X-ray fluoroscopy imaging apparatus and image processing method

Abstract

To reduce an amount of exposure by an X-ray by increasing a ratio of an interpolation image when accuracy and real time property are not required of a transparent image, and to maintain a display frame rate similar to that when the accuracy and real time property are required of a transparent image.SOLUTION: An X-ray fluoroscopy imaging apparatus is capable of changing an irradiation rate according to an operation of an operator. The X-ray fluoroscopy imaging apparatus causes an image display apparatus to display a transparent image generated at an irradiation rate when the irradiation rate is equal to or higher than a reference rate, and generates an interpolation frame so that a display rate is equal to the reference rate when the irradiation rate is lower than the reference rate, and causes the image display apparatus to display the transparent image and the interpolation frame generated at the irradiation rate.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an X-ray fluoroscopic imaging apparatus capable of generating a fluoroscopic image, and an image processing method. [Background technology]

[0002] When an operator performs a procedure on a subject while performing X-ray fluoroscopy, the subject and the operator are exposed to radiation, and therefore techniques for reducing the amount of radiation exposure have been proposed.For example, Patent Document 1 discloses a technique for reducing the amount of radiation exposure in pulse fluoroscopy while maintaining the display frame rate of fluoroscopic images, in which the interval between X-ray irradiations is lengthened and images are interpolated using interpolated images generated from intermediate images of previous and subsequent frames. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2016 / 021240 Summary of the Invention [Problem to be solved by the invention]

[0004] Further reductions in radiation exposure can be expected by reducing the number of times X-ray images are acquired and instead increasing the number of interpolated images. However, increasing the proportion of interpolated images reduces the reliability of the images, and the greater the proportion of interpolated images, the greater the time delay, which impairs real-time performance. On the other hand, if the frame rate is changed during fluoroscopy, observers may feel uncomfortable when reviewing recorded fluoroscopic images later due to the change in frame rate.

[0005] The object of the present invention is to reduce the amount of X-ray exposure by increasing the proportion of interpolated images when the accuracy and real-time performance of fluoroscopic images are not required, while maintaining a display frame rate equivalent to that when the accuracy and real-time performance of fluoroscopic images are required. [Means for solving the problem]

[0006] To achieve the above object, one aspect of the present invention provides an X-ray fluoroscopic imaging apparatus having an irradiation device including an X-ray tube that irradiates X-rays onto a subject and an X-ray detector that detects X-rays that have passed through the subject, a system control device that controls the irradiation rate of X-ray pulses from the irradiation device, an image processing control device that generates fluoroscopic images from the output of the X-ray detector at a rate corresponding to the irradiation rate, and an image processing device that displays the fluoroscopic images generated by the image processing control device on an image display device. The system control device is capable of changing the irradiation rate in response to an operation by an operator. When the irradiation rate is changed to a value lower than that at the start of fluoroscopy while a fluoroscopic image is being displayed on the image display device, the image processing device generates interpolated frames so that the frame rate of the image displayed on the image display device becomes equal to the irradiation rate at the start of fluoroscopy, and displays the fluoroscopic images and the interpolated frames on the image display device. [Effects of the Invention]

[0007] According to one aspect of the present invention, when the accuracy and real-time performance of fluoroscopic images are not required, the amount of exposure to X-rays can be reduced by increasing the proportion of interpolated images, while maintaining a display frame rate equivalent to that when the accuracy and real-time performance of fluoroscopic images are required. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a block diagram showing the overall configuration of an X-ray fluoroscopic imaging apparatus according to a first embodiment of the present invention. [Figure 2] FIG. 4 is a diagram showing the display of an irradiation rate controller according to the first embodiment. [Figure 3] FIG. 4 is a diagram showing the display of an interpolation mode operating device according to the first embodiment. [Figure 4] 5A to 5C are diagrams for explaining the operation of the X-ray fluoroscopic imaging apparatus of the first embodiment in an interpolation mode (constant display rate). [Figure 5] 4 is a flowchart showing the operation of the X-ray fluoroscopic imaging apparatus of the first embodiment. [Figure 6]FIG. 10 is a block diagram showing the overall configuration of an X-ray fluoroscopic imaging apparatus according to a second embodiment. [Figure 7] 10A and 10B are diagrams for explaining the operation of the X-ray fluoroscopic imaging apparatus of the second embodiment in an interpolation mode (constant display rate). [Figure 8] 10 is a flowchart showing the operation of the X-ray fluoroscopic imaging apparatus of the second embodiment. [Figure 9] FIG. 10 is a block diagram showing the overall configuration of an X-ray fluoroscopic imaging apparatus according to a third embodiment. [Figure 10] 10A and 10B are diagrams for explaining the operation of the X-ray fluoroscopic imaging apparatus of the third embodiment in an interpolation mode (constant display rate). [Figure 11] 10 is a flowchart showing the operation of the X-ray fluoroscopic imaging apparatus of the third embodiment. [Figure 12] 10A and 10B are diagrams for explaining the operation of the X-ray fluoroscopic imaging apparatus of the fourth embodiment in an interpolation mode (constant display rate). [Figure 13] 10 is a flowchart showing the operation of the X-ray fluoroscopic imaging apparatus of the fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] An X-ray fluoroscopic imaging apparatus according to an embodiment of the present invention will be described below with reference to the drawings.

