JP2009261684A - Apparatus and method for fluoroscopy - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide fluoroscope capable of reducing exposure of a subject and quickly setting X-ray conditions. <P>SOLUTION: This fluoroscope 1 stores a final fluoroscopic image when stopping the fluoroscopy, and monitors the position of an X-ray diaphragm under suspension of the fluoroscopy to acquire diaphragm position information. When the position of the X-ray diaphragm is changed under suspension of the fluoroscopy, this fluoroscope 1 gives feedback to an X-ray control section, which controls an X-ray generator, to optimize the X-ray conditions of the X-ray generator based on the final fluoroscopic image and the diaphragm position information. This fluoroscope 1 is constantly set to the appropriate X-ray conditions when restarting fluoroscopy so as to improve the efficiency of the fluoroscopy and reduce unnecessary exposure of the subject. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an X-ray fluoroscopic apparatus for imaging a living tissue of a subject. Specifically, the present invention relates to an X-ray fluoroscopic apparatus that sets X-ray conditions before X-ray irradiation.

  An X-ray fluoroscopic apparatus is an apparatus that irradiates a subject with X-rays from an X-ray generator, detects X-rays transmitted through the subject with an X-ray detector, and configures and displays an X-ray fluoroscopic image. The X-ray fluoroscopic apparatus feeds back a signal detected by an X-ray detector to an X-ray generator and determines an X-ray condition (such as an X-ray dose to be irradiated).

  Conventionally, an X-ray fluoroscopic apparatus optimizes the X-ray dose to be irradiated according to the detected amount of X-rays that are transmitted through the subject while irradiating the subject with X-rays, and then the biological tissue of the subject. I was shooting.

  Further, when the position of the X-ray diaphragm provided on the subject side of the X-ray generator is changed, the range of X-rays exposed to the subject is changed. Therefore, every time the position of the X-ray diaphragm is changed, it is necessary to optimize the X-ray dose to be irradiated again.

  In order to reduce the additional X-ray exposure of the subject, a transmitter for transmitting the position of the X-ray diaphragm to the control computer is provided in the X-ray diaphragm, and the action of the video signal due to the diaphragm is simulated according to the diaphragm position. A method is disclosed (for example, see [Patent Document 1]).

JP-A-5-103263

However, [Patent Document 1] is a technique for calculating and displaying the effect of the diaphragm on the original captured image without actually irradiating the subject with X-rays. When obtaining a photographed image of a subject, it is necessary to determine an optimum X-ray dose for a diaphragm set while irradiating X-rays.
Therefore, the subject is exposed to unnecessary exposure while the X-ray dose is adjusted while actually adjusting the X-ray aperture.

  In the conventional fluoroscopic imaging apparatus, in order to optimize the fluoroscopic X-ray dose, it takes time until the X-ray dose becomes stable after the X-ray starts to be irradiated on the subject, and the image is fluoroscopically seen with an unstable X-ray dose. Is not an effective image, and there has been a problem that it is unnecessary exposure for the subject.

In particular, when the fluoroscopy is repeatedly stopped and resumed after the fluoroscopy is started, the X-ray fluoroscopic imaging apparatus optimizes the X-ray dose every time fluoroscopy is restarted. there were.
If the position of the X-ray diaphragm is changed between the stop of fluoroscopy and the restart of fluoroscopy, it takes more time to optimize the X-ray condition (X-ray dose), so unnecessary exposure of the subject becomes a problem. It was.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an X-ray fluoroscopic apparatus capable of reducing exposure of a subject and setting X-ray conditions quickly.

  A first invention for achieving the above-described object is an X-ray generator that irradiates a subject with X-rays, an X-ray diaphragm that adjusts an X-ray dose irradiated to the subject, and the subject that has passed through the subject. An X-ray fluoroscopic imaging apparatus comprising: an X-ray detector that detects X-rays; and a display device that configures and displays an X-ray fluoroscopic image based on detected X-ray information, and the fluoroscopy is performed when fluoroscopy is stopped. X-ray condition feedback signal is calculated based on the final image storage means for storing the final image, the aperture position information acquisition means for acquiring the aperture position information of the X-ray aperture, the fluoroscopic final image, and the aperture position information. An X-ray fluoroscopic apparatus comprising: a feedback signal calculating unit that performs an X-ray condition setting unit that sets an X-ray condition of the X-ray generator based on the X-ray condition feedback signal. .

