JP2013075083A - Radiography apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radiography apparatus and a radiography system capable of reducing the waiting time before radiography if a request for radiography comes while a calibration process is implemented.SOLUTION: The radiography apparatus includes: a defective pixel information holding part for holding positional information of defective pixels included in a radiation detector; a region dividing part for dividing a radiation image into a plurality of processing regions; and a process implementing part for setting the frequency of implementing the calibration process for a processing region with no defective pixels to be lower than the frequency for a processing region including defective pixels, and sequentially implementing the calibration process for the respective processing regions. The defective pixel information holding part updates positional information of defective pixels according to positional information of new defective pixels obtained by implementing the calibration process. The region dividing part further divides the processing region including the new defective pixels based on the updated positional information of defective pixels into two processing regions or more.

Description

  The present invention relates to a radiation imaging apparatus that performs a calibration process of a radiation detector that detects radiation irradiated from a radiation source and transmitted through a subject and captures a radiation image of the subject.

  In a radiographic apparatus, in order to obtain a radiographic image suitable for diagnosis, it is necessary to calibrate the radiation detector before imaging. Conventionally, the calibration processing has been performed based on the operation of the photographing apparatus alone, regardless of the photographing workflow. Therefore, if an imaging request is generated during the calibration process, the patient must wait until the calibration process is completed, and the patient cannot wait for the image to be captured immediately, leading to reduced patient waiting time and reduced work efficiency. It was.

  In addition, the calibration process needs to perform a plurality of different types of calibration, for example, calibration for offset correction, calibration for defect correction (defective pixel correction), and the like according to the purpose. In addition, even for calibration for the same correction process, it is necessary to perform calibration in a plurality of shooting modes with different shooting conditions. Therefore, it takes a lot of time until the series of calibration processes is completed.

  As these countermeasures, for example, when an imaging request is generated during the execution of the calibration process, an imaging apparatus capable of performing the imaging by stopping the calibration process being performed can be considered. However, in such an imaging apparatus, imaging is performed in a state where calibration processing that should be originally performed is not performed, and thus there is a problem that the quality of the captured radiographic image cannot be guaranteed.

  Here, there are Patent Documents 1 and 2 as prior art documents relevant to the present invention.

  In Patent Document 1, a plurality of dark image data obtained during a non-imaging period of X-ray imaging performed intermittently is averaged to generate offset correction data, and the offset correction data generated sequentially An X-ray diagnostic apparatus that stores the latest offset correction data in the image and performs offset correction by subtraction processing between each image data obtained in the imaging period and the latest offset correction data is described.

  In Patent Document 2, the reference image Pref is divided into a plurality of divided regions DR. For example, the reference image Pref is divided into a central region CR and a peripheral region AR. A radiation image processing apparatus is described in which a peripheral region AR, which is often irradiated directly with radiation and is likely to proceed with crystallization of the photoconductive layer, is frequently selected and a calibration process is performed.

JP 2006-75359 A JP 2010-17209 A

  An object of the present invention is to provide a radiation imaging apparatus capable of shortening the waiting time until imaging even when an imaging request is generated during the execution of calibration processing.

In order to achieve the above object, the present invention provides a radiation for performing a calibration process of a radiation detector that detects a radiation irradiated from a radiation source and transmitted through the subject and photographs a radiation image of the subject. A photographing device,
A defective pixel information holding unit for holding position information of defective pixels included in the radiation detector;
An area dividing unit for dividing the radiation image into a plurality of processing areas;
Based on the position information of the defective pixel, the execution frequency of the calibration process for the processing region not including the defective pixel is set lower than the processing region including the defective pixel among the plurality of processing regions, A processing execution unit that sequentially executes the calibration process for the processing region;
The defective pixel information holding unit updates the position information of the defective pixel in accordance with the position information of the new defective pixel acquired by performing the calibration process.
The region dividing unit further divides a processing region including the new defective pixel into two or more processing regions based on the updated position information of the defective pixel. A device is provided.

  Here, it is preferable that the area dividing unit divides the processing area including the new defective pixel into a processing area including the defective pixel and a processing area not including the defective pixel.

  The region dividing unit preferably divides the radiation image into a plurality of rectangular processing regions having an equal size.

  The region dividing unit preferably divides the radiographic image into a plurality of rectangular processing regions each having an arbitrary size.

  The region dividing unit preferably divides the radiographic image into a plurality of rectangular processing regions each including the same number of lines.

The region dividing unit divides the radiation image into a central processing region and a peripheral processing region,
It is preferable that the processing execution unit sets the execution frequency of the calibration process for the central processing region to be lower than that of the peripheral processing region.

  Furthermore, it is preferable that a status display unit that displays an implementation status of the calibration processing is provided for each of the processing regions.

Furthermore, a history recording unit that records imaging history information of the radiation image,
A process dividing unit for dividing the calibration process into a plurality of unit processes;
Based on the imaging history information, calculate a period of idle time from the end of imaging of the radiation image to the start of the next imaging, and determine whether each unit process can be performed within the period of the idle time A process allocation unit that allocates the execution timing of each of the unit processes within the free time period for each of the processing areas;
It is preferable that the processing execution unit is configured to execute each of the unit processes for each of the processing areas at an execution timing within a free time period allocated to each of the unit processes.

The calibration process includes performing a plurality of different types of calibration,
It is preferable that the process dividing unit divides the calibration process using the type of calibration as the unit process.

The calibration includes performing a plurality of shooting modes with different shooting conditions,
It is preferable that the process dividing unit divides the calibration process using the photographing mode as the unit process.

  Moreover, it is preferable that the said area | region division part divides | segments the said radiographic image into the process area | region of the magnitude | size corresponding to the period of the said free time.

  The region dividing unit preferably divides the radiographic image into processing regions having a size corresponding to the processing capability of the radiographic apparatus.

