JP2003033341A - X-ray fluoroscope - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To provide an X-ray fluoroscopic apparatus capable of accurately knowing a change in an imaging part of a subject over time. SOLUTION: A difference detecting unit which detects a difference between first and second time-point images of a same imaging part Ma obtained under the same imaging condition, which is temporally preceding and succeeding, by signal processing of image signals of both images. 17 and the difference display unit 18 for displaying the difference between the detected images in the first time point image or the second time point image, so that there is no risk of overlooking the difference between the images. Since the X-ray detector is the flat panel X-ray detector 2, the first and second time-point images to be compared have no distortion of the image that is difficult to correct, and the difference between the perceived images is the difference in the imaged region Ma. It is possible to accurately cope with the change and accurately know the change of the imaging region Ma of the subject M with the lapse of time from the first time point to the second time point.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray fluoroscopic imaging apparatus for imaging and displaying an X-ray fluoroscopic image of an imaging region of a subject, and particularly for knowing a change in the imaging region of the subject with the passage of time. Of technology.

[0002]

2. Description of the Related Art In medical facilities such as hospitals, how many days
At intervals of several months (of the same subject)
By performing X-ray imaging of the same imaging site under the same imaging conditions, the obtained two X-ray images that are temporally preceding and following are compared, and the change of the imaging site over time is examined. Has been. FIG. 10 shows a conventional photographic film type X.
It is a schematic block diagram of a radiographic apparatus, and shows the X-ray tube 51 to the top plate
X-ray imaging is performed under the same imaging conditions by irradiating the imaging region Ma of the subject M on 2 with X-rays and exposing the photographic film 53 with the X-rays that have passed through the subject M to obtain an X-ray film image. , Obtain two X-ray film images that are temporally before and after. Then, at a later stage where an X-ray film image is obtained, the X-ray film images obtained earlier are arranged side by side and visually compared to grasp the difference between the X-ray film images, and with the passage of time. Know the change in the imaged site Ma.

FIG. 11 is a conventional X-ray fluoroscopic imaging provided with an image intensifier (hereinafter, appropriately referred to as I / I tube) as an X-ray detector for detecting X-rays transmitted through the subject M. FIG. 3 is a schematic configuration diagram of the device, in which an X-ray tube 51 irradiates an imaging region Ma of the subject M with X-rays, the X-rays that have passed through the subject M are detected by the I / I tube 54, and this detection signal is transmitted to the TV.
(Television) Camera 55 converts the signal into an electric signal and sends it as an X-ray detection signal to a signal processing unit 56. The signal processing unit 56 processes the X-ray detection signal to obtain and record an image signal for an X-ray fluoroscopic image. Alternatively, the X-ray imaging in which an image signal is sent to the image display monitor 57 to display the X-ray fluoroscopic image is repeatedly performed under the same imaging conditions, and two X-ray fluoroscopic images temporally preceding and following are obtained. In the case of this X-ray fluoroscope, the X
When the image signal for the X-ray fluoroscopic image is obtained, the image signal for the previous X-ray fluoroscopic image, which was first captured and recorded, is reproduced, and the image signal for both the front and rear X-ray fluoroscopic images is reproduced. The two X-ray fluoroscopic images are compared by signal processing of the image signal, the difference between the two X-ray fluoroscopic images is grasped, and the imaging region Ma with the passage of time
It is possible to know the change of.

[0004]

However, in the case of the conventional X-ray apparatus having such a configuration, it is difficult to accurately know the change in the imaged region Ma of the subject M with the passage of time. There is. The former photographic film type X
In the case of a radiographic device, since the difference between the X-ray film images before and after is detected by visual observation, the difference between the images is apt to be overlooked. However, it is difficult to know the change of the imaging region Ma accurately.

In the latter X-ray fluoroscopic imaging apparatus, since the difference between X-ray fluoroscopic images is detected by the signal processing of the image signal, the difference between images is not overlooked, but the X-ray detector is used. In the case of a certain I / I tube 54, in addition to the complicated image distortion peculiar to the detection system of the I / I tube 54, the weight of the I / I tube 54 of a heavy object causes a mechanical problem in the X-ray imaging system. Since there are distortions and image distortions that are difficult to correct in the X-ray fluoroscopic image itself, the differences between the images often do not accurately correspond to the changes in the imaging region, and the changes in the imaging region Ma are still accurate. It's hard to know.

The present invention has been made in view of such circumstances, and it is an object of the present invention to provide an X-ray fluoroscopic apparatus capable of accurately knowing a change in an imaged region of a subject with the passage of time. To aim.

[0007]

The present invention has the following constitution in order to achieve such an object. That is, the X-ray fluoroscopic imaging apparatus according to claim 1 includes: (a) an X-ray source that irradiates an imaging region of the subject with X-rays; and (b) X-ray detection that detects X-rays that have passed through the subject. And (c) signal processing means for processing the X-ray detection signal output from the X-ray detector to obtain an image signal for the X-ray fluoroscopic image, and (d) image display means for displaying the X-ray fluoroscopic image. (E) The X-ray detector is a flat plate X-ray detector, and (f) the X-ray fluoroscopic image obtained by photographing the imaged region of the subject at the first time point ( Image signal for first time point image) and first
The position on the imaging site based on the image signal for the X-ray fluoroscopic image (second time image) obtained by imaging the same imaging site under the same imaging conditions as at the first time point at the second time point after the time point. Is the same, but the difference detecting means for detecting a difference between the images having different signal intensities, and (g) the difference at the position of the difference detected by the difference detecting means in the first time point image or the second time point image It is characterized in that it is provided with a difference display means for displaying that it is a point.

