Imaging control device, imaging control method, and radiation imaging system

Abstract

To provide an imaging control device and a radiation imaging system capable of performing pre-exposure under appropriate imaging conditions.SOLUTION: An imaging control device includes: an acquisition unit for acquiring first imaging conditions set as imaging conditions for pre-exposure performed before main exposure for performing radiation exposure relative to a subject; and a control unit for performing control based on compatibility between second imaging conditions input as the imaging conditions for the subject and the first imaging conditions acquired by the acquisition unit.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to an imaging control device and a radiation imaging system. [Background technology]

[0002] Among radiation imaging systems, those having an automatic exposure control function that performs a main exposure and a pre-exposure before the main exposure when capturing a radiation image are known. The automatic exposure control function performs a pre-exposure at a lower dose than the main exposure, and determines imaging conditions such as the dose for the main exposure based on the obtained pre-exposure image and supplementary information associated with the pre-exposure image (e.g., the irradiation time for the pre-exposure).

[0003] For example, Patent Document 1 discloses a configuration for determining whether the pre-exposure image has been properly captured based on image analysis of the pre-exposure image. If the result of the image analysis is appropriate, the main exposure continues, and if the result of the image analysis is inappropriate, the main exposure stops.

[0004] Furthermore, Patent Document 2 discloses a configuration in which it is determined whether the dose per unit time during exposure under automatic exposure control is equal to or greater than a specified value, and if it is equal to or greater than the specified value, a warning is issued. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2019-126709 [Patent Document 2] Japanese Patent Application Laid-Open No. 2008-178674 Summary of the Invention [Problem to be solved by the invention]

[0006] However, when deriving the exposure dose from a pre-exposure image, if pre-exposure imaging is performed under inappropriate imaging conditions, it may not be possible to capture an appropriate pre-exposure image, and ultimately it may not be possible to perform the main exposure imaging appropriately.

[0007] In the case of the configuration described in Patent Document 1, whether or not the pre-exposure image was properly captured is determined after the image is captured, so there is a possibility that pre-exposure will be performed unnecessarily. Therefore, there is room for improvement in the configuration for properly capturing the main exposure image.

[0008] Furthermore, when the configuration described in Patent Document 2 is applied to automatic exposure control for performing pre-exposure and main exposure, the cumulative dose of pre-exposure imaging cannot be properly determined by determining only the dose per unit time. For example, even if the dose per unit time is large, if the irradiation time is short, the cumulative dose may be small, resulting in a dose suitable for pre-exposure. Therefore, it is not possible to determine whether the imaging conditions for pre-exposure are appropriate.

[0009] An object of the present invention is to provide an imaging control device and a radiation imaging system that are capable of performing pre-exposure under appropriate imaging conditions. [Means for solving the problem]

[0010] The imaging control device according to the present invention comprises: an imaging condition acquisition unit that acquires first imaging conditions as imaging conditions for pre-exposure that is performed before main exposure that exposes a subject to radiation; an inspection condition acquisition unit that acquires inspection conditions for the subject; The second photographing condition input as the photographing condition of the subject is ,before a control unit that sets the range of the first photographing condition acquired by the photographing condition acquisition unit; Equipped with 、 the imaging condition acquisition unit acquires the first imaging condition based on the inspection condition acquired by the inspection condition acquisition unit; The first imaging condition is an imaging condition that enables appropriate imaging in the pre-exposure. .

[0011] The radiation imaging system according to the present invention comprises: a radiation irradiation device that irradiates radiation; a radiation imaging device that generates image data of an exposed image by receiving the radiation; The above-mentioned imaging control device; Equipped with. [Effects of the Invention]

[0012] According to the present invention, pre-exposure can be performed under appropriate imaging conditions. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a block diagram showing a configuration of a radiation imaging system according to an embodiment of the present invention; [Figure 2] FIG. 2 is a block diagram showing a specific configuration of the radiation imaging apparatus. [Figure 3] FIG. 2 is a block diagram showing a specific configuration of a console. [Figure 4] FIG. 10 is a diagram showing an example of a table in which a plurality of first imaging conditions are described. [Figure 5] FIG. 10 is a diagram showing an example of display in the range of a first shooting condition. [Figure 6] 6 is a diagram showing an example of a display on a button shown in FIG. 5. FIG. [Figure 7] 6 is a diagram showing an example of a display on a button shown in FIG. 5. FIG. [Figure 8] 10 is a ladder chart showing the operation of the radiation imaging system during imaging. [Figure 9] FIG. 10 is a diagram showing an example of a table in which a plurality of first imaging conditions are described. [Figure 10] FIG. 10 is a diagram showing an example of a table in which a plurality of first imaging conditions are described. [Figure 11] FIG. 10 is a diagram showing an example of a table in which a plurality of first imaging conditions are described. [Figure 12] FIG. 10 is a diagram showing an example of a table in which a plurality of first imaging conditions are described. [Figure 13]FIG. 10 is a diagram showing an example in which the irradiation field boundary and the irradiation field are superimposed on the imaging table. [Figure 14] FIG. 10 is a diagram showing an example in which the irradiation field boundary and the irradiation field are superimposed on the imaging table. DETAILED DESCRIPTION OF THE INVENTION

[0014] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings. Fig. 1 is a block diagram showing the configuration of a radiation imaging system 100 according to an embodiment of the present invention.

[0015] 1, a radiation imaging system 100 according to this embodiment includes a radiation irradiation device 1, a radiation imaging device 2, and a console 3. The radiation imaging system 100 is also connectable to a Radiology Information System (RIS), a Picture Archiving and Communication System (PACS), and the like, which are not shown.