  According to a first aspect of the present invention, an X-ray fluoroscopic apparatus stores a fluoroscopic final image when fluoroscopy is stopped, acquires aperture position information of an X-ray aperture, and an X-ray condition feedback signal based on the fluoroscopic final image and aperture position information. And the X-ray condition of the X-ray generator is set based on the X-ray condition feedback signal.

The X-ray diaphragm is disposed on the subject side of the X-ray generator. The X-ray diaphragm restricts the X-ray bundle irradiated to the subject to a necessary visual field, and suppresses exposure and generation of scattered radiation.
The fluoroscopic final image is a fluoroscopic image acquired immediately before fluoroscopy / imaging stop by the X-ray fluoroscopic imaging apparatus. The stored fluoroscopic final image is updated every time fluoroscopy / photographing is stopped.
The X-ray condition set based on the X-ray condition feedback signal is a voltage / current value applied by the X-ray generator. The X-ray dose output from the X-ray generator 5 is determined depending on the voltage / current values which are X-ray conditions.

  In the first invention, since the X-ray fluoroscopic apparatus calculates the X-ray condition feedback signal based on the final fluoroscopic image and the aperture position information, the X-ray condition is quickly set and unnecessary for the subject. Exposure can be reduced.

In addition, the X-ray fluoroscopic apparatus uses an X-ray generator based on statistical values calculated based on the pixel values of the final fluoroscopic image and the changed aperture position information in response to the change in the position of the X-ray aperture. The X-ray condition feedback signal to be set may be calculated.
Further, the X-ray fluoroscopic apparatus may calculate an X-ray condition feedback signal according to a manually selected X-ray fluoroscopic image division mode. Since the position of the X-ray aperture for the division mode is set in advance, it is not necessary to acquire aperture position information, and the X-ray condition feedback signal can be calculated quickly.

  According to a second aspect of the present invention, an X-ray generator that irradiates a subject with X-rays, an X-ray diaphragm that adjusts an X-ray dose irradiated to the subject, and X-ray detection that detects X-rays transmitted through the subject X-ray fluoroscopic imaging method in an X-ray fluoroscopic imaging apparatus comprising: a display device; and a display device configured to display and display an X-ray fluoroscopic image based on detected X-ray information, wherein the fluoroscopic final image when fluoroscopy is stopped A final image storing step for storing X, an aperture position information acquiring step for acquiring aperture position information of the X-ray aperture, a feedback for calculating an X-ray condition feedback signal based on the fluoroscopic final image and the aperture position information An X-ray fluoroscopy method comprising: a signal calculating step; and an X-ray condition setting step for setting an X-ray condition of the X-ray generator based on the X-ray condition feedback signal.

  2nd invention is invention regarding the X-ray fluoroscopy method in the X-ray fluoroscopy apparatus of 1st invention.

  According to the present invention, it is possible to provide an X-ray fluoroscopic apparatus capable of reducing exposure of a subject and setting X-ray conditions quickly.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description and the accompanying drawings, the same reference numerals are given to the constituent elements having the same functional configuration, and the redundant description will be omitted.

(1. Configuration of X-ray fluoroscopic apparatus 1)
First, the configuration of the X-ray fluoroscopic apparatus 1 will be described with reference to FIG.
FIG. 1 is a diagram showing a configuration of the X-ray fluoroscopic apparatus 1.
The X-ray fluoroscopic apparatus 1 includes an X-ray tube 3 that irradiates a subject 17 fixed to a table 15 with X-rays, an X-ray generator 5 that applies voltage / current to the X-ray tube 3, and unnecessary X-rays. An X-ray movable aperture 9 that blocks the X-ray, an X-ray detector 19 that detects the irradiated X-ray 13 that is disposed opposite to the X-ray tube 3 and passes through the subject 17, an image display device 25 that displays an X-ray fluoroscopic image, and the like Consists of

The X-ray control unit 7 controls an X-ray condition that is a voltage / current value applied by the X-ray generator 5. The X-ray dose output from the X-ray generator 5 depends on the X-ray conditions. The X-ray control unit 7 changes the X-ray condition based on the X-ray condition change instruction information (feedback signal 45) sent from the feedback control unit 31.
The X-ray movable diaphragm control unit 11 controls the position, shape, and the like of the X-ray movable diaphragm 9 according to the diaphragm operation instruction information sent from the operation unit (diaphragm operation unit) 29.