[0010] <<Embodiment 1>> The X-ray fluoroscopic imaging device of embodiment 1 will be described with reference to Figures 1 to 5. Figure 1 is a block diagram showing the overall configuration of the X-ray fluoroscopic imaging device of embodiment 1, Figure 2 is a diagram showing the display of an irradiation rate controller, Figure 3 is a diagram showing the display of an interpolation mode controller, Figure 4 is a diagram explaining the operation of the interpolation mode (constant display rate), and Figure 5 is a flowchart showing the operation of the X-ray fluoroscopic imaging device.

[0011] The X-ray fluoroscopic imaging device includes a tabletop 12 on which a subject 50 is placed, an X-ray tube 10 that irradiates the subject 50 with X-rays, a variable aperture 13, an X-ray detector 11 that detects X-rays that have passed through the subject 50, an image processing control device 31 that can generate fluoroscopic images and still X-ray images from the output of the X-ray detector 11, an image processing device 32, an image memory 33, and an image display device 34. The variable aperture 13 includes a plurality of aperture blades 13a and adjusts the irradiation range of the X-rays irradiated from the X-ray tube 10 onto the subject 50. A high-voltage generator 14 that supplies tube current and tube voltage is connected to the X-ray tube 10. A system control device 30 is connected to the high-voltage generator 14 and the variable aperture 13 and controls the operations of the high-voltage generator 14 and the variable aperture 13. The configuration related to X-ray irradiation and detection, including the X-ray tube 10 and the X-ray detector 11, is referred to herein as an "irradiation device."

[0012] A field of view size controller (not shown) is connected to the system control device 30, and the operator can use the field of view size controller to set the desired size, etc., of the field of view size of the adjustable diaphragm 13. A fluoroscopy switch 20 is also connected to the system control device 30, and the operator can operate the fluoroscopy switch 20 to instruct X-ray fluoroscopy to be on, off, etc. The fluoroscopy switch 20 can be a switch operated by foot, a switch operated by hand, or any other type of switch.

[0013] In addition, an irradiation rate controller 21 is connected to the system control device 30, and the operator can use the irradiation rate controller 21 to select the irradiation rate of the X-ray pulses (imaging frame rate or irradiation frame rate; hereinafter referred to as the "irradiation rate").

[0014] An interpolation mode controller 22 is also connected to the system control device 30, and the operator can use the interpolation mode controller 22 to select an interpolation mode, which will be described later.

[0015] The system control device 30 has an operation reception unit 30a that receives operation signals from the field of view size operation device, the fluoroscopy switch 30, and the irradiation rate operation device 21. Note that two or more of these operation devices and switches may be combined into a single device.

[0016] The X-ray tube 10 is supported by an X-ray tube support (not shown). The X-ray tube support is provided with an X-ray tube movement mechanism that moves the position of the X-ray tube 10 at least in the longitudinal direction of the tabletop 12. The tabletop 12 has a built-in mechanism that moves the tabletop 12 up and down. The X-ray detector 11 is provided with a detector movement mechanism (not shown) that moves the X-ray detector 11 at least in the longitudinal direction of the tabletop 12. A mechanism control device (not shown) is connected to the X-ray tube movement mechanism and the detector orbit mechanism, and maintains the X-ray tube 10 and the X-ray detector 11 in an opposing positional relationship.

[0017] The image processing control device 31 can execute a fluoroscopy mode and an imaging mode. In the fluoroscopy mode, the X-ray tube 10 emits X-ray pulses at an irradiation rate set in the irradiation rate controller 21 under the control of the system control device 30. The image processing control device 31 generates a fluoroscopy image from the output of the X-ray detector 11 at a rate equal to the set irradiation rate. In the imaging mode, the X-ray tube 10 emits X-rays only once under the control of the system control device 30. The X-ray dose emitted in the imaging mode is generally greater than the X-ray dose emitted by one X-ray pulse in the fluoroscopy mode. The image processing control device 31 generates a still X-ray image from the output of the X-ray detector 11.

[0018] Each time the image processing control device 31 generates a fluoroscopic image, the generated fluoroscopic image is stored in the image memory 33. The stored fluoroscopic image is held in the image memory 33 until the next fluoroscopic image is generated. In other words, the stored fluoroscopic image is an LIH (Last Image Hold) image. The fluoroscopic image stored in the image memory 33 is displayed on the connected image display device 34.

[0019] In the present embodiment, the following description will be given assuming that the fluoroscopic mode is executed. Note that in this specification, a distinction is made between the irradiation rate at which X-ray pulses are irradiated and the frame rate at which fluoroscopic images are displayed (display frame rate, hereinafter referred to as the "display rate").

[0020] The image processing device 32 is capable of operating in a normal mode, a first interpolation mode, and a second interpolation mode.

