 3, an X-ray tube 4, a collimator 5, a radiation detector 6, a data collection device 7, a bed 8, a gantry control device 9, a bed control device 10, Line control device 11.

  In the center of the rotating disk 3, an opening 3a into which a subject placed on the bed 8 enters is provided. The X-ray tube 4 and the radiation detector 6 are mounted on the rotating disk 3 so as to face each other across the opening 3a. Further, the X-ray tube 4 and the radiation detector 6 rotate around the subject by the rotation of the rotating disk 3.

  The X-ray tube 4 irradiates the subject placed on the bed 8 with X-rays. The collimator 5 limits the radiation range of X-rays emitted from the X-ray tube 4. The radiation detector 6 detects X-rays that have passed through the subject. The data collection device 7 collects the X-ray dose detected by the radiation detector 6 as digital data.

  The gantry control device 9 controls the rotation of the rotating disk 3. The bed control device 10 controls the vertical movement of the bed 8. The X-ray control device 11 controls power input to the X-ray tube 4.

  The console 2 includes an input device 12, an image calculation device 13, a display device 14, a storage device 15, and a system control device 16.

  The input device 12 is a device for inputting a subject name, examination date and time, imaging conditions, and the like, and specifically, a keyboard and a pointing device are used. The image calculation device 13 performs CT processing on the measurement data sent from the data collection device 7 to perform CT image reconstruction. The display device 14 displays the CT image created by the image calculation device 13. For example, a CRT (Cathode-Ray Tube) or a liquid crystal display is used as the display device 14.

  The storage device 15 stores the data collected by the data collection device 7 and the image data of the CT image created by the image calculation device 13. As the storage device 15, for example, an HDD (Hard Disk Drive) or the like is used. The system control device 16 controls the entire system, that is, the console 2, the gantry control device 9, the bed control device 10, and the X-ray control device 11.

  The X-ray controller 11 controls the power input to the X-ray tube 4 on the basis of the imaging conditions input from the input device 12, particularly the X-ray tube voltage and X-ray tube current. X-rays are irradiated to the subject from the X-ray tube 4. The X-ray transmitted through the subject is detected by the radiation detector 6 and the spatial distribution of the transmitted X-ray is measured.

  The rotating disk 3 is controlled by the gantry control device 9 and rotates based on the photographing conditions input from the input device 12, particularly the rotation speed. The bed 8 is controlled by the bed control device 10 and operates based on the photographing conditions input from the input device 12, particularly the helical pitch.

  Projection data from various angles is acquired by repeating the X-ray irradiation from the X-ray tube 4 and the measurement of the transmitted X-ray distribution by the radiation detector 6 along with the rotation of the rotating disk 3. The obtained projection data from various angles is transmitted to the image calculation device 13. Then, the projection data from various angles is back-projected by the image arithmetic unit 13 to reconstruct the CT image. The CT image obtained in this way is displayed by the display device 14.

  FIG. 2 is a circuit diagram showing details of the radiation detector 6 and the data collection device 7 of FIG. The radiation detection apparatus according to this embodiment includes a radiation detector 6 that detects radiation, and a data collection apparatus that collects electrical signals output from the radiation detector 6 and transfers the data to an image calculation device 13 that is a host device. 7.

  The radiation detector 6 has a large number of X-ray detection elements 21 as radiation detection elements. The X-ray detection elements 21 are arranged in an arc shape in the rotation direction of the rotary disk 3 or two-dimensionally arranged in the rotation direction and the rotation axis direction of the rotary disk 3. Each X-ray detection element 21 is connected to the data collection device 7 via a cable, a signal line, or the like.

  The data collection device 7 includes a data collection device main body 22 and data collection control means 23 that controls the data collection device main body 22.

  The data collection device main body 22 includes a plurality of AD conversion means 24, a plurality of serial / parallel conversion means 25, a data collection switching means 26, a plurality of data storage means 27, a pair of memory switching means 28, and a data transfer. Means 29.

  Each AD converter 24 converts the analog electric signal output from the corresponding X-ray detection element 21 into a digital electric signal. Each serial / parallel converter 25 converts the digital data serially output from the corresponding AD converter 24 into parallel data. The data collection switching unit 26 selectively switches the collection of digital data output from the serial / parallel conversion unit 25.

  The data storage unit 27 temporarily stores the digital data from the data collection switching unit 26. In this example, two data storage means 27a and 27b are used. Which of these data storage means 27a and 27b is used to store and read digital data is switched by the memory switching means 28. That is, the memory switching unit 28 switches between the data storage units 27a and 27b that store and read digital data.

  The data transfer unit 29 transfers the digital data read from the data storage unit 27 to the image calculation device 13.

  The AD conversion means 24 is composed of an element such as an AD converter or a DAS chip. The serial / parallel conversion unit 25, the data collection switching unit 26, and the memory switching unit 28 are configured by a single element or a complex of elements such as a register, a flip-flop, a multiplexer, or a demultiplexer.