The X-ray detection data reading unit 21 reads the fluoroscopic image information detected by the X-ray detector 19, and the image processing unit 23 processes the read fluoroscopic image information. Specifically, the image processing unit 23 performs various correction processes such as offset correction and gain correction on the read fluoroscopic image information, and further performs dynamic range compression processing and filter processing on the corrected fluoroscopic image information. The X-ray fluoroscopic image for one frame is generated by performing various image processing such as the above. For example, the image processing unit 23 generates an X-ray fluoroscopic image of 30 frames per second.
An image display device 25 such as a CRT or a liquid crystal display device displays an X-ray fluoroscopic image subjected to image processing.

  The operation unit (aperture operation unit) 29 is an aperture position change operation unit that is manually operated by an operator, or an aperture setting unit that sets a diaphragm position that is set in advance using a division button or the like. For example, the position of the left and right diaphragms in the vertical direction and the position of the upper and lower diaphragms in the horizontal direction can be set independently by an operator's manual operation. For example, when a division button such as vertical two divisions, horizontal two divisions, or four divisions of an image is pressed, each aperture position information registered in advance is read and an aperture position is set.

  When the operation unit (aperture operation unit) 29 is operated, the X-ray movable diaphragm control unit 11, the X-ray condition control unit 27, the feedback control unit 31, and the X-ray control unit 7 perform the X-ray condition of the X-ray generator 5. The change process is performed.

  When the operation unit (aperture operation unit) 29 is operated, position change instruction information is sent from the X-ray movable aperture control unit 11 to the X-ray movable aperture 9 to change the aperture position, and at the same time to the X-ray condition control unit 27. The aperture position change information (aperture position information 43) is notified.

The X-ray condition control unit 27 uses the aperture position change information (aperture position information 43) sent from the X-ray movable aperture control unit 11 and the fluoroscopic image information (X-ray fluoroscopic image pixel value 41) sent from the image processing unit 23. Based on this, a statistical value (for example, an average pixel value 44) relating to the X-ray condition change is calculated and sent to the feedback control unit 31. Details of the processing of the X-ray condition control unit 27 will be described later.
The feedback control unit 31 sends X-ray condition change instruction information (feedback signal 45) to the X-ray control unit 7.

(2. Configuration of X-ray condition control unit 27)
Next, the configuration and processing details of the X-ray condition control unit 27 will be described with reference to FIG.
FIG. 2 is a diagram showing a configuration of the X-ray condition control unit 27.

  The X-ray condition control unit 27 includes an image acquisition unit 33, a pixel value calculation unit 35, an aperture position information acquisition unit 37, and an effective visual field calculation unit 39. The image acquisition unit 33 acquires fluoroscopic image information (X-ray fluoroscopic image pixel value 41) from the image processing unit 23 and sends it to the pixel value calculation unit 35.

  The aperture position information acquisition unit 37 acquires the aperture position information 43 from the X-ray movable aperture control unit 11 and sends it to the effective visual field calculation unit 39. The effective visual field calculation unit 39 calculates, as an effective visual field, a range in which the X-ray exposure range is limited by the X-ray movable diaphragm 9 and is actually irradiated with X-rays.

  The pixel value calculation unit 35 is a statistic for controlling the X-ray condition based on the fluoroscopic image information (X-ray fluoroscopic image pixel value 41) and the calculated effective visual field for a predetermined pixel area (lighting field area). A value (average pixel value 44) is calculated and sent to the feedback control unit 31.

(3. Hardware configuration of X-ray condition control unit 27)
FIG. 3 is a diagram illustrating a hardware configuration of the X-ray condition control unit 27.
The X-ray condition control unit 27 is configured by connecting a CPU 111, a main memory 103, a storage device 105, a display memory 107, an image display device 25, and a mouse 111 and a keyboard 113 connected to the controller 109 via a system bus 115. . The X-ray condition control unit 27 acquires input information 117 from another device via the system bus 115 and sends output information 119 to the other device.

  The CPU 101 is a device that controls the operation of each component. The CPU 101 loads a program stored in the storage device 105 and data necessary for program execution into the main memory 103 and executes the program. The storage device 105 is a device that stores fluoroscopic image information fluoroscopically / photographed by the X-ray fluoroscopic imaging device 1. The storage device 105 stores a program executed by the CPU 101 and data necessary for program execution. The main memory 103 stores programs executed by the CPU 101 and the progress of arithmetic processing.

