JP5548528B2 - X-ray imaging apparatus, control method therefor, and program - Google Patents

Description

  The present invention relates to an X-ray imaging technique that does not require synchronization with X-ray generation timing when, for example, X-ray imaging is performed in a medical facility, and in particular, X-ray detection that can directly convert an X-ray image into a digital output in real time. The present invention relates to an X-ray imaging technique using a scanner.

  Conventionally used as an X-ray sensor for obtaining an X-ray image of a medical examiner at the time of X-ray imaging is a film / screen system (hereinafter referred to as F / S) or a computer with a film and an intensifying screen sandwiched between cassettes. This is an Imaging Plate (IP) in a cassette used in Putted Radiography. These types of X-ray sensors do not need to be synchronized with the X-ray generation timing, and the photographer acquires X-ray images that are free from blurring due to movements of organs and bodies while observing only the state of breathing and movement of the examiner. it can. For this reason, the X-ray generator is configured to irradiate X-rays with a delay of several tens ms to several hundred ms at the latest after the X-ray irradiation button is pressed.

  In recent years, an X-ray sensor that can directly convert an X-ray image into a digital output in real time has been proposed. Such an X-ray detector can be manufactured, for example, by arranging a solid conductive detector and a transparent photoconductive element in a matrix form with an amorphous semiconductor sandwiched on a quartz glass substrate. Thus, the solid-state photodetector and a scintillator that converts X-rays into visible light are stacked.

  An X-ray digital image when this X-ray detector is used is acquired through the following process.

  That is, by irradiating the X-ray detector with X-rays transmitted through the object, the X-rays are converted into visible light by the scintillator, and the visible light is detected as an electrical signal by the photoelectric conversion unit of the solid-state light detection element. .

  This electrical signal is read out from each solid state light detection element by a predetermined readout method, and this electrical signal is A / D converted to obtain an X-ray image signal.

  Details of the X-ray detector are described in Patent Document 1, for example. Many detectors that directly acquire X-rays with a solid-state photodetector without using a scintillator have been proposed.

  Hereinafter, an X-ray sensor capable of directly converting such an X-ray image into a digital output in real time is referred to as an X-ray detector.

  Since these X-ray detectors detect the X-ray intensity as the amount of charge, discharge of charges in the pixels to accurately accumulate the X-ray detection signals, idling to stabilize the potential between the pixels, X-ray detection Accumulation of electric charge for accumulating signals, reading of electric charge in a pixel, and driving of a fixed cycle for acquiring an X-ray image are required.

  Therefore, since the charge accumulation state by the X-ray detector is limited in time, the X-ray generator and the X-ray detector are synchronized so that X-rays are emitted in the X-ray detector accumulation possible state. It was. Specifically, when the X-ray irradiation button is pressed, the X-ray detector is controlled so as to have a plurality of driving states including discharge of charge in the pixel, idling, and accumulation of charge. In anticipation of the accumulation state, an X-ray irradiation signal was transmitted to the X-ray generator to irradiate X-rays.

JP-A-8-116044

  However, when driving necessary for accumulation of the X-ray detector is performed in synchronization with the X-ray irradiation button and X-ray irradiation is performed, the radiographer turns on the X-ray irradiation button until the X-ray irradiation is actually performed. This delay becomes longer than in the case where there is no normal synchronization, and it is difficult to obtain an X-ray image free from blur due to organs or body movements.

  The present invention has been made in view of the above problems, and an object thereof is to realize an X-ray imaging technique that does not require synchronization with X-ray generation timing.

In order to solve the above-described problems and achieve the object, an X-ray imaging apparatus according to the present invention includes a plurality of pixels each having an element that reads an electric signal obtained by converting X-rays in a nondestructive manner and a photodiode. The non-destructive readout is executed a plurality of times while controlling the X-ray detector and the element of the X-ray detector and holding the electric signal accumulated in the photodiode so as not to be reset before the readout. And a detection unit that detects irradiation of X-rays to the X-ray detector based on a change in the difference between a plurality of electrical signals read in response to the control.

  According to the present invention, an X-ray imaging technique that does not require synchronization with X-ray generation timing can be realized.

1 is a schematic configuration diagram illustrating a preferred example of an X-ray imaging apparatus according to a first embodiment. The figure explaining the structure and drive of the X-ray detector 110 demonstrated in FIG. 1 in detail. 6 is a time chart illustrating the interlocking of the driving of the X-ray detector 110, the control of the detector control unit 120, the recognition signal of the notification unit 130, and the X-ray irradiation detection of the X-ray irradiation detection unit 140. The figure which shows the example which used the light for the alerting | reporting part. The figure which shows the example which used the sound for the alerting | reporting part. The figure which shows the example which used the radio | wireless communication for the alerting | reporting part. 3 is a flowchart for explaining a preferable imaging method of the X-ray imaging apparatus according to the first embodiment. The figure which showed one example of the X-ray irradiation detection part 140. FIG. The figure which showed the example in which the X-ray detector 110 has a nondestructive read-out function. 6 is a flowchart for explaining a storage control method of the X-ray detector 110 using a nondestructive readout function. The schematic block diagram which shows a suitable example of the X-ray imaging apparatus which is 2nd Embodiment. 6 is a flowchart for explaining a preferable imaging method of the X-ray imaging apparatus according to the second embodiment.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described with reference to the accompanying drawings.
[First Embodiment]
First, as a first embodiment, an X-ray imaging apparatus including an informing unit that notifies the photographer of the driving state of the X-ray detector so that the photographer can take an image without synchronizing with the X-ray generation apparatus will be described. To do.

  FIG. 1 is a schematic configuration diagram illustrating a preferred example of the X-ray imaging apparatus according to the first embodiment.

  In FIG. 1, reference numeral 100 denotes a drive start unit (including devices, circuits, program codes and others having the function), 110 denotes an X-ray detector, and 120 denotes a detector control unit (devices, circuits, and programs having the function). 130 includes a notification unit (including the device, circuit, program code and others having the function), 140 is an X-ray irradiation detection unit (device, circuit, program code and the like having the function) First, the drive start unit 100 makes the X-ray detector 110 ready for imaging.

  Specifically, this means that the X-ray detector 110 necessary for imaging is started in a state where the X-ray detector 110 is powered on. In general, this is achieved by, for example, turning on an imaging button of an OPU (operation unit) in which the radiographer operates the X-ray detector 110. The X-ray detector 110 that has started driving performs predetermined driving until X-ray irradiation is performed by the detector control unit 120.

  The driving includes driving for stabilizing the X-ray detector 110 after applying a voltage and driving in a state in which the X-ray detector 110 accumulates the irradiated X-ray signal. The notification unit 130 generates an identifiable signal so that the radiographer can recognize the drive for storing the X-ray signal (hereinafter, stored state) and the other drive.