According to a second aspect of the present invention, there is provided an X-ray fluoroscopic imaging apparatus according to the first aspect, wherein the flat plate X-ray detector has a large number of X-ray detecting elements arranged vertically and horizontally. The flat panel type X-ray detector described above is used.

Further, the X-ray fluoroscopic imaging apparatus according to claim 3 is the X-ray fluoroscopic imaging apparatus according to claim 1 or 2, wherein the X-ray fluoroscopic image displayed on the image display means is arbitrary. Point designation input means for designating two points on the screen,
Distance calculation means for calculating the distance between the two points designated by the point designation input means is provided.

An X-ray fluoroscopic imaging apparatus according to a fourth aspect of the present invention is the same as the X-ray fluoroscopic imaging apparatus according to the third aspect.
The point-in-time image and the second point-in-time image are images of a calibration simulation body that causes a mechanical deviation detection index for investigating a deviation in the mechanical positional relationship in the apparatus to appear in the X-ray fluoroscopic image, and the point designation The point on the mechanical deviation detection index in the first time point image or the second time point image is the first point of the distance calculation target by the input means, and the difference corresponding to this first point is the first point of the distance calculation target. When designated as two points, a mechanical deviation excess notifying means is provided to inform that the distance between the first and second points calculated by the distance calculating means exceeds a predetermined distance. It is characterized by that.

[Operation] The operation of the present invention is as follows. That is, according to the invention described in claim 1, first, at the first time point, the X-ray source irradiates the imaging region of the subject with X-rays, and the X-rays transmitted through the subject are detected by the flat plate X-ray detector. In addition to the detection, the X-ray detection signal output from the flat plate X-ray detector is processed by the signal processing means to obtain an image signal for the first time point image, and X-ray photography is performed. At the second time point, the same imaged portion is X-rayed under the same image pickup condition to obtain the image signal for the second time point image, and then the difference detection means detects the image signal for the first time point image and the first time point image. After detecting a difference between images having the same position on the imaged region but different signal intensities based on the image signals for the two time point images, the difference point display means subsequently detects the difference between the first time point image and the second time point image. At the position of the difference detected by the difference detection means Display indicating a difference (hereinafter, appropriately referred to as a difference display.) Is performed. The operator or the doctor grasps the difference between the images at the first time point and the second time point by looking at the difference display displayed on the first time point image or the second time point image.

Therefore, in the case of the first aspect of the invention, the difference between the first time point image and the second time point image is reliably detected by the signal processing of the image signals for both images, and the first time point image or Since it is shown as a difference display in the second time point image, there is no fear of overlooking the difference between the images, and the X-ray detector is a flat plate X-ray detector, and the first time point image to be compared and Since there is no image distortion that is difficult to correct in the second time point image, the difference between the grasped images and the change in the imaging region correspond appropriately. In other words, in the case of the flat plate X-ray detector, even if the detection system has image distortion, the image distortion of the detection system is a simple linear distortion that is uniquely determined by the geometrical arrangement of the X-ray detection elements. The distortion of the X-ray fluoroscopic image due to the image distortion of the system can be easily corrected,
The line detector is lighter than the I / I tube, and the mechanical distortion of the X-ray imaging system due to the weight of the X-ray detector is small. Therefore, the first time point image and the second time point image are difficult to correct. The image can be undistorted.

According to the second aspect of the present invention, the flat panel type X-ray detector in which a large number of X-ray detecting elements are arranged vertically and horizontally detects the X-ray transmitted through the subject. The flat panel type X-ray detector does not require an optical scanning mechanism for signal readout unlike the imaging plate which is another flat plate type X-ray detector, and therefore is lighter than the imaging plate and mechanical in the X-ray imaging system. In addition to less distortion, the reading speed of the X-ray detection signal is high, and the X-ray imaging can be speeded up.

According to the third aspect of the present invention, when the operator designates two points on the X-ray fluoroscopic image displayed on the image display means for measuring the distance by the point designation input means, the distance calculation means The distance between two points is calculated promptly.
Therefore, if a point having a difference display on the image displayed on the image display means is designated by the point designation input means as a distance calculation target point, the distance regarding the difference is calculated. It is possible to numerically grasp the difference between the two time point images.