  The mouse 111 and the keyboard 113 are operation devices for an operator to give an operation instruction to the fluoroscopic imaging apparatus 1. The display memory 107 stores display data to be displayed on the image display device 25 such as a liquid crystal display or a CRT. The controller 109 detects the state of the mouse 111, detects the position of the mouse pointer on the image display device 25, and outputs a detection signal to the CPU 101.

  The input information 117 is, for example, the X-ray fluoroscopic image pixel value 41 sent from the image processing unit 23 or the aperture position information 43 sent from the X-ray movable aperture control unit 11. The output information 119 is, for example, an average pixel value 44 sent to the feedback control unit 31. The input information 117 and the output information 119 are transmitted and received online via the system bus 115, but may be transmitted and received via a network or the like.

  Although the hardware configuration of the X-ray condition control unit 27 has been described above, the X-ray detection data reading unit 21, the image processing unit 23, the X-ray movable diaphragm control unit 11, the X-ray control unit 7, the feedback control unit 31, and the like are also included. Each may have the same configuration as that of the X-ray condition control unit 27 or may partially share the hardware configuration.

<First Embodiment>
(4. Operation of X-ray fluoroscopic apparatus 1)
Next, the first embodiment will be described with reference to FIGS.

(4-1. Overall operation)
FIG. 4 is a flowchart showing the overall operation of the X-ray fluoroscopic apparatus 1.
The operator fixes the subject 17 to the table 15 and turns on the X-ray fluoroscopic switch (step 1001). When the X-ray fluoroscopic switch is turned on, X-rays are emitted from the X-ray tube 3 toward the subject 17 (step 1002).

  The X-ray condition control unit 27 determines whether or not the fluoroscopic final image is stored in the storage device 105 (step 1003). Note that the fluoroscopic final image stored in the storage device 105 may be deleted when a predetermined time (for example, 30 minutes) elapses from the storage. Further, at the start of the first X-ray fluoroscopic imaging related to the subject 17, the final fluoroscopic image is not stored.

  If the fluoroscopic final image is not stored in the storage device 105 (NO in step 1003), the X-ray condition control unit 27 executes an X-ray condition determination process (1) (step 1004).

(4-2. X-ray condition determination process (1))
Next, the X-ray condition determination process (1) will be described with reference to FIG.
FIG. 5 is a flowchart showing the X-ray condition determination process (1).

  The irradiated X-ray 13 passes through the subject 17, is detected by the X-ray detector 19, and is read by the X-ray detection data reading unit 21. The detected transmitted X-ray is processed by the image processing unit 23. The image acquisition unit 33 of the X-ray condition control unit 27 acquires fluoroscopic image information (X-ray fluoroscopic image pixel value 41) from the image processing unit 23 (step 2001).

FIG. 8 is a diagram for explaining the fluoroscopic image information 201 and the daylighting field area 59. The lighting field area 59 is a pixel area for which a feedback signal is calculated.
The fluoroscopic image information 201 is data of a fluoroscopic image displayed on the image display device 25, and is acquired as an X-ray fluoroscopic image pixel value 41 from the image processing unit 23. The pixel area of the fluoroscopic image information 201 does not necessarily match the daylight field area 59. For example, when the effective visual field is narrowed by the X-ray movable diaphragm 9, the pixel area of the fluoroscopic image information 201 may be narrower than the lighting field area 59.
The pixel value calculation unit 35 calculates the average pixel value 44 of all the pixels in the daylighting field area 59 based on the fluoroscopic image information 201, and outputs it to the feedback control unit 31 (step 2002). The pixel value calculation unit 35 calculates a pixel value of a pixel that is not included in the pixel area of the fluoroscopic image information 201 and belongs to the daylighting field area 59 as a black value (pixel value “0”).

The feedback control unit 31 has a conversion table or conversion formula for converting the average pixel value 44 of the lighting field area 59 into the feedback signal 45. The feedback control unit 31 converts the average pixel value 44 into a feedback signal 45 and sends it to the X-ray control unit 7 (step 2003).
The X-ray control unit 7 changes the voltage / current applied to the X-ray generator 5 based on the feedback signal 45, and changes the X-ray dose (X-ray condition) irradiated by the X-ray generator 5 (step 2004). .