  The signal may be a light signal, a sound signal, a vibration signal, or the like. As for the signal using light, there is a method of causing the LED light provided in the housing of the X-ray detector 110 to emit light continuously when the X-ray signal is accumulated and blinking when driving. In addition, there is a method of displaying a notification of the accumulation state on the OPU operated by the photographer. In the case of a signal using sound, there is a method of emitting a continuous sound from the X-ray detector 110, the OPU, or the like during accumulation, and a flashing sound during other driving. For a signal using vibration, there is a method in which a photographer carries a portable monitor that can communicate with the detector control unit 120, and the photographer is notified by vibrate vibration intensity.

  When the notification unit 130 notifies that the X-ray detector 110 is in the accumulation state and the irradiation button of the X-ray generation device is turned on (by a photographer who recognizes it or automatically), X-rays are irradiated. The X-ray detector 110 accumulates the X-ray signal transmitted through the subject. The X-ray irradiation detection unit 140 detects X-ray irradiation to the X-ray detector 110 in time series, and acquires the irradiation start time and irradiation end time when the X-ray is irradiated to the X-ray detector 110.

  The X-ray irradiation detection unit 140 may detect X-ray irradiation in a time series using a detector different from the X-ray detector 110, and includes a nondestructive readout circuit in the X-ray detector 110. X-ray irradiation may be detected in time series by destructive readout. An example of a detector different from the X-ray detector 110 is a detector used for AEC (Auto Exposure Control) of an X-ray generator.

  Based on the acquired irradiation start time and irradiation end time, the detector control unit 120 drives the accumulation state of the X-ray detector 110, acquisition of correction data, voltage drop, and the like.

  As described above, by notifying the driving state of the X-ray detector 110, it can be identified that the X-ray detector 110 is in the accumulation state, and then the irradiation button of the X-ray generator is turned on during the accumulation state. As a result, the X-ray detector 110 and the X-ray generator need not be synchronized. As a result, the photographer can carry and photograph the X-ray detector 110 without worrying about connection.

  Further, when the photographer presses the irradiation button of the X-ray generator and irradiates the X-ray, the irradiation button is confirmed by confirming the accumulation state and confirming the state of the subject before irradiating the X-ray. Due to the X-ray irradiation delay caused by the time required to drive the X-ray detector 110 to the accumulation state after pressing the The blur of the image due to the movement can be eliminated, and when the heartbeat is observed and photographed, the blur around the heart due to the movement of the heart can be eliminated.

  In FIG. 2, the configuration of the X-ray detector 110 described in FIG. 1 and the driving necessary for accumulating and reading X-ray signals will be described.

  The X-ray detector 110 includes an X-ray detector that directly detects X-rays and a type that detects X-rays by converting X-rays into visible light once with a phosphor. However, both are configured by combining pixels for detecting signals in an array. This is called a detector array, and 200 is a detector array.

  A pixel 201 includes a signal detection unit that detects one X-ray or light signal, and a switching TFT that switches between signal accumulation and reading. PDs (1, 1) to (4096) are photoelectric conversion elements corresponding to the signal detection unit. SW (1, 1) to (4096) are switches corresponding to the switching TFT. These are hereinafter referred to as photoelectric conversion elements PD (m, n) and switches SW (m, n) for the pixels of m rows and n columns. G (electrode) and D (electrode) are respectively a gate electrode and a common electrode of the photoelectric conversion element PD (m, n), and charge is accumulated and discharged by applying different voltages to the respective electrodes. The photoelectric conversion part of the photoelectric conversion element PD (m, n) is connected to the gate electrode G with an insulator interposed therebetween. In addition, the photoelectric conversion unit of the photoelectric conversion element PD (m, n) is connected to the common electrode D with the semiconductor interposed therebetween. Lcm is an m column signal line, and Lrn is an n row selection line. Lb is a bias wiring, and 205 is a bias power source.

  The gate electrode G is connected to the common column signal line Lcm for the column via the corresponding switch SW (m, n), and the control terminal of the switch SW (m, n) is connected to the common row selection line Lrn. . The common electrode D of all the photoelectric conversion elements PD (1, 1) to (4096) is connected to the bias power source 205 via the bias wiring Lb.

  Reference numeral 232 denotes a line selector that selects which row of the pixels 101 is to be read out, and is connected to row selection lines Lr1 to 4096. Reference numeral 234 denotes an address decoder that decodes a control signal from the detector control unit 120 and determines which line of the photoelectric conversion element PD (m, n) should be read out. A switch element 236 is opened and closed according to the output of the address decoder 234. The line selector 232 includes an address decoder 234 and 4096 switch elements 236-1 to 4096.

  Reference numeral 240 denotes a signal readout circuit that reads out signal charges of the pixel 201. Reference numeral 241 denotes a reset reference potential for resetting the accumulated charge of the photoelectric conversion element PD (m, n), and the voltage thereof is Vb. Reference numeral 242 denotes a reset switch, and reference numeral 246 denotes a preamplifier that amplifies the signal potential from the column signal line Lcm. A sample and hold circuit 248 samples and holds the output of the preamplifier 246. An analog multiplexer 250 multiplexes the output of the sample and hold circuit 248 on the time axis. Reference numeral 252 denotes an A / D converter that digitizes the analog output of the analog multiplexer 250. Reference numeral 262 denotes a driver that actually drives the X-ray detector 110.

  Hereinafter, the most basic driving in the X-ray detector 110, such as refresh of the photoelectric conversion element (discharge of accumulated charges), accumulation of charges, reading of charges, and empty reading, will be described. Here, refresh may or may not be necessary depending on the structure of the photoelectric conversion element. For example, one structure of a photoelectric conversion element that needs refreshing is an MIS structure.

  First, refresh of the photoelectric conversion element will be described.

  The driver 262 sets the potential of all the common electrodes D connected to the bias wiring to the refresh potential Vr by applying a voltage to the bias power source 205. Further, the driver 262 turns on all the reset switches 242 to connect all the column signal lines Lc1 to 4096 to the reset reference potential 241Vbt. Furthermore, the driver 262 applies the potential Vgh to all the row selection lines Lr1 to 4096, thereby turning on all the switches SW (1, 1) to (4096, 4096), so that the potentials of all the gate electrodes G are turned on. Is set to Vbt. Then, due to the potential difference Vbt−Vr between the potential Vbt of the gate electrode G and the potential Vr of the common electrode D, excess charges of the photoelectric conversion elements PD (1, 1) to (4096, 4096) are discharged from the common electrode D and refreshed. The

  Next, charge accumulation will be described.

  The driver 262 sets the potentials of all the common electrodes D connected to the bias wiring to the bias potential Vs at the time of photoelectric conversion by changing the voltage of the bias power source 205.