The region dividing unit divides the radiation image into the plurality of processing regions according to an instruction input by a user via an input device,
It is preferable that the process assigning unit assigns the execution timing of each unit process for each process area according to an instruction input by the user.

  According to the present invention, the processing area including the new defective pixel is further divided into two or more processing areas, so that the processing area including the defective pixel is reduced when the next calibration process is performed. The amount can be greatly reduced.

  The calibration processing for each processing region is completed in a shorter time compared to a case where all the regions of the radiation image are subjected to calibration processing collectively. Even when a shooting request is generated during the execution of the calibration process, the calibration process is completed in a short time and the camera is ready for shooting, so the waiting time until shooting can be shortened. In addition, since the amount of data to be processed at a time is small, even a radiographic apparatus with a small processing capability can be implemented in a short time.

  On the other hand, if the calibration process is canceled halfway for shooting, the calibration process is not performed for the canceled process area, but the process area for which the calibration process has already been completed is performed. It becomes. Therefore, a high-quality radiographic image can be taken, and it is not necessary to restart the calibration process from the beginning for the entire area of the radiographic image, and the process can be resumed from the stopped processing area.

It is a block diagram of a 1st embodiment showing composition of a radiography system concerning the present invention. It is a block diagram of an example showing the structure of the imaging device shown in FIG. It is a block diagram of an example showing the structure of the control apparatus shown in FIG. It is a flowchart of an example showing the flow of a series of calibration processes. It is a flowchart of an example showing operation | movement of the radiography system shown in FIG. It is a flowchart of an example showing operation | movement of the conventional radiography system. It is a block diagram of an example showing the structure of the control apparatus used with the radiography system of 2nd Embodiment. It is an example conceptual diagram showing a mode that the radiographic image was divided | segmented into nine rectangular process areas of equal magnitude | size. It is an example conceptual diagram showing a mode that the radiographic image was divided | segmented into the three rectangular processing area | regions of the equal size containing the same number of lines. It is an example conceptual diagram showing a mode that the radiographic image was divided | segmented into the process area | region containing a defective pixel, and the process area | region which does not contain a defective pixel. It is an example conceptual diagram showing a mode that the radiographic image was divided | segmented into the process area of the center part, and the process area of the peripheral part. It is a conceptual diagram showing a mode that a calibration process is implemented in the conventional radiography system. It is a conceptual diagram showing a mode that a calibration process is implemented in the radiography system of 2nd Embodiment.

  Hereinafter, a radiation imaging apparatus of the present invention will be described in detail based on preferred embodiments shown in the accompanying drawings.

  FIG. 1 is a block diagram of a first embodiment showing a configuration of a radiation imaging system according to the present invention. The radiation imaging system 10 shown in FIG. 1 performs the radiation processing of the radiation detector that detects the radiation irradiated from the radiation source and transmitted through the subject and captures the radiation image of the subject. The operation is divided into two or more different periods that are not performed, and includes a plurality of radiation imaging apparatuses 12 (12a, 12b,...) And servers 14 and 15.

  Each of the radiation imaging apparatuses 12 (12a, 12b,...) Includes an imaging apparatus 18 (18a, 18b,...) And a console 20 (20a, 20b,...) As shown in FIG. The imaging devices 18 and consoles 20 of all the radiation imaging devices 12 and the servers 14 and 15 are connected to each other via the hospital network 16 and can communicate with each other.

  FIG. 2 is a block diagram illustrating an example of the configuration of the photographing apparatus illustrated in FIG. Each imaging device 18 (18a, 18b,...) Captures a radiation image of the subject 36 under the control of the corresponding console 20 (20a, 20b,...). A lowering device 24, a radiation control device 26, an imaging table 28, a radiation detector 30, a moving device 32, and a control device 34 are provided.

  The radiation source 22 irradiates a predetermined intensity of radiation for a predetermined time when the radiation image of the subject 36 is taken under the control of the radiation control device 26. That is, a predetermined amount of radiation (dose) is irradiated. The radiation source 22 is suspended from the ceiling of the photographing room by a suspension device 24. The position and height of the radiation source 22 can be freely adjusted manually by the suspension device 24 according to the imaging region.

  The radiation control device 26 controls the operation of the radiation source 22 (radiation irradiation start, irradiation intensity, irradiation time, etc.) according to the imaging conditions under the control of the control device 34.

  The imaging table 28 in the illustrated example is a supine position imaging table, and is a table for positioning the subject 36 when radiographic images are captured. It should be noted that a stand-up photographing table can be used as the photographing table 28. The radiation detector 30 is disposed below the imaging table 28.

  The radiation detector 30 is, for example, a flat panel type (FPD: flat panel detector), and the subject 36 is photographed by detecting radiation irradiated from the radiation source 22 and transmitted through the subject 36. An image signal (image data) of the radiographic image is output. The radiation detector 30 can be moved to an arbitrary position in the left-right direction in FIG. 2 by the moving device 32 controlled by the control device 34 according to the imaging region.

  The control device 34 controls the operation of the entire photographing device 18 by controlling the console 20. The control device 34 sets the imaging condition transmitted from the console 20 in the radiation control device 26 when capturing the radiation image, and controls the capturing of the radiation image. In addition, the control device 34 performs a series of calibration processes of the radiation detector 30 during a period in which no radiographic image is captured. Furthermore, the control device 34 performs various correction processes including offset correction, defect correction, gain correction, afterimage correction, and the like on the captured radiation image.

  FIG. 3 is a block diagram showing the configuration of the control device shown in FIG. As shown in the figure, the control device 34 includes a history recording unit 38, a process dividing unit 40, a process assigning unit 42, a process executing unit 44, and a warning generating unit 46. In the figure, for the purpose of facilitating the description, the description of the part that controls the radiographic image capturing is omitted, and only the part that controls the execution of the calibration process is shown.