Further, according to the invention as set forth in claim 4, a calibration simulation object for causing a mechanical displacement detection index for investigating a displacement of a mechanical positional relationship in the apparatus to appear on an X-ray fluoroscopic image is covered. As a sample, X-ray imaging is performed at the first time point and the second time point. In this way, after the image signal for the first time point image and the image signal for the second time point image are obtained, the difference point detection means and the difference point display means make a difference between the first time point image and the second time point image. After the display, the operator uses the point designation input means to designate the point on the index for mechanical deviation detection in the first time point image or the second time point image as the first point for distance calculation, and The difference corresponding to the first point is the second point of the distance calculation target.
When the point is designated as a point, the distance calculating means immediately calculates the distance between the first and second points, and if the calculated distance exceeds a predetermined distance, it is notified by the mechanical deviation excess notifying means. Be informed.

That is, the distance between the first point and the second point designated here corresponds to the amount of positional deviation of the mechanical deviation detection index generated between the first time point and the second time point, Since the calibration simulation body itself does not change with time, the distance between the first point and the second point corresponds to the deviation of the mechanical positional relationship in the device. Therefore,
If the machine deviation excess notifying means notifies that the distance between the first and second points exceeds a predetermined distance, the mechanical position in the apparatus between the first time point and the second time point. It can be seen that there was a certain amount of deviation in the relationship.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of an X-ray fluoroscopic imaging apparatus of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing an X-ray fluoroscopic imaging apparatus according to an embodiment. This X-ray fluoroscopic imaging apparatus is an X-ray tube 1 that is an X-ray source that irradiates the imaging region Ma of the subject M with X-rays, and a flat X-ray detector that detects X-rays that have passed through the subject M. A panel-type X-ray detector 2 (hereinafter, appropriately referred to as a panel-type detector 2) is disposed so as to face each other with a top plate 3 interposed therebetween, and the panel-type detector 2 is provided downstream of the panel-type detector 2. A signal processing unit 4 for processing an X-ray detection signal output from the device to obtain an image signal for an X-ray fluoroscopic image, an image display monitor 5 as an image display unit for displaying the X-ray fluoroscopic image, and the like are provided. There is. In the X-ray fluoroscopic imaging apparatus, the panel-type detection is performed when the X-ray tube 1 irradiates the X-ray tube 1 to the imaging region Ma of the subject M on the top plate 3 during the X-ray imaging. The X-ray detection signal output from the instrument 2 is processed by the signal processing unit 4 to obtain an image signal for an X-ray fluoroscopic image, and when this image signal is sent to the image display monitor 5, the X-ray fluoroscopic image is displayed. It is configured to be. Hereinafter, the configuration of each part of the embodiment apparatus will be specifically described.

In the case of the X-ray fluoroscopic imaging apparatus of the embodiment, in addition to the above, the input unit 6 is composed of an input device such as a console or a mouse for performing operations necessary for executing X-ray imaging and inputting necessary data. And an imaging control unit 7 that transmits command signals to each unit in a timely manner in response to an input operation from the input unit 6 or progress of X-ray imaging. It controls power supply of the high-voltage generator 8 that supplies a voltage, control of the mechanical positional relationship between the X-ray tube 1 and the panel type detector 2, and horizontal / vertical movement control of the top plate 3. .

The image display control unit 9 interposed between the signal processing unit 4 and the image display monitor 5 is the X obtained by the signal processing unit 4.
The signal for simultaneous display is superimposed on the image signal for the fluoroscopic image, and the image recording unit 10 includes the signal processing unit 4.
The image signal for the X-ray fluoroscopic image obtained in step 1 is stored together with necessary data such as imaging conditions.

The X-ray tube 1 is provided with a collimator 11 on the front surface thereof. From the X-ray tube 1, a cone-beam-shaped X-ray that matches the set irradiation conditions such as the tube voltage and the tube current is imaged at the imaging site Ma of the subject M. Is irradiated. X-rays transmitted through the subject M are projected on the surface of the panel type detector 2. Since the X-rays irradiated on the imaging region Ma are cone-beam shaped, the panel type detector 2
The shape of the X-rays projected on the surface of is square. In the case of the X-ray fluoroscopic imaging apparatus of this embodiment, a flat panel X-ray detector (FP) is used as a detector for detecting X-rays transmitted through the subject M.
Since D) 2 is one of the structural features, the flat panel X-ray detector 2 will be specifically described.

The flat panel X-ray detector 2 detects a transmitted X-ray image of the subject M generated by the X-ray irradiation by the X-ray tube 1, converts it into an electric signal as an X-ray detection signal, and outputs it. As shown in FIG. 2, the X-ray detector is a so-called two-dimensional matrix type X-ray detector in which a large number of X-ray detection elements Du are arranged vertically and horizontally. The array of the X-ray detection elements Du in the panel type detector 2 of the embodiment is, for example, the horizontal (Y) direction 1024, the vertical (X) direction 102.
It is assumed that the matrix structure is 4 square matrices, and FIG. 2 shows only a matrix structure for a total of 9 vertical 3 × 3 horizontal matrix structures. The panel-type detector 2 having a rectangular plane shape is different from the I / I tube in which the detection surface is limited to a circle, and is also capable of forming a square detection surface suitable for imaging a large region such as the chest or abdomen. , A useful X-ray detector.

