JP6287817B2 - X-ray fluoroscopic equipment - Google Patents

Description

  The present invention relates to an X-ray fluoroscopic imaging apparatus that is effective for interventional treatment and the like that captures an image of a region including a device inserted into a body of a subject, and particularly emphasizes and emphasizes the device in the image. The present invention relates to a technique for displaying an image.

  In the medical field, interventional treatment (IVR: Interventional Radiography) is performed on a patient whose blood vessel is narrowed by atheroma or calcified blood vessel wall. In interventional therapy, a catheter having a guide wire and a device inside is inserted into a blood vessel of a subject, and a device is used to treat an affected area of a narrowed blood vessel.

  Examples of the device for performing an intravascular treatment include a stent that expands a vascular stenosis part, in addition to a roller blader that cuts a blood vessel wall. The stent is a grid-like cylindrical body made of a metal wire such as stainless steel, and a balloon is provided inside. In IVR, a stent is placed on a narrowed portion of a blood vessel. Then, the placed stent is expanded by a balloon to open the stent. By placing the expanded stent in the blood vessel, the narrowed portion of the blood vessel can be expanded and the blood flow can be kept normal.

  When performing an IVR technique using a stent, an X-ray image is acquired using an X-ray fluoroscopic apparatus in order to confirm the position of the stent. That is, the operator irradiates the subject with a low dose of X-rays, and continuously acquires X-ray images on which the catheter and stent are projected. The operator refers to the real-time X-ray image P continuously displayed, and confirms the position of the catheter or stent in the blood vessel as needed. Then, as shown in FIG. 8A, the catheter 103 is passed through the blood vessel 101 in the direction of the arrow so that the stent 105 reaches the stenosis 107, which is the affected part.

  The surgeon refers to the X-ray image P, confirms the positional relationship between the stenosis 107 and the stent 105 as needed, and inflates the balloon as shown in FIG. Expand. By tracing the blood vessel 101 and withdrawing the catheter 103 from the body of the subject, the expanded stent 105 is retained in the blood vessel, so that the blood flow in the affected area is kept normal.

  In recent years, a plurality of stents are often placed in order to improve the therapeutic effect. In this case, when a gap is generated between the stents, there is a possibility that the blood vessel is narrowed in the gap. Therefore, confirming the position of the stent in the blood vessel is extremely important in interventional treatment.

  Conventionally, in order to improve the visibility of a stent inserted into the body of a subject, X-ray images are continuously captured using a stent 105 having a radiopaque marker 109. Then, the captured X-ray images for a plurality of frames are superimposed. At the time of superposition, the position coordinates of the marker 109 are detected in each X-ray image, and the position of the stent 105 reflected in each X-ray image is matched with the detected marker 109 as a reference. By aligning the stent and superimposing the X-ray image, real-time image data in which the stent is highlighted can be acquired (see, for example, Patent Documents 1 and 2).

JP 2005-510288 A JP 2013-215247 A

However, the conventional example having such a configuration has the following problems.
That is, in the X-ray fluoroscopic apparatus according to the conventional example, when superimposing X-ray images, an object having high radiopacity, such as a pacemaker or a point where guide wires intersect, is erroneously recognized as a marker. There is a case. In this case, it is difficult to accurately highlight the stent because the stent is not accurately aligned.

  As a result of studying measures for preventing such erroneous recognition of marker analogs, the operator has obtained knowledge about a method for setting a marker detection range on an image with reference to an X-ray image. In IVR, the stent moves periodically so as to draw a constant trajectory according to the heartbeat of the subject. That is, as shown in FIG. 9A, X-ray images P generated in a cycle of one heartbeat are X-ray images Pa to Pe. The markers 109 reflected in the respective X-ray images Pa to Pe are referred to as markers 109a to 109e, respectively. In this case, the marker 109 moves along a locus K drawn by the markers 109a to 109e in the cycle of the heartbeat (FIG. 9B).

  Therefore, a predetermined region including the movement locus of the periodic marker 109 is set on the X-ray image on which the stent 105 is reflected by a method of enclosing and displaying the region L including the locus K with a cursor. Then, the marker is detected only within the set region L. In this case, it is possible to prevent the analog F of the marker 109 located outside the region L from being erroneously detected as the marker 109. Examples of the target for setting the marker movement locus area include any of the X-ray images Pa to Pe obtained as a still image, or a moving image that continuously displays the X-ray images Pa to Pe.

  However, when setting the range of the marker movement trajectory in the configuration according to the comparative example, there is a concern that the burden on the operator is heavy. That is, when the region L is set for the X-ray image Pa that is a still image, the operator cannot confirm the locus K without referring to each of the X-ray images Pa to Pe. At this time, since it is necessary to project all five X-ray images on the screen and to visually recognize the positions of the markers reflected in the respective X-ray images, the work of confirming the locus K becomes complicated. In actual operation, X-ray images obtained for one cycle of the heartbeat are several tens, so the operation of confirming the locus K becomes more complicated.