  The history recording unit 38 records the start time and end time of each process including imaging, movement of the radiation source 22, movement of the radiation detector 30, etc., as radiographic image capturing history information. In addition, as imaging history information, whether or not the subject 36 has changed, which imaging menu has been switched to which imaging menu, who is the imaging technician, whether it is a busy time period, or how many radiographic imaging devices 12 have the same purpose at the same time Information such as the age of the subject 36 may be recorded.

  The history recording unit 38 collects shooting history information for about 10 weeks for each day of the week, for example. The collection timing of the shooting history information is, for example, at the time of starting or ending the apparatus every day, but the collection of shooting history information may be started in response to a request from a shooting engineer.

  The process dividing unit 40 divides the calibration process into a plurality of unit processes. In this embodiment, as will be described later, the calibration process is divided into a plurality of shooting modes with different types of calibration (calibration for offset correction, calibration for defect correction, etc.) or different shooting conditions. To do. From the process dividing unit 40, information (unit process information) of a plurality of unit processes obtained by dividing the calibration process is output.

  Based on the imaging history information, the process allocating unit 42 calculates a free time period during which no radiographic image is captured from the end of radiographic image capture to the start of the next radiographing, and is represented by unit processing information. It is determined whether or not the unit processing can be performed within the free time period, and the execution timing of each unit process is assigned within the free time period. From the process allocation unit 42, a calibration execution schedule is output.

  Based on the shooting history information, the processing allocation unit 42 statistically analyzes, for example, the distribution status of the time zone in which shooting is performed in one day, and calculates a time zone suitable for performing calibration. Furthermore, a unit process to be performed is determined from information such as the calculated position of the time zone (early morning or just before the end), the length of the time zone, the degree of time dispersion, etc., and a calibration execution schedule is generated.

  For example, the process assigning unit 42 can assign the timing at which the hanging device 24 or the moving device 32 starts to move or the operation to the execution timing of the unit process. Also, the timing at which the console 20 starts image processing on the radiographic image, or the timing at which the console 20 starts transmitting / receiving the radiographic image during image processing, or the transmission / reception can be assigned to the execution timing of the unit processing. .

  The calibration execution schedule is automatically generated from the contents of the calibration process and the shooting history information. However, if there is not enough free time for calibration due to actual results, the imaging engineer may arbitrarily decide the execution timing of the unit processing, or the calibration that gives up the division and performs the calibration processing collectively as before An action execution schedule may be generated.

  It is also possible to generate a calibration execution schedule in which unit processing does not necessarily fall within the free time period. For example, if the calibration time required for unit processing is 5 minutes and the shooting interval is 4 minutes, a waiting time of 1 minute occurs until the camera is ready for shooting. Such an implementation schedule may be generated. However, it is desirable to generate the implementation schedule so that no waiting time is generated only during the idle time period during which the subject 36 is positioned.

  In addition, when the process allocation unit 42 determines that two or more unit processes can be performed within the idle time period, the process allocation unit 42 can allocate the execution timing of the two or more unit processes within the idle time period. .

  Subsequently, the processing execution unit 44 executes each unit process at an execution timing within a free time period allocated to each unit process according to the calibration execution schedule.

  The warning generator 46 warns that the calibration process is being performed during the calibration process. The warning may display a message indicating that the calibration process is being performed, or may be notified by voice. As a warning, it is desirable to display the remaining time until the unit processing in progress is completed or to notify by voice.

  Subsequently, the console 20 goes to the server 14 to receive a radiographic image capturing request (imaging order) of the subject 36 and registers the received imaging order in the imaging menu (imaging order list) of the console 20. Thereafter, the photographing condition corresponding to the photographing order selected from the photographing menu by the photographing engineer is transmitted to the photographing device 18 to instruct photographing. In addition, the console 20 receives an image signal (image data) of a radiographic image captured by the imaging device 18, performs various image processing on the received radiographic image, and then performs image processing as necessary. The radiographic image is printed or the image signal of the radiographic image after image processing is transmitted to the server 15.

  Subsequently, the server 14 is a server such as a RIS (radiation information system) or a HIS (hospital information system), and receives a radiographic image capturing request of the subject 36 from a terminal device (not shown). The radiographic image capturing schedule is managed in the image capturing device 12. The console 20 goes to receive the imaging request received by the server 14, that is, the radiographic image imaging request (imaging order) of the subject 36.

  Finally, the server 15 is a server such as a PACS (image storage communication system), and receives and stores an image signal of a radiographic image after image processing from the console 20. The console 20 can read out the image signal of the radiation image stored in the server 15 as necessary, and display the image signal on the display device of the console 20 or create a print, for example.

Next, the calibration process will be described.
First, the types of calibration performed by the photographing apparatus 18 will be described.

  In the control device 34 of the imaging device 18, various correction processes including, for example, offset correction, defect correction (defective pixel correction), gain correction, afterimage correction, and the like are performed on the captured radiographic image.

  Here, the offset correction corrects the influence of the difference in dark current (dark current) flowing through each pixel (radiation detection element) of the radiation detector 30 on the captured radiation image in a state where no radiation is irradiated. It is processing.

  Defect correction corrects an image signal captured by a pixel (defective pixel) that cannot detect radiation or generate an image signal corresponding to the radiation dose among the pixels of the radiation detector 30. It is processing to do.

  The gain correction is performed by pixels (gain defective pixels) that are different in detection sensitivity from the other pixels (normal pixels) among the pixels of the radiation detector 30 and cannot output an image signal proportional to the dose of received radiation. This is a process for correcting a photographed image signal.

  In the radiation detector 30, after the radiographing, when the readout interval of the radiographic image taken is short, an afterimage (remaining charge) of the radiographic image at the previous radiographic imaging may be read out. The afterimage correction is a process of correcting the influence of the afterimage due to the radiation image at the previous radiation imaging.

