JP2008284017A - Radiographic imaging system, method and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To match a specific phase of interest in a cyclic reagent movement with imaging timing of a radiographic image. <P>SOLUTION: A radiographic imaging system is provided with: a radiographic imaging part for imaging a radiographic image of a reagent accompanied with a cyclic movement; an imaging phase specifying part for specifying a phase of a reagent movement to be imaged among the reagent movement; a specific phase timing prediction part for predicting timing with which the movement phase of the reagent becomes a specified phase in a site specified by the imaging phase specifying part; an imaging condition storage part for storing conditions to define timing with which the image of the reagent is imaged; an imaging timing determination part for determining timing with which the image of the reagent is imaged on the basis of the condition stored by the imaging condition storage part; and an imaging control part for causing the radiographic image imaging part to image the radiographic image of the reagent with the timing predicted by the specific phase timing prediction part and the timing determined by the imaging timing determination part. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a radiation imaging system, method, and program. In particular, the present invention relates to a radiation imaging system, method, and program capable of capturing a radiation image in synchronization with a specific phase of a subject with periodic movement.

  Radiation imaging systems are used in the medical field. In a radiation imaging system, for example, a subject with periodic movements such as the heart or lungs can be imaged with radiation such as X-rays, and the movements can be observed. Since these radiation imaging systems can observe the real-time movement of the subject, it can contribute to an accurate diagnosis of the observer.

For example, Patent Document 1 discloses a dynamic X-ray imaging method having a detection process for detecting a respiratory cycle of a subject and a control process for automatically controlling the imaging timing of an X-ray image according to the respiratory cycle. Further, for example, in Patent Document 2, after continuously capturing an object that is changing within a predetermined range at a predetermined time interval at a low dose, the phase of the object is detected by detecting the phase of the object from continuously captured images. Disclosed is a radiographic image capturing apparatus that captures images with a normal dose when becomes a predetermined phase. Further, for example, Patent Document 3 discloses a frame rate for storing fluoroscopic images continuously acquired by subject's heart pulsation, ecological movement due to respiration, or movement of the subject obtained by image processing analysis of the fluoroscopic image. An X-ray imaging apparatus for changing the above is disclosed.
JP 2003-245272 A JP-A-2005-342088 JP 2004-073490 A

  When an observer tries to make a diagnosis by using a continuous image captured by a radiation imaging system, he or she may want to pay attention to a specific phase of a subject with movement. For example, there is a case where it is desired to observe a radiographic image of the heart while paying attention to the peak point of QRS wave in the electrocardiogram. In such a case, it is necessary to match the peak point of the QRS wave, which is a specific phase of interest, with the radiographic image capturing timing. Moreover, in order to contribute to an accurate diagnosis, it is preferable to provide more radiation images in the vicinity of a specific phase of interest. Furthermore, it is preferable to provide a clear radiographic image at a specific phase of interest or in the vicinity thereof.

  In order to solve the above-described problems, in one aspect of the present invention, a radiographic image capturing unit that captures a radiographic image of a subject with periodic movement, and the subject is moved in the movement of the subject. An imaging phase identification unit that identifies the phase of the movement of the subject to be imaged, a specific phase timing prediction unit that predicts the timing at which the phase of the movement of the subject is the phase identified by the imaging phase identification unit, and an image of the subject An imaging condition storage unit that stores conditions for determining the timing to be performed, an imaging timing determination unit that determines the timing at which the subject should be imaged based on the conditions stored in the imaging condition storage unit, and a specific phase timing prediction unit An imaging control unit that causes the radiographic imaging unit to capture a radiographic image of the subject at a timing predicted by the imaging timing and a timing determined by the imaging timing determination unit To provide an imaging system.

  It should be noted that the above summary of the invention does not enumerate all the necessary features of the present invention. A sub-combination of these feature groups can also be an invention.

  As is clear from the above description, according to the present invention, it is possible to match the specific phase of interest of the subject with periodic movement and the radiographic imaging timing. In addition, more radiographic images can be provided in the vicinity of the specific phase of interest. Furthermore, a clear radiographic image can be provided at or near the specific phase of interest.

  Hereinafter, the present invention will be described through embodiments of the invention. However, the following embodiments do not limit the invention according to the scope of claims, and all combinations of features described in the embodiments are not necessarily essential to the solution of the invention.