[0021] In normal mode, the image processing device 32 displays, on the image display device 34, perspective images generated by the image processing control device 31 at a rate equal to the irradiation rate without interpolating them with interpolated images (interpolated frames) (display rate = irradiation rate).

[0022] In the first interpolation mode, the image processing device 32 generates an interpolated image that interpolates between perspective images generated at a rate equal to the irradiation rate so that the display rate is N times the irradiation rate (N is a preset value, for example, 2 times), and displays the perspective image and the interpolated image on the image display device 34 (display rate = N times the irradiation rate).

[0023] In the second interpolation mode, when the fluoroscopy switch 20 is turned on to start fluoroscopy, the image processing device 32 causes the image display device 34 to display fluoroscopic images generated by the image processing control device 31 at a rate equal to the irradiation rate set in the operation device 21 without interpolating them with interpolated images (display rate = irradiation rate). On the other hand, if the operator changes the irradiation rate to a value lower than that at the start of fluoroscopy by scanning the operation device 21 while fluoroscopic images are being displayed on the image display device 34, the image processing device 32 generates interpolated images so that the frame rate (display rate) of the images displayed on the image display device 34 becomes equal to the irradiation rate at the start of fluoroscopy. In other words, the image processing device 32 generates interpolated images that interpolate between fluoroscopic images generated at a rate equal to the changed irradiation rate, and causes the image display device 34 to display the fluoroscopic images and interpolated images at a display rate equal to the irradiation rate at the start of fluoroscopy.

[0024] The generated interpolated image may be stored in the image memory 33, or in another image memory (not shown) to which the image display device 34 is connected.

[0025] The irradiation rate can be selected by the operator on a screen displayed on the touch panel of the irradiation rate controller 21, as shown in Fig. 2, for example. In Fig. 2, buttons corresponding to irradiation rates (unit: FPS) of "3.75", "7.5", "15", and "30" are displayed. The selected button (e.g., "30") is displayed in a manner that makes it distinguishable from the other buttons. Of course, the irradiation rate controller 21 is not limited to a touch panel, and may be configured with input devices such as hardware buttons, a mouse, or a keyboard.

[0026] The interpolation mode can be selected by the operator on a screen displayed on the touch panel of the interpolation mode operator 22, as shown in Fig. 3, for example. In Fig. 3, the buttons corresponding to the normal mode, the first interpolation mode, and the second interpolation mode are "normal mode: interpolation off" 22a, "first interpolation mode: display rate is N times the irradiation rate" 22b, and "second interpolation mode: constant display rate" 22c, respectively. The selected button "second interpolation mode: constant display rate" 22c is displayed in a manner that makes it distinguishable from the other buttons 22a and 22b. Of course, the interpolation mode operator 22 is not limited to a touch panel and may be configured with an input device such as a hardware button, a mouse, or a keyboard.

[0027] In the second interpolation mode, as shown in Fig. 4, for example, at the start of fluoroscopy, no interpolated images are generated, and fluoroscopic images generated at a rate equal to the irradiation rate selected by the operator on the irradiation rate controller 21 are displayed on the image display device 34. If, while fluoroscopic images are being displayed, the operator 40 operates the irradiation rate controller 21 to select a button for a lower irradiation rate than that at the start of fluoroscopy and change the irradiation rate, the irradiation rate at which X-ray pulses are irradiated is changed, but the display rate displayed on the image display device 34 is controlled to be equal to the irradiation rate at the start of fluoroscopy. In other words, the image processing device 32 generates interpolated images that interpolate between fluoroscopic images generated at a rate equal to the changed irradiation rate, and displays the fluoroscopic images and interpolated images on the image display device 34, thereby displaying images on the image display device 34 at the same display rate as at the start of fluoroscopy.

[0028] The system control device 30, the image processing control device 31, and the image processing device 32 are configured by a computer or the like equipped with a processor such as a CPU (Central Processing Unit) or a GPU (Graphics Processing Unit) and a storage unit such as a memory. The processor reads and executes programs stored in the memory, thereby realizing the functions of the system control device 30, the image processing control device 31, and the image processing device 32.

[0029] Furthermore, the system control device 30, the image processing control device 31, and the image processing device 32 can be configured in part or in whole by hardware. For example, circuits can be designed to realize the functions of the system control device 30, the image processing control device 31, and the image processing device 32 using a custom IC such as an ASIC (Application Specific Integrated Circuit) or a programmable IC such as an FPGA (Field-Programmable Gate Array).

[0030] A more detailed explanation will be given below using the flowchart in Fig. 5. This flowchart starts when the operator selects the interpolation mode by operating the interpolation mode operating device 22. After that, X-ray fluoroscopy starts by turning on the fluoroscopy switch 20.

[0031] After the start of X-ray fluoroscopy, the operator can change the irradiation rate at any time by operating the irradiation rate controller 21. Also, the operator can turn off X-ray fluoroscopy at any time by operating the fluoroscopy switch 20.