  Various specific implementation methods for each correction process are known, and known implementation methods can also be used in the present invention. Further, the control device 34 may perform a correction process other than the above.

  In the photographing apparatus 18, a series of calibration processes for each correction process is performed as shown in Table 1 corresponding to the correction process performed by the control device 34.

  Since the calibration for gain correction and afterimage correction is performed only under specific conditions such as during installation and during regular maintenance (the frequency of execution is low), a series of calibration processes performed in the photographing apparatus 18 according to the present invention. It is not necessary to add to. Hereinafter, in the photographing apparatus 18, as a series of calibration processes, as shown in FIG. 4, after calibration for offset correction is performed, calibration for defect correction is performed. In FIG. 4, the division positions of the calibration process are indicated by arrows.

  As shown in Table 1, calibration for offset correction is performed at the time of installation, at the time of regular maintenance, at the time of activation of the apparatus, and during the period of activation. This calibration includes six types of imaging modes (modes 0 to 5) with different imaging conditions, and image signals are read out 16 times from the radiation detector 30 for each imaging mode. Further, as shown in FIG. 4, every time an image signal is read from the radiation detector 30, offset data for offset correction is generated, and the average value of 16 offset data is used as correction data for offset correction. used.

  Here, the imaging condition in the imaging mode is, for example, the length of time during which radiation is emitted from the radiation source 22 when capturing a radiation image.

  Further, as shown in Table 1, calibration for defect correction is performed at the time of installation, regular maintenance, and at the time of starting the apparatus. This calibration includes three types of imaging modes (modes 0 to 2), and image signals are read from the radiation detector 30 five times for each imaging mode. Also, as shown in FIG. 4, every time an image signal is read from the radiation detector 30, defect correction data for defect correction is generated, and the average value of defect correction data for five times is corrected for defect correction. Used as data.

  That is, in the case of the present embodiment, 16 times × 6 mode = 96 times for calibration for offset correction, 5 times × 3 mode = 15 times for calibration for defect correction, 96 + 15 = 111 times in total, radiation Reading of the image signal from the detector 30 is performed.

  Conventionally, as a calibration process for the correction process, for example, reading of the image signal 111 times from the radiation detector 30 has been performed continuously and collectively. In this case, when a radiographic image capturing request is received during the calibration process, the capturing is performed after a long waiting time until the calibration process ends. Alternatively, it may be possible to stop the calibration process and perform shooting.

  On the other hand, in the present embodiment, the calibration process is divided into a plurality of unit processes using the type of calibration or the photographing mode as a unit process, and each unit process is performed in two or more different periods.

  In other words, when the calibration process is divided according to the type of calibration, it is divided into two unit processes: calibration for offset correction and calibration for defect correction. Further, when the calibration process is divided in the photographing mode, six calibrations for offset correction and three calibrations for defect correction are divided into nine unit processes in total.

  In this way, the calibration process is divided into a plurality of unit processes, and is performed in two or more different periods during which no radiographic image is captured, so that a radiographic image capture request is issued during the calibration process. Even in the case of reception, shooting can be performed after a short time until the unit processing is completed. In addition, after the photographing is finished, the calibration process can be continuously performed from the unit process next to the unit process finished before the photographing.

  Note that, during the calibration process, the calibration process can be stopped halfway and a radiographic image can be captured at the discretion of the imaging engineer. In this case, after the radiographic image capturing is completed, the unit processing is performed again from the beginning of the unit processing that has been stopped.

  Further, the calculation processing for generating correction data for correction processing may be divided. In the present embodiment, for example, addition processing, division processing, and the like are performed in order to obtain correction data, that is, an average value of offset data and defect correction data. Such a calculation process can be continued from the calculation process next to the calculation process ended before shooting even after shooting.

  Next, the operation of the radiation imaging system 10 will be described with reference to the flowchart shown in FIG.

  In the radiation imaging system 10 of the present embodiment, as shown in the flowchart of the figure, the first unit process is performed before reception of the next imaging order. Since it is a period during which imaging is not performed before reception of the imaging order, there is a sufficient period for performing the first unit processing.

  During the execution of the first unit process, the console 20 goes to the server 14 to receive the radiographic image radiography order of the subject 36 and registers the received radiography order in the radiography menu of the console 20. After that, when a desired shooting order is selected from the shooting menu of the console 20 by the shooting engineer, a shooting order to be shot next is determined. As a result, the console 20 transmits the imaging condition corresponding to the selected imaging order to the control device 34 of the imaging device 18 to instruct imaging.

  Since the shooting order is received during the execution of the first unit processing, the shooting cannot be started immediately. However, the time required for the first unit processing is shorter than the conventional unit, so the waiting time is short. The camera is ready for shooting.

  Subsequently, the photographing engineer confirms the contents of the next photographing menu on the console 20 and starts preparation for photographing. As preparation for imaging, for example, the subject 36 is called and positioned on the imaging table 28. Further, the position and height of the radiation source 22 are manually adjusted by the suspending device 24 according to the imaging region, and the radiation irradiation field is set. Further, the radiation detector 30 is moved to a predetermined position in the left-right direction in FIG. 2 by the moving device 32 according to the imaging region.

  During this shooting preparation, the second unit process is performed. Since the shooting preparation is a period in which shooting is not performed, there is a sufficient period for performing the second unit processing.

  Depending on the contents of the unit processing to be performed and the division unit of the unit processing (length of processing time), the unit processing may not be completed until the preparation for photographing is completed. In this case, a waiting time is generated with the subject 36 positioned, which is not particularly preferable. For this reason, when the unit process does not end before the preparation for shooting is completed, it is desirable to stop the unit process that is currently being processed, and re-execute after the end of shooting from the beginning of the stopped unit process.

  However, if the unit process being executed is completed in the remaining few seconds, it may be better to start shooting after the end of the unit process. Therefore, the photographic engineer may determine whether to stop the unit processing or to execute the unit processing based on the warning from the warning generation unit 46.