  Furthermore, the marker image shown in the X-ray image Pa is only the marker 109a. Therefore, when setting the region L in the X-ray image Pa, the operator needs to move the cursor while imagining the position of the marker locus K based on the position of the marker shown in each of the other X-ray images Pb to Pe. There is. As a result, the range of the region L displayed in the X-ray image Pa may be significantly different from the actual range of the locus K. In other words, there are cases where the trajectory K actually protrudes from the region L, or the region L is set in a wider range than necessary compared to the trajectory K (FIG. 9C).

  When the region L is set for a moving image based on the X-ray images Pa to Pe, the operator sets the region L with reference to the marker 109 that constantly moves. In this case, high concentration and skill are required to accurately enclose the locus K of the moving marker 109 with the cursor, so that the burden on the operator increases. As a result, the range of the region L displayed on the moving image may be significantly different from the actual range of the trajectory K.

  When the locus K protrudes from the set region L, the marker 109 that has moved out of the range of the region L cannot be detected, so that the marker 109 cannot be aligned. When the area L to be displayed is larger than necessary than the actual trajectory K, the marker analog F is included in the area L, so that erroneous marker detection occurs. As described above, in the apparatus according to the comparative example, it is difficult to set the region L in which the marker 109 moving along the locus K can be accurately and reliably detected.

  The present invention has been made in view of such circumstances, and provides an X-ray fluoroscopic imaging apparatus that can preferably avoid erroneous detection of a marker when superimposing X-ray images of a stent in interventional therapy. For the purpose.

In order to achieve such an object, the present invention has the following configuration.
That is, the X-ray fluoroscopic apparatus according to the present invention detects an X-ray source that irradiates a subject with X-rays, and X-rays that have passed through the subject and an X-ray opaque marker, and outputs a detection signal. X-ray detection means for generating, an image generation means for generating an X-ray image for each predetermined frame period using the detection signal, and a locus generation for generating a locus of the marker based on the plurality of X-ray images And an attention area setting means for setting an area including the locus as an attention area, and the X-ray generated by the image generation means after the plurality of X-ray images used for generation of the locus of the marker. It further has marker detecting means for detecting the position of the marker in the X-ray image by searching within the range of the attention area that is a part of the X-ray irradiation area in the image.

  [Operation / Effect] The X-ray fluoroscopic apparatus according to the present invention includes a trajectory generating means and an attention area setting means. The image generation means generates an X-ray image every predetermined frame period, and the locus generation means generates an X-ray opaque marker locus based on the plurality of X-ray images. The attention area setting means sets an area including the locus as the attention area. The operator can easily set the region of interest by referring to the marker trajectory generated by the trajectory generating means. Therefore, the burden on the operator when setting the attention area can be reduced.

The marker detection means searches for the region of the attention area that is a part of the X-ray irradiation area in the X-ray image generated by the image generation means after the plurality of X-ray images used for generating the marker trajectory . The position of the marker is detected from the X-ray image. Since the region of interest includes a trajectory traced by the marker periodically, the marker detection unit can reliably detect the position of the marker from the X-ray image by searching within the region of the region of interest in the X-ray image.

Furthermore, even when a similar marker is shown in the X-ray image, the marker detection unit avoids erroneous recognition of the similar as a marker by setting the position of the similar object outside the region of interest. it can. As a result, since the marker can be detected more reliably, the operator can execute more precise interventional treatment.
In order to achieve such an object, the present invention may take the following configurations.
That is, the X-ray fluoroscopic apparatus according to the present invention detects an X-ray source that irradiates a subject with X-rays, and X-rays that have passed through the subject and an X-ray opaque marker, and outputs a detection signal. X-ray detection means for generating, an image generation means for generating an X-ray image for each predetermined frame period using the detection signal, and a locus generation for generating a locus of the marker based on the plurality of X-ray images Means for displaying the marker trajectory generated by the trajectory generating means, input means for operating the surgeon and inputting information relating to the range selected by the operator as the region including the trajectory, A region-of-interest setting unit configured to set a region including the trajectory input by the input unit as a region of interest, and the image generating unit generates after the plurality of X-ray images used to generate the marker trajectory Shi The apparatus further comprises marker detection means for detecting the position of the marker in the X-ray image by searching within the range of the attention area that is a part of the X-ray irradiation area in the X-ray image. It is.
According to the fluoroscopic imaging apparatus of the present invention, the marker locus generated by the locus generating means is displayed by the display means. The operator can easily and precisely select a region including the locus by referring to the locus of the marker displayed by the display means. The selected area is input to the input means and set as the attention area. Therefore, the burden on the operator when setting the attention area can be reduced.

  In the above-described invention, it is preferable that the trajectory generating unit generates a composite image showing a trajectory traced by the marker periodically by adding the plurality of X-ray images.