The panel type detector 2, as shown in FIG.
X-ray conversion layer 12 for converting incident X-rays into charges or light
And a detection array layer 13 in which elements for detecting charges or light generated in the X-ray conversion layer 12 are vertically and horizontally arranged in a matrix. The plane size of the X-ray conversion layer 12 of the panel type detector 2 may be, for example, about 30 cm in length and width.

The panel type detector 2 includes a direct conversion type shown in FIG. 4A and an indirect conversion type shown in FIG. 4B. In the case of the former direct conversion type,
The X-ray conversion layer 12 is composed of a selenium layer or a CdZnTe layer that directly converts incident X-rays into charges, and is a charge collection electrode group formed on the surface of the detection array layer 13 as a charge detection element 14 facing the surface electrode 15. Accordingly, the charge is detected and stored in the capacitor Cs, and one X-ray detection element Du is formed by each charge detection element 14 and a part of the X-ray conversion layer 12 thereon. . In the case of the latter indirect conversion type, the X-ray conversion layer 12 is composed of a scintillator layer that converts incident X-rays into light, and light is detected by a photodiode group formed as a photodetection element 16 on the surface of the detection array layer 13. The capacitor Cs is charged and stored in the capacitor Cs.
One X-ray detection element Du is formed with a part of 2.

The panel type detector 2, as shown in FIG.
An X-ray detection substrate 41 on which the X-ray conversion layer 12 and the detection array layer 13 are formed, and a capacitor Cs that stores a collection carrier (collection charge) via a carrier collection electrode (charge collection electrode) of the X-ray detection substrate 41. , A thin film transistor (TF) which is a normally-off (cut-off) charge extraction switch element 42 for extracting charges accumulated in the capacitor Cs.
T) and the multiplexer 4 of the read circuit in the X and Y directions.
5 and a gate driver 47.

Further, in the panel type detector 2, as shown in FIG. 2, the source of the thin film transistor for the switch element 42 of the X-ray detecting element Du is connected to the vertical read wiring 43 arranged in the X-axis direction, and the gate is formed. Are connected to the horizontal read wiring 46 arranged in the Y-axis direction. Read wiring 43
Is connected to the multiplexer 45 via the charge-voltage converter group (preamplifier group) 44, and the read wiring 46 is connected to the gate driver 47. In the charge-voltage converter group 44, although not shown, the charge-voltage converter group 44 is provided for one read wiring 43.
Are respectively connected.

In the case of the panel type detector 2, a scanning signal for signal extraction is sent to the multiplexer 45 and the gate driver 47. Each X-ray detecting element Du in the panel type detector 2 is specified in the X direction and Y direction.
Since the scanning is performed based on the addresses (in the case of 1024 X-ray detecting elements Du, for example, 1 to 1024) sequentially assigned to each X-ray detecting element Du along the arrangement in the direction, scanning for extraction is performed. The signals are signals that specify an X-direction address or a Y-direction address, respectively.

Each X-ray detecting element Du is selected in a column unit as a voltage for extraction is applied from the gate driver 47 to the read wiring 46 in the Y direction in accordance with the scanning signal in the X direction. Then, the multiplexer 45 is switched in accordance with the scanning signal in the X direction, so that the charge accumulated in the capacitor Cs of the X-ray detection element Du in the selected column is passed through the charge-voltage converter group 44 and the multiplexer 45 in this order to the outside. Will be sent to. Thus, the X-ray detection signals detected by the panel type detector 2 are sequentially output to the signal processing unit 4 in real time and processed. Of course, each X-ray detection element Du corresponds to each pixel of the X-ray fluoroscopic image.

In the case of the flat panel type X-ray detector 2, even if the detection system has image distortion, the image distortion of the detection system is X.
Since it is a simple linear distortion that is uniquely determined by the geometrical arrangement of the line detection element Du, the distortion of the X-ray fluoroscopic image due to the image distortion of the detection system can be easily corrected, and compared with the I / I tube. Since it is lightweight, mechanical distortion of the X-ray imaging system due to the weight of the X-ray detector is reduced, and an X-ray fluoroscopic image without distortion of the image that is difficult to correct can be obtained. Not only that, the panel type detector 2 does not require an optical scanning mechanism for signal reading unlike the imaging plate which is another flat plate type X-ray detector, and therefore it is lighter than the imaging plate and has an X-ray imaging system. In addition to the reduction of mechanical distortion, the reading speed of the X-ray detection signal is high, which enables high-speed X-ray imaging.

Further, in the X-ray fluoroscopic imaging apparatus of the embodiment, the image signal for the X-ray fluoroscopic image (first time point image) obtained by imaging the imaging site Ma of the subject M at the first time point and the first time point. Based on the image signal for the X-ray fluoroscopic image (second time point image) obtained by imaging the same imaging site under the same imaging conditions as at the first time point at the subsequent second time point, the position on the imaging site is the same. A difference detection unit (difference detection means) 17 for detecting a difference between images having different signal intensities, and a first time point image or a second time point image
At the position of the difference detected by the difference detection unit 17 in the point-in-time image, a display indicating the difference (difference display)
Since a structural feature is that a difference display section (difference display means) 18 for performing the above is provided, this will be specifically described. Below, the difference display part 18 demonstrates as what displays a difference for a 2nd time point image.