  Also, based on the estimated time based on past results (shooting history information, experience, etc.), if the time required for the unit processing to be performed is considered to be longer than the time required for shooting preparation, The unit process may not be performed.

  Here, if the predicted time is set to the shortest time that is assumed as the time required for shooting preparation, it is possible to reduce the possibility that a waiting time may occur while shooting is possible during the unit processing. Even if there is no past record, for example, when the same subject 36 repeatedly shoots without substantially changing the photographic conditions, the time until the next shoot is short. It is desirable not to perform.

  When the unit processing is completed, the camera is ready for photographing. As described above, a warning is generated by the warning generation unit 46 during the unit processing, but not only this, but it may be locked so that shooting cannot be performed during the generation period of the warning.

  Subsequently, the radiographer checks the correspondence between the arrangement of the apparatus and the subject 36 and the radiographing menu, and starts radiographic imaging. In response to an instruction from the radiographer (pressing a radiation exposure button or the like), the imaging apparatus 18 controls the radiation control apparatus 26 to irradiate the subject 36 with radiation from the radiation source 22, The transmitted radiation is detected by the radiation detector 30 and a radiation image of the subject 36 is taken.

  When the imaging is completed, an image signal of the captured radiographic image is transmitted from the radiation detector 30 to the control device 34. The control device 34 performs various correction processes including offset correction and defect correction on the captured radiographic image based on the received radiographic image signal, and controls the radiographic image signal after the correction process. Sent from the device 34 to the console 20.

  In the present embodiment, the latest (last) processing result obtained by each unit process obtained by dividing a series of calibration processes is stored in the storage device. Then, processing results of a plurality of unit processes corresponding to a series of calibration processes prior to the unit processes performed before radiographic image capturing are read from the storage device, and the plurality of units read Various correction processes are performed using the processing results of the processes.

  In the console 20, various image processes are performed on the radiographic image after the correction process based on the received radiographic image signal. The radiographic image after image processing is displayed on the display device of the console 20 and is confirmed by the radiographer. If there is no problem with the radiographic image after image processing, a print is created as necessary, and the image signal is transmitted from the console 20 to the server 15 and stored. Thereafter, the next shooting is started.

  During the image processing on the console 20, the third unit processing is performed. Since the image processing is a period in which no image is taken, there is a sufficient period for performing the third unit process.

  In the radiation imaging system 10, since calibration can be performed at a timing when imaging is not performed, a period during which imaging cannot be performed because of waiting for calibration processing can be shortened. In addition, since only necessary unit processing can be performed at an appropriate timing, it is possible to perform imaging without waiting for all calibration processing and maintaining sufficient accuracy. Even in a system that is not linked to other radiographic apparatuses, the timing of calibration can be made more appropriate by referring to past results.

  Next, for comparison with the present embodiment, the operation of the conventional radiation imaging system will be briefly described with reference to the flowchart shown in FIG.

  In the conventional radiation imaging system, as shown in the flowchart of FIG. 3, a series of calibration processes are performed in a lump before receiving the next imaging order.

  During the execution of the calibration process, the console goes to the server to receive the imaging order and registers the received imaging order in the imaging menu of the console. After that, when a desired shooting order is selected from the shooting menu of the console by the shooting engineer, the console transmits shooting conditions corresponding to the selected shooting order to the control device, and instructs shooting. .

  Since the imaging order is received during the calibration process, the imaging cannot be started immediately. Depending on the reception timing of the imaging order, a long waiting time is required before the imaging can be performed.

  Subsequently, the cameraman confirms the contents of the next shooting menu on the console and starts preparation for shooting.

  Although preparation for shooting is mainly performed manually, it takes a long time, but shooting is not performed during preparation for shooting.

  When preparation for imaging is completed, a radiographic image of the subject is captured by the imaging device, and the image signal is transmitted from the radiation detector to the control device.

  In the control device, various correction processes are performed on the captured radiographic image based on the received radiographic image signal, and the image signal is transmitted from the control device to the console.

  In the console, various image processes are performed on the corrected radiographic image based on the received radiographic image signal. The radiographic image after image processing is displayed on the display device of the console and is confirmed by the radiographer. If there is no problem with the radiographic image after image processing, a print is created as necessary, and the image signal is transmitted from the console to a server such as PACS and stored. Thereafter, the next shooting is started.

  Although it takes a long time to perform image processing at this console and image confirmation by a photographing engineer, similarly, photographing is not performed during this processing and confirmation.

  As described above, in the conventional radiation imaging system, when an imaging request is generated during the execution of the calibration process, the time required for the calibration process is longer than in the case of the present embodiment. Requires a long waiting time.

  Note that, as in the present embodiment, instead of providing the history recording unit 38, the process dividing unit 40, and the process assigning unit 42 in each radiation imaging apparatus 12, a single remote maintenance apparatus may be provided in the entire radiation imaging system 10. Good. The remote maintenance device plays the same role as the history recording unit 38, the process dividing unit 40, and the process allocating unit 42, and collects imaging history information of a plurality of radiation imaging apparatuses 12 via the hospital network 16. And manage.

  That is, the remote maintenance device collects and records the imaging history information of all the radiation imaging devices 12, divides the calibration process into a plurality of unit processes, and radiographic images are taken based on the imaging history information. Calculate the period of unused time, determine whether each unit process can be performed within the period of free time, assign the execution timing of each unit process within the period of free time, and perform calibration Create a schedule.

  When creating a calibration execution schedule, the remote maintenance device calculates a free time period based not only on the imaging history information of one radiation imaging device 12 but also on the imaging history information of a plurality of devices that satisfy a predetermined condition. May be.

  The remote maintenance device uploads the created calibration execution schedule to the control device 34 of the radiation imaging apparatus 12, and the processing execution unit 44 of the control device 34 performs calibration according to the uploaded calibration execution schedule.