  [Operation / Effect] According to the fluoroscopic imaging apparatus of the present invention, the trajectory generating means generates a composite image showing a trajectory traced by a marker periodically by adding a plurality of X-ray images. Since the marker is radiopaque, the pixel value corresponding to the marker position is significantly different from that of the other pixels. For this reason, in a composite image generated by adding a plurality of X-ray images, the pixel value differs between the pixel corresponding to the locus followed by the marker and the other pixels. Accordingly, the operator can easily confirm the trajectory that the marker periodically follows with reference to the composite image, and thus it is possible to easily set the attention area including the trajectory that the marker periodically follows.

  In the above-described invention, it is preferable that the composite image generated by the trajectory generation unit is a peak hold image.

  [Operation / Effect] According to the fluoroscopic imaging apparatus of the present invention, the trajectory generating means generates a peak hold image based on a plurality of X-ray images. The peak hold image is an image generated by selecting a minimum value (or maximum value) of pixel values for each pixel at the same position for each X-ray image. Since the marker is radiopaque, the pixel value corresponding to the marker position is significantly different from that of the other pixels. That is, in the peak hold image, an X-ray image of the marker is shown in the pixel corresponding to the trajectory followed by the marker. Therefore, the pixel value differs greatly between the pixel corresponding to the locus followed by the marker and the other pixels. Accordingly, the operator can more easily confirm the trajectory that the marker periodically follows with reference to the composite image, and thus it is possible to more easily set the attention area including the trajectory that the marker periodically follows.

  The X-ray fluoroscopic apparatus according to the present invention includes a trajectory generating unit and an attention area setting unit. The image generation means generates an X-ray image every predetermined frame period, and the locus generation means generates an X-ray opaque marker locus based on the plurality of X-ray images. The attention area setting means sets an area including the locus as the attention area. The operator can easily set the region of interest by referring to the marker trajectory generated by the trajectory generating means. Therefore, the burden on the operator when setting the attention area can be reduced.

  The marker detection means detects the position of the marker from the X-ray image by searching within the region of interest. Since the region of interest includes a trajectory traced by the marker periodically, the marker detection unit can reliably detect the position of the marker from the X-ray image by searching within the region of the region of interest in the X-ray image.

  Furthermore, even when a similar marker is shown in the X-ray image, the marker detection unit avoids erroneous recognition of the similar as a marker by setting the position of the similar object outside the region of interest. it can. As a result, since the marker can be detected more reliably, the operator can execute more precise interventional treatment.

It is a front view explaining the structure of the X-ray fluoroscopic imaging apparatus which concerns on an Example. It is a functional block diagram explaining the structure of the X-ray fluoroscopic apparatus which concerns on an Example. It is the schematic explaining the structure of the catheter system which concerns on an Example. It is a flowchart explaining the process of an operation | movement of an Example. It is the schematic explaining the process of step S2 which concerns on an Example. The upper diagram shows a series of X-ray images detected by the X-ray image detector, and the lower diagram shows a peak hold image generated based on the series of X-ray images. It is the schematic explaining the process of step S3 which concerns on an Example. (A) is a figure which shows the attention area set in an Example, (b) is a figure which shows the attention area set in a modification. It is the schematic explaining the process of step S5 which concerns on an Example. The upper diagram is a diagram showing each X-ray image R from which feature points have been detected, the lower left diagram is a diagram showing an integrated image generated by superimposing X-ray images, and the lower right diagram is an integrated image superimposed. It is the figure which cut out and expanded. It is a figure explaining the process of IVR which concerns on a prior art example. (A) is a figure explaining the process of reaching a stent to a stenosis part, (b) is a figure explaining the process of detaining the expanded stent in a stenosis part. It is a figure explaining the structure of the comparative example with respect to the trouble of a prior art example. (A) is a figure which shows the position of the stent and marker which are reflected in each X-ray image in each period of a heartbeat, (b) is a figure explaining the locus | trajectory which a marker follows periodically, (c) is a comparison. It is a figure which shows the problem of the attention area set in the example.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a front view illustrating the configuration of the X-ray fluoroscopic apparatus according to the embodiment, and FIG. 2 is a functional block diagram illustrating the configuration of the X-ray fluoroscopic apparatus according to the embodiment.

<Description of overall configuration>
The X-ray fluoroscopic imaging apparatus 1 according to the embodiment includes a top plate 3 on which a subject M taking a horizontal posture is placed, an X-ray tube 5 that irradiates the subject M with X-rays, and an X-ray tube 5. And an X-ray detector 7 for detecting the irradiated X-ray and converting it into a charge signal. The X-ray tube 5 and the X-ray detector 7 are arranged to face each other with the top plate 3 interposed therebetween.