That is, at the first time point, the imaged part Ma of the subject M is taken.
5, the first time point image P1 is obtained, and the image signal of the first time point image P1 is recorded in the image recording unit 10 together with the imaging conditions. During the X-ray imaging at the first time point, for example, two positioning markings (not shown) having an X-ray shielding property are attached to an appropriate portion of the subject M, and the first time point image P1 is displayed. The marking images PA and PB are imprinted therein. The first
The imaging conditions to be recorded together with the image signal of the time point image P1 are the X-ray tube 1, the panel type detector 2 and the subject M.
And the geometrical position conditions such as the X-ray incident direction, and the X-ray irradiation conditions such as the X-ray tube voltage and the tube current.

Further, at a second time point after a lapse of time from the first time point, X-ray imaging is performed under the same imaging condition for the same imaging site Ma (of the same subject M), as shown in FIG. Then, the second time point image P2 is obtained. That is, the X-ray imaging performed at the second time point is performed under the imaging conditions recorded in the image recording unit 10 together with the image signal of the first time point image P1. In addition, the positioning marking (not shown) to be attached to the subject M is also attached to the same position as the first time point by observing the first time point image P1 and the like, and the positioning mark is used as a mark to perform positioning. The two-time point image P2 is set to be the same image of the imaging region Ma as the first time point image P1.

The positioning with the positioning marking as a mark may be performed automatically or manually. The position where the positioning markings are attached at the second time point is displaced from the attachment position at the first time point.
When the appearance positions of the marking images PA and PB in the time point image P1 and the appearance positions of the marking images Pa and Pb in the second time point image P2 do not match and the positioning is insufficient, a positioning marking (not shown). ) You should correct the pasting position.

Further, for example, when the interval between the first time point and the second time point is short, instead of attaching the positioning marking, a mark is put on the object M with the ink which is hard to be erased at the first time point. The ink mark is used as a mark to perform positioning by a positioning projector (not shown) or the like of the X-ray fluoroscopic imaging apparatus, and the image is taken. The ink mark is left as it is, and the X-ray imaging at the second time is performed. Even when the same ink mark is used as a mark, positioning is performed by a positioning projector (not shown) or the like of the X-ray fluoroscopic imaging apparatus.
The time point image P2 is the same imaging part Ma as the first time point image P1.
It is also possible to use the image of.

In this way, when the image signal of the first time point image P1 and the image signal of the second time point image P2 which are temporally behind each other are obtained, the difference detecting section 17 causes the difference point detecting unit 17 to detect the first time point image P1 and the second time point image. Pixel values (signal intensities) of pixels having the same position on the imaged region Ma in the image P2 are compared,
Pixels whose pixel values have a certain difference or more are detected one after another as differences between images. That is, the change occurring in the imaging region Ma from the first time point to the second time point appears as a difference between the images, but the difference in the image is captured by the difference in the pixel value of the pixel. The part 17 is an imaging part Ma
Differences between images can be detected by comparing pixel values between pixels having the same upper position.

When the difference detecting unit 17 detects a difference, the difference displaying unit 18 causes the image display control unit 9 to move to the position of the difference detected by the difference detecting unit 17 in the second time point image. Indication Q that clearly shows the difference
(Hereinafter, appropriately referred to as difference display Q). For example, the difference display Q can be easily performed by using a color different from the color of the second time point image P2 or a brightness different from the brightness of the second time point image P2. The difference display Q in the case of FIG. 6 forms an abnormal region in which a large number of different points are densely gathered into one shape, and at the imaged site Ma, some abnormal change (for example, from the first time point to the second time point) is performed. It can be seen that a tumor has occurred. In addition, the area | region (area | region regarding the difference display Q) shown by the dashed-dotted line in FIG. 6 is expanded and shown in the lower right.

In the above case, the difference detecting section 17 detects the difference by using one pixel as one point, but the difference detecting section 17 detects the difference by using 4 × 4 16 pixels as one point. In this case, for example, the pixel values are compared for each of the 16 pixels, and when a difference is recognized among a plurality of pixels, it is determined as a difference, or the total value of the pixel values of 16 pixels is determined. A comparison is made to determine whether or not there is a difference. In this case, the difference display unit 18, like the difference detection unit 17, does not use one pixel as a unit of one difference display Q, but instead, for example, 4 × 4 16 pixels of one difference display Q. It may be a unit.

Furthermore, in the case of the X-ray fluoroscopic imaging apparatus of the embodiment, the input unit 6 displays two points, ie, arbitrary first and second points on the X-ray fluoroscopic image displayed on the image display monitor 5, on the screen. It also serves as a point designating input means for designating at 1, and is provided with a distance computing section (distance computing means) 19 for computing the distance between the first and second points designated by the input section 6. Therefore, as shown in FIG. 6, the difference display Qa at each position of the upper right end and the lower left end of the abnormal region where the differences are densely formed in the second time point image P2 in the input unit 6 and form one tumor-like shape. , Qb
If the difference point indicated by is designated as the first point and the second point of the distance calculation target, the distance calculation section 19 immediately determines the coordinates of both the difference point displays Qa and Qb based on the image signal to obtain the coordinate interval, Further, if necessary, image magnification correction is added to calculate the distance QL between the designated differences, and the calculated distance QL is displayed on the screen of the image display monitor 5. In the case of the panel type detector 2, even if there is image distortion in the detection system, it is a simple linear distortion that is uniquely determined by the geometrical arrangement of the X-ray detection elements, so image magnification correction is also simple, and there is a difference. It is possible to accurately calculate the distance QL between the points. The operator can quantitatively know the change caused in the imaging region Ma from the value of the distance QL displayed on the screen of the image display monitor 5.

