JP3453902B2 - Rotary X-ray equipment - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary type X-ray apparatus, and more particularly to an image in the same angular direction obtained by rotating at least two times during each rotation. The present invention relates to a rotary X-ray imaging apparatus that performs a subtraction process between them. 2. Description of the Related Art Conventionally, an X-ray tube and an imaging system combining an X-ray image intensifier and an X-ray television camera are held by a single holding mechanism called a C-shaped arm. 2. Description of the Related Art There is known a rotary X-ray imaging apparatus that captures images from various angular directions around a subject by rotating the entire holding mechanism around the subject. [0003] Using such a rotary X-ray apparatus, D
When performing SA (Digital Subtraction Angiography), typically, first, while injecting a contrast medium into a blood vessel of a subject (patient), the entirety of the holding mechanism is rotated around the subject while rotating the same. An X-ray transmission image (non-contrast agent image) from each direction is obtained for each rotation angle of, and this is digitized and stored, and after this is finished, the contrast agent is injected after returning to the initial angular position, An X-ray transmission image (contrast agent image) from each angular direction is obtained while rotating under the same conditions, and digitized, a non-contrast agent image is read out, and a subtraction process is performed between the non-contrast agent image and the corresponding contrast agent image. Perform
Thereby, the image of the background is canceled, and the image of only the contrast agent, that is, the image of only the blood vessel filled with the contrast agent,
Obtained in each angular direction. [0004] That is, according to the rotational DSA, image information of the subject from multiple directions can be obtained by a single contrast examination. This means that the burden on the subject due to the injection of the contrast agent and the X-ray exposure of both the subject (patient) and the operator are reduced, and rotational DSA is expected as a very effective X-ray imaging method. Have been. [0005] However, in the conventional rotary X-ray imaging apparatus, the X-ray tube and the holding mechanism of the imaging system are rotated several times around the subject, and the image from each angular direction is obtained. However, there is a problem that the subject is unprotected from moving the subject during each rotation. Thus X
When the subject moves relative to the holding mechanism of the tube and the imaging system, even if a subtraction process is performed between the non-contrast agent image and the contrast agent image at the same angle, all the background is not canceled and the contrast agent is not changed. You cannot extract parts. Such deviation of the subject cannot be determined only by the operator observing the state of the subject from outside. Further, in the conventional rotary X-ray imaging apparatus, there is a problem that it is difficult to start rotation at a timing when the contrast agent has flowed to a desired part. Normal,
The rotation for collecting the contrast agent image is started at the timing when the contrast agent is injected by the injector. However, the rotation speed of the X-ray tube and the holding mechanism of the imaging system and the device for storing the non-contrast agent image are used. Acquisition time of the contrast agent image is limited due to limitations such as capacity. Therefore, the rotation may end when the desired part is filled with the contrast agent. In such a case, it is possible to set a delay time before the rotation is started after the injection of the contrast agent, but since the operator must predict and set the delay time based on the experience. , May be different and incomplete. SUMMARY OF THE INVENTION In view of the above, the present invention has been improved in that a rotational X-ray has been improved so that a positional deviation of an object can be reliably determined, thereby eliminating the deviation and obtaining a complete subtraction image. It is an object to provide a photographing device. Another object of the present invention is to provide a rotary X-ray imaging apparatus improved so that the timing of starting rotation according to the state of the contrast agent can be easily determined. In order to achieve the above object, a rotary X-ray imaging apparatus according to the present invention comprises: an X-ray irradiating means for irradiating an X-ray toward a subject; X-ray imaging means for obtaining an image signal of an X-ray transmission image by causing X-rays transmitted through the X-ray to be incident thereon; rotating