[0032] 5, steps 111 to 116 are in the first interpolation mode (interpolation on (N times the irradiation rate)), and steps 121 to 128 are in the second interpolation mode (interpolation on (constant display rate)). Processing in the normal mode (interpolation off) is omitted.

[0033] (Step 101) In step 101, the operation receiving unit 30a of the system control device 30 determines which of the interpolation mode buttons 22a to 22c on the interpolation mode operating unit 22 is currently selected.

[0034] If the selected interpolation mode button is “First interpolation mode: display rate is N times the illumination rate” 22 b , the system control device 30 proceeds to step 111 .

[0035] If the "Second Interpolation Mode: Constant Display Rate" 22c is selected, the system controller 30 proceeds to step 121.

[0036] On the other hand, if "Normal mode: Interpolation off" 22a is selected, the system control device 30 proceeds to processing in the normal mode.

[0037] (Steps 111 and 112) If "First interpolation mode: display rate is N times the irradiation rate" 22b is selected, the operation receiving unit 30a determines in step 111 whether the fluoroscopy switch 20 has been pressed by the operator and is on or not. If it is on (Yes), the system control device 30 proceeds to step 112 and acquires the irradiation rate F selected in the irradiation rate operator 21.

[0038] (Step 114) The system controller 30 supplies a predetermined tube voltage and tube current for fluoroscopy from the high voltage generator 14 to the X-ray tube 10 at an irradiation rate Fn, and causes the X-ray tube 10 to irradiate the subject 50 with X-ray pulses at an irradiation rate F. The X-rays that have passed through the subject 50 are detected by the X-ray detector 11. The image processing controller 31 uses the output of the X-ray detector 11 to generate fluoroscopic images at a rate equal to the irradiation rate F.

[0039] (Step 115) The image processing device 32 generates an interpolated image that interpolates between the perspective images so that the display rate becomes N times (for example, twice) the irradiation rate F.

[0040] (Step 116) The image processing device 32 displays the perspective images and the generated interpolated images on the image display device 34. As a result, the display rate of the images displayed on the image display device 34 becomes N times the irradiation rate F.

[0041] The system control device 30 returns to step 112 and determines whether the fluoroscopy switch 20 continues to be in the on state. If the fluoroscopy switch 20 continues to be in the on state, steps 112 to 116 are repeated. If the fluoroscopy switch 20 is in the off state, the process ends.

[0042] On the other hand, if the "second interpolation mode: constant display rate" 22c is selected in step 101, the system control device 30 proceeds to step 121.

[0043] (Step 121) In step 121, the system controller 30 acquires the irradiation rate F0 currently selected in the irradiation rate controller 21 as the irradiation rate at the start of fluoroscopy and stores it in the built-in memory. In the example of Fig. 4, 30 pulses / s is selected by the operator in the irradiation rate controller 21 as the irradiation rate F0 at the start of fluoroscopy, so 30 pulses / s is stored.

[0044] (Steps 122-125) Next, the system controller 30 performs steps 122 to 125 in the same manner as steps 111 to 124 in the first interpolation mode described above. That is, when the operator steps on the fluoroscopy switch 20 and turns it on, the system controller 30 obtains the irradiation rate Fn set in the irradiation rate controller 21 and causes the X-ray tube 10 to irradiate the subject 50 with X-ray pulses at the irradiation rate Fn (here, 30 pulses / s). The image processing controller 31 uses the output of the X-ray detector 11 to generate fluoroscopic images at a rate equal to the irradiation rate Fn (30 frames / s).

[0045] (Step 126) The image processing device 32 displays the fluoroscopic images generated in step 125 on the image display device 34 without interpolation. Therefore, the display rate of the image display device 34 is the same rate (30 frames / s) as the irradiation rate Fn (=F0) set at the start of fluoroscopy.

[0046] (Step 127) Next, the system control device 30 proceeds to step 127 and determines whether the irradiation rate Fn obtained in step 123 is equal to or greater than the irradiation rate F0 at the start of fluoroscopy obtained in step 121. If the answer is Yes, the system control device 30 returns to step 122; if the answer is No, the system control device 30 proceeds to step 128.

[0047] At the start of fluoroscopy, the irradiation rate Fn obtained in step 123 is equal to the irradiation rate F0 obtained in step 121, so the process returns to step 122.

[0048] In step 122, the system controller 30 determines whether the fluoroscopy switch 20 remains on. If the fluoroscopy switch 20 remains on, in step 123, the irradiation rate Fn currently set in the irradiation rate controller 21 is acquired, and steps 124 to 126 are repeated. If the fluoroscopy switch 20 is in the off state, the process ends.

[0049] In step 127, the control device 30 again determines whether the irradiation rate Fn acquired in this step 123 is equal to or greater than the irradiation rate F0 at the start of fluoroscopy acquired in step 121. If the irradiation rate Fn acquired in this step 123 has been changed from the irradiation rate F0 at the start of fluoroscopy and is smaller than the irradiation rate F0 at the start of fluoroscopy, the process proceeds to step 128.