  The X-ray detector 7 has a detection surface for detecting X-rays, and X-ray detection elements are two-dimensionally arranged on the detection surface. In the embodiment, a flat panel detector (FPD) is used as the X-ray detector 7. The X-ray tube 5 corresponds to the X-ray source in the present invention, and the X-ray detector 7 corresponds to the X-ray detection means in the present invention.

  The X-ray tube 5 and the X-ray detector 7 are provided at one end and the other end of the C-arm 9, respectively. The C-shaped arm 9 is held by an arm holding member 11 and is configured to slide along the arc path of the C-shaped arm 9 indicated by reference sign RA. The arm holding member 11 is disposed on the side surface portion of the support column 13 and can rotate around the horizontal axis RB parallel to the x direction (the longitudinal direction of the top 3 and the body axis direction of the subject M). Configured as follows. The C-shaped arm 9 held by the arm holding member 11 rotates around the axis in the x direction according to the arm holding member 11.

  The support column 13 is supported by a support base 15 disposed on the floor surface, and is configured to be horizontally movable in the y direction (the short direction of the top plate 3). The arm support member 11 and the C-arm 9 supported by the support column 13 move in the y direction according to the horizontal movement of the support column 13. The collimator 17 is provided in the X-ray tube 5 and limits the X-rays emitted from the X-ray tube 5 to a cone shape that is a pyramid.

  Here, the configuration of the X-ray imaging apparatus 1 will be described in more detail. As shown in FIG. 2, the X-ray imaging apparatus 1 includes an X-ray irradiation control unit 19, a detector control unit 21, an arm drive control unit 23, and an image processing unit 25. The X-ray irradiation control unit 19 is configured to output a high voltage to the X-ray tube 5. Based on the high voltage output given by the X-ray irradiation control unit 19, the X-ray dose irradiated by the X-ray tube 5 and the timing of X-ray irradiation are controlled. The detector control unit 21 controls the operation of reading the charge signal converted by the X-ray detector 7, that is, the X-ray detection signal.

  The arm drive control unit 23 controls the sliding movement of the C-arm 9. As the C-arm 9 slides in the direction indicated by the symbol RA, the spatial positions of the X-ray tube 5 and the X-ray detector 7 change while maintaining the opposed arrangement state. The arm drive control unit 23 controls the rotational movement of the arm support member 11 in addition to the sliding movement of the C-arm 9. Since the X-ray tube 5 and the X-ray detector 7 are provided on the C-type arm 9, the spatial positions of the X-ray tube 5 and the X-ray detector 7 are changed in accordance with the rotational movement of the arm support member 11 while maintaining the opposed arrangement state.

  The image processing unit 25 includes an X-ray image generation unit 27, an X-ray image detection unit 29, a peak hold image generation unit 31, an attention area display unit 33, a feature point detection unit 35, and an integration unit 37. ing. The image generation unit 27 is provided in a subsequent stage of the X-ray detector 7 and intermittently generates an X-ray image based on the X-ray detection signal output from the X-ray detector 7. The X-ray image detection unit 29 is provided in the subsequent stage of the image generation unit 27, and detects a predetermined plurality of X-ray images generated most recently among a series of generated X-ray images. The X-ray image generation unit 27 corresponds to image generation means in the present invention.

  The peak hold image generation unit 31 is provided at the subsequent stage of the X-ray image detection unit 29, and generates a peak hold image using a plurality of X-ray images detected by the X-ray image detection unit 29. The peak hold image is an image generated by selecting a minimum value (or maximum value) of pixel values for each pixel at the same position for each of a plurality of X-ray images. The peak hold image corresponds to the composite image in the present invention, and the peak hold image generation unit 31 corresponds to the locus generation means in the present invention.

  The attention area display section 33 is provided in the subsequent stage of the peak hold image generation section 31, and displays the attention area superimposed on the peak hold image in accordance with the instruction content input to the input section 39 described later. The feature point detection unit 35 is provided in the subsequent stage of the attention area display unit 33 and the X-ray image generation unit 27. The feature point detection unit 35 searches the range of the attention area set in the peak hold image for each of the X-ray images generated by the X-ray image generation unit 27 to detect the feature points.

  The integrating unit 37 is provided at the subsequent stage of the feature point detecting unit 35. The integrating unit 37 generates an integrated image by superimposing the X-ray images generated by the image generating unit 27 on the basis of the feature points detected by the feature point detecting unit 35. The feature point detection unit 35 corresponds to the marker detection means in the present invention.

  The X-ray imaging apparatus 1 further includes an input unit 39, a monitor 41, a storage unit 43, and a main control unit 45. The input unit 39 is used to input an operator's instruction, and examples thereof include a keyboard input type, mouse input type, or touch input type panel. The operator operates the input unit 39 to set a region of interest for the peak hold image. The input unit 39 corresponds to attention area setting means in the present invention.