  When the work status of the day deviates from the calibration execution schedule based on the past results, it is possible to stop the calibration process and take a picture. When the calibration process is canceled, the unit process is restarted from the beginning, and therefore the calibration execution schedule needs to be readjusted. Normally, all unit processes are shifted backward by the amount of unit processes that have been canceled, and the execution order is advanced as planned.

  Further, due to the addition of the radiation imaging apparatus 12 or the change of the operation rule, there is a possibility that the calibration schedule that has been planned in the past may become incompatible with the latest implementation environment. For this reason, the remote maintenance device continuously records the shooting history information and updates the calibration execution schedule.

  In addition, the radiation imaging system 10 may include an imaging control device that controls execution and cancellation of the calibration process.

  For example, during the execution of the calibration process, the imaging control apparatus stops the calibration process being performed in the middle according to the imaging instruction input via the instruction input device included in the imaging control apparatus, and displays the radiation image. It can be controlled to shoot. In this case, the imaging control apparatus performs control so that the unit processing is resumed from the beginning after the radiographic image capturing is completed.

  In addition, the imaging control device can control the execution of the calibration processing of the radiation detectors 30 of the plurality of radiation imaging devices 12 that capture radiographic images.

  For example, the imaging control device performs control so that the radiographic imaging device 12 performs imaging of the radiographic image with the smallest difference between the scheduled radiographic imaging start time and the waiting time until the end of the calibration process. In addition, the imaging control device controls a plurality of radiation imaging devices 12 used for the same application so that the calibration process is not performed simultaneously in a predetermined time zone.

  Further, for example, the imaging control device acquires the execution status of the first calibration process from the control device 34 of the first radiographic imaging device 12a, and displays the acquired execution status of the first calibration processing of the second radiographic imaging device 12b. By supplying to the control device 34, it is also possible to perform control so that the second radiation imaging apparatus 12b can confirm the execution status of the calibration process in the first radiation imaging apparatus 12a.

  Next, the radiation imaging system of 2nd Embodiment is demonstrated.

  The radiation imaging system of the second embodiment is different from the radiation imaging system 10 of the first embodiment shown in FIG. 1 only in the configuration of the control device 34 shown in FIG. The description will be continued with reference to each component.

  FIG. 7 is a block diagram illustrating an example of a configuration of a control device used in the radiation imaging system according to the second embodiment. As shown in the figure, the control device 34 of the present embodiment includes a defective pixel information holding unit 48, a region dividing unit 50, a processing execution unit 52, and a status display unit 54. Similarly, in the figure, for the purpose of facilitating the description, the description of the part that controls the radiographic image capturing is omitted, and only the part that controls the execution of the calibration process is shown.

  The defective pixel information holding unit 48 holds position information of defective pixels included in the radiation detector 30. The position information of the defective pixel is acquired by performing calibration processing (calibration of the defective pixel). Since normal pixels that are not defective pixels may change to defective pixels over time, the defective pixel information holding unit 48 uses the defective pixel information according to the position information of the new defective pixels acquired by performing the calibration process. The position information of the defective pixel held in the holding unit 48 is updated.

  The area dividing unit 50 divides the radiation image captured by the radiation detector 30 into a plurality of processing areas for sequentially performing the calibration process. For example, the area dividing unit 50 divides the radiation image into a plurality of rectangular processing areas having an equal size as shown in FIG. FIG. 8 is an example in which a radiation image (that is, the light receiving surface of the radiation detector 30 to be calibrated) is divided into nine rectangular processing areas of equal size. The star (*) shown in the figure represents the position of the defective pixel, and so on.

  The area dividing unit 50 may divide the radiographic image into a plurality of rectangular processing areas each having the same size or each having an arbitrary size, and each of them is not a rectangular processing area. You may divide | segment into the processing area of arbitrary shapes. Further, as shown in FIG. 9, the radiographic image is divided into a plurality of rectangular processing regions, each of which includes the same number of lines, or each of which includes an arbitrary line (including all pixels of a predetermined number of lines). Also good. FIG. 9 is an example in which a radiographic image is divided into three rectangular processing areas of equal size including the same number of lines.

  Further, when a new defective pixel occurs in the processing region, the region dividing unit 50 selects a processing region including the new defective pixel based on the position information of the defective pixel updated by the defective pixel information holding unit 48. Further, it is divided into two or more processing areas. For example, as illustrated in FIG. 10, the region dividing unit 50 divides a region including a new defective pixel into a processing region including a defective pixel and a processing region including no defective pixel. Thereby, it is possible to reduce the processing area including defective pixels, which should be calibrated frequently, and to greatly reduce the processing amount.

  Subsequently, the processing execution unit 52 uses the processing region including the defective pixel among the plurality of processing regions divided by the region dividing unit 50 based on the position information of the defective pixel held in the defective pixel information holding unit 48. Also, the execution frequency of the calibration process for the processing area not including the defective pixel is set low, and the calibration process is sequentially executed for each processing area according to the set execution frequency of the calibration process.

  It is more likely that normal pixels around the defective pixel change to defective pixels over time in the processing region that includes the defective pixel, rather than new defective pixels that occur in the processing region that does not include the defective pixel. It is done. Therefore, for example, when the execution frequency of the calibration process for the processing area including the defective pixel is 20 times / day, the processing execution unit 52 sets the execution frequency of the calibration process for the processing area not including the defective pixel to 5 As in the case of times / day, the processing area including the defective pixel is set relatively low.

  By setting the execution frequency of the calibration process for the processing area not including the defective pixel to be low, the processing amount (that is, the processing time) can be reduced as compared with the case where the calibration process is uniformly performed for the entire area of the radiation image. . However, even when the execution frequency of the calibration process for the processing region that does not include the defective pixel is set to be low, the processing execution unit 52, when a new defective pixel occurs in the processing region that does not include the defective pixel, Re-set the execution frequency of the calibration process for the processing area to a high value.