  FIG. 1 shows an example of a radiation imaging system 100 of this embodiment together with a subject 300. The radiation imaging system 100 includes a radiation image imaging unit 110, an imaging phase identification unit 120, a specific phase timing prediction unit 130, an imaging condition storage unit 140, an imaging timing determination unit 150, an imaging control unit 160, and a subject. Motion detection unit 170, image processing unit 180, optical image capturing unit 190, and image display unit 200.

  The subject 300 may be an organ or part such as a human body with periodic movement, and examples thereof include a heart, lungs, blood vessels, and the like. However, the subject 300 is not limited to a human organ or the like, and is included in the subject 300 as long as it is a living thing, an inanimate object, or any other thing having a periodic movement. Here, the “periodic movement” includes, in addition to a movement having a clear cycle, a movement in which a cycle is lost or a cycle fluctuates in a small number of operations among a large number of cycles. For example, heartbeat movement or breathing movement is not an objection as "periodic movement", but if strictly examined, arrhythmia or stuttering or shortness of breath may occur, and "period missing" or "cycle fluctuation" It becomes a movement including. However, “periodic movement” in this specification includes movements that cause “missing of period” or “cycle fluctuation” such as arrhythmia.

  The radiographic image capturing unit 110 captures a radiographic image of the subject 300. The radiation image imaging unit 110 includes a radiation source 112, a radiation sensor 114, a radiation source control unit 116, and an imaging signal processing unit 118. The radiation image capturing unit 110 exposes the subject 300 with radiation emitted from the radiation source 112 controlled by the radiation source control unit 116, and detects radiation transmitted through the subject 300 with the radiation sensor 114. The detection signal detected by the radiation sensor 114 is processed by the imaging signal processing unit 118 and is provided to the image processing unit 180 or the like as digital data, for example.

  The radiation source 112 generates radiation such as X-rays. When the radiation source 112 is an X-ray source, for example, characteristic X-rays generated by irradiating copper, tungsten, molybdenum, or the like with an electron beam can be used. Alternatively, radiant light (X-rays) emitted by abruptly changing the movement of electrons by a braking voltage or a magnetic field can be used. The radiation source 112 is not limited to the X-ray source, and for example, alpha rays, beta rays, gamma rays, neutron rays, or other radiation can be applied.

  The radiation sensor 114 detects radiation that has passed through the subject 300. Examples of the radiation sensor 114 include a combination of a phosphor that absorbs radiation and emits visible light and an image sensor or line sensor that detects the visible light. The radiation sensor 114 outputs an analog signal corresponding to the detected radiation intensity for each pixel.

  The radiation source control unit 116 controls the radiation source 112 under the control of the imaging control unit 160. When the radiation source 112 is an X-ray source, the radiation source control unit 116 controls the acceleration voltage, electron beam density (tube current), electron braking voltage, applied magnetic field intensity, and the like of the electron beam to be supplied. Control. The radiation source control unit 116 may include a safety device such as a cooling device for the radiation source 112 or a fail-safe interlock.

  The imaging signal processing unit 118 performs AD conversion on the analog output for each pixel from the radiation sensor 114 and converts the analog output into, for example, 14-bit luminance data. The imaging signal processing unit 118 may perform gamma conversion so as to obtain contrast by adjusting the luminance data for each pixel. The imaging signal processing unit 118 provides the luminance data to the image processing unit 180.

  The imaging phase specifying unit 120 specifies the phase of movement of the subject 300 to be imaged of the subject 300 in the movement of the subject 300. Since the subject 300 has a periodic movement, the phase in the period can be defined. For example, a heartbeat phase can be defined in a heartbeat motion that is a heart motion, and a breathing phase can be defined in a breathing motion that is a lung motion. In such a phase of movement of the subject 300, the imaging phase specifying unit 120 specifies a phase to be imaged in a phase that is observed by the observer, that is, a phase of movement of the subject 300.

  The specific phase timing prediction unit 130 predicts the timing at which the phase of movement of the subject 300 becomes the phase specified by the imaging phase specification unit 120. In the following description of the present specification, “timing at which the phase of movement of the subject 300 becomes the phase specified by the imaging phase specifying unit 120” is simply referred to as “specific phase timing”. However, the phrase “specific phase timing” includes “timing at which the phase specified by the imaging phase specifying unit 120 has already arrived” at the present time. That is, the concept of both the future timing that has not yet arrived at the present time and the past timing that has already passed at the present time is included in the “specific phase timing”.