[0016] The radiation irradiation device 1 is connected to the console 3 so as to be able to communicate with it via wire or wirelessly. The radiation irradiation device 1 is also configured to include a generator 11, an exposure switch 12, and a radiation source 13.

[0017] The generator 11 is configured to be able to apply a voltage to the radiation source 13 according to the preset radiation exposure conditions (tube voltage, tube current, irradiation time, tube current time product (mAs value), etc.) based on the operation of the exposure switch 12.

[0018] The radiation source 13 (tube) has a rotating anode, a filament, etc. (not shown). When a voltage is applied from the generator 11, the filament irradiates the rotating anode with an electron beam according to the applied voltage, and the rotating anode generates radiation X (X-rays, etc.) at a dose according to the intensity of the electron beam.

[0019] 1 illustrates an example in which the generator 11, exposure switch 12, and radiation source 13 are separate, but they may also be configured as an integrated unit. Also, while FIG. 1 illustrates an example in which the exposure switch 12 is connected to the generator 11, the exposure switch 12 may be provided in another device. Furthermore, the radiation irradiation device 1 may be installed in an imaging room, or may be configured to be mobile by being incorporated into a medical cart or the like.

[0020] The radiation imaging device 2 is connected to the console 3 via wire or wireless communication. The radiation imaging device 2 is configured to be able to generate image data of an exposure image of a subject by receiving radiation X from the radiation irradiator 1 via the subject.

[0021] As shown in FIG. 2, the radiation imaging apparatus 2 includes an imaging control unit 21, a radiation detection unit 22, a readout unit 23, a communication unit 24, a storage unit 25, and a bus 26 connecting the respective units.

[0022] The imaging control unit 21 is configured with a CPU (Central Processing Unit), RAM (Random Access Memory), etc. Upon receiving a control signal or the like from an external device such as the console 3, the CPU of the imaging control unit 21 reads out various programs stored in the storage unit 25, loads them into the RAM, executes various processes in accordance with the loaded programs, and centrally controls the operations of each unit in the radiation imaging apparatus 2.

[0023] The radiation detection unit 22 is configured by a substrate on which pixels, each having a radiation detection element that receives radiation X and generates a charge according to the dose, and a switch element, are arranged two-dimensionally (in a matrix).

[0024] The readout unit 23 is configured to be able to read out the amount of charge emitted from each pixel as a signal value and generate image data from a plurality of signal values.

[0025] The communication unit 24 is configured to be able to receive various control signals and various data from external devices, and to transmit various control signals and generated image data to external devices.

[0026] The storage unit 25 is configured with a non-volatile semiconductor memory, a hard disk, etc., and stores various programs executed by the imaging control unit 21 and parameters required for executing processing by the programs. The storage unit 25 is also capable of storing image data generated by the readout unit 23 and various data processed by the imaging control unit 21.

[0027] When the radiation imaging device 2 configured in this manner is exposed to radiation with the imaging control unit 21 turning off each switch element of the radiation detection unit 22, each pixel accumulates a charge corresponding to the radiation dose. When the imaging control unit 21 turns on each switch element to release charge from each pixel, the readout unit 23 converts each charge amount into a signal value and reads it out as image data.

[0028] The radiographic imaging device 2 may have a built-in scintillator or the like, which converts the irradiated radiation X into light of another wavelength such as visible light and generates charges according to the converted light, or may generate charges directly from the radiation X without using a scintillator or the like. The radiographic imaging device 2 may be a dedicated device integrated with an imaging table, or a portable device.

[0029] The console 3 is configured from a PC, a mobile terminal, or a dedicated device, and is connected to the radiation irradiating device 1 and the radiation imaging device 2, etc., so that they can communicate with each other via wired or wireless communication. The console 3 is capable of setting the imaging conditions and the region to be imaged for the radiation irradiating device 1 and the radiation imaging device 2, based on imaging orders from an external device (RIS, etc.) and operations by the user. The console 3 corresponds to the "imaging control device" of the present invention.

[0030] As shown in FIG. 3, the console 3 comprises a control unit 31, a communication unit 32, a storage unit 33, a display unit 34, an operation unit 35, and a bus 36 connecting each unit.

[0031] The control unit 31 is composed of a CPU, RAM, etc. The CPU of the control unit 31 reads out various programs stored in the storage unit 33 in response to operations on the operation unit 35, loads them into the RAM, executes various processes in accordance with the loaded programs, and centrally controls the operations of each unit of the console 3.

[0032] The communication unit 32 includes a LAN adapter, a modem, a TA (Terminal Adapter), etc., and controls data transmission and reception between each device connected to the communication network.

[0033] The storage unit 33 is configured with a non-volatile semiconductor memory, a hard disk, etc., and stores various programs executed by the control unit 31 and parameters required for executing processes by the programs, etc. The storage unit 33 is also capable of storing image data received from the radiation imaging device 2 and image data processed by the control unit 31 in association with accompanying information.

[0034] The display unit 34 is composed of a monitor such as an LCD (Liquid Crystal Display) or CRT (Cathode Ray Tube), and displays input instructions and data from the operation unit 35 according to instructions of a display signal input from the control unit 31.

[0035] The operation unit 35 is configured with a keyboard having cursor keys, numeric input keys, various function keys, etc., and a pointing device such as a mouse, and outputs instruction signals input by operating the keyboard or the mouse to the control unit 31. The operation unit 35 may also be provided with a touch panel on the display screen of the display unit 34, and in this case, outputs instruction signals input via the touch panel to the control unit 31.