Next, referring to the drawings, the radiographing operation for quantitatively examining the change occurring in the image pickup site Ma between the first time point and the second time point by the X-ray radiographing of the apparatus of the above-mentioned embodiment will be described. While stating. FIG. 7 is a flowchart showing the process of X-ray photography when examining the change occurring in the imaging region Ma with the passage of time by the apparatus of the embodiment.

[Step S1] The subject M is placed on the top plate 3 and set at the photographing position.

[Step S2] At the first time point, X-ray imaging of the imaging region Ma of the subject M is executed, and as shown in FIG.
The image signal of the first time point image P1 is collected and recorded in the image recording unit 10 together with the shooting conditions.

[Step S3] Since the X-ray imaging at the first time point is completed, the subject M is lowered from the top plate 3.

[Step S4] When the time comes to perform X-ray imaging again after a lapse of time from the first time point, the same subject M is placed on the top plate 3 and set to the imaging position again.

[Step S5] At the second time point, the same X-ray image of the imaged region Ma as before is executed under the same imaging conditions as at the first time point, and the second time point image P2 is obtained as shown in FIG. obtain.

[Step S6] The difference detecting section 17 is the first
The difference between the images is detected based on the image signal of the time point image P1 and the image signal of the second time point image P2.

[Step S7] The difference display unit 18 displays the difference Q at the position of the difference in the second time point image.

[Step S8] The operator operates the input unit 6
As a result, the difference display Qa, Qb is displayed at the upper right end and the lower left end of the abnormal area where the differences in the second time point image P2 are dense.
Is designated as the first point and the second point of the distance calculation target.

[Step S9] The distance calculation unit 19 calculates the distance QL between the two different points designated by the input unit 6, and displays it on the screen of the image display monitor 5. From the value of the distance QL displayed on the screen of the image display monitor 5, the operator can immediately quantitatively know the change occurring in the imaging region Ma between the first time point and the second time point.

[Step S10] Since the X-ray imaging at the second time point is also completed, the subject M is lowered from the top plate 3.

As described above, according to the apparatus of the embodiment, the difference between the first point-in-time image P1 and the second point-in-time image P2, which are temporally before and after, for the same imaged portion obtained under the same imaging condition. Is reliably detected, and the detected difference is indicated by the difference display Q in the second time point image P2. Therefore, there is no fear of overlooking the difference between the images P1 and P2 and the X-ray detector. Is the flat panel X-ray detector 2, and is the first time point image P1 and the second time point image P to be compared.
2 has no image distortion that is difficult to correct, and the difference between the images P1 and P2 that is grasped corresponds accurately to the change in the imaged site Ma, so that the time elapses from the first time point to the second time point. It is possible to accurately know the accompanying change in the imaging region Ma of the subject M.

Further, in the X-ray fluoroscopic imaging apparatus of the embodiment,
A characteristic structure is also provided for checking whether or not the mechanical positional relationship in the device has a shift that requires readjustment. That is, the first time point image and the second time point image are shown in FIG.
As shown in, the mechanical displacement detection index ma for examining the displacement of the mechanical positional relationship in the device is an image of the calibration simulation object m to appear in the X-ray fluoroscopic image, and the device of this embodiment is The point on the mechanical deviation detection index in the first time point image or the second time point image is the first point for distance calculation by the input unit 6, and the difference corresponding to this first point is for distance calculation. When the distance between the first and second points calculated by the distance calculation unit 19 exceeds a predetermined distance, the mechanical deviation excess notification unit (mechanical deviation) Excess notification unit means)
Equipped with 20.

As shown in FIG. 9 (a), the calibration simulation object m having the cross mark-shaped mechanical deviation detection index ma formed of the X-ray shielding material is the first time point image P3.
The index ma for detecting mechanical deviation appears in the shape of a cross. The calibration mock m has virtually no change over time, and therefore the mechanical displacement detection index ma is displaced between the first time point image P3 and the second time point image P4. The amount is proportional to the amount of mechanical positional deviation in the device. If there is no deviation in the mechanical positional relationship in the apparatus, the mechanical deviation detection index ma appears in the second time point image P4 at exactly the same position as in the first time point image P3, and there is a gap between both images. Although there is no difference, if there is a deviation in the mechanical positional relationship in the device, as shown in FIG. 9B, in the second time point image P4, the mechanical deviation detection index ma is shown by a dotted line. It appears at the position indicated by the solid line, which is deviated from the position in the first time point image P3, and there is a difference between both images.