[0050] For example, in the example of FIG. 4, the irradiation rate Fn has been changed to 7.5 pulses / s in the irradiation rate controller 21, which is lower than the rate at the start of fluoroscopy (30 pulses / s).

[0051] (Step 128) In step 128, the image processing device 32 generates an interpolated image 41 that interpolates between the fluoroscopic images so that the display rate of the image displayed on the image display device 34 reaches a rate (30 frames / s) equal to the irradiation rate F0 at the start of fluoroscopy obtained in step 121.

[0052] (Step 129) In step 129, the image processing device 32 displays the perspective image and the interpolated image on the image display device 34. As a result, the display rate of the images displayed on the image display device 34 becomes equal to the initial irradiation rate F0 (30 frames / s).

[0053] Thereafter, the system controller 30 returns to step 122 and repeats steps 123 to 129 until the fluoroscopy switch 20 is turned off.

[0054] If normal mode (interpolation off) is selected in step 101, X-rays are irradiated at the set irradiation rate F, and a fluoroscopic image is generated at a rate equal to the irradiation rate F, and then displayed on the image display device 34 without interpolation, as in steps 111 to 114.

[0055] As described above, in the X-ray fluoroscopic imaging apparatus of embodiment 1, in the second interpolation mode "second interpolation mode: constant display rate" 22c, the operator changes the irradiation rate to a lower value than at the start of fluoroscopy while fluoroscopy is being performed, thereby reducing the irradiation rate, but frame interpolation is performed so that the display rate remains the same as at the start of fluoroscopy. Therefore, during fluoroscopy, in a time period when the operator determines that reliability and real-time performance of fluoroscopic images are not required, the operator 40 can reduce the irradiation rate by operating the operator 40, thereby maintaining the display rate while reducing the radiation exposure of the operator 40 and the subject. This reduces the discomfort felt by a person viewing fluoroscopic images when the display rate is changed midway.

[0056] <<Embodiment 2>> The X-ray fluoroscopic imaging apparatus of the second embodiment will be described with reference to FIGS.

[0057] The X-ray fluoroscopic imaging apparatus of the second embodiment is configured so that the irradiation rate can be set by the operator's speech or gestures.

[0058] FIG. 6 is a block diagram showing the overall configuration of the X-ray fluoroscopic imaging apparatus of the second embodiment, FIG. 7 is a diagram explaining the operation in the interpolation mode (constant display rate), and FIG. 8 is a flowchart showing the operation of the X-ray fluoroscopic imaging apparatus.

[0059] The following description will focus on the differences from embodiment 1, and will omit the description of the commonalities with embodiment 1 as appropriate. Of the components of embodiment 2 in Fig. 6, those common to embodiment 1 will be given the same reference numerals and their description will be omitted. Furthermore, of the steps of embodiment 2 in Fig. 8, those common to embodiment 1 will be given the same reference numerals and their description will be omitted.

[0060] The X-ray fluoroscopic imaging device of the second embodiment is provided with at least one of a camera 23 and a microphone 24 instead of the irradiation rate controller 21 (FIG. 1). At least one of the camera 23 and the microphone 24 is connected to the system control device 30, and an operator can select the irradiation rate by indirect operation using at least one of the camera 23 and the microphone 24 without touching the controller.

[0061] The camera 23 captures an image of the operator. The operation accepting unit 30a recognizes the operator's body movements from the captured image (video or still image) by, for example, image recognition processing, and accepts a change in the irradiation rate if the recognized body movements are predetermined body movements instructing the selection of an irradiation rate. The body movements are so-called gestures, and include movements of the fingers and arms, head movements, blinking, mouth movements, etc.

[0062] The microphone 24 acquires the voice of the operator. The operation accepting unit 30a recognizes the operator's utterance from the voice signal, for example, by voice recognition processing, and accepts a change in the irradiation rate if the recognized utterance is a predetermined utterance instructing selection of an irradiation rate.

[0063] In the second interpolation mode, as shown in Fig. 7, for example, when an operator 40 such as a surgeon selects an irradiation rate lower than the reference rate by indirectly operating via the camera 23 or microphone 24, an interpolated image is generated that interpolates between the fluoroscopic images generated at the set irradiation rate so that the display rate becomes equal to the reference rate, and the fluoroscopic image and the interpolated image are displayed on the image display device 34. Note that, similar to the display on the touch panel of the irradiation rate controller 21 (Fig. 2), irradiation rate selection buttons may be displayed on a predetermined display device (not shown).

[0064] A more detailed explanation will be given below using the flowchart in FIG.

[0065] In the second embodiment, steps 212, 221, and 223 are inserted in place of steps 112, 121, and 123 in the first embodiment.

[0066] (Step 101) As in step 101 of the first embodiment, the operation receiving unit 30 a of the system control device 30 determines the interpolation mode currently selected by the interpolation mode operating unit 22 .

[0067] (Step 111) If the first interpolation mode is selected, system controller 30 proceeds to step 212 if the fluoroscopy switch is turned on in step 111 .

[0068] (Step 212) The system control device 30 acquires the irradiation rate F selected by the operator through an indirect operation via the camera 23 or microphone 24 .