  Thus, in the X-ray condition determination process (1), the X-ray condition control unit 27 sends the average pixel value 44 of the lighting field region 59 to the feedback control unit 31 with the X-ray fluoroscopic switch ON, and the feedback control unit 31 31 converts the average pixel value 44 into a feedback signal 45 and sends it to the X-ray controller 7, which optimizes the X-ray conditions of the X-ray generator 5.

  By executing the X-ray condition determination process (1) (the process from step 2001 to step 2004), the X-ray condition of the X-ray fluoroscopic apparatus 1 is optimized, and a stable X-ray fluoroscopic image of the subject 17 is obtained. Obtainable. After executing the X-ray condition determination process (1), the process proceeds to step 1005 (FIG. 4).

(4-3. Relationship between processing of X-ray fluoroscopic apparatus 1 and X-ray irradiation time)
Here, the relationship between the process of the X-ray fluoroscopic apparatus 1 and the X-ray irradiation time will be described.
FIG. 7 is a diagram showing the relationship between the processing of the X-ray fluoroscopic apparatus 1 and the X-ray irradiation time. The vertical axis represents time 51. Time T ₁ to time T ₆ indicate the required time.

The first fluoroscopy of the subject 17 is defined as fluoroscopy (1) 53. The fluoroscopy that has been resumed after the fluoroscopy is stopped is referred to as fluoroscopy (2) 55 and fluoroscopy (3) 57. Fluoroscopy (1) 53, fluoroscopy (2) 55, and fluoroscopy (3) each time required for 57 time _{T 1,} a _{T 6} time _{T 4,} and the time during which fluoroscopic X-ray is irradiated to the object 17 The
Note that during the period of time T ₃ and time T ₅ , the fluoroscopy of the X-ray fluoroscopic imaging apparatus 1 is stopped, and during that time, the subject 17 is not irradiated with fluoroscopic X-rays.

The time T ₂ required for the first fluoroscopy (1) 53 X-ray condition determination process (1) (the process from step 2001 to step 2004) is a time for optimizing the X-ray condition before fluoroscopy. During the time T ₂ of the X-ray condition determination process (1), the object 17 will be subjected to unnecessary radiation exposure.

(4-4. Execution of fluoroscopic imaging and storage of final fluoroscopic image)
After completion of the X-ray condition determination process (1) (FIG. 4: step 1004) or when the fluoroscopic final image is stored in the storage device 105 in step 1003 (FIG. 4), the X-ray fluoroscopic imaging apparatus 1 17 X-ray fluoroscopic imaging is executed (step 1005). As will be described later, when the fluoroscopic final image is stored in the storage device 105, the X-ray condition of the X-ray fluoroscopic apparatus 1 has already been optimized.

  In addition, when X-ray fluoroscopic imaging is being executed (step 1005), when the position of the diaphragm is changed by the operator, the average pixel value 44 of the lighting field region 59 changes, so that feedback processing by the X-ray condition control unit 27 and the like is performed. And the X-ray conditions are changed. That is, as in the X-ray condition determination process (1) in step 1004, feedback processing is performed based on the average pixel value 44 of the lighting field area 59, and the X-ray conditions are optimized.

The operator turns off the X-ray fluoroscopic switch of the X-ray fluoroscopic imaging apparatus 1 to stop the X-ray fluoroscopy (step 1006). The time required for fluoroscopy from step 1001 to step 1006 is indicated by time T ₁ of fluoroscopy (1) 53 (FIG. 7).

  The X-ray fluoroscopic apparatus 1 stores the most recent fluoroscopic image of the X-ray fluoroscopic switch OFF in the storage device 105 (step 1007). The fluoroscopic image that is closest to the X-ray fluoroscopic switch OFF is taken as the final fluoroscopic image.

(4-5. X-ray condition determination process (2))
The X-ray fluoroscopic apparatus 1 executes X-ray condition determination processing (2) after the X-ray fluoroscopic switch is turned OFF (step 1008).
The X-ray condition determination process (2) will be described with reference to FIG.
FIG. 6 is a flowchart showing the X-ray condition determination process (2).
The X-ray condition control unit 27 acquires a fluoroscopic final image that is the X-ray fluoroscopic image pixel value 41 from the image processing unit 23 (step 3001).

  Next, the X-ray condition control unit 27 acquires the aperture position information 43 from the X-ray movable aperture control unit 11 (step 3002). The acquired aperture position information 43 corresponds to the shape and area of the effective visual field of the final fluoroscopic image.