  The specific phase timing prediction unit 130 calculates a period of motion from the motion of the subject 300 detected by the subject motion detection unit 170, and arbitrarily defines a phase reference in the cycle to determine the current phase. If the period and the current phase are known, the arbitrary phase in the period (in the period after the period if the period is maintained) can be calculated as a time difference from the current time, that is, a timing. Therefore, the specific phase timing prediction unit 130 Predicts the specific phase timing from the period and the current phase.

  The specific phase timing prediction unit 130 can detect the movement of the subject 300 from a heartbeat signal such as an electrocardiogram or a respiratory signal such as a respiratory sound, and can predict the specific phase timing. Further, the specific phase timing prediction unit 130 can predict the specific phase timing based on image contents of a plurality of radiographic images already captured by the radiographic image capturing unit 110, for example, image contents indicating the size of the heart or lungs. Furthermore, the specific phase timing prediction unit 130 can predict the specific phase timing based on the image contents of a plurality of optical images already captured by the optical image capturing unit 190.

  The imaging condition storage unit 140 stores conditions that determine the timing at which the subject 300 should be imaged. In the following description of the present specification, “timing for imaging the subject 300” is simply referred to as “imaging timing”. The concept of “imaging timing” may include the concept of “specific phase timing”.

  The imaging timing determination unit 150 determines the timing at which the subject 300 should be imaged, that is, the imaging timing, based on the conditions stored in the imaging condition storage unit 140. The following conditions can be exemplified as conditions stored in the imaging condition storage unit 140, and imaging timings determined based on such conditions are as follows.

  For example, the condition stored in the imaging condition storage unit 140 can be exemplified by a condition in which the imaging timing is determined at a shorter imaging interval as the imaging timing to be determined is closer to the specific phase timing. Based on such conditions, as the imaging timing determined by the imaging timing determination unit 150 is closer to the specific phase timing, the imaging interval becomes shorter.

  For example, the condition stored in the imaging condition storage unit 140 can be exemplified by a condition in which the imaging timing between two specific phase timings is determined by a time interval at which continuous imaging is possible (hereinafter simply referred to as “continuous imaging possible interval”). Based on such conditions, the imaging timing determined by the imaging timing determination unit 150 is the shortest imaging interval even during the specific phase timing.

  For example, when the imaging timing between two specific phase timings is determined as a condition stored by the imaging condition storage unit 140 at a continuous imaging possible interval, if a remaining time shorter than the continuous imaging possible interval occurs, the two specific phase timings are stored. An example of a condition for including the remaining time in the imaging interval in the vicinity of the middle of the image. Based on such a condition, the imaging timing determined by the imaging timing determination unit 150 is the shortest imaging interval except for the intermediate imaging interval even during the specific phase timing, and the imaging timing is reliably determined at the specific phase timing. Enable.

  For example, as a condition stored in the imaging condition storage unit 140, when the time difference between the determined imaging timing and the specific phase timing is less than twice the continuous imaging possible interval, a condition for setting the next imaging timing as the specific phase timing can be exemplified. . Based on such conditions, as the imaging timing determined by the imaging timing determination unit 150, it is possible to reliably determine a timing that matches the specific phase timing.

  For example, as a condition stored in the imaging condition storage unit 140, when the time difference between the imaging timing to be determined and the specific phase timing is equal to or smaller than a predetermined time difference, the imaging timing is determined at the first imaging interval, and the predetermined time difference is determined. When it is large, the condition for determining the imaging timing at the second imaging interval longer than the first imaging interval can be exemplified. Based on such conditions, the imaging timing determined by the imaging timing determination unit 150 becomes a short imaging interval in a time region close to the specific phase timing (a time region equal to or less than a predetermined time difference), and is away from the specific phase timing. The imaging interval becomes long in a certain time region (a time region larger than a predetermined time difference).

  The imaging controller 160 sends the radiographic image of the subject 300 to the radiographic imaging unit 110 at the timing predicted by the specific phase timing prediction unit 130, that is, the specific phase timing, and at the imaging timing determined by the imaging timing determination unit 150, that is, the imaging timing. To image. That is, the imaging control unit 160 ensures the imaging at the specific phase timing that is observed by the observer, and appropriately determines the imaging timing at the imaging timing other than the specific phase timing by the imaging timing determination unit 150, A radiographic image is taken.

  In addition, the imaging control unit 160 causes the radiographic image capturing unit 110 to capture a radiographic image at the first radiation dose at a timing other than the specific phase timing, and at the specific phase timing, the radiographic image at a second radiation dose that is higher than the first radiation dose. The imaging unit 110 is caused to capture a radiation image. Alternatively, the imaging control unit 160 causes the radiographic image capturing unit 110 to capture a radiographic image at a higher dose as the time difference between the timing at which the radiographic image capturing unit 110 attempts to capture the radiographic image and the specific phase timing is shorter. Thereby, the radiographic image in specific phase timing or the timing of the vicinity can be made clear.