  The monitor 41 displays various images such as X-ray images generated by the image generation unit 29. The storage unit 43 stores various images generated by the image generation unit 29, the peak hold image generation unit 31, and the like. The main control unit 45 controls each of the X-ray irradiation control unit 19, the detector control unit 21, the arm drive control unit 23, the image processing unit 25, the monitor 41, and the storage unit 43.

  FIG. 3 is a schematic view showing the configuration of a catheter system 46 used for interventional treatment. The catheter system 46 includes a catheter 47, a guide wire 49, and a stent 51. The guide wire 49 is inserted into the tubular catheter 47. The stent 51 is provided inside the catheter 47 and has a configuration that allows movement in the direction indicated by the arrow along the guide wire 49. The stent 51 corresponds to the device in the present invention.

  The stent 51 is formed in a cylindrical shape of a mesh by a metal wire such as stainless steel, and a balloon (not shown) is provided inside. The stent 51 includes a plurality of markers 53. In the embodiment, the number of markers 53 is two, but the number of markers 53 may be changed as appropriate. Of the two markers 53, one marker 53 </ b> A is provided on the distal end side of the stent 51, and the other marker 53 </ b> B is provided on the proximal end side of the stent 51.

  In the intervention treatment, the stent 51 is placed in a portion where the blood vessel is narrowed. The placed stent 51 is inflated with a balloon, and the inflated stent 51 is placed in the blood vessel, so that the blood vessel that has been narrowed can be expanded to keep the blood flow normal. Each of the markers 53 is made of a radiopaque material and clearly indicates the position of the stent 51 in the X-ray image. As an example of the material constituting the marker 53, metals such as gold, platinum, and tantalum can be cited. The stent 51 corresponds to the device in the present invention. The marker 53 corresponds to a feature point in the present invention.

<Description of operation>
Next, the operation of the X-ray fluoroscopic apparatus 1 according to the embodiment will be described. In the description, a process of performing interventional treatment using the X-ray fluoroscopic apparatus 1 will be used as an example. FIG. 4 is a flowchart for explaining an operation process of the X-ray fluoroscopic apparatus 1 according to the embodiment.

Step S1 (Generation of X-ray image)
In performing interventional treatment, first, a small hole is made in the base of the thigh of the subject M and the catheter system 46 is inserted into the blood vessel. And after inserting the catheter system 46, an X-ray image is continuously produced | generated by X-ray fluoroscopy. That is, a low dose of X-rays is intermittently emitted from the X-ray tube 5 to the subject M. X-rays transmitted through the subject M are detected by the X-ray detector 7. The detected X-ray is converted into an X-ray detection signal that is an electric signal, and the converted X-ray detection signal is output to the X-ray image generation unit 27.

  The X-ray image generation unit 27 intermittently generates an X-ray image P on which the catheter 47, the stent 51, and the like are projected, based on the output X-ray detection signal. In the embodiment, the X-ray image P is generated at a frame rate of about 15 to 30 FPS as an example. Each of the X-ray images P generated by the X-ray image generation unit 27 is transmitted to the X-ray image detection unit 29. The monitor 41 displays each of the X-ray images P generated intermittently in real time. The operator refers to the real-time X-ray image P displayed on the monitor 41 and causes the stent 51 to reach the stenosis portion of the blood vessel.

Step S2 (Generation of peak hold image)
When a new stent placement is performed, if there is a gap between the stent already placed, there is a possibility that the blood vessel will restenect. Therefore, particularly after the stent 51 has reached the stenosis, it is necessary to acquire an X-ray image with higher visibility of the stent 51 in order to confirm the precise position of the stent 51. As a characteristic configuration of the embodiment, in order to acquire an X-ray image with high visibility of the stent 51, a peak hold image is generated.

  In order to generate the peak hold image, first, the operator operates the input unit 39 to stop the X-ray irradiation and turns on the stent view mode. When the stent view mode is on, the main control unit 45 turns on each of the X-ray image detection unit 29, the peak hold image generation unit 31, the attention area display unit 33, the feature point detection unit 35, and the integration unit 37. State.

  The X-ray image detection unit 29 detects a series of X-ray images P generated during the most recent predetermined time T among the X-ray images P generated by the X-ray image generation unit 27. The predetermined time T is preferably a time corresponding to at least one cycle of the heartbeat of the subject M. As an example, when the predetermined time T is 2 seconds and the frame rate of the X-ray image P is 15 FPS, the X-ray image detection unit 29 detects the 30 X-ray images P generated most recently.

  Here, for convenience of explanation, it is assumed in the embodiment that the predetermined time T is a time corresponding to one heartbeat. In the embodiment, it is assumed that four frames of the X-ray image P are generated in one heartbeat. In this case, the X-ray image detection unit 29 detects X-ray images Pa to Pe as a series of X-ray images P generated most recently. Each of the detected X-ray images Pa to Pe is transmitted to the peak hold image generation unit 31.