Therefore, as described above, if the difference detecting section 17 detects a difference in the second time point image P4, the difference shown in FIG.
As shown in (b), the difference display unit 18 causes the difference display q to appear in a cross shape with a dotted line on the second time point image P4. Therefore, the operator designates the center point Ca in the mechanical deviation detection index ma in the second time point image P4 as the first point for distance calculation target with the input unit 6, and at the difference corresponding to the first point. As the second point of a certain distance calculation target, the center point Cb in the difference display q indicated by a dotted line in a cross shape is designated.

Thus, the center point Ca in the mechanical deviation detection index ma and the center point Cb in the difference display q are shown.
When these two points are designated as distance calculation targets, the distance calculation unit 19 immediately calculates the distance between the first time point image P3 and the second time point image P4 regarding the positional deviation of the mechanical deviation detection index ma. At the same time, if the distance calculated by the distance calculating unit 19 exceeds a predetermined distance, the mechanical deviation excess notifying unit 20 notifies that. The notification of the mechanical deviation excess notification unit 20 is performed by a screen display of the image display monitor 5, a voice display by a speaker, or the like.

A predetermined distance, which is a threshold value used by the mechanical deviation excess notifying unit 20 to determine whether or not there is a notification, is set to the amount of deviation required to be readjusted in the mechanical positional relationship in the apparatus. In other words, the notification of the mechanical deviation excess notification unit 20 immediately recognizes that the mechanical positional relationship in the apparatus needs to be readjusted, so the operator promptly requests the manufacturer to perform readjustment. Alternatively, when there is a notification from the mechanical deviation excess notification unit 20, the manufacturer may be automatically notified of the readjustment request via the communication line.

According to the X-ray fluoroscopic imaging apparatus of the embodiment, in practice, the calibration mimetic m with the mechanical deviation detection index ma is used as the subject M, and the screen of the second time point image P4 By the input unit 6, the center point Ca on the mechanical deviation detection index ma and the center point C of the difference display q
If b is designated as the distance calculation target point, and if the degree of deviation of the mechanical positional relationship in the device is a certain amount or more, it is immediately detected.
Therefore, it is easy to maintain the mechanical positional relationship in the device.

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

(1) In the above embodiment, the difference display section 1
8 is configured to be able to display the difference point with respect to the first time point image or the second time point image, the difference point display unit 18 only has one of the first time point image and the second time point image. Alternatively, the configuration may be such that different points can be displayed.

(2) In the above embodiment, the X-ray detector is a flat panel type X-ray detector, but the X-ray detector may be an imaging plate.

[0060]

As is clear from the above description, according to the X-ray fluoroscopic imaging apparatus of the first aspect, the first radiographic image of the same radiographic region obtained under the same radiographic conditions is moved forward and backward in time. The difference between the time point image and the second time point image is detected by signal processing of the image signals of both images, and the difference between the detected images is displayed in the first time point image or the second time point image. Therefore, there is no fear of overlooking the differences between the images, and the X-ray detector is a light-weight flat panel X-ray detector, and the first time point image and the second time point image to be compared are difficult to correct images. Since there is no distortion, the difference between the captured images accurately corresponds to the change of the imaging region.
It is possible to accurately know the change in the imaging region of the subject with the passage of time from the time point to the second time point.

Further, according to the X-ray fluoroscopic imaging apparatus of the second aspect, the X-ray transmitted through the subject by the flat panel X-ray detector in which a large number of X-ray detecting elements are arranged vertically and horizontally.
Since the flat panel X-ray detector does not need an optical scanning mechanism for signal readout, which is required for an imaging plate which is another flat plate X-ray detector, the imaging plate has a configuration for detecting a line. In addition to being lighter and less mechanically distorted in the X-ray imaging system, the read-out speed of the X-ray detection signal is high, which enables high-speed X-ray imaging.

Further, according to the X-ray fluoroscopic apparatus of the third aspect, the point on the difference display on the image displayed on the image display means is designated by the point designation input means as the point for distance calculation. Then, the distance regarding the difference is calculated, and the first
Since the difference between the time point image and the second time point image can be numerically grasped, it is possible to quantitatively know the change in the imaging region of the subject with the passage of time from the first time point to the second time point.

According to the X-ray fluoroscopic imaging apparatus of the present invention, a mechanical deviation detection index for investigating a deviation of the mechanical positional relationship in the apparatus is used for calibration for causing the X-ray fluoroscopic image to appear. The simulated object is used as the subject, and the points on the mechanical deviation detection index are calculated by the point designation input means with respect to the first time point image or the second time point image for which the difference display is performed after the X-ray imaging. First of target
By designating as a point and designating the difference corresponding to this first point as the second point of the distance calculation target, the degree of deviation of the mechanical positional relationship in the device can be set to a certain level or more. For example, since the mechanical deviation excess notifying means immediately notifies that, the maintenance of the mechanical positional relationship in the device becomes easy.

[Brief description of drawings]

FIG. 1 is a block diagram showing an X-ray fluoroscopic imaging apparatus according to an embodiment.

FIG. 2 is a configuration diagram of a flat panel type X-ray detector.