  In addition, the driver 262 turns off all the reset switches 242 to release all the column signal lines Lc1 to 4096 from the reset reference potential 241Vbt.

  Furthermore, the driver 262 applies all the row selection lines Lr1 to 4096 to the potential Vgl to turn off all the switches SW (1, 1) to (4096, 4096). Since the gate electrode G and the photoelectric conversion elements PD (1, 1) to (4096, 4096) are insulated, and the common electrode D and the photoelectric conversion elements PD (1, 1) to (4096, 4096) are semiconductive, the gate By reversing the magnitude of the potential of the electrode G and the potential Vs of the common electrode D at the time of refresh, the photoelectric conversion elements PD (1, 1) to (4096, 4096) are in a state in which charges due to photoelectric conversion can be accumulated.

  When X-rays are irradiated to the X-ray detector 110, charges proportional to the X-ray dose are accumulated in the photoelectric conversion elements PD (1, 1) to (4096, 4096). In the photoelectric conversion element PD (m, n), there is a dark current that is excited and flows by temperature in addition to the X-ray signal, and the charge due to the dark current also accumulates with the charge proportional to the X-ray dose.

  Next, charge reading will be described.

  With the potentials of all the common electrodes D set to the bias potential Vs at the time of photoelectric conversion, the driver 262 turns on all the reset switches 242 and sets all the column signal lines Lc1 to 4096 to the reset reference potential 241Vbt. To. In this state, the driver 262 turns off all the reset switches 242. Furthermore, the driver 262 turns on the switches SW (1, 1) to (1, 4096) by applying a potential Vgh to the row selection line Lr1. As a result, the column signal lines Lc1 to 4096 having the potential Vbt are connected to the gate electrode G. However, since charges are accumulated in the photoelectric conversion elements PD (m, n), the column signal lines Lc1 to 4096 are induced by the charges. Is shifted from Vbt to Vbt ′. Since the deviation amount Vbt−Vbt ′ is proportional to the accumulated charge amount, the deviation amount Vbt−Vbt ′ is amplified by the preamplifier 246. The output of the preamplifier 246 is sampled and held by the sample and hold circuit 248, the output of the sample and hold circuit 248 is multiplexed on the time axis by the analog multiplexer 250, and the analog output of the analog multiplexer 250 is digitally converted by the A / D converter 252. Read out and output to the image processing apparatus.

  By repeating this operation for all 1 to 4096 rows, the accumulated charges of all the pixels are read out. At this time, the magnitude relationship between the bias potential Vs of the common electrode D and the potentials Vbt and Vbt ′ of the gate electrode is the same as that during charge accumulation.

  The accumulated charge includes a charge proportional to X-rays and a charge due to dark current. In order to read out only the accumulated charge proportional to the X-ray dose, the charge due to the dark current is accumulated once again for the same time, read and subtracted. Further, in order to accurately detect the accumulated charge proportional to the X-ray, it is preferable to provide driving such as discharging of the charge remaining in the pixel before accumulation. This can be replaced by repeating read driving.

  As described above with reference to FIG. 2, it can be seen that the X-ray detector 110 needs to be driven to store and read out X-ray signals in order to acquire an X-ray image.

  In FIG. 3, a detector control unit 120 that controls driving of the X-ray detector 110, a notification unit 130 that transmits a recognition signal for reporting the driving state of the X-ray detector 110, and the X-ray detector 110 It is the time chart explaining the interlocking of the X-ray irradiation detection part 140 which detects the irradiated X-ray.

  The upper stage of the convex signal shown in FIG. 3 represents the ON state, and the lower stage represents the OFF state.

  Reference numeral 310 denotes detection of X-ray irradiation by the X-ray irradiation detection unit 140. Reference numeral 315 denotes a transmission state of the recognition signal by the notification unit 130. Reference numeral 320 denotes an X-ray irradiation state in which the irradiation button of the X-ray generation device is turned on (by the photographer or automatically). Reference numeral 330 denotes electric charges generated in the photoelectric conversion element PD (m, n). Reference numeral 340 denotes an ON / OFF state of the switch SW (m, n) corresponding to the switching TFT in the detector array 200 shown in FIG. Reference numeral 350 denotes a signal readout state of the analog multiplexer 250 in the detector array 200 shown in FIG. Further, it can be seen from 350 that when the switch SW (m, n) in one row is ON, the charge accumulated in the pixels 201 in one row is read out by the analog multiplexer 250. The drive control of the X-ray detector 110 is performed by the detector control unit 120 according to 340 and 350.

  First, a voltage is applied to the X-ray detector 110 by the driving start unit 100, and driving starts. If the X-ray detector 110 needs to be refreshed by the detector control unit 120, the refresh is performed first. The idle reading indicated by 340 indicates driving to read out without being irradiated with X-rays during accumulation, and the time is Tk. Times T1 and T2 (T1 = T2) between empty reading and empty reading indicate limit accumulation times when X-ray irradiation cannot be performed by the X-ray irradiation detection unit 140.

  As indicated by 340, the switches SW (m, n) are sequentially turned on and read out, so that the accumulated state is shifted for each row. In X-ray irradiation, since all rows must be in an accumulated state, the time during which X-rays can actually be irradiated before the limit is T1−Tk. In order to be able to irradiate X-rays during the time T1-Tk, the notification unit 130 continues to transmit a T1-Tk time recognition signal.

  It is easier for the photographer to understand the X-ray irradiation timing when the recognition signal indicating that the X-ray cannot be irradiated is also transmitted in the OFF state at 315. The idle reading and accumulation states described above are continuously performed immediately after the driving is started. In FIG. 3, idle reading before accumulation is described only once, but it may be performed many times. Also, since the X-ray detector 110 often cannot acquire a stable image immediately after starting driving, it is better to repeat the idle reading accumulation cycle, and it is better to perform the number of idle readings many times. good. This repetition is hereinafter referred to as idling driving.

  In accordance with idling driving, the notification unit 130 repeatedly issues a recognition signal as to whether X-rays can be emitted. The photographer can estimate the timing from the recognition signal and irradiate the X-ray detector 110 with X-rays. This is indicated by 320. At that time, charges are generated in the photoelectric conversion element PD (m, n) as indicated by 330. When X-rays are irradiated when X-rays cannot be irradiated, the photographer can immediately determine whether or not the shooting has failed by notifying with a recognition signal.

  As indicated by 310, the irradiation start time of the irradiated X-ray is detected by the X-ray irradiation detection unit 140, and the signal 310 is turned ON. This signal is sent to the detector control unit 120, and the X-ray detector 110 is set in the accumulation state while the X-ray is irradiated. When the X-ray irradiation is completed and the irradiation end time is detected by the X-ray irradiation detection unit 140 and the signal 310 is turned OFF, the main reading shown in 340 is started immediately.