means for integrally rotating the X-ray irradiating means and the X-ray imaging means at least twice; Image storage means for storing an image signal at each angle in a rotation performed prior to one rotation, and a corresponding angle between the image signal at each angle in the subsequent rotation and the image signal stored in the previous rotation Operating means for performing a subtraction process between the rotating means, operating means for stopping the rotating operation of the rotating means at the initial position of the subsequent rotation, and starting the rotating operation of the rotating means, Rotation stops at the initial position Between the image signal obtained from the X-ray imaging means by the X-rays from the X-ray irradiating means and the image signal stored at the angle in the previous rotation corresponding to this initial position. Image display means for displaying the subtraction processed image by the means, and displaying the subtraction processed image of each angle sequentially output from the calculation means after the subsequent rotation is started by the operation means. Is the feature. The image in each angular direction obtained by the first rotation and the image in each angular direction obtained by the next rotation are subjected to subtraction processing between the images in the corresponding angular directions, whereby each angular direction is obtained. A subtraction image is obtained. Therefore, for example, if the contrast agent is not injected at the first rotation, and the contrast agent is injected at the next rotation, a subtraction image between the images with and without the contrast agent can be obtained from the same angle. Other than the agent is canceled, and an image of only the contrast agent (blood vessel portion) is obtained. Such a subtracted image is obtained in each angular direction. In the subtraction image obtained in this way, if there is no displacement of the subject between the first rotation and the next rotation, the portion other than the contrast agent portion is almost completely canceled. However, if there is a misalignment, the part is not canceled and the part remains. In the present invention, as described above, the operating means for stopping the rotating operation of the rotating means at the initial position of the subsequent rotation and starting the rotating operation of the rotating means is provided. The image display means displays the subtraction processed image at the corresponding angle between the image signal at each angle in the subsequent rotation and the image signal stored in the previous rotation, and stops at the initial position of the subsequent rotation. The image after the subtraction process between the image signal acquired when the image is obtained and the image signal stored at the angle at the previous rotation corresponding to the initial position is also displayed. Therefore, observe the subtraction image while stopped at the initial position before starting the subsequent rotation, and confirm that there is no displacement of the subject between the initial position during the subsequent rotation and the corresponding angle during the previous rotation. You can check. When this is confirmed, the subsequent rotation can be started. As a result, it is possible to easily obtain a complete subtraction image without displacement of the subject. Further, a subtraction image at the initial position of the later rotation is displayed, and this image shows a state in which the contrast agent flows. Then, observe this display image,
It is possible to confirm the state of the contrast agent, operate the operation means when the contrast agent reaches a desired site, and start rotation for acquiring a contrast agent image from each angular direction. Thus, it is easy to determine the timing to start rotation according to the state of the contrast agent. A preferred embodiment of the present invention will be described below in detail with reference to the drawings. In FIG. 1, an object 10 is laid on a bed of a bed, and an X-ray tube 21 and an X-ray combined with an X-ray image intensifier 22 and an X-ray television camera 23 so as to sandwich the object 10. The imaging systems are arranged to face each other. These X-ray tubes 21
And the X-ray imaging system are held at both ends of a C-arm 24. The C-arm 24 is held by a rotation driving device 25, and is thereby driven to rotate in the arc direction (indicated by an arrow) of the C-arm. It is supposed to be. This rotary drive device 25 is provided on a stand 2 installed on the floor of an examination room.
6. The rotation drive device 25 is controlled by the control device 31 to rotate the C-arm 24. The control device 31 controls the injector 3 for injecting a contrast agent into the subject 10.