  The data storage means 27 is composed of an element such as SRAM or DRAM. The data transfer means 29 is comprised by elements, such as a driver or communication IC, for example. The data collection control unit 23 is composed of an element such as a CPU. Moreover, you may comprise a part or all of these elements with elements, such as ASIC and FPGA.

  The digital data output from the AD conversion means 24 can be selectively collected as digital data corresponding to the X-ray detection element 21 by the serial / parallel conversion means 25, the data collection switching means 26, and the data collection control means 23. ing. In addition, the data storage means 27, the memory switching means 28, the data transfer means 29, and the data collection control means 23 can store and read the collected digital data in different data storage means 27, respectively. However, data can be transferred continuously.

  Next, the operation will be described. The X-rays incident on the radiation detection apparatus are converted into electrical signals by the X-ray detection elements 21 arranged in the radiation detector 6, and further AD converted by the AD conversion means 24. The digital data output from the AD conversion unit 24 is parallelized by the serial / parallel conversion unit 25 and output to the data collection switching unit 26. In the data collection switching means 26, the connection between the serial / parallel conversion means 25 and the memory switching means 28 is sequentially switched in accordance with a command from the host apparatus or the data collection control means 23, and digital data corresponding to each X-ray detection element 21. Are selectively collected.

  As a result, the AD conversion means 24 capable of storing data in the data storage means 27 does not depend on the number of input signals of the data storage means 27, and the number of components and the mounting area when the data collection device 7 is configured in one printed circuit board. Can be reduced. In FIG. 2, the X-ray detection element 21 and the AD conversion means 24 correspond 1: 1, but for example, by using the AD conversion means 24 corresponding to two or more X-ray detection elements 21. Further efficiency improvement of data collection can be achieved.

  3 is an explanatory diagram showing a first example of a digital data collecting method by the data collecting device 7 of FIG. 2, and FIG. 4 is an explanatory diagram showing a second example of the digital data collecting method by the data collecting device 7 of FIG. is there. For example, when collecting digital data corresponding to the radiation detector 6 having m slices and n channels, data is sequentially collected in each slice direction as shown in FIG. It can be performed sequentially in the channel direction.

  In FIGS. 3 and 4, slice numbers and channel numbers are collected in ascending order, but they may be collected in descending order. Further, it may be collected in the order of a preset unique slice number and channel number. Further, in FIG. 3 and FIG. 4, data for one element is collected sequentially, but for example, data of the same slice number and the same channel number can be collected simultaneously.

  In this way, by collecting digital data corresponding to all X-ray detection elements 21 obtained at the same measurement in an arbitrary data array, the data storage / readout process in the data storage means 27 is performed in the same order as the data collection. The data collection control means 23 can be simplified, and a series of processes from data collection to data transfer can be efficiently performed.

  In addition, by using a data array suitable for the image calculation device 13, it is possible to give a degree of freedom to an image processing method as a subsequent process, and to improve calculation efficiency during image processing.

  FIG. 5 is a timing chart showing a method for storing and reading data by the data collection device 7 of FIG. The data collection control means 23 switches the data storage means 27 by the memory switching means 28 based on a data collection trigger signal that is a signal that triggers data collection. Specifically, the data collection control unit 23 switches the data storage unit 27 by the memory switching unit 28 for each data collection trigger signal.

  In FIG. 5, for convenience of explanation, the data storage means 27a is a memory a, and the data storage means 27b is a memory b. Each of the memory a and the memory b has a capacity capable of storing digital data corresponding to m × n elements generated by one X-ray measurement.

  When X-ray measurement is performed at regular intervals during imaging, the data collection trigger signal is transmitted from the host device to the data collection device 7 at regular intervals. The data collection device 7 collects digital data for m × n elements in synchronization with the received data collection trigger signal. At this time, the memory switching signal which is a signal for switching the memory switching means 28 is inverted every time the data collection trigger signal is received, and the connection between the memories a and b and the memory switching means 28 is switched.

  All the collected data is sent to the data transfer means 29 by switching the connection. Then, data transfer is executed by a signal requesting data transfer from the host device, that is, a data transfer request signal.

  As a result, the data can be read from the memory b while the data is stored in the memory a, and the data can be read from the memory a while the data is stored in the memory b. Even in continuous measurement, data of m × n channels can be collected and transferred at once and continuously.

  Further, by switching the data storage means 27 by the memory switching means 28 based on the data acquisition trigger signal, even in the multi-slice / high speed rotation scan X-ray CT apparatus, the signal from the radiation detector 6 Can be efficiently collected, and a large amount of digital data can be efficiently transferred to the image calculation device 13.

  Furthermore, by collecting data and transferring data according to the data collection signal and data transfer request signal from the host device, it is possible to selectively transfer the collected data while preventing the AD converter 24 from being charged up. It is.

Embodiment 2. FIG.
Next, FIG. 6 is a timing chart showing a data storing and reading method of the data collecting apparatus according to the second embodiment of the present invention. In the data collection device of the second embodiment, the memory switching signal is inverted every minute cycle of the data collection trigger signal, here, every half cycle, and the data storage means for performing data storage and data reading are alternately switched. Other configurations and operations are the same as those in the first embodiment.