[0036] Next, we will explain the imaging control of the radiation imaging device 2 by the control unit 31. The control unit 31 performs automatic exposure control to determine the imaging conditions for performing main exposure based on the pre-exposure image obtained by pre-exposure and the accompanying information linked to the pre-exposure image. Pre-exposure is performed before main exposure, at a lower dose than main exposure.

[0037] The control unit 31 acquires the first imaging conditions for pre-exposure based on the examination conditions for the subject and the second imaging conditions set by the user. The control unit 31 corresponds to the "acquisition unit" of the present invention.

[0038] The examination conditions for the subject include conditions such as the imaging region of the subject (chest, abdomen, lumbar spine, etc.) and imaging direction (front, back, side, oblique, etc.). The second imaging conditions set by the user include conditions related to the cumulative dose, such as the tube voltage (kV) and tube current time product (mAs) used for pre-exposure. The tube current time product may also be a combination of the tube current and the irradiation time. The imaging conditions, such as the first imaging conditions for pre-exposure, include conditions related to the cumulative dose range, such as the tube voltage (kV) and tube current time product (mAs) used for pre-exposure. The tube current time product may also be a combination of the tube current and the irradiation time.

[0039] The first imaging conditions in the pre-exposure are imaging conditions that enable appropriate imaging in the pre-exposure, and are set for each examination condition of the subject. A table in which a plurality of first imaging conditions associated with each examination condition of the subject is stored is stored in the storage unit 33. For example, Fig. 4 illustrates a table in which the range of tube voltage and the upper limit value of the tube current time product associated with the imaging part and imaging direction are listed.

[0040] The control unit 31 selects a first imaging condition corresponding to the examination condition of the subject from among a plurality of first imaging conditions, with reference to the table in the storage unit 33. For example, when the user inputs chest, front, tube voltage 120 kV, and tube current time product 15 mAs, the control unit 31 acquires the first imaging condition No. 2 from the table shown in Fig. 4, which corresponds to chest, front, and a tube voltage range of 100 kV or more.

[0041] Then, the control unit 31 performs control based on the compatibility between the second photographing conditions input as photographing conditions of the subject and the acquired first photographing conditions. That is, the control unit 31 performs control to support the user so that the second photographing conditions of the subject set by the user fall within the range of the first photographing conditions. Specifically, the control unit 31 compares the first photographing conditions with the second photographing conditions and determines whether the second photographing conditions fall within the range of the first photographing conditions.

[0042] In the above case, the tube current time product input by the user is 15 mAs, while the upper limit of the tube current time product is 10 mAs under the first imaging condition No. 2. Therefore, the control unit 31 determines that the second imaging condition is not within the range of the first imaging condition.

[0043] If the second imaging condition is not within the range of the first imaging condition, the control unit 31 prohibits the radiation imaging device 2 from performing exposure and generating an exposure image during the exposure, and outputs a warning command to the user. The warning command may be, for example, a command related to an operation of the device that affects the user's visual sense, such as a command displayed on the display unit 34, or a command related to an operation of the device that affects the user's tactile sense, such as a command applied to the operation unit 35 by vibration, etc.

[0044] This makes it possible to make the user aware that the second imaging condition is not within the range of the first imaging condition, thereby guiding the user so that the second imaging condition set by the user falls within the range of the first imaging condition for pre-exposure, and ultimately enabling pre-exposure to be performed under optimal conditions.

[0045] An example of a device operation command that affects the user's visual sense is a command to change the color of the light on the hand switch used by the user to a warning color. An example of a device operation command that affects the user's tactile sense is a command to provide a vibration function on the hand switch to activate the vibration when a warning is issued or to change the vibration pattern. When pressing the hand switch, users often focus their attention on whether the subject is in an appropriate state for photography. Therefore, notifying the user via the hand switch, which is in the user's hand, allows the user to know whether or not a notification has been received with less eye movement than if the display unit 34 alone were used, thereby improving operability. Alternatively, the user may be notified via both the display unit 34 and the hand switch. For example, the hand switch may simply notify the user that the subject is out of range, and the display unit 34 may also notify the user with more detailed information than the hand switch, as described below. This reduces the user's eye movement and allows them to accurately understand the cause of the abnormality and the appropriate action, further improving operability.

[0046] In addition to the warning command, the control unit 31 may also notify the result of the determination as to whether the second shooting conditions are within the range of the first shooting conditions, such as by issuing a command to display in text or the like that the second shooting conditions are outside the range of the first shooting conditions, or by issuing a command to communicate in voice or the like that the second shooting conditions are outside the range of the first shooting conditions.

[0047] Furthermore, the control unit 31 may notify the user of the acquired range of the first imaging condition. Specifically, the control unit 31 may display the range of the first imaging condition on the display unit 34. For example, Fig. 5 shows an example in which the range of the tube voltage, the range of the tube current, and the range of the irradiation time are displayed on the display unit 34.

[0048] In this example, the position of the arrow indicates the input value for the second shooting condition, and a dot is shown outside the range of the first shooting condition. In this example, a button B1 for increasing the input value and a button B2 for decreasing the input value are displayed.

[0049] By doing so, the user can easily determine whether the input value of the second photographing condition is within the range of the first photographing condition.

[0050] In addition, the buttons B1 and B2 for increasing and decreasing the input value may also be displayed so that the user can determine whether the second shooting conditions fall within the range of the first shooting conditions after pressing the buttons B1 and B2.