  The subject motion detection unit 170 detects the motion of the subject 300. The movement of the subject 300 can be detected by various measurements. For example, heart movement can be detected from a heartbeat signal such as an electrocardiogram, and lung movement can be detected from an expiration signal such as a breathing sound. Further, the movement of the subject 300 can be obtained from a radiographic image, and when the movement of the subject 300 appears in the appearance, it can also be obtained from a visible light image.

  When the subject motion detection unit 170 obtains the motion of the subject 300 from image data such as a radiographic image or a visible light image, a plurality of images obtained by imaging the subject 300 at regular time intervals or at known time intervals. By analyzing the image, the movement of the subject 300 can be digitized. For example, in a plurality of consecutive captured images with known imaging times, a reference point or a point of interest whose relative position from the reference point is known is determined, and the variation of the reference point or the point of interest in each image with respect to time is quantified. The change of the numerical reference point or the point of interest with respect to time can be grasped as a periodic movement of the subject 300.

  The motion of the subject 300 detected by the subject motion detection unit 170 can be provided as a signal or data to the specific phase timing prediction unit 130, and the specific phase timing prediction unit 130 can detect the motion detected by the subject motion detection unit 170. Specific phase timing can be predicted. That is, the specific phase timing prediction unit 130 can predict the specific phase timing from a heartbeat signal such as an electrocardiogram, a respiratory signal such as a respiratory sound, and the like.

  Note that the motion detection method of the subject 300 exemplified as the subject motion detection unit 170 may be combined to form the subject motion detection unit 170. For example, a method of analyzing a plurality of radiographic images to detect the motion of the subject 300 and a method of analyzing a plurality of optical images to detect the motion of the subject 300 may be combined. When the subject 300 is the heart or lungs, the reference point may be shifted according to enlargement or reduction of the heart or the like. In such a case, the movement of the subject 300 can be directly detected from the radiographic image, and the reference point deviation can be corrected by the optical image.

  The image processing unit 180 processes the imaging data acquired from the imaging signal processing unit 118. For example, the image processing unit 180 can analyze a plurality of image data and signal the motion of the subject 300, and provide the signaled motion data to the specific phase timing prediction unit 130. The optical image capturing unit 190 captures the movement of the subject 300 as an optical image. Further, the optical image capturing unit 190 can analyze a plurality of optical images obtained by capturing the motion of the subject 300 to convert the motion of the subject 300 into a signal, and can provide the signaled motion data to the specific phase timing prediction unit 130. . The image display unit 200 displays the radiation image processed by the image processing unit 180.

  FIG. 2 shows a heartbeat signal representing the movement of the heart, which is an example of the subject 300, for two cycles. The heartbeat signal can be acquired as an electrocardiogram, and characteristic signal peaks appear at t1 to t6. P waves having peaks at t1 and t4 are caused by atrial muscle excitation, and QRS waves having peaks at t2 and t5 are caused by ventricular muscle excitation. T waves with peaks at t3 and t6 are due to extinction of ventricular muscle excitability.

  FIG. 3 shows a respiratory signal representing the movement of the lung, which is an example of the subject 300, for a plurality of cycles. Peaks at the time of reduction appear at t10, t12, t14, and t16, and peaks at the time of expansion appear at t11, t13, and t15.

  It is possible to easily determine the period in each signal representing the movement of the subject 300 having periodicity. For example, in FIG. 2, the section from t1 to t4 is one cycle, and in FIG. 3, the section from t10 to t12 is one cycle. Since each operation of the subject 300 appears within one period, the observer can designate a radiation image to be observed by designating a phase within one period. For example, if attention is paid to ventricular muscle excitement, a phase corresponding to t2 in FIG. 2 is designated. These designated phases are specified by the imaging phase specifying unit 120. For example, the imaging phase specifying unit 120 receives an input of a phase from an observer, and specifies the phase of movement of the subject 300 to be imaged.

  FIG. 4 shows an overall flow in the radiation imaging system 100 of the present embodiment. First, the imaging phase is specified by the imaging phase specifying unit 120 (S400). The specified phase is, for example, a phase input to the imaging phase specifying unit 120 by the observer, and is a phase of movement of the subject 300 that the observer is paying attention to.