  When there is no change in the aperture position information 43 in the fluoroscopic stop state (NO in step 3003) and the X-ray fluoroscopic switch is OFF (NO in step 3009), the X-ray fluoroscopic imaging apparatus 1 does not perform processing. Keep the state of fluoroscopy stopped.

  When there is no change in the aperture position information 43 in the state where fluoroscopy is stopped (NO in step 3003), and when the X-ray fluoroscopy switch is turned on (YES in step 3009), the X-ray fluoroscopic imaging apparatus 1 uses the X-ray condition. The determination process (2) is terminated, and the X-ray condition is not changed, and the process returns to step 1002 (FIG. 4). In the next step 1003, since the final fluoroscopic image is stored (YES in step 1003), the X-ray fluoroscopic apparatus 1 immediately executes the X-ray fluoroscopic imaging process (step 1005).

Perspective processing from the X-ray fluoroscopy switch ON (YES in step 3009) until the X-ray fluoroscopy switch OFF (step 1006) is shown in phantom (2) 55 (FIG. 7), the time required for fluoroscopy process is a _{T 4} . Since the fluoroscopic final image is stored, the X-ray condition determination processing (1) as in the case of fluoroscopy (1) 53 is not necessary.

Returning to step 3003 (FIG. 6), when the operator operates the operation unit 29 and the aperture position information 43 is changed (YES in step 3003) in the state of fluoroscopy stop, the X-ray condition control unit 27 Based on the stored fluoroscopic final image, the average pixel value of the lighting field area 59 is calculated (step 3004).
That is, the average pixel value P _x of the pixel values P _{0 to} P _n of all the pixels in the lighting field area 59 is calculated.

  The X-ray condition control unit 27 acquires the aperture position information 43 after the aperture position change from the X-ray movable aperture control unit 11, calculates the effective field of view based on the aperture position information 43, and the lighting field after the aperture position change. An average pixel value 44 of the region 59 is calculated (step 3005).

With reference to FIG. 9, the aperture position change and the calculation process (X-ray condition calculation process) of the average pixel value 44 of the lighting field area 59 after the aperture position change will be described.
FIG. 9 is a diagram showing an X-ray condition calculation image 202.

  The aperture position information acquisition unit 37 of the X-ray condition control unit 27 uses, as the aperture position information 43 after the aperture position change, aperture left wing coordinates (X1) 65-1, aperture right wing coordinates (X2) 65-2, aperture upper wings. A coordinate (Y1) 65-3 and a diaphragm lower wing coordinate (Y2) 65-4 are acquired. The effective visual field calculation unit 39 calculates an effective visual field (S2) 63 after changing the aperture position.

The pixel value calculation unit 35 replaces the pixel value of a pixel in the lighting field area 59 that is not within the range of the effective field of view 63 after changing the aperture position with the black value (pixel value “0”), thereby changing the original lighting field area 59. Are replaced with P _{m0 to} P _mn . The pixel value calculation unit 35 calculates the average value P _mx of the pixel values P _{m0 to} P _{mn and} sets it as the average pixel value 44 of the lighting field region 59.

The pixel value calculation unit 35 outputs the average pixel value 44 of the lighting field area 59 after changing the aperture position to the feedback control unit 31 (step 3006).
The feedback control unit 31 converts the average pixel value 44 (P _mx ) into a feedback signal 45 based on the conversion table or the conversion formula, and sends it to the X-ray control unit 7 (step 3007).
The X-ray control unit 7 changes the voltage / current applied to the X-ray generator 5 based on the feedback signal 45, and changes the X-ray dose (X-ray condition) irradiated by the X-ray generator 5 (step 3008). .

  While the X-ray fluoroscopic switch is OFF (NO in step 3009), the X-ray condition control unit 27 repeats the processing from step 3003 to step 3009, and changes the X-ray condition every time the aperture position information 43 is changed. I do.

  When the X-ray fluoroscopic switch is turned on (YES in Step 3009), the X-ray fluoroscopic imaging apparatus 1 ends the X-ray condition determining process (2) and returns to Step 1002 (FIG. 4). In the next step 1003, since the final fluoroscopic image is stored (YES in step 1003), the X-ray fluoroscopic apparatus 1 immediately executes the X-ray fluoroscopic imaging process (step 1005). In this case, while the X-ray fluoroscopic switch is OFF, the X-ray fluoroscopic imaging apparatus 1 executes the X-ray condition determining process (2) (step 1008) to optimize the X-ray conditions.