  In addition, the radiation detector 30 is more likely to be destroyed at the peripheral part (further edge part) than the central part due to the influence of moisture (electric corrosion) or static electricity (discharge breakdown). That is, the central processing region has relatively few defective pixels, and the peripheral processing region has relatively many defective pixels. Therefore, as shown in FIG. 11, the radiographic image is divided into a central processing region and a peripheral processing region, and the frequency of performing the calibration process on the peripheral processing region rather than the central processing region is changed. It is desirable to set it high. In addition, it is desirable that the execution order of calibration gives priority to the processing areas arranged successively rather than the processing areas arranged apart from each other.

  Finally, the status display unit 54 displays the execution status of calibration processing for each processing region. The implementation status display method is not limited in any way. For example, for each processing region, the longer the elapsed time after the calibration process is performed, the more graphically the color changes from white (shorter elapsed time) to black (longer elapsed time). Change and display. Thereby, the radiographer can confirm that the calibration process is performed by dividing the radiation image into a plurality of processing regions and the progress of the execution.

  Next, before describing the operation of the radiation imaging system of the present embodiment, the operation of a conventional radiation imaging system will be described as a comparative example.

  FIG. 12 is a conceptual diagram showing how calibration processing is performed in a conventional radiation imaging system. As shown in the figure, the conventional calibration processing is performed collectively for the entire region (1) of the radiation image (that is, the radiation detector 30) composed of M vertical pixels × N horizontal pixels.

  Therefore, it may take a long time from the start to the end of the calibration process, and if a shooting request is generated during the calibration process, it may take a long time before the calibration process ends and the camera is ready for shooting. there were.

  On the other hand, if the calibration process is inevitably stopped in order to perform imaging, the calibration process is not performed on the entire region (1) of the radiation image. In this case, the quality of the radiographic image is deteriorated, and it is necessary to restart the calibration process from the beginning for the entire region (1) of the radiographic image after the end of imaging.

  Next, the operation of the radiation imaging system of this embodiment will be described.

  Next, FIG. 13 is a conceptual diagram showing how calibration processing is performed in the radiation imaging system of the second embodiment. As shown in the figure, the calibration processing of the present embodiment performs the same processing as that shown in FIG. 12 on the entire region of the radiation image consisting of vertical M pixels × horizontal N pixels, for example, vertical M / 2 pixels × The process is divided into four process areas (1) to (4) each having N / 2 horizontal pixels, and the process areas (1) to (4) are sequentially performed.

  That is, in the case of this embodiment, the radiographic image is divided into four rectangular processing areas (1) to (4) having an equal size as shown in FIG.

  Based on the position information of the defective pixel held in the defective pixel information holding unit 48 by the processing execution unit 52, the defect is selected from the four processing regions (1) to (4) divided by the region dividing unit 50. The execution frequency of the calibration process for the processing area not including the defective pixel is set lower than the processing area including the pixel, and each of the processing areas (1) to (4) is set according to the set execution frequency of the calibration process. The calibration processing is sequentially performed according to the set execution frequency.

  In this way, by setting the frequency of performing the calibration process for the processing area not including the defective pixel to be low, the processing amount (that is, the processing time) can be reduced as compared with the case where the calibration process is uniformly performed for the entire area of the radiation image. Can be reduced.

  During the execution of the calibration process, the status display unit 54 displays the execution status of the calibration process for each processing area. Thereby, the imaging engineer can confirm the progress status of the execution of the calibration process.

  When the execution of the calibration process ends, the defective pixel information holding unit 48 determines the defective pixel held in the defective pixel information holding unit 48 according to the position information of the new defective pixel acquired by performing the calibration process. Update location information.

  When the calibration process is finished, the area dividing unit 50, when a new defective pixel is generated in the processing area, based on the position information of the defective pixel updated by the defective pixel information holding unit 48. The processing area including the new defective pixel is divided into, for example, a processing area including the defective pixel and a processing area not including the defective pixel. As a result, when the next calibration process is performed, the processing area including the defective pixel can be reduced, and the processing amount can be greatly reduced.

  In the case of the present embodiment, the calibration process for each of the processing regions (1) to (4) is completed in a shorter time compared to a case where all the regions of the radiation image are subjected to a calibration process all at once. For this reason, even when an imaging request is generated during the execution of the calibration process, the calibration process is completed in a shorter time than before, and the camera is ready for imaging. That is, it is possible to shorten the waiting time until shooting. Further, since the amount of data to be processed at a time is small, it can be implemented in a short time even with a radiographic apparatus having a small processing capability.

  On the other hand, if the calibration process is canceled halfway for shooting, the calibration process is not performed for the canceled process area, but the process area for which the calibration process has already been completed is performed. It becomes. Therefore, it is possible to take a radiographic image with higher quality than before. In addition, it is possible to take an image with a subject (region of interest) placed in a processing region for which calibration processing has already been completed. Furthermore, it is not necessary to restart the calibration process from the beginning for the entire region of the radiographic image, and the process can be resumed from the stopped processing region.

  In the radiation imaging system 10 of the first embodiment, the case where the calibration process is divided into a plurality of unit processes in time and sequentially performed is illustrated. In the radiation imaging system of the second embodiment, a radiographic image is spatially generated. In the above example, the processing is divided into a plurality of processing regions and sequentially performed. However, the unit processing can be sequentially performed for each processing region by combining the two.

  For example, the radiographic image may be divided into processing areas having a size corresponding to the length of free time in which the calibration process can be performed. For example, the radiographic image is divided into processing areas having a size in which a series of calibration processes are completed within a free time period. Further, the radiographic image may be divided into processing areas having a size corresponding to the processing capability of the radiation imaging apparatus 12. For example, the radiation image is divided into processing areas having a size corresponding to the calculation speed of the radiation imaging apparatus 12 and the memory capacity of the main storage area.