  Next, the movement of the subject is detected by the movement detection unit 170 of the subject (S402). After that, the specific phase timing is predicted by the specific phase timing prediction unit 130 (S404). Next, an imaging timing is determined by the imaging timing determination unit 150 (S406), and a radiation dose at the time of imaging for each imaging timing is determined (S408). For the determination of the imaging timing, a sequential determination method for determining the latest imaging timing for each shooting and a plurality of scheduled methods for determining a plurality of shooting timings such as all shooting timings within one cycle are selected. it can.

  Next, the imaging controller 160 is caused to capture a radiation image at the determined imaging timing and radiation dose (S410). If there are a plurality of determined imaging timings, that is, a plurality of imaging timings determined by a plurality of scheduled methods, it is determined whether imaging at all imaging timings has been completed (S412). If there is a scheduled imaging timing that has not yet been captured, the process returns to step S410 to repeat imaging. If it is determined that imaging at all scheduled imaging timings has been completed, it is determined whether an imaging end signal has been received. (S414). The imaging end signal may be a signal input by an observer when imaging is ended. When the imaging end signal is received, imaging is terminated.

  If it is determined in step S414 that the imaging end signal has not yet been received, it is determined whether to re-predict the specific phase timing (S416). For example, when one or more cycles elapse after predicting the specific phase timing, the motion cycle of the subject 300 may be fluctuating. In such a case, it can be selected to re-predict the specific phase timing. When the specific phase timing is re-predicted, the process returns to step S402, and when the specific phase timing is not re-predicted, the process returns to step S406 and the process is continued.

  FIG. 5 shows an example of an imaging timing determination flow. First, two adjacent specific phase timings are extracted (S502). Next, an imaging timing determination mode is selected (S504). Here, two modes are illustrated as imaging timing determination modes. These modes correspond to conditions stored in the imaging condition storage unit 140, for example.

  When the mode proceeding to step S506 is selected from the two modes, the interval between the two specific phase timings is divided at the continuous imaging possible interval (S506). Next, it is determined whether or not there is a remaining section that does not satisfy the continuous imaging interval (S508). If it is determined that there is a remaining section, the remaining section is included in the section including the midpoint of the two specific phase timings. Add (S510) and go to step S512. If it is determined that there is no remaining section, the process proceeds to step S512 without passing through step S510. In step S512, the boundary of each section is determined as the imaging timing (S512), and the process returns to the overall flow.

  When the mode proceeding to step S514 is selected from the two modes, the interval between the two specific phase timings is divided into a plurality of sections (S514). Next, a shorter imaging interval is assigned to each divided section as the time difference to the specific phase timing is shorter (S516). Then, starting from the specific phase timing, adjacent imaging timings are sequentially determined according to the imaging interval assigned to the section including the timing (S518). Then return to the overall flow.

  FIG. 6 shows an example of a radiation dose determination flow. First, a radiation dose determination mode is selected (S520). When the mode to proceed to step S522 is selected from the two modes, it is determined whether the imaging timing to be determined is a specific phase timing (S522). If it is determined that the specific phase timing is reached, the radiation dose at the imaging timing is set to a high dose (S524). If it is determined that it is not the specific phase timing, the radiation dose at the imaging timing is set to a low dose (S526).

  If the mode proceeding to step S528 is selected from the two modes, it is determined whether the time difference between the imaging timing to be determined and the specific phase timing is shorter than a predetermined value (S528). If it is determined that it is shorter than the predetermined value, the radiation dose at the imaging timing is set to a high dose (S524). If it is determined that it is not shorter than the predetermined value, the radiation dose at the imaging timing is set to a low dose (S526). After setting the dose, return to the overall flow.

  FIG. 7 shows an example of the imaging timing. This example shows an example of imaging timing determined when the mode that proceeds to step S514 is selected from the two modes in step S504 of FIG.

  The interval between the two specific phase timings S1 and S2 is divided into sections R1 to R5, and a shorter imaging interval is assigned as it is closer to the specific phase timings S1 and S2. That is, the imaging interval ta is assigned in the sections R1 and R5, the imaging interval tb is assigned in the sections R2 and R4, and the imaging interval tc is assigned in the section R3. As for the relationship between the imaging intervals, ta is the shortest, tc is the longest, and tb may be an intermediate length between them. The imaging interval ta is the same as or longer than the continuous imaging possible interval tfm.