[0051] For example, if pressing a button any further would cause the second imaging condition to fall outside the range of the first imaging condition, a dot may be displayed on the button. Fig. 6 shows a display example in which the user can determine that the second imaging condition falls outside the range of the first imaging condition by pressing button B1 for the input value of the irradiation time to increase the input value. Note that the example shown in Fig. 6 may be the example shown in Fig. 5 to which buttons B1 and B2 according to the example shown in Fig. 6 are applied, or an example in which the range of the tube voltage in Fig. 5, etc., is not displayed may be used.

[0052] Furthermore, when the second photographing condition is outside the range of the first photographing condition, a display may be displayed that allows the user to determine that the second photographing condition will approach the range of the first photographing condition by pressing a button.

[0053] For example, Fig. 7 shows a display example in which the user can determine that the second imaging condition approaches the range of the first imaging condition by pressing button B2 for the input value of the irradiation time to decrease the input value. A hatch is displayed on button B2. Note that the example shown in Fig. 7 may be the example shown in Fig. 5 to which buttons B1 and B2 according to the example shown in Fig. 7 are applied, or an example in which the range of the tube voltage in Fig. 5 is not displayed may be used.

[0054] The number of times the button must be pressed until the second photographing condition falls within the range of the first photographing condition may also be displayed. For example, if pressing the button three times brings the second photographing condition into the range of the first photographing condition, the number "3" may be displayed near the button. By indicating the direction in which the second photographing condition becomes appropriate or inappropriate in this way, the user can input appropriate second photographing conditions with fewer operations. This also prevents the user from inputting inappropriate second photographing conditions.

[0055] In the case of control in which only main exposure is performed without performing pre-exposure, imaging conditions that are different from the first imaging conditions in pre-exposure are used.

[0056] Next, a description will be given of the operation of the radiation imaging system 100. Fig. 8 is a ladder chart showing the operation of the radiation imaging system 100 during imaging.

[0057] The console 3 acquires the examination conditions and the second imaging conditions of the subject (step S101). The console 3 acquires the first imaging conditions from the storage unit 33 based on the acquired examination conditions and the second imaging conditions, and displays them on the display unit 34 (step S102).

[0058] The console 3 compares the first and second photographing conditions and determines whether the second photographing conditions are within the range of the first photographing conditions (step S103). If the determination result shows that the second photographing conditions are not within the range of the first photographing conditions (step S103, NO), the process returns to step S101. At this time, the console 3 may output a warning to the user.

[0059] On the other hand, if the second imaging conditions are within the range of the first imaging conditions (YES in step S103), the console 3 outputs the imaging conditions for pre-exposure to the radiation irradiating apparatus 1 and the radiation imaging apparatus 2 (step S104).

[0060] When the pre-exposure imaging conditions are input, the radiation irradiator 1 compares the pre-exposure imaging conditions with the range of the fifth imaging conditions stored in the radiation irradiator 1. If the pre-exposure imaging conditions are within the range of the fifth imaging conditions, the radiation irradiator 1 sets the pre-exposure imaging conditions and prepares for pre-exposure (Step A1). Generally, the fifth imaging condition is the narrower of the tube voltage range, tube current range, and tube current-time product range supported by the generator 11 of the radiation irradiator 1 and the tube voltage range, tube current range, and tube current-time product range supported by the radiation source 13. For example, if the tube voltage range of the generator 11 is 50 kV to 150 kV and the tube voltage range of the radiation source 13 is 40 kV to 125 kV, the tube voltage range of the fifth imaging condition is 50 kV to 125 kV. These ranges are limitations imposed by the performance of the radiation irradiator 1. Because the same range is used for both pre-exposure and main exposure, it is not possible to determine whether the imaging conditions are appropriate for pre-exposure. When the imaging conditions for pre-exposure are input, the radiation imaging apparatus 2 sets the imaging conditions for pre-exposure and prepares for performing pre-exposure (Step B01).

[0061] Thereafter, when the user presses the exposure switch 12, the radiation irradiating device 1 irradiates the subject and the radiation imaging device 2 with radiation based on the imaging conditions for pre-exposure (step A2).

[0062] When the radiographic imaging device 2 is exposed to radiation, it accumulates the electric charge generated by each radiation detection element based on the radiation dose in each pixel, converts the amount of electric charge of each pixel into a signal value, reads it out as pre-image data, and outputs the pre-image data to the console 3 (step B02).

[0063] The console 3 acquires the pre-image data (step S105), performs image analysis processing on the acquired pre-image data, etc., to calculate the imaging conditions for the actual exposure, and outputs the imaging conditions to the radiation irradiation device 1 and the radiation imaging device 2 (step S106).

[0064] When the imaging conditions for the main exposure are input, the radiation irradiating device 1 and the radiation imaging device 2 each set the imaging conditions and make preparations for the main exposure (steps A3, B03).

[0065] Thereafter, when the user presses the exposure switch 12, the radiation irradiating device 1 irradiates the subject and the radiation imaging device 2 with radiation based on the imaging conditions for the main exposure (step A4).

[0066] When the radiographic imaging device 2 is exposed to radiation, it accumulates the electric charge generated by each radiation detection element based on the radiation dose in each pixel, converts the amount of electric charge of each pixel into a signal value, reads it out as actual image data, and outputs the actual image data to the console 3 (step B04).

[0067] Furthermore, the radiation imaging apparatus 2 accumulates dark charge in each pixel, converts the amount of dark charge in each pixel into a signal value, reads it out as offset data, and outputs the offset data to the console 3 (step B05). Note that the processing of step B05 may be performed before step B04.