  Note that the markers 53A reflected in the respective X-ray images Pa to Pe are referred to as markers 53Aa to 53Ae, respectively. In addition, the markers 53B reflected in the respective X-ray images Pa to Pe are set as markers 53Ba to 53Be, respectively (see the upper diagram of FIG. 5). In this case, since the X-ray image P generated in one cycle of heartbeat is four frames, the X-ray image Pa and the X-ray image Pe have the same phase. That is, the position of the X-ray image shown in the X-ray image Pa and the position of the X-ray image shown in the X-ray image Pe are substantially the same.

  The peak hold image generation unit 31 generates a peak hold image Q by selecting the minimum pixel value for each pixel at the same position for the X-ray images Pa to Pe detected by the X-ray image detection unit 29. Since the marker 53 is made of a radiopaque material, the pixel where the marker 53 is located has a very small pixel value compared to other pixels. Therefore, in the peak hold image Q, the X-ray image of the marker 53 is selected and reflected as the minimum pixel value in each of the pixels in which the marker 53 appears in any of the X-ray images Pa to Pe.

  Accordingly, the X-ray images of the markers 53Aa to 53Ae and the markers 53Ba to 53Be are all reflected in the peak hold image Q (see the lower diagram in FIG. 5). For convenience of explanation, in the peak hold image Q, an X-ray image having a configuration excluding the marker 53 is omitted. The image data of the peak hold image Q is transmitted to the attention area display unit 33 and displayed on the monitor 41.

Step S3 (Setting of attention area)
The operator refers to the peak hold image Q displayed on the monitor 41 and sets the attention area. The attention area is an area where the marker 53, which is a feature point, is detected in step S4 described later. As an example, the operator operates the input unit 39 to set the attention area L so that all the markers 53 shown in the peak hold image Q are within the area range (FIG. 6A). The attention area display unit 33 superimposes and displays the range of the attention area L on the peak hold image Q displayed on the monitor 41 in accordance with the instruction content input to the input unit 39. Note that when setting the attention area L, the attention area L is set so that the marker analog F is outside the range of the area.

  In the IVR, each of the stent 51 and the marker 53 periodically moves so as to draw a constant trajectory depending on the heartbeat of the subject. That is, the markers 53Aa to 53Ae move along the locus KA, and the markers 53Ba to 53Be move along the locus KB. (FIG. 6A). When the number of X-ray images detected by the X-ray image detection unit 29 is large, the peak hold image Q includes a large number of markers 53A located along the locus KA and a large number of markers 53B located along the locus KB. Reflect. Therefore, as the number of X-ray images detected by the X-ray image detection unit 29 increases, the operator can easily confirm the precise locus followed by the marker 53.

  As a configuration for setting the attention area L, there are a method of displaying a cursor in a range corresponding to the attention area L by a mouse operation or a joystick operation, and a method of directly writing a range corresponding to the attention area L on the monitor 41 using a touch pen. It is done. Particularly in the latter case, the operator can easily set the attention area L for the minimum range including all of the markers 53 according to the shape of the trajectory followed by the markers 53. Information regarding the position and range of the region of interest L set in the peak hold image Q is transmitted to the feature point detection unit 35.

Step S4 (X-ray image capturing and feature point detection)
After step S3 is completed, an enhanced X-ray image of the stent 51 is generated. That is, the operator operates the input unit 39 to perform X-ray irradiation again. In the embodiment, in step S4, a plurality of X-ray images R are generated by X-ray imaging having a larger irradiation X-ray dose than X-ray fluoroscopy. In the embodiment, the number of X-ray images R generated is four, and the respective images are X-ray images Ra to Rd. Note that the number of X-ray images R may be changed as appropriate, or each X-ray image R may be generated by X-ray fluoroscopy. Each of the X-ray images Ra to Rd is transmitted to the feature point detection unit 35.

  The feature point detector 35 refers to the information on the attention area L and detects the marker 53 from each of the X-ray images Ra to Rd generated by the X-ray irradiation again. That is, the feature point detection unit 35 sets the attention area L in each of the X-ray images R based on the information on the attention area L, and searches for the marker 53 only within the set attention area L (upper part of FIG. 7). ). All trajectories that the marker 53 periodically follows according to the heartbeat and the like are included in the region of interest L. Therefore, by searching within the attention area L, the feature point detection unit 35 can reliably detect the marker 53 from each of the X-ray images Ra to Rd. Each of the X-ray images Ra to Rd from which the marker 53 has been detected is transmitted to the integrating unit 37.

Step S5 (Generation image generation)
The accumulating unit 37 superimposes each of the X-ray images Ra to Rd in order to highlight the X-ray image of the stent 51. That is, the integrating unit 37 superimposes the X-ray images Ra to Rd using each of the markers 53 as a reference to generate an integrated image S (lower left in FIG. 7). The accumulated image S is appropriately cut out and enlarged and rotated as necessary, and is displayed on the monitor 41 (lower right in FIG. 7). The search of the marker 53 is performed within the range of the attention area L in the entire X-ray image R. Therefore, when the similar substance F of the marker exists outside the attention area L, the similarity F is the marker. 53 is not mistakenly recognized.