  When the imaging timing is determined according to the imaging interval assigned to each section, the imaging intervals in the sections R1 and R5 are short, the imaging intervals in the sections R2 and R4 are intermediate, and the imaging interval in the section R3 is long. The As a result, as shown in the figure, the imaging interval between the imaging timings is short near the specific phase timings S1 and S2, and the imaging interval between the imaging timings becomes longer as the distance from the specific phase timings S1 and S2 increases. By determining the imaging timing in this manner, imaging is performed at a high frame rate in the specific phase timings S1 and S2 and the vicinity thereof, and the motion of the subject 300 focused by the observer can be displayed in detail.

  FIG. 8 shows another example of the imaging timing. This example shows an example of imaging timing determined when the mode that proceeds to step S506 is selected from the two modes in step S504 of FIG. The interval between the two specific phase timings S1 and S2 is divided by the imaging interval ta (interval for continuous imaging tfm), and the imaging interval tb including the intermediate point between the specific phase timings S1 and S2 was not divided and divided. Extra time is added. That is, the imaging interval tb is longer than the imaging interval ta and is located at the midpoint between the specific phase timings S1 and S2.

  When the imaging timing is determined in this manner, imaging is surely performed at the specific phase timings S1 and S2. Therefore, imaging is performed at a high frame rate in the specific phase timings S1 and S2 and the vicinity thereof, and the movement of the subject 300 that is observed by the observer can be displayed in detail.

  FIG. 9 shows another example of an imaging timing determination flow. In this example, an example in which imaging timing is sequentially determined for each imaging is shown. First, an imaging timing to be determined next at a previous imaging interval is provisionally determined (S530). Next, it is determined whether the interval between the temporarily determined imaging timing and the specific phase timing is equal to or smaller than a predetermined time difference (S532). When it is determined that the difference is equal to or less than the predetermined time difference, a short interval is assigned as the imaging interval (S534), and when it is determined that it is not equal to or less than the predetermined time difference, a long interval is assigned as the imaging interval (S536).

  Next, the next imaging timing is determined according to the allocated imaging interval (S538). Further, it is determined whether the interval between the determined imaging timing and the specific phase timing is shorter than twice the continuous imaging possible interval (S540). If it is determined that the interval is shorter than twice the continuous imaging interval, the next imaging timing after the determined imaging timing is set as the specific phase timing (S542), and if it is determined that the interval is not shorter than twice the continuous imaging interval, step S542 Return to the overall flow without going through.

  FIG. 10 shows an example of imaging timing. This example shows an example of the imaging timing determined according to the imaging timing determination flow shown in FIG. In a time region that is separated from the specific phase timing S by a predetermined time tth or more, the imaging interval between the imaging timings is tc, which is long.

  On the other hand, in the time region where the time from the specific phase timing S is smaller than the predetermined time tth, the imaging interval between the imaging timings is ta and is short. And in the imaging timing just before the specific phase timing S, the imaging interval with the specific phase timing S is tb. The imaging interval tb is shorter than twice the imaging interval ta, and ensures imaging at a specific phase timing S when imaging timing is sequentially determined.

  When the imaging timing is determined in this way, imaging is surely performed at the specific phase timing S. Therefore, imaging is performed at the specific phase timing S noted by the observer, and the state at the specific phase timing S of the subject 300 noted by the observer can be displayed as an image.

  As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. It will be apparent to those skilled in the art that various modifications or improvements can be added to the above-described embodiment. It is apparent from the scope of the claims that the embodiments added with such changes or improvements can be included in the technical scope of the present invention. For example, the radiation imaging system described in the above embodiment can be configured by an electronic information processing apparatus such as a personal computer or a network-connected server.

  FIG. 11 shows an example of a hardware configuration when the radiation imaging system of the present application is configured by an electronic information processing apparatus such as a personal computer. The radiation imaging system includes a CPU peripheral part, an input / output part, and a legacy input / output part. The CPU peripheral section includes a CPU 1505, a RAM 1520, a graphic controller 1575, and a display device 1580 that are connected to each other by a host controller 1582. The input / output unit includes a communication interface 1530, a hard disk drive 1540, and a CD-ROM drive 1560 that are connected to the host controller 1582 by the input / output controller 1584. The legacy input / output unit includes a ROM 1510, a flexible disk drive 1550, and an input / output chip 1570 connected to the input / output controller 1584.