Perspective processing from the X-ray fluoroscopy switch ON (YES in step 3009) until the X-ray fluoroscopy switch OFF (step 1006) is shown in phantom (3) 57 (FIG. 7), the time required for fluoroscopy treatment is _{T 6} . Fluoroscopy (2) 55 for a time _{T 5} from after the end until the fluoroscopic (3) 57 starts, X-rays condition determination processing (2) (step 1008) is executed, X-rays condition for each the aperture position is changed Is optimized. Also in the case of fluoroscopy (3) 57, since the final fluoroscopic image is already stored, the X-ray condition determination process (1) as in the case of fluoroscopy (1) 53 is not necessary.

  In the X-ray condition determination process (2), the X-ray condition control unit 27 calculates the average pixel value of all the pixels in the lighting field area 59 after changing the aperture position and outputs it to the feedback control unit 31. However, the median value of all pixels may be used instead of the average pixel value of all pixels.

(4-6. Effects of the first embodiment)
As described above, in the first embodiment, the X-ray fluoroscopic apparatus 1 optimizes the X-ray condition of the X-ray generator every time there is a change in the position of the X-ray diaphragm while the fluoroscopy is stopped. The X-ray conditions have already been adjusted appropriately. Therefore, when the X-ray fluoroscopic imaging is repeatedly stopped and fluoroscopically restarted for the same subject, it is not necessary to optimize the X-ray conditions when the fluoroscopy is resumed, so that efficient imaging can be performed and unnecessary for the subject. Exposure can be reduced.

Second Embodiment
(5. Image division mode setting)
Next, a second embodiment will be described with reference to FIGS.
The X-ray fluoroscopic apparatus 1 according to the second embodiment includes a division button in which image division is set in advance as an operation unit (aperture operation unit) 29.

  FIG. 10 is a diagram showing a vertically divided screen 203 using a vertically divided button. When the operator selects the vertically divided button on the operation unit (aperture operation unit) 29, the aperture position is set to the left aperture coordinate (X1) 69-1 and the right aperture coordinate (X2) 69 registered in advance. -2 is set in advance so that an effective visual field 67 is obtained.

  FIG. 11 is a diagram showing a horizontally divided screen 204 using a horizontally divided button. When the horizontal two-divided button of the operation unit (aperture operation unit) 29 is selected, the aperture position is set to the aperture upper wing coordinate (Y1) 73-1 and aperture lower wing coordinate (Y2) 73-2 registered in advance. The effective field of view 71 is obtained in advance.

  FIG. 12 is a diagram showing a four-divided screen 205 with four-divided buttons. When the four-division button of the operation unit (aperture operation unit) 29 is selected, the aperture position is registered as a left diaphragm coordinate (X1) 69-1, a right diaphragm coordinate (X2) 69-2, a diaphragm, The upper wing coordinate (Y1) 73-1 and the aperture lower wing coordinate (Y2) 73-2 are changed to be set in advance so that an effective visual field 75 is obtained.

When the division button is selected while fluoroscopy / photographing is stopped, the X-ray movable diaphragm 9 is switched to the diaphragm position registered in advance corresponding to the division button, and the X-ray condition control unit 27 has an effective field of view corresponding to the diaphragm position. Get. The X-ray condition control unit 27 calculates the average pixel value 44 for the daylighting field region when the effective field of view is changed, and outputs the average pixel value 44 to the feedback control unit 31 to optimize the X-ray condition. Plan.
The X-ray fluoroscopic apparatus 1 selects the division button, so that the aperture position information acquisition process and the effective visual field calculation process by the X-ray condition control unit 27 become unnecessary. Efficiency can be improved.

  As described above, in the second embodiment, the effective field of view can be obtained immediately by selecting the division button, so that the process of calculating the effective field of view by detecting continuously changing aperture position information becomes unnecessary. The efficiency of the X-ray condition optimization process can be improved.

(6. Others)
Although the first embodiment and the second embodiment have been described above, the X-ray fluoroscopic apparatus 1 may be configured by combining them.

  The feedback signal may be calculated using a predetermined table that associates the average pixel value of the daylighting field area registered in advance with the feedback signal value, or may be calculated using a predetermined relational expression. Also good.

  The preferred embodiments of the X-ray fluoroscopic apparatus according to the present invention have been described above, but the present invention is not limited to such examples. It will be apparent to those skilled in the art that various changes or modifications can be conceived within the scope of the technical idea disclosed in the present application, and these are naturally within the technical scope of the present invention. Understood.