  The main reading indicates reading of the accumulated charge after the X-ray irradiation with respect to the empty reading. Accumulation time immediately before the main reading is T3, T4 (T3 = T4), and this time is determined by ON / OFF of the 310 signal detected by the X-ray irradiation detection unit 140. The detector control unit 120 stores the accumulation times T3 and T4 (T3 = T4) and acquires correction data for accumulated charges due to dark current immediately after the main reading, so the same accumulation times T3 and T4 (T3 = T4) Is stored and corrected readings are made.

  Thereafter, the driving of the X-ray detector 110 is stopped, and the voltage applied to the X-ray detector 110 is lowered if necessary. This has the effect that reducing the applied voltage of the X-ray detector 110 leads to power saving and further extends the life of the X-ray detector 110.

  By using the X-ray irradiation detection unit 140, a state where X-rays can be irradiated can be repeated. However, when there is no X-ray irradiation detection unit 140, it is possible to eliminate the need for X-ray irradiation detection by notifying the state in which X-rays can be irradiated only once and irradiating X-rays during that time. In this case, the accumulation time immediately before the main reading and the accumulation time immediately before the correction reading are the same and may be determined in advance.

  As described above, by including the X-ray irradiation detection unit 140 that detects X-ray irradiation in time series, it is determined that X-rays have been irradiated without being synchronized with the X-ray generator, There is an effect that the detector 110 can be driven. Further, by detecting the irradiation start time and irradiation end time by the X-ray irradiation detection unit 140, it becomes possible to acquire correction data for correcting the accumulated charge due to the dark current, and the X-ray signal can be accurately imaged. There is an effect that can be done. Furthermore, by issuing a recognition signal that notifies the accumulating state in which X-ray irradiation is possible and other states by the notification unit 130, there is an effect that imaging can be performed without synchronizing with the X-ray generation apparatus.

  Even if you temporarily lose the timing of X-ray irradiation by repeating the cycle of the recognition signal that informs you of the accumulated state and other states where X-ray irradiation is possible, you can measure the timing in the next cycle immediately There is an effect of X-ray irradiation. By performing idling driving, there is an effect that instability immediately after starting driving of the X-ray detector 110 and immediately after refreshing can be removed.

  FIG. 4 is an example in which a recognition signal is emitted to the notification unit 130 using light.

A housing 400 stores the X-ray detector 110, the detector control unit 120, and the X-ray irradiation detection unit 140. Reference numeral 420 denotes a light emitting unit, and here, an example of five LEDs is shown.
The detector control unit 120 controls to emit a recognition signal, and causes the LED in the housing 400 to emit light.

  There is an example in which five LEDs emit light in the accumulation state where X-ray irradiation is possible and two LEDs emit light in other states so that the accumulation state where X-ray irradiation is possible and other states can be distinguished. The photographer can irradiate the subject and the light of this LED to irradiate X-rays at an appropriate timing.

  FIG. 5 is an example in which a recognition signal is transmitted to the notification unit 130 using sound.

  A housing 500 stores the X-ray detector 110, the detector control unit 120, and the X-ray irradiation detection unit 140. 520 is a speaker, and 530 is a communication line to the speaker.

  The detector control unit 120 controls to generate a recognition signal, and generates sound from the speaker through the communication line 530 from the housing 500. There is an example in which a continuous sound is generated in an accumulation state where X-ray irradiation is possible and a pulse sound is generated in other states so that the accumulation state where X-ray irradiation is possible and other states can be distinguished. The photographer can irradiate the subject and the sound while irradiating the subject with X-rays at an appropriate timing.

  FIG. 6 is an example in which a recognition signal is transmitted to the notification unit 130 using wireless communication.

  A housing 600 stores the X-ray detector 110, the detector control unit 120, and the X-ray irradiation detection unit 140. Reference numeral 610 denotes an OPU that transmits shooting information to the housing 600 and transmits a signal to start driving. Reference numeral 620 denotes a light emitting unit, which is an example displayed on the OPU 610 here. 630 is a first wireless communication unit, and 640 is a second wireless communication unit. Reference numeral 650 denotes a shooting start button.

  When the shooting start button 650 is turned on, a signal is emitted from the second wireless communication unit 640 of the OPU 610. The first wireless communication unit 630 receives this signal and causes the detector control unit 120 to start driving the X-ray detector 110. This portion corresponds to the drive start unit 100 described above. Next, when the X-ray detector 110 starts driving, the detector control unit 120 performs control so as to emit a recognition signal, and emits a signal from the first wireless communication unit 630 of the housing 600. The second wireless communication unit 640 receives this signal, and a recognition signal is displayed on the screen of the OPU 610. This portion corresponds to the notification unit 130 described above. In order to distinguish between an accumulated state in which X-ray irradiation is possible and other states, there is an example in which red is displayed in an accumulated state where X-ray irradiation is possible, and yellow is displayed in other states.

  The photographer can irradiate X-rays at an appropriate timing while viewing the display and the subject. In addition, when the OPU 610 is small and can be carried, the recognition signal may be vibration of the portable OPU 610.

  As described above with reference to FIGS. 4 to 6, if the LED light or radio signal attached to the housing 400 is used for the notification unit 130, the connection with the X-ray generator is not required because it is not synchronized. In addition, the portability of the X-ray detector 110 is further enhanced. Using sound for the notification unit 130 has an effect that the eyes can be focused on the subject and the ear can be concentrated on the recognition signal sound.

  Similarly, using vibration for the notification unit 130 has an effect that the user can take an image while directing the eyes toward the subject and feeling the vibration as the recognition signal on the skin. Sending a recognition signal with the light of the LED attached to the housing 400 has an effect of making it easy to see both the subject and the light of the LED in the same direction.

  FIG. 7 is a diagram illustrating a driving flow of the X-ray imaging apparatus in the detector control unit of FIG.

  710 is a driving start module for starting driving of the X-ray detector, 715 is an X-ray incident enabling notification module for notifying that X-ray incidence is possible on the X-ray detector, and 717 is an X-ray incident on the X-ray detector. X-ray incidence detection module for detecting whether or not a signal charge has been accumulated, 718 is a number determination module for determining how many times signal charge can be accumulated, and 720 notifies the X-ray detector that X-ray incidence is not possible X-ray incidence impossibility notification module, 725 is an X-ray image storage module that accumulates signal charges of an X-ray image, 727 is an X-ray end detection module that detects whether or not X-ray irradiation has ended on the X-ray detector, 730 Is a corrected image acquisition module that acquires an image for correction, and 735 is a drive end module that ends the drive of the X-ray detector.

  First, the drive start unit 100 starts driving the X-ray detector, and the drive start module 710 receives the signal from the drive start unit 100 and starts driving the X-ray detector. After the predetermined drive is performed until the X-ray detector 110 is stabilized, the signal charge accumulation state of the X-ray detector 110 is repeated. To generate a recognition signal.