[0068] The console 3 acquires the main image data and the offset data (step S107), performs predetermined image processing, and then performs image synthesis processing on the main image data using the preliminary image data (step S108). After that, imaging in the radiation imaging system 100 is completed.

[0069] In step S108, the preliminary image data and the actual image data are subjected to image synthesis processing, but in a configuration in which image synthesis processing is not performed, the processing of step S108 may be omitted. However, from the viewpoint of utilizing the exposure dose in pre-exposure for diagnosing the patient without wasting it, it is preferable to perform image synthesis processing on the preliminary image data and the actual image data.

[0070] According to the present embodiment configured as described above, control is performed to assist the user so that the second shooting conditions fall within the range of the first shooting conditions in pre-exposure, so that pre-exposure can be performed under optimal shooting conditions.

[0071] Here, if the pre-exposure performed before the main exposure is performed under inappropriate imaging conditions, imaging by the radiation imaging system 100 cannot be performed appropriately.

[0072] For example, if the cumulative dose in the pre-exposure is too large, pixels will occur whose pixel values ​​are stuck at the maximum value. Since it is unclear whether such pixel values ​​are equivalent to the maximum value or greater than the maximum value, if such pixel values ​​are used, the dose in the pre-exposure cannot be calculated accurately.

[0073] Furthermore, if the cumulative dose in the pre-exposure is too small, the signal-to-noise ratio of the pixel values ​​will deteriorate, and even if the pixel values ​​are used, the dose in the pre-exposure cannot be accurately calculated. For these reasons, it is necessary to set the cumulative dose in the pre-exposure under appropriate conditions.

[0074] Furthermore, if the irradiation time for pre-exposure is too short, the radiation output generally becomes unstable when the irradiation time is extremely short, and therefore the dose of pre-exposure calculated from pixel values ​​also becomes unstable, and as a result, the shooting conditions for the main exposure also become unstable.

[0075] Furthermore, if the irradiation time for pre-exposure is too long, the subject's body movements tend to be large from the start to the end of imaging, which increases the likelihood of imaging failure in imaging where the body movements need to be kept within a certain range.

[0076] For these reasons, it is necessary to set the irradiation time in the pre-exposure to an appropriate condition.

[0077] Furthermore, if the irradiation field in the pre-exposure is not adjusted accurately, the dose due to the pre-exposure cannot be calculated accurately.

[0078] As described above, if pre-exposure is performed under inappropriate imaging conditions, appropriate imaging cannot be performed in the radiation imaging system 100, and the subject may be unnecessarily exposed to radiation.

[0079] In this embodiment, by determining whether the second imaging condition is within the range of the first imaging condition, the user can be guided to bring the second imaging condition into the range of the first imaging condition. That is, in this embodiment, pre-exposure can be performed under appropriate imaging conditions, and as a result, imaging by main exposure can be performed appropriately.

[0080] Furthermore, since the range of the first photographing condition is displayed (notified) to the user, the user can easily notice whether the second photographing condition is within the range of the first photographing condition.

[0081] In the above embodiment, the first shooting conditions are acquired by referring to the table shown in FIG. 4, but the present invention is not limited to this. For example, the first shooting conditions may be acquired by referring to the table shown in FIG.

[0082] In this table, combinations of an imaging region and an imaging direction are associated with combinations of tube voltage and the upper limit of the tube current time product. Three tube voltages are set for each combination of an imaging region and an imaging direction. In other words, three combinations of tube voltage and the upper limit of the tube current time product are set for each combination of an imaging region and an imaging direction.

[0083] In such a table, the tube current time product can be calculated by linear interpolation. For example, assume that the examination conditions are that the imaging region is the chest, the imaging direction is the front, and the tube voltage under the second imaging condition is 110 kV and the tube current time product is 12 mAs.

[0084] In this case, the tube voltage in the second imaging condition is a value between the tube voltage in No. 2 and the tube voltage in No. 3. Therefore, the control unit 31 refers to the upper limit value (30 mAs) of the tube current time product in No. 2 and the upper limit value (10 mAs) of the tube current time product in No. 3.

[0085] The control unit 31 calculates a first ratio between the absolute value of the difference between the tube voltage at No. 2 and the tube voltage at No. 3 (120 kV - 80 kV = 40 kV) and the absolute value of the difference between the tube voltage at No. 3 and the input tube voltage (120 kV - 110 kV = 10 kV). The first ratio is 4:1.

[0086] Next, the control unit 31 calculates a second ratio of the absolute value of the first difference between the upper limit value of the tube current time product at No. 2 and the upper limit value of the tube current time product at No. 3 to the second difference between the upper limit value of the tube current time product at 110 kV and the upper limit value of the tube current time product at No. 3. The first difference is 30 mAs - 10 mAs = 20 mAs.

[0087] The second ratio is equal to the first ratio, so considering that the first difference is 20 mAs and the first ratio is 4:1, the second difference is 5 mAs. Considering that the upper limit of the tube current time product in No. 3 is 10 mAs, the tube current time product at 110 kV is 15 mAs.

[0088] The tube current time product for the second imaging condition is 12 mAs, which is lower than the 15 mAs of the first imaging condition calculated by linear interpolation. As a result, the control unit 31 determines that the second imaging condition is within the range of the first imaging condition. Because there are many combinations of imaging region and imaging direction, creating a table for each combination would result in a very large data size. However, by calculating the second imaging condition from the table values ​​in this way, the data size of each table can be compressed, allowing for the use of a less expensive computer, which is economical. Furthermore, since a range of highly accurate second imaging conditions can be provided with a smaller data size, the user's options for the first imaging condition increase, allowing the user to perform imaging under the first imaging condition more easily.