2 is also controlling. The rotation control switch 33 provided in the control device 31 is controlled by the rotation driving device 25
This is for controlling the rotation of the mold arm 24. By manually turning it off, the rotation is started, and when it is turned on, the rotation is stopped. An image signal obtained from the X-ray television camera 23 is sent to an image processing device 41. This image processing device 4
1 includes a switching unit 42, an image memory 43, and a computing unit 44. The image signal output from the arithmetic unit 44 is sent to the image monitor 45 to display an image. The image processing device 41 includes an A / D converter for A / D converting an input image signal, and a D / A converter for converting a digital image signal output from a calculator 44 into an analog image signal. , But is omitted in the figure. Here, the case of performing the rotational DSA will be described. First, the X-ray tube 21, the X-ray image intensifier 22, and the X-ray television camera 23 are rotated from an angular position (position A) like a solid line to an angular position (position B) like a dotted line as shown by an arrow a. So that the rotation driving device 25
Drives the C-arm 24 to rotate. At this time, the subject 1
At 0, no contrast agent is injected. During the rotation of the arrow a, X-rays are emitted from the X-ray tube 21 to obtain an image signal from the X-ray television camera 23. This image signal represents a non-contrast agent image of the subject 10 from each angle direction. At this time, in the image processing device 41, since the switch 42 is switched to the image memory 43 side,
An image signal from the X-ray television camera 23 is stored in an image memory 43.
Are sequentially stored. When the rotation (arrow a) for collecting the non-contrast agent image in the image memory 43 is completed, the rotation as indicated by the arrow b for returning from the position B to the initial position A is performed. Then, the contrast agent image is acquired by rotating from the initial position A as indicated by an arrow c. At this time, when the X-ray tube is stopped at the initial position A before the rotation, X-rays are emitted from 21 and an image signal is obtained from an X-ray television camera 23. This image signal is sent to the image processing device 41.
2 has been switched to the computing unit 44 side. On the other hand, the non-contrast agent image at the initial position A collected in the first rotation is read from the image memory 43 and sent to the computing unit 44. Then, the arithmetic unit 44 obtains an image obtained by subtracting the previous image and the current image from the initial position A, and this image is displayed on the image monitor 45. Therefore, when observing this image, the canceling effect between the two images is obvious, and it can be seen that there is a shift between the two images if the image is not completely canceled. That is, if the subject 10 has not moved at all, a completely subtracted image can be observed, and if the subject has moved even a little, the moved portion will remain without being canceled, and the image of the remaining portion will be observed. it can. In addition to displaying the subtracted image, the image signal sent to the arithmetic unit 44 via the switching unit 42 may be led to another image monitor device (not shown) to display a simple X-ray transmission image. As a result, by observing the image displayed on the image monitor device 45, the position of the subject 10 can be adjusted to be completely matched. According to the observation of the image displayed on the image monitor device 45, the subject 10
Not only that the whole has moved, but also for example, the displacement of the tissue near the diaphragm in a state of holding breath can be determined,
It is possible to make them coincide. After the positions are matched, a contrast agent is injected into the subject 10 by the injector 32, and the rotation from the position A to the position B is performed as indicated by an arrow c. At this time, X-rays are emitted from the X-ray tube 21 and a contrast agent image from each angle direction is obtained from the X-ray television camera 23. The contrast agent image from each angular direction is subtracted by the arithmetic unit 44 from the non-contrast agent image from the corresponding angular direction read from the image memory 43, and a DSA image from each angular direction is obtained. This is displayed on the image monitor device 45. It should be noted that the DSA image thus obtained can be recorded not only on a display but also on an image recording device (not shown). Here, only the initial position A of the rotation for acquiring the non-contrast agent image and the rotation for acquiring the contrast agent image is checked whether there is any displacement with respect to the subject 10. This positional deviation may be confirmed in all the angular directions to obtain. In this case, for example, position B
During the rotation (arrow b) when returning from the position to the position A, the X-ray tube 21 emits X-rays, and the X-ray television camera 23 sequentially obtains image signals of X-ray transmission images from various angular directions. Then, the switching unit 42 is switched to the computing unit 44 side, and the computing unit 44 subtracts the image from each of the above-described angular directions and the image from the corresponding angular direction sequentially read from the image memory 43. Is performed, and the image is displayed on the image monitor device 45 for observation. Then, it can be observed whether or not the cancellation effect by the subtraction processing is complete in all the angular directions, and it can be seen that the subject 10 has moved in all the angular directions. In the above description, these images are respectively collected in the order of the non-contrast agent image and then the contrast agent image. However, in the reverse order, the order of the contrast agent image and then the non-contrast agent image is acquired. It is needless to say that the image may be collected in such a case. Further, after collecting images in the process of rotation from position A to position B (arrow a), the image is returned from position B to position A (arrow b), and rotated from position A to position B again (arrow b). Although the image is collected by the arrow c), the present invention can be applied to the case where the image is collected in the process of returning as indicated by the arrow b. In that case, before starting the rotation from the position B to the position A (arrow b), a subtraction image is obtained and displayed at the position B,
At the position B, it is confirmed whether or not the subject 10 is displaced. In the configuration shown in FIG.