[0069] (Steps 113-116) The system controller 30 performs steps 113 to 116 in the same manner as in the first embodiment.

[0070] On the other hand, if the second interpolation mode is selected in step 101 , the process proceeds to step 221 .

[0071] (Step 221) In step 221, the system control device 30 acquires the irradiation rate F0 selected by the operator through indirect operation via the camera 23 or microphone 24, and stores it in the built-in memory.

[0072] (Step 122) If the fluoroscopy switch is turned on in step 122, the system controller 30 proceeds to step 223.

[0073] (Step 223) The system control device 30 acquires the irradiation rate Fn selected by the operator through an indirect operation via the camera 23 or microphone 24 .

[0074] (Steps 124-129) The system controller 30 performs steps 124 to 129 in the same manner as in the first embodiment. The system controller 30 then proceeds to step 124.

[0075] In the case of normal mode (interpolation off), the process is executed in the same manner as in the normal mode of the first embodiment.

[0076] As described above, in the X-ray fluoroscopic imaging apparatus of embodiment 2, the irradiation rate can be selected by the operator's speech, gestures, etc. In other words, the operator can easily change the irradiation rate without directly touching the operation device.

[0077] The configuration, operation and effects of the X-ray fluoroscopic imaging apparatus of the second embodiment other than those described above are the same as those of the first embodiment, and therefore description thereof will be omitted.

[0078] <<Embodiment 3>> The X-ray fluoroscopic imaging apparatus of the third embodiment will be described with reference to FIGS.

[0079] The X-ray fluoroscopic imaging apparatus of the third embodiment reduces the irradiation rate when the operator 40 is not looking at the image display device .

[0080] FIG. 9 is a block diagram showing the overall configuration of the X-ray fluoroscopic imaging apparatus of the third embodiment, FIG. 10 is a diagram explaining the operation in the interpolation mode (constant display rate), and FIG. 11 is a flowchart showing the operation of the X-ray fluoroscopic imaging apparatus.

[0081] The following description will focus on the differences from embodiment 1, and will omit the description of the commonalities with embodiment 1 as appropriate. Of the components of embodiment 3 in Fig. 9, those common to embodiment 1 will be given the same reference numerals and their description will be omitted. Also, of the steps of embodiment 3 in Fig. 11, those common to embodiment 1 will be given the same reference numerals and their description will be omitted.

[0082] The X-ray fluoroscopic imaging device of the third embodiment includes, in addition to the irradiation rate controller 21 (FIG. 1), a field of view camera 25 that can capture the operator's field of view. The field of view camera 25 is connected to the system control device 30, and in the second interpolation mode, the irradiation rate is reduced when the operator is not looking at the image display device 34.

[0083] The field of view camera 25 is worn by the operator and captures an image of a range including at least a part of the operator's field of view. Preferably, the field of view camera 25 is worn on the operator's head so that the imaging direction faces forward of the operator. The method and form of wearing the camera are not limited, and it may be, for example, in the form of glasses, goggles, pen, etc.

[0084] The operation reception unit 30a determines whether the operator is looking at the screen displaying the X-ray fluoroscopic image of the image display device 34. The operation reception unit 30a determines whether the fluoroscopic image display screen is included in the captured image (video or still image) by, for example, image recognition processing. If included, it determines that the operator is looking at the fluoroscopic image display screen. To improve accuracy, it may be determined that the operator is looking at the fluoroscopic image display screen when, for example, the fluoroscopic image display screen is located within a predetermined distance from a reference position such as the center of the captured image, or when the size (area) of the fluoroscopic image display screen in the captured image is equal to or greater than a predetermined value. Both the position and area of ​​the fluoroscopic image display screen may be used for the determination. Furthermore, to prevent erroneous determination that the operator is not looking at the screen when they are, the irradiation rate may be changed after a certain time has elapsed since the operator looked away from the screen.

[0085] When the operation reception unit 30a determines that the operator is looking at the fluoroscopic image display screen, it sets a predetermined irradiation rate Fp. On the other hand, when it determines that the operator is not looking at the fluoroscopic image display screen, it sets a predetermined irradiation rate Fr. The irradiation rate Fr is an irradiation rate lower than the irradiation rate Fp. The values ​​of the irradiation rates Fp and Fr may be configured to be set in advance by the operator.

[0086] 10 , in the second interpolation mode, when an operator 40 such as a surgeon moves their line of sight 40a away from the fluoroscopic image display screen of the image display device 34, an irradiation rate Fr lower than the irradiation rate Fp when the line of sight 40a is looking at the screen is automatically selected. Then, an interpolated image 41 that interpolates between the fluoroscopic images is generated so that the display rate becomes equal to the irradiation rate Fp, and the fluoroscopic image and the interpolated image are displayed on the image display device 34.

[0087] The operation of the X-ray fluoroscopic imaging apparatus of the third embodiment will be described in more detail below with reference to the flowchart of FIG.