[0089] In addition, in the table shown in FIG. 9, an interpolation method other than linear interpolation may be used.

[0090] Furthermore, in the above embodiment, the table uses combinations of the range of tube voltages and the upper limit of the tube current-time product, but the present invention is not limited to this. For example, it is also possible to use combinations of the range of tube voltages, the upper limit of the tube current-time product, and the lower limit of the tube current-time product, as in the table shown in FIG.

[0091] By using such a table, the lower limit of the tube current time product is set within the range of the first imaging condition, so that the second imaging condition in which the cumulative dose of radiation is too small is determined to be outside the range of the first imaging condition, thereby preventing the cumulative dose of radiation from being set too small.

[0092] 11, a table may be used that associates the type of radiation irradiator 1 with the irradiation time. In this table, the lower limit of the irradiation time is associated with each type of device. In other words, the second imaging condition and the first imaging condition include the condition of the irradiation time in pre-exposure.

[0093] It is generally known that if the exposure time of the device is extremely short, the radiation output becomes unstable. Therefore, if the exposure time as the second imaging condition is too short, the cumulative dose from the pre-exposure will become unstable, and ultimately the cumulative dose from the main exposure will also become unstable.

[0094] Therefore, by referring to a table in which the lower limit of the irradiation time for each device to be used is recorded, it is possible to prevent the integrated dose from becoming unstable due to the irradiation time being too short, and ultimately to stabilize the integrated dose. Also, it is possible to set the first imaging conditions taking into account the differences between the devices to be used.

[0095] Furthermore, when the second imaging condition is the tube current time product, the tube current and the irradiation time are separated by the console 3 or the like, and the separated irradiation time should not fall below the lower limit value of the irradiation time in the table.

[0096] Furthermore, when imaging areas prone to body movement or patients prone to body movement (for example, children or the elderly), prioritizing shorter irradiation time over radiation stability may result in a lower frequency of imaging failures. In such cases, a table can be created that associates the imaging area and patient attributes with the lower limit of the irradiation time.

[0097] Furthermore, the longer the irradiation time, the greater the patient (subject)'s body movement that occurs from the start to the end of imaging. Therefore, when imaging an area where body movement is likely to occur or an area where body movement is likely to occur (for example, a child or elderly person), the upper limit of the irradiation time is set using a table that associates the area to be imaged, patient attributes, and the upper limit of the irradiation time. This can reduce the frequency of imaging failures due to body movement.

[0098] Determining the first irradiation condition taking into account the influence of body movement is effective even in a configuration in which preliminary image data is used and image synthesis processing is not performed on the actual image data, but it is particularly effective in a configuration in which image synthesis processing is performed (step S108 shown in Figure 8 above), because it can reduce changes in the geometric arrangement of the subject between the preliminary image and the actual image, enabling more accurate image synthesis.

[0099] 12, a table may be used which associates the imaging region and imaging direction with the irradiation field in the radiation imaging system. This table associates four distances with the imaging region and imaging direction: the upper boundary of the irradiation field is the distance from the center of the irradiation surface of the imaging table to the upper boundary of the expected irradiation field; the lower boundary of the irradiation field is the distance from the center of the irradiation surface of the imaging table to the lower boundary of the expected irradiation field; the left boundary of the irradiation field is the distance from the center of the irradiation surface of the imaging table to the left boundary of the expected irradiation field; and the right boundary of the irradiation field is the distance from the center of the irradiation surface of the imaging table to the right boundary of the expected irradiation field. In other words, the second imaging condition and the first imaging condition include conditions related to the geometric arrangement of the irradiation field in the radiation imaging system.

[0100] If the geometric region used to derive the cumulative dose is not included in the irradiation field, the cumulative dose cannot be calculated accurately, and as a result, the imaging conditions for this exposure will not be appropriate.

[0101] For example, in a configuration in which a region of interest (ROI) is detected from pre-image data in pre-exposure and the integrated dose is derived from pixel value information within the ROI, it is desirable that the ROI be contained within the irradiation field. The range of the ROI is roughly determined by the imaging region and imaging direction, so the irradiation field boundary where the expected ROI falls can be associated with the imaging region and imaging direction and recorded in a table.

[0102] For example, when the imaging region is the chest and the imaging direction is the front, the control unit 31 refers to the table and acquires information on the irradiation field boundary No. 1 as the first imaging condition. In Fig. 13, the information on the irradiation field boundary No. 1 is shown by a solid line on the imaging table.

[0103] As the second imaging condition, the control unit 31 acquires information on the irradiation range from, for example, a collimator provided in the radiation irradiation device 1. For example, assume that information is acquired that indicates 19 cm above, 19 cm below, 20 cm to the left, and 20 cm to the right from the center of the irradiation field.

[0104] The radiation irradiation device 1 derives the relative positions of the center of the irradiation field and the center of the irradiation surface of the imaging table from information on the focal position and direction of the tube and the center position of the irradiation surface of the imaging table, and outputs this information to the console 3. For example, this information may indicate that the center of the irradiation field is shifted 1 cm upward from the center of the irradiation surface of the imaging table, but is not shifted horizontally.

[0105] Considering the relative position between the center of the irradiation field and the center of the irradiation surface of the imaging table, the above-mentioned irradiation field range information is assumed to be the position of the broken line. In this case, the irradiation field boundary under the first imaging condition protrudes 1 cm downward from the irradiation field (broken line) under the above-mentioned second imaging condition. Therefore, the control unit 31 determines that the second imaging condition is not within the range of the first imaging condition.