FIG. 3 is a perspective view showing a schematic configuration of a flat panel X-ray detector.

4A and 4B are cross-sectional views showing a layer structure of a flat panel X-ray detector.

FIG. 5 is a schematic diagram showing an example of a first time point image obtained by the apparatus of the embodiment.

FIG. 6 is a schematic diagram showing an example of a second time point image by the device of the embodiment.

FIG. 7 is a flowchart showing a process of radiography by the apparatus of the embodiment.

FIG. 8 is a plan view showing a calibration simulation body of the apparatus of the embodiment.

9A and 9B are schematic diagrams showing another example of the first time point image and the second time point image by the apparatus of the embodiment.

FIG. 10 is a schematic configuration diagram of a conventional photographic film type X-ray imaging apparatus.

FIG. 11 is a schematic configuration diagram of a conventional X-ray fluoroscopic imaging apparatus.

[Explanation of symbols]

1 ... X-ray tube (X-ray source) 2 ... Flat panel type X-ray detector (flat plate X-ray detector) 4 ... Signal processing unit (signal processing means) 5 ... Image display monitor (image display means) 6 ... Input Part (point designation input part) 17 ... Difference detection part (difference detection means) 18 ... Difference display part (difference display means) 19 ... Distance calculation part (distance calculation means) 20 ... Machine deviation excess notification part (machine Deviation excess notification means) Du ... X-ray detection element M ... Subject Ma ... Imaging site m ... Simulating body ma for calibration ... Mechanical deviation detection indicators P1, P3 ... First point image P2, P4 ... Second point image

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G01T 1/17 G01T 1/20 E 1/20 1/24 1/24 7/00 C 7/00 G06T 1 / 00 290A G06T 1/00 290 A61B 6/00 350D (72) Inventor Takayoshi Okamura 1 Nishinokyo Kuwabara-cho, Nakagyo-ku, Kyoto Incorporated company Shimadzu Corporation (72) Inventor Masahiro Kono 1 Nishinokyo-Kuwabara-cho, Nakagyo-ku, Kyoto Shares Company Shimadzu (72) Inventor Hiroshi Miyata 1 Nishinokyo Kuwabara-cho, Nakagyo-ku, Kyoto Stock Company Shimadzu (72) Inventor Katsunori Yuan 1 Nishinokyo Kuwabara-cho, Nakagyo-ku, Kyoto F-Term Reference) 2G088 EE01 FF02 GG19 GG20 GG21 JJ05 JJ27 KK07 KK24 KK32 KK35 LL13 LL28 MM04 MM06 MM09 4C093 AA01 AA16 EB12 EB13 EB17 FC13 FC27 FD09 FF09 FF13 FF2 2 FF34 FF37 FG01 FG02 FG13 FH03 5B057 AA08 BA03 BA12 DA16 DB02 DB05 DB09 DC32

Claims (4)

[Claims] 1. An X-ray source for irradiating an imaging region of a subject with X-rays, and (b) X for detecting X-rays transmitted through the subject.
A line detector, (c) signal processing means for processing an X-ray detection signal output from the X-ray detector to obtain an image signal for an X-ray fluoroscopic image, and (d) an image displaying the X-ray fluoroscopic image In an X-ray fluoroscopic imaging apparatus including a display means, (e) the X-ray detector is a flat plate X-ray detector, and (f) the X-ray fluoroscopic image obtained by imaging the imaging site of the subject at the first time point. Image (first time image)
And an image signal for an X-ray fluoroscopic image (second time point image) obtained by imaging the same imaging site under the same imaging conditions as the first time point at the second time point after the first time point. On the basis of the difference detection means for detecting a difference between images having the same position on the imaged region but different signal intensities, (g) the difference detection means for the first time point image or the second time point image. An X-ray fluoroscopic imaging apparatus, characterized in that it is provided with difference display means for displaying the difference at the position of the difference. 2. The X-ray fluoroscopy apparatus according to claim 1, wherein the flat plate X-ray detector is a flat panel X-ray detector in which a large number of X-ray detection elements are arranged vertically and horizontally. An X-ray fluoroscopic imaging device characterized by: 3. The X-ray fluoroscopic apparatus according to claim 1 or 2, wherein the X displayed on the image display means is displayed.
The present invention is characterized by comprising point designation input means for designating arbitrary two points on the fluoroscopic image on the screen, and distance calculation means for computing the distance between the two points designated by the point designation input means. X-ray fluoroscope. 4. The X-ray fluoroscopic apparatus according to claim 3, wherein the first point-in-time image and the second point-in-time image indicate a mechanical deviation detection index for investigating a deviation of a mechanical positional relationship in the apparatus. It is an image of a calibration simulation body that appears in a fluoroscopic image, and the point on the mechanical deviation detection index in the first time point image or the second time point image is the distance calculation target by the point designation input means. When one point and the difference corresponding to this first point are designated as the second point of the distance calculation target, the distance between the first and second points calculated by the distance calculation means is set to a predetermined value. An X-ray fluoroscopic imaging apparatus comprising: a mechanical deviation excess notifying means for notifying that the distance has been exceeded.