Is provided with the rotation control switch 33 as described above. The rotation control switch 33 controls the injector 32 by the operation of the operator to control the injector 32 to activate the injector 32, start the injection of the contrast agent into the body of the subject 10, and the X-ray tube 21. When the X-ray irradiation is started, it is turned on. Then, the rotation drive of the C-arm 24 by the rotation drive device 25 remains stopped. That is, in the first example,
After the non-contrast agent image is collected in the image memory 43 in the process of rotation from the position A to the position B (arrow a), the position A is shifted to the position A.
Then, the position A is maintained again (arrow b). The image signal at the position A is transmitted from the X-ray television camera 23 through the switching unit 42 (at this time, the switching unit 42 is switched to the computing unit 44 side).
4 From the image memory 43, the image signal at the time of the first position A is read and sent to the arithmetic unit 44. The arithmetic unit 44 performs a subtraction process between these images, and sends the resulting image signal to the image monitor device 45. Therefore, the image monitor device 45
The DSA image at position A (the image obtained by subtracting the non-contrast agent image from the contrast agent image) is displayed in real time.
Therefore, by observing the image monitor 45, the current state of the contrast agent (such as flowing in a blood vessel).
Will be understood as if picked up. It can be confirmed that the contrast agent has reached the desired site and is full, and when this is confirmed, the rotation control switch 33 is turned off. Then, at that timing, the arrow c of the C-arm 24
Is started, a contrast agent image from each angle direction can be obtained with good timing, and a DSA image when the contrast agent is at a desired site can be obtained reliably. The DSA image at the position A can be used simply for displaying and determining the timing, but may be recorded in an image recording device (not shown). As described above, determining the rotation start timing by manual operation while observing the DSA image in real time means that the non-contrast agent image is converted in the process of rotation from position A to position B (arrow a) as described above. After collecting, from position B to position A
The contrast agent image is collected not only in the process of collecting the contrast agent image by turning back from the position A to the position B (arrow b) and rotating it again from the position A to the position B (arrow c), but also in the process of returning as indicated by the arrow b. Also applicable to cases. In this case, by turning on the rotation control switch 33 at the position B, the rotation is stopped at this position, and the DSA image at the position B is displayed on the image monitor 45 in real time. Then, by confirming that the contrast agent has come to the desired site by observing the displayed image, the rotation control switch 33 is turned off, and the position B
Then, rotation from the position A to the position A is started to obtain a contrast agent image from each angular direction. In addition to the case where these images are respectively collected in the order of the non-contrast agent image and then the contrast agent image, not only the order of the contrast agent image but the non-contrast agent image is reversed. The present invention is also applicable to the case of collecting images.
In this case, since the non-contrast agent image is not stored in the image memory 43 when the contrast agent image is obtained, the image monitor device 4
In FIG. 5, an X-ray transmission image in which an image of the contrast agent appears is merely displayed, and it is difficult to understand the state of the contrast agent other than the DSA image, but it is possible to grasp the state of the contrast agent. The specific configuration in the above embodiment can be variously changed. For example, an X-ray imaging unit that obtains an image signal of an X-ray transmission image is an X-ray image intensifier 2.