  With such a configuration, the integrating unit 37 can accurately align the stent 51 shown in each of the X-ray images Ra to Rd. As a result, in the integrated image S, the stent 51 is more reliably highlighted and displayed as an X-ray image with high visibility. The operator can confirm the stent 51 highlighted in the integrated image S and can keep the stent 51 in a more suitable position in the stenosis portion of the blood vessel.

<Effects of Configuration of Example>
Thus, the X-ray fluoroscopic apparatus according to the embodiment includes the peak hold image generation unit. The peak hold image generation unit 31 generates a peak hold image Q based on a series of X-ray images generated during at least one heartbeat period. The operator operates the input unit 39 to set the attention area L based on the position of the marker 53 shown in the peak hold image Q. The feature point detection unit 35 searches for the marker 53 in the range of the attention area L, and detects the marker 53 from each of the X-ray images.

  In general, the marker 53 and the stent 51 move periodically according to the heartbeat of the subject. The peak hold image Q is generated by selecting the minimum pixel value for each pixel at the same position in a series of X-ray images P generated during one cycle of heartbeat. Each of the series of X-ray images P shows one of the markers 53 that follow a periodic trajectory. In addition, since the marker 53 is made of a radiopaque material, the pixel where the marker 53 is located has a very small pixel value compared to other pixels. Accordingly, the peak hold image Q includes an entire image of the trajectory that each of the markers 53 periodically follows.

  The operator refers to the entire movement trajectory of the marker 53 shown in the peak hold image Q, and sets the attention area L in the minimum range including the entire trajectory traced by the marker 53 periodically. Since the peak hold image Q is a still image, the operator does not need to confirm the image of the marker 53 that moves constantly. Therefore, the attention area L can be easily set. Further, since the entire locus traced by the marker 53 periodically appears in the peak hold image Q, it is not necessary to refer to an X-ray image other than the peak hold image when setting the attention area L. Therefore, the burden on the operator when setting the attention area L can be greatly reduced.

  The feature point detection unit 35 searches the range of the attention area L for each of the X-ray images R based on the set information of the attention area L. Since the attention area L includes the entire trajectory traced by the marker 53 periodically, the feature point detection unit 35 can reliably detect the marker 53 by searching the area of the attention area.

  Further, the range in which the feature point detection unit searches for the marker 53 is limited to the range of the attention area L. Therefore, even if the marker analog F appears in the X-ray image R, by setting the attention area L so that the position of the similarity F is outside the range of the attention area L, the marker analog Misrecognition as the marker 53 can be avoided. Furthermore, by limiting the search range of the marker 53 to the region of interest, the time and procedure required to detect the marker 53 can be shortened.

  The integrating unit 37 superimposes each of the X-ray images R on the basis of the position of each marker 53 detected by the feature point detecting unit 35. Since the misrecognition of the marker 53 is preferably avoided by setting the attention area L, the accumulating unit 37 can appropriately match the position of the stent 51 shown in each of the X-ray images R. Therefore, the X-ray image of the stent 51 is preferably emphasized in the integrated image S generated by superimposing the X-ray images R. Thus, by using the X-ray fluoroscopic apparatus 1 according to the embodiment, the operator can acquire an integrated image in which a stent with higher visibility is reflected. As a result, the stent can be retained at a more suitable position in the interventional treatment technique.

  The present invention is not limited to the above embodiment, and can be modified as follows.

  (1) In each of the above-described embodiments, a peak hold image Q is generated based on a series of X-ray images P generated during one cycle of heartbeat, and a region of interest L is set for the peak hold image Q. However, the target for setting the attention area L is not limited to the peak hold image. In other words, the target of setting the attention area L may be an image that reflects the entire trajectory of the marker 53 periodically moving. As a specific example other than the peak hold image, there is an addition processing image V generated by adding a series of X-ray images P generated during one cycle of heartbeat.

  Further, the present invention is not limited to points based on a series of X-ray images P generated during one cycle of heartbeat. For example, the peak hold image Q may be generated based on all of the X-ray images P after a certain time. However, the use of the X-ray image P for the most recent cycle is effective in that the range of the trajectory can be appropriately followed even when the subject or the X-ray fluoroscopic apparatus 1 moves.

  In each of the X-ray images P, the pixel value of the pixel corresponding to the position of the marker 53 is very small. Therefore, when each of the X-ray images P is subjected to addition processing, in the addition processing image V, the pixel corresponding to the locus that the marker 53 periodically follows has a smaller pixel value than the other pixels. Therefore, the locus followed by the marker 53 is reflected in the added image V as a region having a small pixel value. In such a modification, the operator can visually recognize the entire locus of the marker 53 shown in the addition processing image V, which is a still image, and operate the input unit 39 to suitably set the attention area L.