[0106] Furthermore, if the second imaging condition is not within the range of the first imaging condition, the collimator is set so that the irradiation field boundary is contained within the irradiation field or so that the irradiation field is larger than the irradiation field boundary. In other words, the control unit 31 controls the irradiation field based on the geometric arrangement of the irradiation field. In a configuration in which an ROI is detected from pre-image data in pre-exposure and the integrated dose is derived from pixel value information within the ROI, the irradiation field boundary where the expected ROI falls changes for each imaging region, which places a heavy burden on the user to grasp the subject boundary for each imaging region. As a result, the user frequently sets an inappropriate irradiation field. In contrast, by having the control unit 31 control the irradiation field, user convenience can be significantly improved.

[0107] For example, as shown in Fig. 14, the irradiation field (broken line) is set to completely cover the irradiation field boundary (solid line). By doing so, the control unit 31 determines that the second imaging condition is within the range of the first imaging condition.

[0108] Furthermore, by setting the timing for checking the irradiation field to after a certain time has elapsed since the irradiation field was changed, or after the exposure switch 12 is pressed, etc., the latest irradiation field information can be constantly acquired by the console 3. This reduces the frequency with which the second imaging conditions are determined to be outside the range of the first imaging conditions due to a change in the irradiation field by the user.

[0109] Although the table shown in Figure 12 does not mention the physique of the user (patient), it is also possible to prepare multiple tables relating to the boundaries of the irradiation field according to the physique of the patient, and switch between tables depending on the physique information of the patient.

[0110] Furthermore, two or more of the tables shown in the above-mentioned FIGS. 4, 9, 10, 11, and 12 may be used in combination.

[0111] In addition to the imaging region and imaging direction, the first imaging condition may also be associated with the subject's body pressure, the subject's body shape, the presence or absence of implants, the focus-receptor distance, the focus-skin distance, the inherent filtration value of the radiation irradiator 1, the presence or absence and type of additional filter, the presence or absence and type of anti-scatter grid, etc. A table may be created by combining all of these conditions, or the upper limit of the tube current time product may be set by selecting, for example, the minimum condition from all of these conditions. This increases the user's freedom in selecting imaging conditions.

[0112] These examination conditions may be acquired by methods other than user input. For example, in the case of the focus-receptor distance and focus-skin distance, the control unit 31 may acquire a value derived from position information of the tube and imaging table on the radiation irradiator 1 side, a value measured by a distance measuring meter, or a value associated with the imaging table recognized by user operation. Furthermore, the focus-receptor distance may be a predetermined value, such as 180 cm for a stereoscopic imaging table or 100 cm for a supine imaging table.

[0113] The information on the additional filter and the information on the anti-scatter grid may be acquired by the radiation irradiator 1. Information such as the subject's body pressure, body shape, and presence or absence of implants attached to the patient information from the RIS may also be used. The subject's body pressure and body shape determined based on the patient's age attached to the patient information from the RIS may also be used.

[0114] Furthermore, the sensitivity and dynamic range of pixel values ​​may differ depending on the type of radiation imaging device 2. Furthermore, two types of detectors (for example, Gos and CsI) may be used in one radiation imaging device 2. These differences in devices affect the upper limit of the tube current time product, so different tables may be used depending on the type of device.

[0115] In the above embodiment, during pre-exposure, it is determined whether the second imaging condition is within the range of the first imaging condition, but the present invention is not limited to this. For example, the control unit 31 may determine whether the second imaging condition is within the range of both the third imaging condition of pre-exposure and the fourth imaging condition of main exposure.

[0116] For example, in a configuration in which a tube voltage and a tube current common to both pre-exposure and main exposure are input as the second imaging condition, the respective irradiation times of pre-exposure and main exposure are determined by the console 3 etc. Then, the console 3 calculates the tube current time product (dose range per time) based on each irradiation time and the input tube voltage and tube current, and determines whether the imaging condition is suitable for both pre-exposure and main exposure.

[0117] Considering the influence of the subject's body movement, it is also preferable that the irradiation time of the main exposure be relatively short. However, if the tube voltage and tube current in the second imaging condition are set to relatively small values, it becomes necessary to extend the irradiation time of the main exposure. Therefore, by determining whether the input tube voltage and tube current fall within the range of the optimal irradiation time for the main exposure (fourth imaging condition) based on the input tube voltage and tube current, the irradiation time for the main exposure can be set to an appropriate condition.

[0118] Furthermore, the control unit 31 may notify the user of the range that satisfies both the third and fourth photographing conditions.

[0119] In the above embodiment, the second imaging condition is set by user input, but the present invention is not limited to this. For example, when the imaging region, imaging direction, etc. are input, the tube voltage and tube current time product associated with them may be automatically set as the second imaging condition, or the second imaging condition may be automatically set based on an examination order from the RIS.

[0120] In the above embodiment, the control unit 31 includes any one of the cumulative dose range in pre-exposure, the irradiation time in pre-exposure, and the geometric arrangement of the irradiation field in the radiation imaging device in the first imaging condition, but the present invention is not limited to this. For example, the control unit 31 may include two or more of the cumulative dose range, the irradiation time, and the geometric arrangement of the irradiation field in the first imaging condition.

[0121] In the above embodiment, after determining that the second photographing condition is not within the range of the first photographing condition, the user is prompted to re-input the second photographing condition. However, the present invention is not limited to this. The device may automatically re-input the second photographing condition so that it falls within the range of the first photographing condition. In this case, the user may be notified of the second photographing condition after re-input. This can assist the user in bringing the second photographing condition into the range of the first photographing condition.