[0088] In the third embodiment, as shown in FIG. 11, steps 301 to 309 are executed instead of steps 121 to 129 in the second interpolation mode of the first embodiment.

[0089] (Step 101) In step 101, the system control device 30 determines the interpolation mode currently selected in the interpolation mode operator 22, as in the first embodiment.

[0090] (Steps 111-116) In the first interpolation mode, steps 111 to 116 are performed in the same manner as in the first embodiment.

[0091] (Step 301) If the fluoroscopy switch 20 is pressed by the operator and turned on, the system controller 30 proceeds to step 302 .

[0092] (Step 302) The operation reception unit 30a of the system control device 30 determines whether the operator is looking at the fluoroscopic image display screen. If the operator is looking at the fluoroscopic image display screen (Yes), the system control device 30 proceeds to step 303. If the operator is not looking at the fluoroscopic image display screen (No), the system control device 30 proceeds to step 306.

[0093] (Step 303) In step 303, the system controller 30 causes X-ray pulses to be emitted at a predetermined irradiation rate Fp.

[0094] (Step 304) The image processing control device 31 uses the output of the X-ray detector 11 to generate fluoroscopic images at a rate equal to the irradiation rate Fp.

[0095] (Step 305) The image processing device 32 displays the fluoroscopic images on the image display device 34 without interpolating them with the interpolated images. The display rate is equal to the initial irradiation rate Fp. The system controller 30 returns to step 301.

[0096] (Step 306) On the other hand, if the system controller 30 determines in step 302 that the operator is not looking at the fluoroscopic image display screen, then in step 306, X-ray pulses are irradiated at a predetermined irradiation rate Fr.

[0097] (Step 307) The image processing control device 31 uses the output of the X-ray detector 11 to generate fluoroscopic images at a rate equal to the irradiation rate Fr.

[0098] (Step 308) In step 308, the image processing device 32 generates an interpolated image 41 that interpolates between the perspective images so that the display rate of the images displayed on the image display device 34 reaches a display rate equal to the irradiation rate Fp.

[0099] (Step 129) In step 129, the image processing device 32 displays the perspective image and the interpolated image on the image display device 34. As a result, the display rate of the image displayed on the image display device 34 becomes equal to the display rate in step 305 (=Fp).

[0100] After this, the system controller 30 returns to step 301.

[0101] As described above, in the third embodiment, the irradiation rate is set low while the operator is not looking at the screen of the image display device 34 on which the fluoroscopic images are displayed, thereby reducing the radiation exposure of the operator 40 and the subject. Furthermore, even while the operator is not looking at the screen and the irradiation rate is set low, the display rate is interpolated with interpolated images, so that the display rate is maintained at the same rate as while the operator was looking at the fluoroscopic images. Therefore, even when the recorded fluoroscopic images are reviewed later, the display rate is kept constant during fluoroscopy, thereby reducing the sense of discomfort that may occur when the display rate is changed.

[0102] <<Embodiment 4>> The X-ray fluoroscopic imaging apparatus of the fourth embodiment will be described with reference to FIGS.

[0103] In the X-ray fluoroscopic imaging apparatus of the fourth embodiment, when frame interpolation is performed in the second interpolation mode, an image 34c indicating that an interpolated image is being displayed is additionally displayed on the image display device 34 as shown in Fig. 12. In the example of Fig. 12, "FRC" (Frame Rate Conversion) is displayed.

[0104] FIG. 12 is a diagram for explaining the operation in the interpolation mode (constant display rate) of the fourth embodiment, and FIG. 13 is a flowchart showing the operation of the X-ray fluoroscopic imaging apparatus.

[0105] The following description will focus on the differences from embodiment 1, and will omit the description of the commonalities with embodiment 1 as appropriate. Among the steps of embodiment 4 in FIG. 13, the steps common to embodiment 1 will be assigned the same reference numerals and their description will be omitted.

[0106] The X-ray fluoroscopic imaging apparatus of the fourth embodiment includes the same components as those of the first embodiment (FIG. 1).

[0107] In the second interpolation mode, as shown in Fig. 12, for example, while irradiation is being performed at the irradiation rate set at the start of fluoroscopy, no interpolated images are generated, and fluoroscopic images (normal images) generated at that rate are displayed on the image display device 34 (34a). If an operator 40, such as a surgeon, operates the irradiation rate control device 21 during fluoroscopy to change the irradiation rate to a rate lower than that at the start of fluoroscopy, an interpolated image is generated to interpolate between the fluoroscopic images generated at the set irradiation rate so that the display rate is equal to that at the start of fluoroscopy, and the fluoroscopic image and the interpolated image are displayed on the image display device 34 (34b). If frame interpolation is being performed, an image 34c indicating that an interpolated image is being displayed is displayed on the image display device 34. In Fig. 13, "FRC" (Frame Rate Conversion) is displayed.

[0108] A more detailed explanation will be given below using the flowchart in FIG.

[0109] In the fourth embodiment, steps 101, 111 to 116, and 121 to 129 are executed in the same manner as in the first embodiment, and step 401 is inserted immediately after step 129.