  In the calibration process according to the present invention, the amount of data to be processed at a time is small in the execution of the calibration process for each processing region, so that it is possible to perform the calibration process in a short time even with a radiographic apparatus having a small processing capability. It is. In addition, it is possible to divide a region having an appropriate size according to the processing capability and use environment of the radiation imaging apparatus, and to appropriately determine the processing region to be calibrated and the number of executions.

  It is also possible to set the execution timing (execution schedule, execution order) of the calibration process (or unit process) for each divided processing area.

  For example, a radiographer (a user of a radiography apparatus) inputs a processing area and an execution timing instruction via an input device such as a keyboard and a mouse, and sets the processing area and the execution timing according to the input instruction. May be. In this case, for example, when it is limited so that the calibration processing of the same processing region cannot be performed continuously, or there remains a processing region that is not instructed to execute the calibration processing among a plurality of processing regions. It is desirable to prevent the setting from being completed.

  In addition, record the performance of the calibration process for at least the number of divided processing areas, and perform the calibration process for the processing area that has the longest time since the previous calibration process. May be. For example, even if the actual performance of the calibration process is not recorded, the order in which the calibration process is simply performed for a plurality of processing areas is determined in advance and the calibration process is repeatedly performed. It can be realized by doing.

  Further, the execution frequency may be set for each processing area. In this case, the subject is arranged based on the operation in which the region of interest (imaging object) is difficult to be arranged in the periphery, the irradiation field is determined based on a predetermined corner or side of the radiation detector 30, and the like. It is desirable to be able to preferentially implement easy processing areas. Further, it is desirable to warn when the usage frequency of the peripheral portion is high in conjunction with past trimming results, or to warn when the irradiation range is set to the peripheral portion in conjunction with the collimator.

The present invention is basically as described above.
Although the present invention has been described in detail above, the present invention is not limited to the above-described embodiment, and it is needless to say that various improvements and modifications may be made without departing from the gist of the present invention.

DESCRIPTION OF SYMBOLS 10 Radiography system 12 Radiography apparatus 14, 15 Server 16 Hospital network 18 Imaging apparatus 20 Console 22 Radiation source 24 Hanging apparatus 26 Radiation control apparatus 28 Imaging stand 30 Radiation detector 32 Moving apparatus 34 Control apparatus 36 Subject 38 History recording unit 40 Processing division unit 42 Processing allocation unit 44 Processing execution unit 46 Warning generation unit 48 Defective pixel information holding unit 50 Region division unit 52 Processing execution unit 54 Status display unit

Claims (13)

A radiation imaging apparatus that performs a calibration process of a radiation detector that detects radiation that has been irradiated from a radiation source and transmitted through a subject and captures a radiation image of the subject,
A defective pixel information holding unit for holding position information of defective pixels included in the radiation detector;
An area dividing unit for dividing the radiation image into a plurality of processing areas;
Based on the position information of the defective pixel, the execution frequency of the calibration process for the processing region not including the defective pixel is set lower than the processing region including the defective pixel among the plurality of processing regions, A processing execution unit that sequentially executes the calibration process for the processing region;
The defective pixel information holding unit updates the position information of the defective pixel in accordance with the position information of the new defective pixel acquired by performing the calibration process.
The region dividing unit further divides a processing region including the new defective pixel into two or more processing regions based on the updated position information of the defective pixel. apparatus.   The radiographic apparatus according to claim 1, wherein the region dividing unit divides a processing region including the new defective pixel into a processing region including the defective pixel and a processing region not including the defective pixel. .   The radiation imaging apparatus according to claim 1, wherein the region dividing unit divides the radiation image into a plurality of rectangular processing regions having an equal size.   The radiation imaging apparatus according to claim 1, wherein the region dividing unit divides the radiation image into a plurality of rectangular processing regions each having an arbitrary size.   The radiation imaging apparatus according to claim 1, wherein the region dividing unit divides the radiation image into a plurality of rectangular processing regions each including the same number of lines. The region dividing unit divides the radiation image into a central processing region and a peripheral processing region,
3. The radiographic apparatus according to claim 1, wherein the processing execution unit sets the execution frequency of the calibration process for the central processing region to be lower than that of the peripheral processing region.   Furthermore, the radiography apparatus in any one of Claims 1-6 provided with the condition display part which displays the implementation condition of the said calibration process about each said process area | region. Furthermore, a history recording unit that records imaging history information of the radiation image,
A process dividing unit for dividing the calibration process into a plurality of unit processes;
Based on the imaging history information, calculate a period of idle time from the end of imaging of the radiation image to the start of the next imaging, and determine whether each unit process can be performed within the period of the idle time A process allocation unit that allocates the execution timing of each of the unit processes within the free time period for each of the processing areas;
The said process implementation part implements each said unit process with respect to each said process area | region at the implementation timing in the period of the free time allocated to each said unit process. A radiation imaging apparatus according to claim 1. The calibration process includes performing a plurality of different types of calibration,
The radiographic apparatus according to claim 8, wherein the processing division unit divides the calibration process using the type of calibration as the unit process. The calibration includes performing a plurality of shooting modes with different shooting conditions,
The radiation imaging apparatus according to claim 9, wherein the process dividing unit divides the calibration process using the imaging mode as the unit process.   The radiographic apparatus according to claim 8, wherein the region dividing unit divides the radiographic image into processing regions having a size corresponding to the idle time period.   The radiographic apparatus according to claim 8, wherein the region dividing unit divides the radiographic image into processing areas having a size corresponding to a processing capability of the radiographic apparatus. The region dividing unit divides the radiation image into a plurality of the processing regions according to an instruction input by a user via an input device,
The radiation imaging apparatus according to any one of claims 8 to 12, wherein the process assignment unit assigns an execution timing of each of the unit processes for each of the process areas in accordance with an instruction input by the user.

Images