  When the X-ray generator irradiates X-rays in an accumulative state, the X-ray incidence detection module 717 detects the X-ray incidence on the X-ray detector 110 based on a signal from the X-ray irradiation detection unit 140. To do. When the X-ray incidence is detected, the X-ray image storage module 725 leaves the X-ray detector 110 in the signal charge storage state, and the X-ray end detection module 727 detects the end of the X-ray irradiation. Or when a predetermined accumulation time has elapsed, the accumulation of signal charges is terminated.

  The X-ray end detection module 727 detects the end of X-ray irradiation to the X-ray detector 110 by a signal from the X-ray irradiation detection unit 140, and when detected, the X-ray image storage module 725 detects the detection. Inform. When the signal charge accumulation is completed, the corrected image acquisition module 730 acquires a corrected image for correcting the accumulated signal charge image. The corrected image is an image obtained by the correction reading shown in FIG.

  The X-ray detector 110 obtains the accumulation time that has been in the signal charge accumulation state, and obtains a corrected image with the same accumulation time. When the correction reading is completed, the driving end module 735 ends the driving of the X-ray detector 110.

  If the X-ray detector 110 does not detect that the X-ray has been irradiated in spite of the accumulation possible state, the number determination module 718 determines how many times the accumulation is possible or the X-ray detector 110 starts driving. Then, it is determined how much time has passed, and when the predetermined number of times or more than the predetermined time has passed, control is transferred to the drive end module 735 in order to end the drive of the X-ray detector 110.

  If it is less than a predetermined number of times or less than a predetermined time, X-ray irradiation is impossible by the X-ray incidence impossibility notification module 720 immediately before the driving of the X-ray detector 110 becomes a state in which signal charge cannot be accumulated. Issue a recognition signal. During this time, the X-ray detector 110 performs idle reading driving, and when it becomes accumulable again, the X-ray incident possibility notifying module 715 issues an accumulating state recognition signal from the notifying unit 130.

  In the driving flow shown in FIG. 7, the signal charge accumulating state corresponds to the accumulating state described in FIG. The signal charge non-accumulation state corresponds to the idle reading described with reference to FIG. 3, but since the idle reading drive time is fast, the signal in the non-accumulation state generated during that time is too fast and the photographer cannot recognize it. There is. At that time, the driving state in which the accumulation and idle reading of the X-ray detector 110 are repeated several times may be set as one set to correspond to the accumulation impossible state.

  In addition, in the case of erroneous irradiation such that X-ray irradiation has been performed in the accumulation disabled state, the X-ray incident impossibility notification module 720 determines the erroneous irradiation based on a signal from the X-ray irradiation detection unit 140, and the erroneous irradiation is not performed. The notification unit 130 notifies that there has been.

  As described above, as shown in FIG. 7, by providing an imaging flow for detecting the presence or absence of X-ray irradiation, it is possible to realize imaging that is not synchronized with the X-ray generator, and the portability of the X imaging apparatus is improved. .

  8 and 9 show specific examples of the X-ray detector 110 and the X-ray irradiation detection unit 140 described in FIG.

  FIG. 8 is an example in which an X-ray irradiation detection unit 140 is provided on the opposite side of the X-ray incident side with respect to the X-ray detector 110 described in FIG. The X-ray irradiation detection unit 140 has the same configuration as that of the X-ray detector 110 shown in FIG. 2, but the time for scanning the entire detector surface is much faster than the X-ray detector 110, and X-rays on the order of several ms. It is a detector that can store and read out several tens of times during irradiation. With this detector, the time from the start of X-ray incidence to the end of X-ray incidence to the X-ray detector 110 can be measured in time series.

  As shown in FIG. 8, when the X-ray irradiation detection unit 140 and the X-ray detector 110 are separately provided, the X-ray detector 110 does not reduce the pixel pitch to such an extent that an X-ray image of the subject can be accurately acquired. However, the X-ray irradiation detection unit 140 has an effect that it can be made a detector structure suitable for each role by increasing the pixel pitch so that the scanning speed is high and the sensitivity is very good. . Further, if the X-ray irradiation detection unit 140 is provided on the opposite side of the X-ray incident side to detect X-rays transmitted through the X-ray detector 110, X-ray irradiation to the X-ray detector 110 is hindered. And there is an effect that a good X-ray image can be obtained.

  FIG. 9 shows an example in which the X-ray detector 110 and the X-ray irradiation detection unit 140 shown in FIG. 8 are different from the configuration in which the X-ray detector 110 and the X-ray irradiation detection unit 140 are provided in the X-ray detector 110. In this example, each pixel of the X-ray detector 110 has a part of the function of the X-ray irradiation detection unit 140.

  900 is a pixel, 905 is a photodiode that accumulates X-ray absorbed phosphor light as signal charge, 907 is an accumulated charge holding unit that holds the accumulated signal charge, and 910 is a signal that transfers an amplified signal by X-rays 912 is an amplifying element that amplifies the held signal charge, 915 is a first common potential that provides a bias voltage to the photodiode 905, 920 is a second common potential that provides an applied voltage to the amplifying element 912, and 925 Is a third common potential for resetting the signal charge held in the accumulated charge holding unit 907, 930 is a first control for controlling transfer of the accumulated charge of the photodiode 905 to the accumulated charge holding unit 907, and 935 is accumulated. The second control for controlling the resetting of the held charge of the charge holding unit 907, the third control for controlling the transfer of the amplified signal by the amplifying element 912 to the signal line 910, and the second control for turning on and off 950 by the first control 930. 1 switch, 955 is the second system A second switch 950 that is turned on / off by the control 930 is a third switch that is turned on / off by the third control 930.

  The driving of this pixel will be described below.

  First, the second switch 955 is turned on by the second control 935, and the accumulated charge holding unit 907 is reset to the third common voltage 925. When the second switch 955 is closed, the accumulated charge holding unit 907 is in a floating state while being reset. Next, the first switch 950 is turned on by the first control 930, the signal charge stored in the photodiode 905 is transferred to the stored charge holding unit 907, and the potential of the stored charge holding unit 907 is raised according to the signal charge. When the third switch 960 is turned on by the third control 940, a signal amplified according to the increased potential is output to the signal line.

  By repeating the above operation in the accumulation state of the X-ray detector 110, it is possible to read the signal charge transferred and accumulated from the photodiode 905 to the accumulated charge holding unit 907, and before and after the read signal. By seeing the change in the difference, it is possible to detect whether the X-ray has started to enter the X-ray detector 110 and has ended.

Further, if the saturation threshold of the signal charge of the accumulated charge holding unit 907 is known, the first switch 950 is detected before saturation of the signal charge of the accumulated charge holding unit 907 by detecting the signal charge accumulated and held at any time. , The stored charge transfer to the stored charge holding unit 907 can be stopped.