The figure which shows the structure of X-ray fluoroscopic imaging apparatus 1 The figure which shows the structure of the X-ray condition control part 27 The figure which shows the hardware constitutions of the X-ray condition control part 27 The figure which shows the flowchart of operation | movement of X-ray fluoroscopic imaging apparatus 1. The figure which shows the flowchart of a X-ray condition determination process (1). The figure which shows the flowchart of a X-ray condition determination process (2). The figure which shows the relationship between the process of X-ray fluoroscopic apparatus 1, and X-ray irradiation time The figure explaining fluoroscopic image information 201 and the lighting field area 59 The figure which shows the X-ray condition calculation image 202 The figure which shows the vertical 2 split screen 203 The figure which shows the horizontal 2 split screen 204 The figure which shows the quadrant screen 205

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ......... X-ray fluoroscopic imaging device 3 ......... X-ray tube 5 ......... X-ray generator 7 ......... X-ray control part 9 ......... X-ray movable diaphragm 11 ......... X-ray movable diaphragm control part 13... Irradiated X-ray 15... Table 17... Subject 19... X-ray detector 21... X-ray detection data reading unit 23. 27... X-ray condition control unit 29... Operation unit (aperture operation unit)
31 ......... Feedback control unit 33 ......... Image acquisition unit 35 ......... Pixel value calculation unit 37 ......... Aperture position information acquisition unit 39 ......... Effective visual field calculation unit 41 ......... X-ray fluoroscopic image pixel value 43 ......... Aperture position information 44 ......... Average pixel value 45 ......... Feedback signal 51 ......... Times 53, 55, 57 ......... Shooting 59 ......... Lighting field area 60, 63, 67, 71, 75 ... ...... Effective field of view 61... Biological tissue 65-1, 65-2, 65-3, 65-4, 69-1, 69-2, 73-1, 73-2. CPU
103 ......... Main memory 105 ......... Storage device 107 ......... Display memory 109 ......... Controller 111 ......... Mouse 113 ......... Keyboard 115 ......... System bus 117 ......... Input information 119 ......... Output Information 201... Perspective image information 202... X-ray condition calculation image 203... Vertically divided screen 204... Horizontally divided screen 205.

Claims (4)

An X-ray generator that irradiates the subject with X-rays, an X-ray diaphragm that adjusts an X-ray dose irradiated to the subject, an X-ray detector that detects X-rays transmitted through the subject, and A X-ray fluoroscopic apparatus comprising: a display device configured to display an X-ray fluoroscopic image based on X-ray information;
A final image storage means for storing the final fluoroscopic image when fluoroscopy is stopped;
Aperture position information acquisition means for acquiring aperture position information of the X-ray aperture;
Feedback signal calculating means for calculating an X-ray condition feedback signal based on the fluoroscopic final image and the aperture position information;
X-ray condition setting means for setting an X-ray condition of the X-ray generator based on the X-ray condition feedback signal;
An X-ray fluoroscopic apparatus comprising:   The feedback signal calculating means, based on the statistical value calculated based on the pixel value of the fluoroscopic final image and the changed aperture position information, corresponding to the change of the aperture position information, The X-ray fluoroscopic apparatus according to claim 1, wherein the X-ray condition feedback signal to be set is calculated.   The X-ray fluoroscopic imaging apparatus according to claim 2, wherein the feedback signal calculating unit calculates a feedback signal of an X-ray condition according to a manually selected X-ray fluoroscopic image division mode. An X-ray generator that irradiates the subject with X-rays, an X-ray diaphragm that adjusts an X-ray dose irradiated to the subject, an X-ray detector that detects X-rays transmitted through the subject, and A X-ray fluoroscopic imaging method in an X-ray fluoroscopic imaging apparatus comprising: a display device configured to display an X-ray fluoroscopic image based on X-ray information;
A final image storage step for storing the final fluoroscopic image when fluoroscopy is stopped;
An aperture position information acquisition step for acquiring aperture position information of the X-ray aperture;
A feedback signal calculation step of calculating an X-ray condition feedback signal based on the fluoroscopic final image and the aperture position information;
An X-ray condition setting step for setting an X-ray condition of the X-ray generator based on the X-ray condition feedback signal;
X-ray fluoroscopic imaging method comprising:

Images