  The host controller 1582 connects the RAM 1520, the CPU 1505 that accesses the RAM 1520 at a high transfer rate, and the graphic controller 1575. The CPU 1505 operates based on programs stored in the ROM 1510 and the RAM 1520 to control each unit. The graphic controller 1575 acquires image data generated by the CPU 1505 or the like on a frame buffer provided in the RAM 1520 and displays the image data on the display device 1580. Alternatively, the graphic controller 1575 may include a frame buffer that stores image data generated by the CPU 1505 or the like.

  The input / output controller 1584 connects the host controller 1582 to the hard disk drive 1540, the communication interface 1530, and the CD-ROM drive 1560, which are relatively high-speed input / output devices. The hard disk drive 1540 stores programs and data used by the CPU 1505. The communication interface 1530 is connected to the network communication device 1598 to transmit / receive programs or data. The CD-ROM drive 1560 reads a program or data from the CD-ROM 1595 and provides it to the hard disk drive 1540 and the communication interface 1530 via the RAM 1520.

  The input / output controller 1584 is connected to the ROM 1510, the flexible disk drive 1550, and the relatively low-speed input / output device of the input / output chip 1570. The ROM 1510 stores a boot program that is executed when the radiation imaging system is started up, a program that depends on the hardware of the radiation imaging system, and the like. The flexible disk drive 1550 reads a program or data from the flexible disk 1590 and provides it to the hard disk drive 1540 and the communication interface 1530 via the RAM 1520. The input / output chip 1570 connects various input / output devices via the flexible disk drive 1550 or a parallel port, serial port, keyboard port, mouse port, and the like.

  A program executed by the CPU 1505 is stored in a recording medium such as the flexible disk 1590, the CD-ROM 1595, or an IC card and provided by the user. The program stored in the recording medium may be compressed or uncompressed. The program is installed in the hard disk drive 1540 from the recording medium, read into the RAM 1520, and executed by the CPU 1505. The program executed by the CPU 1505 is caused to function as the imaging control unit 160 described with reference to FIGS.

  The program shown above may be stored in an external storage medium. As the storage medium, in addition to the flexible disk 1590 and the CD-ROM 1595, an optical recording medium such as a DVD or PD, a magneto-optical recording medium such as an MD, a tape medium, a semiconductor memory such as an IC card, or the like can be used. Further, a storage device such as a hard disk or RAM provided in a server system connected to a dedicated communication network or the Internet may be used as a recording medium to provide a radiation imaging system as a program via the network.

  The present invention relates to an imaging timing determination technique that can be used in a radiation imaging system. Therefore, the present invention can be used in industries related to radiation imaging systems and industries using the technology.

An example of the radiation imaging system 100 of the present embodiment is shown together with a subject 300. A heartbeat signal representing the movement of the heart, which is an example of the subject 300, is shown for two cycles. A respiratory signal representing the movement of the lung, which is an example of the subject 300, is shown for a plurality of cycles. The whole flow in the radiation imaging system 100 of this embodiment is shown. An example of an imaging timing determination flow is shown. An example of the determination flow of a radiation dose is shown. An example of imaging timing is shown. The other example of an imaging timing is shown. The other example of the determination flow of an imaging timing is shown. An example of imaging timing is shown. An example of a hardware configuration when the radiation imaging system of the present application is configured by an electronic information processing apparatus such as a personal computer is shown.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Radiation imaging system 110 Radiation image imaging part 112 Radiation source 114 Radiation sensor 116 Radiation source control part 118 Imaging signal processing part 120 Imaging phase specific | specification part 130 Specific phase timing estimation part 140 Imaging condition storage part 150 Imaging timing determination part 160 Imaging control part 170 Motion Detection Unit 180 Image Processing Unit 190 Optical Image Imaging Unit 200 Image Display Unit 300 Subject 1505 CPU
1510 ROM
1520 RAM
1530 Communication interface 1540 Hard disk drive 1550 Flexible disk drive 1560 CD-ROM drive 1570 Input / output chip 1575 Graphic controller 1580 Display device 1582 Host controller 1584 Input / output controller 1590 Flexible disk 1595 CD-ROM
1598 Network communication device

Claims (12)