  As described above, the method of reading the signal charge transferred and accumulated from the photodiode 905 to the accumulated charge holding unit 907 at any time can read the signal charge transferred to the accumulated charge holding unit 907 and stored. Therefore, the reading method is hereinafter referred to as nondestructive reading. By configuring the X-ray irradiation detection unit 140 including the non-destructive readout and the readout signal difference circuit, the X-ray detector 110 starts and enters X-rays without synchronizing with the X-ray generator. There is an effect that the end can be detected.

  FIG. 10 is a diagram illustrating a flow for detecting the start of X-ray incidence and the end of X-ray incidence using the nondestructive readout function.

  1010 is an accumulated charge reset module that discharges charges accumulated in the accumulated charge holding unit 907, 1015 is an accumulated charge transfer module that transfers accumulated charges from the photodiode 905 to the accumulated charge holding unit 907, and 1020 is held in the accumulated charge holding unit 907. 1025 is an incident start determination module that determines whether the start of X-ray incidence is detected, and 1030 transmits the start of X incidence to the detector control unit 120 to drive the X-ray detector 110. X-ray incidence start detection module 1035 to be reflected, 1035 is a held charge readout module for reading out the charge held in the accumulated charge holding unit 907, 1040 is an incidence end determination module for determining whether the X-ray incidence end is detected, and 1045 is a predetermined The accumulated charge determination module 1050 for determining whether the amount of accumulated charge is equal to or less than the total accumulated charge held in the accumulated charge holding unit 907 during shooting A total accumulated charge readout module 1055 that is an image is an accumulation end module that terminates the accumulation of the X-ray detector 110.

  First, before the X-ray detector 110 accumulates charges, the accumulated charge reset module 1010 resets the charges of the photodiode 905 and the accumulated charge holding unit 907, and closes the first switch 950 by the first control 930. Then, the photodiode 905 is brought into an accumulation state.

  Next, the charge accumulated in the photodiode 905 is transferred to the accumulated charge holding unit 907 by the accumulated charge transfer module 1015. After the photodiode 905 is brought into the accumulation state again, the charge held by the accumulated charge holding unit 907 is read by the held charge reading module 1020. The incidence start determination module 1025 reads out the read signals and takes a difference before and after the readout order to determine an increase in accumulated charges due to X-rays, and detects the start of X-ray incidence. If no X-ray incidence is detected after a predetermined time, the driving of the X-ray detector 110 is terminated.

  When detecting that X-rays are incident, the X-ray incidence start detection module 1030 transmits the X incident start to the detector control unit 120, and keeps driving of the X-ray detector 110 in the signal charge accumulation state. Let it fall. While the X-ray detector 110 is in the accumulated state, the held charge reading module 1035 reads the charge held by the accumulated charge holding unit 907 at any time in order to monitor the signal charge accumulation state due to the X-ray incidence. The incident end determination module 1040 takes the difference between before and after the read-out order of the read-out signals, monitoring the change in the accumulated charges due to the X-rays and ending the X-ray incidence and eliminating the increase in signal charges. Is detected.

  When the end of X-ray incidence is detected, the total accumulated charge readout module 1050 reads out all the signal charges accumulated during the X-ray irradiation held by the accumulated charge holding unit 907 and forms an X-ray image. When the end of X-ray incidence is not detected, the accumulated charge determination module 1045 determines whether or not a predetermined total accumulated charge amount has been reached while monitoring the charge accumulation state.

  When it is detected that the predetermined total accumulated charge amount has been reached, the first switch 950 is kept closed so that no more charge is accumulated in the accumulated charge holding unit 907, and the total accumulated charge readout module 1050 is immediately controlled. Move.

  When the end of X-ray incidence is detected or the arrival of a predetermined total accumulated charge amount is detected, the total accumulated charge readout module 1050 is executed, and the accumulation end module 1055 ends the accumulation of the X-ray detector 110.

As described above, by providing the X-ray detector 110 capable of nondestructive readout, it is not necessary to provide a detector that functions as the X-ray irradiation detection unit 140 separately from the X-ray detector 110. The mechanical structure of the detector 110 is simpler, thinner and lighter, and the portability of the X photographing apparatus is improved.
[Second Embodiment]
Next, as a second embodiment, an X-ray imaging apparatus including a notification unit that notifies the driving state of the X-ray detector so that imaging can be performed without synchronizing with the X-ray generation apparatus will be described.

  FIG. 11 is a schematic configuration diagram illustrating a preferable example of the X-ray imaging apparatus according to the second embodiment. 1100 is a drive start unit (including devices, circuits, program codes and others having the function), 1110 is an X-ray detector, 1120 is a detector control unit (devices, circuits, program codes and others having the function) 1130 is a notification unit (including a device, a circuit, a program code, and the like having the function).

  First, the X-ray detector 1110 is brought into a state where imaging can be performed from the drive start unit 1100. Specifically, this means that the X-ray detector 1110 necessary for imaging is started to be driven in a state where the X-ray detector 1110 is powered on. Generally, this is accomplished by the photographer turning on an imaging button on the OPU that operates the X-ray detector 1110, for example. The X-ray detector 1110 that has started driving is subjected to predetermined driving by the detector control unit 1120. The driving includes driving for stabilizing the X-ray detector 1110 after applying a voltage and driving in a state in which the X-ray detector 1110 accumulates the irradiated X-ray signal.

  The notification unit 1130 emits an identifiable signal so that the radiographer can identify the drive for storing the X-ray signal (hereinafter, stored state) and the other drive. The signal may be a light signal, a sound signal, a vibration signal, or the like.

  As for the signal using light, there is a method in which the LED light provided in the housing of the X-ray detector 1110 continuously emits light when the X-ray signal is accumulated, and blinks at other times. In addition, there is a method of displaying a notification of the accumulation state on the OPU operated by the photographer. In the case of a signal using sound, there is a method of emitting a continuous sound from the X-ray detector 1110, OPU, etc. during accumulation, and a blinking sound during other driving. For signals using vibrations, there is a method in which a photographer carries a portable monitor that can communicate with the detector control unit 1120, and the photographer is notified by vibrate vibration intensity.

  When the X-ray detector 1110 enters the accumulation state by the notification unit 1130 and the irradiation button of the X-ray generator is turned on by the photographer, the X-ray detector 1110 accumulates the X-ray signal transmitted through the subject. The detector control unit 1120 drives the X-ray detector 1110 such as completion of accumulation state, acquisition of correction data, and voltage drop. Detailed operation and driving of the X-ray detector 1110 are the same as those in FIG.