[0122] In addition, in the above embodiment, the first shooting conditions are acquired by referring to a table stored in the memory unit 33, but the present invention is not limited to this, and the first shooting conditions stored in an external storage device may be acquired.

[0123] In the above embodiment, the imaging control device is a console provided in the radiation imaging system, but the present invention is not limited to this. For example, the imaging control device may be an external device provided in a location different from the radiation imaging system. In this case, the imaging control device outputs information based on the compatibility between the first imaging condition and the second imaging condition to the radiation imaging system via, for example, wireless communication.

[0124] In addition, in the above embodiment, the imaging control device is configured separately from the radiation irradiation device and the radiation imaging device, but the present invention is not limited to this and may be incorporated into the radiation irradiation device or the radiation imaging device.

[0125] In the above embodiment, the control unit in the imaging control device is configured integrally with the storage unit, display unit, operation unit, etc. However, the present invention is not limited to this and may be configured separately from the storage unit, display unit, operation unit, etc. In this case, the control unit may be provided in, for example, the radiation irradiation device. When the control unit is provided in the radiation irradiation device, depending on the radiation irradiation system, input of imaging conditions is received on the radiation irradiation device side, and image processing is performed on a console, etc.

[0126] In the above embodiment, one pre-exposure is followed by one main exposure, but the present invention is not limited to this and may be configured to perform multiple main exposures after one pre-exposure. In this case, the control unit 31 performs automatic exposure control to determine the imaging conditions for performing multiple main exposures based on the pre-exposure image obtained by the pre-exposure and the accompanying information linked to the pre-exposure image.

[0127] Furthermore, the above-described embodiments are merely examples of specific embodiments for carrying out the present invention, and the technical scope of the present invention should not be construed as being limited by these embodiments. In other words, the present invention can be carried out in various forms without departing from the gist or main features thereof. [Explanation of symbols]

[0128] 1 Radiation irradiation device 2. Radiography equipment 3 Console 11. Generator 12 Exposure switch 13 Radiation source 21 Shooting control unit 22 Radiation detection unit 23 Reading section 24 Communications Department 25 Memory section 31 Control Unit 32 Communications Department 33 Storage section 34 Display section 35 Control section 100 Radiography System

Claims

1. an imaging condition acquisition unit that acquires first imaging conditions as imaging conditions for pre-exposure that is performed before main exposure that exposes a subject to radiation; an inspection condition acquisition unit that acquires inspection conditions for the subject; a control unit that sets a second photographing condition input as a photographing condition of the subject within a range of the first photographing condition acquired by the photographing condition acquisition unit; Equipped with the imaging condition acquisition unit acquires the first imaging condition based on the inspection condition acquired by the inspection condition acquisition unit; The first imaging condition is an imaging condition that enables appropriate imaging in the pre-exposure. Shooting control device.

2. the second photographing condition is input by a user; The imaging control device according to claim 1 .

3. The examination conditions are one or more of the following: patient size, imaging region, imaging direction, subject body thickness, subject body shape, presence or absence of implant, focus-receptor distance, focus-skin distance, inherent filtration value of the radiation irradiation device, presence or absence of an additional filter, type of additional filter, presence or absence of an anti-scatter grid, type of anti-scatter grid, type of radiation irradiation device, and type of radiation imaging device. The imaging control device according to claim 1 .

4. The examination conditions are based on any one of imaging order information from an external device, patient information from an external device, user operation, patient information, and patient age. The imaging control device according to claim 3 .

5. the radiation irradiation device acquires one or more of the inspection conditions, including the presence or absence of the additional filter, the type of the additional filter, the presence or absence of the anti-scatter grid, and the type of the anti-scatter grid. The imaging control device according to claim 3 .

6. At least one of the test conditions, the focus-to-image-receptor distance and the focus-to-skin distance, is one derived from position information of a tube and an imaging table, one measured by a distance measuring meter, or one associated with an imaging table used for imaging that is recognized from a user operation. The imaging control device according to claim 3 .

7. the range of the first imaging condition is one or more ranges of a tube voltage, a tube current, an irradiation time, and a tube current-time product; The imaging control device according to claim 1 .

8. decomposing the tube current time product of the second imaging condition into a tube current and an irradiation time so as to fall within the range of the first imaging condition; The imaging control device according to claim 7 .

9. the range of the first photographing condition is any one of an upper limit value, a lower limit value, and a combination of an upper limit value and a lower limit value; The imaging control device according to claim 1 .

10. the range of the first imaging condition is related to a geometric arrangement of an irradiation field in a radiation imaging system including the imaging control device, The imaging control device according to claim 1 .

11. notifying a user of the second photographing condition set by the control unit; The imaging control device according to claim 1 .

12. An imaging control method for an imaging control device having an inspection condition acquisition unit, an imaging condition acquisition unit, and a control unit, comprising: acquiring inspection conditions for the subject by the inspection condition acquisition unit; acquiring, by the imaging condition acquisition unit, first imaging conditions as imaging conditions for pre-exposure that is performed before main exposure that exposes the subject to radiation; setting, by the control unit, a second photographing condition input as a photographing condition of the subject within a range of the first photographing condition acquired by the photographing condition acquisition unit; and the imaging condition acquisition unit acquires the first imaging condition based on the inspection condition acquired by the inspection condition acquisition unit; The first imaging condition is an imaging condition that enables appropriate imaging in the pre-exposure. Shooting control method.

13. a radiation irradiation device that irradiates radiation; a radiation imaging device that generates image data of an exposed image by receiving the radiation; The imaging control device according to claim 1 ; A radiography system comprising:

Images