A radiographic image capturing unit that captures a radiographic image of a subject with periodic movement;
An imaging phase specifying unit for specifying a phase of movement of the subject to be imaged of the subject in the movement of the subject;
A specific phase timing prediction unit that predicts a timing at which the phase of movement of the subject is the phase specified in the imaging phase specification unit;
An imaging condition storage unit that stores conditions for determining the timing at which the subject should be imaged;
An imaging timing determination unit that determines a timing at which the subject should be imaged based on the conditions stored in the imaging condition storage unit;
An imaging control unit that causes the radiographic image capturing unit to capture a radiographic image of the subject at a timing predicted by the specific phase timing prediction unit and a timing determined by the imaging timing determination unit;
A radiation imaging system comprising:   The imaging timing determination unit captures an image of the subject by shortening a timing interval at which the subject should be imaged as the time difference between the timing to be determined and the timing predicted by the specific phase timing prediction unit is shorter. The radiation imaging system according to claim 1, wherein a timing to be determined is determined.   The imaging timing determination unit images the subject by dividing the interval between the two timings predicted by the specific phase timing prediction unit at an imaging possible interval at which the radiographic image capturing unit can continuously capture radiographic images. The radiation imaging system according to claim 1, wherein a timing to be determined is determined.   When the interval between the two timings predicted by the specific phase timing prediction unit is not an integer multiple of the imageable interval, the imaging timing determination unit is near the midpoint between the two timings predicted by the specific phase timing prediction unit. The radiation imaging system according to claim 3, wherein a timing interval at which the subject is to be imaged is lengthened, and a timing interval at which the other subject is to be imaged is set to the imaging possible interval.   In the imaging timing determination unit, the interval between the determined predetermined timing and the timing predicted by the specific phase timing prediction unit is greater than twice the imaging possible interval at which the radiographic image capturing unit can continuously capture radiographic images. 2. The radiation imaging system according to claim 1, wherein when the time is short, the timing predicted by the specific phase timing prediction unit is a timing at which the subject is to be imaged next to the predetermined timing.   When the time difference between the timing to be determined and the timing predicted by the specific phase timing prediction unit is equal to or less than a predetermined time difference, the imaging timing determination unit determines the timing at which the subject should be imaged as the first imaging 2. The radiation imaging system according to claim 1, wherein the radiation imaging system determines at a second imaging interval that is longer than the first imaging interval when the subject is to be imaged when the interval is larger than the predetermined time difference.   The imaging control unit causes the radiographic image capturing unit to capture a radiographic image with a first radiation dose at a timing other than the timing predicted by the specific phase timing prediction unit, and at the timing predicted by the specific phase timing prediction unit. The radiation imaging system according to claim 1, wherein the radiation image capturing unit captures a radiation image with a second radiation dose that is higher than one radiation dose.   The imaging control unit causes the radiation image capturing unit to emit radiation at a higher dose as the time difference between the timing at which the radiation image capturing unit attempts to capture the radiation image and the timing predicted by the specific phase timing prediction unit is shorter. The radiation imaging system according to claim 1, wherein an image is captured.   The specific phase timing prediction unit predicts the timing at which the phase of the movement of the subject becomes the phase specified by the imaging phase specifying unit based on the image contents of a plurality of radiographic images already captured by the radiographic image capturing unit. The radiation imaging system according to claim 1. An optical image capturing unit that captures an optical image of the subject;
The specific phase timing prediction unit predicts a timing at which the phase of movement of the subject becomes a phase specified by the imaging phase specification unit based on image contents of a plurality of optical images already captured by the optical image capturing unit. The radiation imaging system according to claim 1. An imaging phase identifying step for identifying a phase of movement of the subject to be imaged of the subject in motion of the subject with periodic motion;
A specific phase timing prediction step for predicting a timing at which the phase of the movement of the subject is the phase specified in the imaging phase specification step;
An imaging condition storage step for storing a condition for determining a timing at which the subject should be imaged;
An imaging timing determination step for determining a timing at which the subject should be imaged based on the conditions stored in the imaging condition storage step;
An imaging control step of capturing a radiographic image of the subject at the timing predicted in the specific phase timing prediction step and the timing determined in the imaging timing determination step;
A method comprising: A program for a radiation imaging system that captures a radiation image of a subject, the radiation imaging system comprising:
A radiographic image capturing unit that captures a radiographic image of the subject with periodic movement;
An imaging phase specifying unit for specifying a phase of movement of the subject to be imaged of the subject in the movement of the subject;
A specific phase timing prediction unit that predicts a timing at which the phase of movement of the subject is the phase specified in the imaging phase specification unit;
An imaging condition storage unit for storing conditions for determining the timing at which the subject should be imaged;
An imaging timing determination unit that determines a timing at which the subject should be imaged based on the conditions stored in the imaging condition storage unit; and
An imaging control unit that causes the radiographic imaging unit to capture a radiographic image of the subject at a timing predicted by the specific phase timing prediction unit and a timing determined by the imaging timing determination unit;
Program to function as.

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