[0110] (Step 401) In step 401, the image processing device 32 additionally displays an image 34c indicating that an interpolated image is being displayed on the image display device 34. The system control device 30 then returns to step 122. Note that the image processing device 32 continues to display the image 34c until the determination in step 127 is Yes.

[0111] Incidentally, immediately after step 116, a process similar to step 401 may be executed.

[0112] In the fourth embodiment, when frame interpolation is being performed at least in the second interpolation mode, an image 34c indicating that an interpolated image is being displayed is displayed, allowing the operator to intuitively recognize that frame interpolation is being performed. Another advantage is that when a non-operator other than the operator looks at the screen, the image 34c indicating that an interpolated image is being displayed allows the non-operator to recognize that frame interpolation is being performed.

[0113] Of course, in the first to third embodiments as well, when frame interpolation is enabled, an image indicating that an interpolated image is being displayed may be displayed.

[0114] The present invention is not limited to the above-described embodiments, and various modifications are possible. For example, the above-described embodiments have been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to those including all of the described configurations. Furthermore, it is possible to replace part of the configuration of one embodiment with or add to the configuration of another embodiment. [Explanation of symbols]

[0115] 10 X-ray tube 11 X-ray detector 12 Top plate 13 Adjustable aperture 13a aperture blades 14 High voltage generator 20 X-ray Switch 21 Irradiation rate controller 22 Interpolation mode controller 23 Camera 24 microphones 25 Field of View Camera 30 System control device 30a Operation reception section 31 Image processing control device 32 Image processing device 33 Image Memory 34 Image display device 34a Image 34b Image 34c Image 40 Operator 40a line of sight 50 subjects

Claims

1. an irradiation device including an X-ray tube that irradiates an object with X-rays and an X-ray detector that detects the X-rays that have passed through the object; a system control device for controlling the irradiation rate of the X-ray pulses of the irradiation device; an image processing control device that generates a fluoroscopic image from the output of the X-ray detector at a rate corresponding to the irradiation rate; an image processing device that displays the fluoroscopic image generated by the image processing control device on an image display device, the system control device is capable of changing the irradiation rate in response to an operation by an operator; When the irradiation rate is changed to a value lower than that at the start of fluoroscopy while the fluoroscopic image is being displayed on the image display device, the image processing device generates an interpolated frame so that the frame rate of the image displayed on the image display device becomes equal to the irradiation rate at the start of fluoroscopy, and displays the fluoroscopic image and the interpolated frame on the image display device. An X-ray fluoroscopic imaging device.

2. 2. The X-ray fluoroscopic imaging apparatus according to claim 1, an irradiation rate operator that accepts the setting of the irradiation rate from the operator; The system control device controls the irradiation device to irradiate the X-ray pulses at the irradiation rate accepted by the irradiation rate controller. An X-ray fluoroscopic imaging device characterized by:

3. 2. The X-ray fluoroscopic imaging apparatus according to claim 1, a microphone for capturing the voice of the operator or a camera for capturing an image of the body movement of the operator, The system control device changes the irradiation rate in accordance with a selection operation by voice via the microphone or a selection operation by body movement via the camera. An X-ray fluoroscopic imaging device characterized by:

4. 2. The X-ray fluoroscopic imaging apparatus according to claim 1, a field of view camera mounted on the operator's head, The system control device changes the irradiation rate in accordance with at least one of the position and the size of the screen of the image display device included in the image captured by the field of view camera. An X-ray fluoroscopic imaging device characterized by:

5. 2. The X-ray fluoroscopic imaging apparatus according to claim 1, The system control device, based on at least one of the position and size of the screen of the image display device, When it is determined that the operator is not looking at the screen, the irradiation rate is reduced; If it is determined that the operator is looking at the screen, the irradiation rate is set to a reference rate. An X-ray fluoroscopic imaging device characterized by:

6. The X-ray fluoroscopic imaging apparatus according to any one of claims 1 to 5, When the image processing device displays the interpolated frame, the image processing device causes the image display device to display an image indicating that the interpolated frame is being displayed. An X-ray fluoroscopic imaging device characterized by:

7. A method for capturing a fluoroscopic image using an X-ray fluoroscopic imaging device, comprising: When an instruction to start fluoroscopy is received from an operator, irradiating the subject with X-ray pulses at a preset irradiation rate, generating fluoroscopic images at a rate equal to the irradiation rate, and displaying the images on a connected image display device; When the irradiation rate is changed during fluoroscopy, irradiating the subject with X-ray pulses at the changed irradiation rate and generating a fluoroscopic image at a rate equal to the changed irradiation rate; determining whether the changed irradiation rate is smaller than the irradiation rate at the start of fluoroscopy, and if the changed irradiation rate is smaller than the irradiation rate at the start of fluoroscopy, generating interpolated frames so that images are displayed on the image display device at a rate equal to the irradiation rate at the start of fluoroscopy, and displaying the interpolated frames and the fluoroscopic images generated at the rate equal to the changed irradiation rate on the image display device; An image processing method comprising:

Images