  As described above, by notifying the driving state of the X-ray detector 1110, it can be identified that the X-ray detector 1110 is in the accumulation state, and thereafter, the irradiation button of the X-ray generator is pressed and the X-ray detector 1110 is pressed. Therefore, there is no need to synchronize the X-ray detector 1110 and the X-ray generator. As a result, the photographer can carry and photograph the X-ray detector 1110 without worrying about connection.

  Further, when the X-ray generator is pressed to irradiate X-rays, the X-ray irradiation delay caused by the time required to drive the X-ray detector 1110 to the accumulation state after the irradiation button is pressed. Thus, there is an effect that blur due to the motion of the subject, for example, blur around the heart due to the motion of the heart can be eliminated.

  FIG. 12 is a diagram illustrating a driving flow of the X-ray imaging apparatus in the detector control unit of FIG.

  Reference numeral 1210 denotes a drive start module for starting driving of the X-ray detector, reference numeral 1215 denotes an X-ray incident preparation notification module for notifying the state until the X-ray detector 1110 becomes ready for X-ray irradiation, and reference numeral 1220 denotes an X-ray detector 1110 X-ray incidence enabling notification module for notifying that X-ray incidence is possible, 1225 is an X-ray image accumulation module for accumulating signal charges of the X-ray image, and 1230 is X-ray incidence impossibility to the X-ray detector 1110 X-ray incidence impossibility notification module for informing the user, 1235 a correction image acquisition module for acquiring a correction image, and 1240 a drive end module for ending the drive of the X-ray detector. Reference numeral 1245 denotes a determination module that determines whether continuous shooting is designated by the drive start unit 1100.

  First, the drive start unit 1100 starts driving the X-ray detector, and the drive start module 1210 starts driving the X-ray detector 1110 in response to a signal from the drive start unit 1100. The X-ray detector 1110 performs predetermined driving until the X-ray detector 1110 is stabilized, but the X-ray incident preparation notifying module 1215 notifies the X-ray detector 1110 that the X-ray detector 1110 is in the preparation stage until the driving is stabilized. A signal is issued.

  When the X-ray detector 1110 is ready to accumulate, the X-ray incidence possible notification module 1220 issues a signal for notifying that X-ray irradiation is possible by the notification unit 1130. This is continued until the X-ray detector 1110 finishes accumulation. The X-ray image storage module 1225 sets the X-ray detector 1110 in the storage state simultaneously with the signal from the X-ray incidence enable notification module 1220 and maintains this state for a predetermined time. After a predetermined accumulation time has elapsed, the X-ray detector 1110 finishes accumulating signal charges. After the accumulation is completed, the X-ray incidence impossibility informing module 1230 issues a signal for informing the informing unit 1130 that the X-ray detector 1110 is in an accumulating impossible state.

  When the accumulation of signal charges is completed, the corrected image acquisition module 1235 acquires a corrected image for correcting the accumulated signal charge image. When the acquisition of the corrected image ends, the drive end module 1240 ends the drive of the X-ray detector 110.

  The determination module 1245 restarts the driving of the X-ray detector 1110 when continuous imaging is designated by the driving start unit 1100. When continuous imaging is not designated, the voltage of the X-ray detector 1110 is dropped to enter the sleep state (power off state).

  Depending on the type of X-ray detector 1110, X-ray images may not be continuously stored. For example, a detector in which accumulated charge cannot be completely reset by read driving needs to always put the detector in a sleep state after the detector is set in a signal charge accumulation state.

As described above, as shown in FIG. 12, there is provided an imaging flow for emitting a signal capable of identifying that the X-ray detector 1110 is in the preparation stage at the preparation stage until the X-ray detector 1110 enters the X-ray image accumulation state. Thus, even with a detector that has to be put into a sleep state by accumulating signal charges once, imaging that is not synchronized with the X-ray generator can be realized, and the portability of the X-ray imaging apparatus is improved.
[Other Embodiments]
The present invention supplies a software program (each module shown in the flow of FIGS. 7, 10, and 12) that implements the functions of the above-described embodiments directly or remotely to a system or apparatus, and the computer of the system or apparatus This includes a case where the program code is also achieved by reading and executing the supplied program code. In that case, the form does not have to be a program as long as it has the function of the program.

  Accordingly, since the functions of the present invention are implemented by computer, the program code installed in the computer also implements the present invention. That is, the claims of the present invention include the computer program itself for realizing the functional processing of the present invention.

  In this case, the program may be in any form as long as it has a program function, such as an object code, a program executed by an interpreter, or script data supplied to the OS.

  As a recording medium for supplying the program, for example, floppy disk, hard disk, optical disk, magneto-optical disk, MO, CD-ROM, CD-R, CD-RW, magnetic tape, nonvolatile memory card, ROM, DVD (DVD-ROM, DVD-R).

  As another program supply method, a client computer browser is used to connect to an Internet homepage, and the computer program of the present invention itself or a compressed file including an automatic installation function is downloaded from the homepage to a recording medium such as a hard disk. Can also be supplied. It can also be realized by dividing the program code constituting the program of the present invention into a plurality of files and downloading each file from a different homepage. That is, a WWW server that allows a plurality of users to download a program file for realizing the functional processing of the present invention on a computer is also included in the claims of the present invention.

  In addition, the program of the present invention is encrypted, stored in a storage medium such as a CD-ROM, distributed to users, and key information for decryption is downloaded from a homepage via the Internet to users who have cleared predetermined conditions. It is also possible to execute the encrypted program by using the key information and install the program on a computer.

  In addition to the functions of the above-described embodiments being realized by the computer executing the read program, the OS running on the computer based on the instruction of the program is a part of the actual processing. Alternatively, the functions of the above-described embodiment can be realized by performing all of them and performing the processing.

  Furthermore, after the program read from the recording medium is written in a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer, the function expansion board or The CPU or the like provided in the function expansion unit performs part or all of the actual processing, and the functions of the above-described embodiments are realized by the processing.

  As described above, according to the present embodiment, since the driving state of the X-ray detector is notified, it can be identified that the X-ray detector is in the accumulation state, and then the irradiation button of the X-ray generator is pressed. Therefore, it is not necessary to synchronize the X-ray detector and the X-ray generator. As a result, the photographer can carry and photograph the X-ray detector without worrying about connection. Further, when the X-ray generation apparatus is pressed to irradiate X-rays, X-rays are generated by the time required for driving from the time when the X-ray detector is put into the accumulation state after the irradiation button is pressed. Due to the irradiation delay, there is an effect that blur due to the movement of the subject, for example, blur around the heart due to the movement of the heart can be eliminated.