  (2) In each embodiment described above, the X-ray image detection unit 29 detects all X-ray images P generated during the most recent predetermined time T, but the reference for detecting the X-ray images is limited to time. Absent. That is, the X-ray image detection unit 29 may detect a predetermined number (for example, 20) of X-ray images P generated most recently and transmit the detected number to the peak hold image generation unit 31.

  (3) In the embodiment described above, one attention area L is set so as to surround all the markers 53 shown in the peak hold image Q in step S3, but this is not restrictive. That is, the number and range of the attention areas L to be set may be changed as appropriate in accordance with conditions such as the number of X-ray images P used to generate the integrated image R. That is, the attention area L may be set to 2 so as to surround each of the trajectory KA followed by each of the markers 53A and the trajectory KB followed by each of the markers 53B (FIG. 6B). In this case, the attention area L includes the whole of the trajectories KA and KB, and has a more limited range, so that it is possible to more suitably avoid erroneous recognition of the marker analog F as the marker 53.

  (4) In the embodiment described above, the peak hold image generation unit 31 generates the peak hold image Q by selecting the minimum pixel value for each pixel at the same position. However, in contrast to the embodiment, when the X-ray image is configured so that the pixel value of the pixel corresponding to the X-ray opaque object is high (in the case of a negative image), the peak hold image generation unit 31 is the same. The peak hold image Q may be generated by selecting the maximum pixel value for each pixel at the position.

  (5) In the above-described embodiment, the peak hold image Q is generated in step S2, but the present invention is not limited to generating an image. For example, in step S2, only the marker trajectory in each frame period may be held in the form of coordinate data, and the coordinate area including the held coordinate data group may be set as the attention area L in step S3.

  (6) In the above-described embodiment, the movement range of the marker due to the periodic body movement of the subject such as heartbeat and respiration is set as the trajectory, but it is not limited to the movement of the subject. For example, even when the imaging device rotates around the subject or reciprocates, the locus of the marker in the X-ray image is recorded, and the range including the locus is set as the search region. Also good.

  In addition, various embodiments can be changed as long as an area including a marker position in a plurality of X-ray images is set as an attention area.

DESCRIPTION OF SYMBOLS 1 ... X-ray fluoroscopic imaging device 3 ... Top plate 5 ... X-ray tube (X-ray source)
7 ... X-ray detector (X-ray detection means)
DESCRIPTION OF SYMBOLS 9 ... C-type arm 17 ... Collimator 19 ... X-ray irradiation control part 23 ... Arm drive control part 27 ... X-ray image generation part (image generation means)
29 ... X-ray image detection unit 31 ... Peak hold image generation unit (trajectory generation means)
33... Attention area display section 35... Feature point detection section (marker detection means)
37 ... integration unit 39 ... input unit (attention area setting means)

Claims (4)

An X-ray source for irradiating the subject with X-rays;
X-ray detection means for detecting X-rays transmitted through the subject and the radiopaque marker and outputting a detection signal;
Image generating means for generating an X-ray image for each predetermined frame period using the detection signal;
Locus generating means for generating a locus of the marker based on the plurality of X-ray images;
An attention area setting means for setting an area including the locus as an attention area;
By searching within the range of the attention area that is a part of the X-ray irradiation area in the X-ray image generated by the image generation means after the plurality of X-ray images used for generating the locus of the marker An X-ray fluoroscopic apparatus, further comprising marker detection means for detecting the position of the marker in the X-ray image. An X-ray source for irradiating the subject with X-rays;
X-ray detection means for detecting X-rays transmitted through the subject and the radiopaque marker and outputting a detection signal;
Image generating means for generating an X-ray image for each predetermined frame period using the detection signal;
Locus generating means for generating a locus of the marker based on the plurality of X-ray images;
Display means for displaying a locus of the marker generated by the locus generation means;
An input means that is operated by the surgeon and inputs information related to a range selected by the surgeon as a region including the trajectory;
An attention area setting means for setting an area including the locus input by the input means as an attention area;
By searching within the range of the attention area that is a part of the X-ray irradiation area in the X-ray image generated by the image generation means after the plurality of X-ray images used for generating the locus of the marker An X-ray fluoroscopic apparatus, further comprising marker detection means for detecting the position of the marker in the X-ray image. The X-ray fluoroscopic apparatus according to claim 2 ,
The trajectory generating unit is an X-ray fluoroscopic imaging apparatus that generates a composite image that reflects a trajectory that the marker periodically follows by adding the plurality of X-ray images. The X-ray fluoroscopic apparatus according to claim 3 ,
An X-ray fluoroscopic apparatus in which the composite image generated by the locus generation means is a peak hold image.

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