  For example, a data collection device having two data storage means having a capacity capable of storing output data for 64 slices × 900 channels = 57600 elements is assumed as in the first embodiment. In this case, storage and reading with respect to each data storage means are executed for each half of the amount of data collected in one measurement every half cycle of the data collection trigger signal.

  As a result, even with a data collection apparatus that supports a data capacity for 64 slices, the same apparatus can support the data capacity of the radiation detector 6 for 128 slices, and data can be collected and transferred. is there.

  In the second embodiment, the radiation detector for 64 slices and 128 slices has been described as an example. However, for example, the data storage means is switched in a quarter cycle of the data collection trigger, and digital data is stored and read out by 1 as well. By performing / 4 each, it is possible to correspond to a radiation detector for 256 slices. As described above, even if the number of slices of the radiation detector increases, by using the same principle, it is possible to deal with radiation detectors having different slices by using the same data collection device.

Embodiment 3 FIG.
Next, FIG. 7 is a timing chart showing a data storing and reading method of the data collecting apparatus according to the third embodiment of the present invention. In the data collection device of the third embodiment, the memory switching signal is inverted every double period of the data collection trigger signal, here every two data collection trigger signals, and the data storage means for performing data storage and data reading alternately Can be switched. Other configurations and operations are the same as those in the first embodiment.

  For example, a data collection device having two data storage means having a capacity capable of storing output data for 64 slices × 900 channels = 57600 elements is assumed as in the first embodiment. In this case, storage and reading in each data storage means are executed twice for the amount of data collected in one measurement every two data collection trigger signals.

  As a result, even a data collection device corresponding to a data capacity for 64 slices can correspond to the data capacity of a radiation detector for 32 slices with the same device, and data can be collected and transferred. .

  In the third embodiment, the radiation detector for 64 slices and 32 slices has been described as an example. For example, the data storage means is switched every four data acquisition trigger signals, and digital data is stored and read out four times. By performing each step, it is possible to correspond to a radiation detector for 16 slices. As described above, even if the number of slices of the radiation detector is reduced, it is possible to deal with radiation detectors of different slices by using the same data collection device by using the same principle.

As mentioned above, although embodiment of this invention was described, this invention is not limited to these embodiment.
For example, in the above example, two data storage units 27 are used, but three or more may be used.

  6 Radiation detector, 7 Data collection device, 21 X-ray detection device (radiation detection device), 22 Data collection device body, 23 Data collection control means, 24 AD conversion means, 25 Serial / parallel conversion means, 26 Data collection switching means 27 Data storage means, 28 Memory switching means, 29 Data transfer means.

Claims (12)

AD conversion means for converting an analog signal from a radiation detector into a digital signal, serial / parallel conversion means for converting digital data serially output from the AD conversion means, and output from the serial / parallel conversion means Data collection switching means for selectively switching the collection of digital data, a plurality of data storage means for temporarily storing the digital data, and a memory switching means for switching the data storage means for storing and reading the digital data A data collection device main body having data transfer means for transferring the digital data read from the data storage means to a host device, and a data collection control means for controlling the data collection device main body,
The data collection control means performs switching of the data storage means by the memory switching means on the basis of a data collection trigger signal which is a trigger signal for starting data collection. apparatus.   2. The data collection apparatus for a radiation detection apparatus according to claim 1, wherein the data collection control means switches the data storage means by the memory switching means for each data collection trigger signal.   2. The data collection device for a radiation detection apparatus according to claim 1, wherein the data collection control means performs switching of the data storage means by the memory switching means for every half period of the data collection trigger signal.   2. The data collection device of a radiation detection apparatus according to claim 1, wherein the data collection control unit performs switching of the data storage unit by the memory switching unit every double cycle of the data collection trigger signal. The radiation detector has a plurality of radiation detection elements,
The data collection device main body according to any one of claims 1 to 4, wherein the data collection device main body selectively collects digital data corresponding to each of the radiation detection elements. apparatus.   6. The data collection apparatus of a radiation detection apparatus according to claim 5, wherein the data collection apparatus main body collects electrical signals from the radiation detection elements simultaneously in units of slices.   6. The data collection apparatus of a radiation detection apparatus according to claim 5, wherein the data collection apparatus main body sequentially collects electrical signals from the radiation detection elements in a slice direction.   6. The data collection device of a radiation detection apparatus according to claim 5, wherein the data collection device main body collects electrical signals from the radiation detection elements simultaneously in channel units.   6. The data collection device of a radiation detection device according to claim 5, wherein the data collection device main body sequentially collects electrical signals from the radiation detection elements in a channel direction.   6. The data collection apparatus of a radiation detection apparatus according to claim 5, wherein the data collection apparatus main body collects electrical signals from the radiation detection elements in a unique slice number and channel number order.   The radiation detection according to any one of claims 1 to 10, wherein the data collection control unit causes the data transfer unit to perform data transfer in response to a data transfer request from a host device. Device data collection device.   An X-ray CT apparatus comprising the data collection apparatus according to any one of claims 1 to 11.

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