  In addition, there is an effect that an appropriate X-ray image can be obtained by notifying both of a signal accumulation state capable of X-ray irradiation and a readout state where X-ray irradiation cannot be performed. In addition, by detecting the start and end of X-ray irradiation, the X-ray detector can be driven in accordance with the X-ray irradiation, and an X-ray image can be obtained quickly and accurately without unnecessary driving. There is an effect that it can be acquired. In addition, by separately providing a detector used for the X-ray irradiation detection unit and an X-ray detector for acquiring an X-ray image, it is possible to use a detector specialized for each role, and to improve performance and accuracy. There is an effect that it can have a good function. In addition, by separately providing a detector used for the X-ray irradiation detection unit and an X-ray detector for acquiring an X-ray image, it is possible to use a detector specialized for each role, and to improve performance and accuracy. There is an effect that it can have a good function. An uncorrected X-ray image is an image obtained from the sum of offset charge due to dark current and signal charge due to X-rays. The offset charge due to the dark current depends on the accumulation time. If the signal charge accumulation time by X-rays and the correction image accumulation time are the same, there is an effect that an X-ray image having almost no offset charge can be obtained by the difference.

  For example, the photographer turns on the X-ray irradiation button while watching the patient's movement and breathing. However, according to the X-ray imaging apparatus of this embodiment, the driving state of the X-ray detector can be grasped by sound, and the patient's There is an effect that it is possible to shoot while concentrating only on movement. The radiographer turns on the X-ray irradiation button while watching the patient's movement and breathing. However, according to the X-ray imaging apparatus of the present embodiment, the X-ray detector is driven by holding the vibration source in the hand. It is possible to grasp the image of the patient and focus on only the patient's movement.

  In addition, when displaying the driving state of the X-ray detector on the OPU or the like, there is an effect that the portability of the X-ray imaging apparatus is improved because the X-ray detector is not connected by wire. The photographer turns on the X-ray irradiation button while observing the patient's movement and breathing. However, according to the X-ray imaging apparatus of this embodiment, the driving state of the X-ray detector is grasped by holding the vibration source in the hand. It is possible to focus on only the patient's movement and to take an image. The photographer turns on the X-ray irradiation button while observing the patient's movement and breathing. However, according to the X-ray imaging apparatus of this embodiment, the X-ray detector is driven by the light emitted from the X-ray detector casing. It is possible to grasp the state and to take an image while simultaneously viewing the movement of the patient in contact with the X-ray detector casing. The driving of the X-ray detector was started by turning on the X-ray irradiation button. However, according to the X-ray imaging apparatus of this embodiment, the driving start unit can be pushed to start driving the X-ray detector. There is an effect that synchronization with the X-ray generator is not required, and portability of the X-ray imaging apparatus is improved.

  In addition, the X-ray detector is stabilized by idling driving, and the idling driving can be stopped simultaneously with the X-ray irradiation to move to the accumulation state, so that a stable X-ray image can be obtained. Further, it is possible to detect the end of X-ray irradiation and end the driving of the X-ray detector, thereby reducing power consumption without performing unnecessary driving. In addition, once the accumulation state is established, the applied applied voltage is reduced, and it is necessary to reset the accumulated charge in the pixel, so that even an X-ray detector that cannot be accumulated in a continuous cycle is synchronized with the X-ray generator. There is an effect that it is not necessary to take. In addition, it is possible to capture an appropriate X-ray image by informing the X-ray detector in an identifiable manner of the accumulation state that is the X-ray irradiation enabled state and the storage preparation drive state that is the X-ray irradiation disabled state. There is. In addition, it is possible to capture an appropriate X-ray image by informing the X-ray detector in an identifiable manner of the accumulation state that is the X-ray irradiation enabled state and the storage preparation drive state that is the X-ray irradiation disabled state. There is.

Claims (11)

An X-ray detector in which a plurality of pixels each including an element that reads an electric signal obtained by converting X-rays in a nondestructive manner and a photodiode ;
A control unit that controls the element of the X-ray detector, performs control to execute non-destructive reading a plurality of times while holding the electric signal accumulated in the photodiode so as not to be reset before reading;
An X-ray imaging apparatus comprising: a detection unit configured to detect irradiation of X-rays to the X-ray detector based on a change in a difference between a plurality of electrical signals read in accordance with the control.   The difference part which acquires the difference of the 1st electric signal read according to the said control, and the 2nd electric signal read after the said 1st electric signal is further provided. X-ray imaging equipment.   The control unit stores the amount of charge held in a plurality of pixels of the X-ray detector when the amount of charge held in the pixel corresponding to the electrical signal exceeds a threshold value. The X-ray imaging apparatus according to claim 1, wherein the X-ray imaging apparatus is controlled as follows.   The control unit detects the X-ray so that when the amount of charge held in the pixel corresponding to the electrical signal is larger than a threshold value, charge equal to or more than the amount of held charge is not accumulated. The X-ray imaging apparatus according to claim 1, wherein the apparatus is controlled. The further plurality of pixels of the X-ray detector has a holding portion for accumulating the charge, and a switching element for connecting the said holding part and the photodiode,
5. The X according to claim 4, wherein the control unit makes the switching element non-conductive when the amount of charge held in the pixel corresponding to the electrical signal exceeds a threshold value. X-ray equipment. Pixel of the X-ray detector, characterized by having said photodiode to obtain a signal charge, a power source for supplying a bias voltage to the photodiode, and other switching element for resetting said signal charges The X-ray imaging apparatus according to any one of claims 1 to 5. An X-ray detector in which a plurality of pixels each having an element that reads an electric signal obtained by converting X-rays in a nondestructive manner is disposed;
  A control unit for controlling the elements of the X-ray detector to perform non-destructive reading repeatedly;
  A detection unit that detects irradiation of X-rays to the X-ray detector based on a change in a difference between a plurality of electrical signals read in accordance with the control,
  When the X-ray irradiation is not detected within a specific time after starting the non-destructive readout that is repeatedly executed, the control unit ends the non-destructive readout and detects the X-ray. X-ray imaging apparatus characterized by terminating driving of the instrument.   8. The X according to claim 1, wherein the detection unit detects the start of X-ray irradiation by monitoring the difference and determining an increase in accumulated charge due to X-rays. X-ray equipment.   9. The detection unit according to claim 1, wherein the detection unit detects the end of X-ray irradiation by monitoring the difference and detecting that there is no longer an increase in accumulated charge due to X-rays. X-ray imaging apparatus described in the paragraph. A control method of X-ray imaging by an X-ray detector in which a plurality of pixels each having an element that reads an electric signal obtained by converting X-rays in a non-destructive manner and a photodiode is arranged,
A control step for controlling the element of the X-ray detector and performing a non-destructive reading a plurality of times while holding the electric signal accumulated in the photodiode so as not to reset before reading;
A detection step of detecting X-ray irradiation to the X-ray detector based on a change in a difference between a plurality of electrical signals read in accordance with the control, which is performed in parallel with the control step; A control method comprising:   A program for causing a computer connected to the X-ray detector to execute the control method according to claim 10.

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