Other than the combination of the X-ray television camera 23 and the X-ray television camera 23, a mechanism for holding and rotating the X-ray tube 21 and the X-ray imaging means by the combination of the X-ray image intensifier 22 and the X-ray television camera 23 is also available. The present invention is not limited to the above-described C-arm 24. Another configuration of the image processing device 41 that obtains a subtraction image is also conceivable. As described above, according to the rotary X-ray apparatus of the present invention, the image in each angular direction obtained by the first rotation and the image in each angular direction obtained by the next rotation are obtained. In the case of obtaining a subtraction image by performing subtraction processing between objects in the corresponding angular directions, to display the above subtraction image at the initial position of later rotation, by observing this display image, It is possible to reliably determine the displacement of the subject between the next rotation. Furthermore, according to the present invention, since the rotation accompanying the acquisition of the image signal at each angle, which is performed later, is provided with operation means for starting the rotation at an arbitrary timing, the displayed subtraction image is observed. Then, after confirming that there is no displacement of the subject between the previous rotation and the later rotation, the subsequent rotation can be started. Therefore, D due to the displacement of the subject
The possibility of SA failure can be greatly reduced, and the utility of rotary DSA can be further enhanced,
Mental and physical pain of the operator and the subject (patient) can be reduced. Further, the above-mentioned subtraction image at the initial position of the later rotation also shows how the contrast agent flows. Then, by observing this image, confirming the state of the contrast agent, operating the operation means, and starting rotation for collecting the contrast agent image, it is possible to timely grasp that the contrast agent has arrived at a desired site. A contrast agent image can be obtained from each angle direction. In this way, it is possible to check the injection state of the contrast agent in real time and start rotation later,
For example, when it is desired to record and observe the timing of the flow of the contrast agent from the arterial phase to the venous phase using the rotational DSA, the rotation can be started from the most effective point, and the rotation can obtain image information from multiple directions at once. DSA can be used more effectively. From this, the diagnosis efficiency based on the image information of the rotation DSA is increased, and the rotation D due to a selection error at the start of rotation is increased.
It is possible to prevent a decrease in the value of the SA image, reduce the possibility of re-contrast, and reduce mental and physical distress of the operator and the subject (patient). Further, troublesome procedures such as setting of a delay time for determining a rotation start point are not required, so that the possibility of making a mistake is greatly reduced, and the burden on the operator can be reduced.

[Brief description of the drawings] FIG. 1 is a block diagram of one embodiment of the present invention. [Explanation of symbols] 10 subject 21 X-ray tube 22 X-ray image intensifier 23 X-ray TV camera 24 C type arm 25 Rotary drive 26 stand 31 Control device 32 injector 33 Rotation control switch 41 Image processing device 42 Switch 43 Image memory 44 arithmetic unit 45 Image monitor

────────────────────────────────────────────────── ─── Continued on the front page (56) References JP-A-6-2766437 (JP, A) JP-A-4-115677 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) A61B 6/00 A61B 6/02

Claims (1)

(57) [Claims] 1. An X-ray irradiating means for irradiating an X-ray toward a subject, and an image signal of an X-ray transmission image when the X-ray transmitted through the subject is incident. X-ray imaging means to be obtained, rotating means for integrally rotating these X-ray irradiating means and X-ray imaging means at least twice, and storing image signals at respective angles in rotation performed prior to the two rotations. An image storage means for performing the subtraction processing between the image signals at the respective angles in the subsequent rotation and the image signals stored in the previous rotation at the corresponding angles, and an initial operation for the subsequent rotation. Operating means for stopping the rotating operation of the rotating means at the position, and starting the rotating operation of the rotating means, and operating the X-ray irradiating means when the rotation is stopped at the initial position of the subsequent rotation. Image signals obtained from the X-ray imaging means by X-rays And displaying the subtraction processed image by the calculating means between the initial position and the image signal stored at the angle at the previous rotation corresponding to the initial position, and after the subsequent rotation is started by the operating means. And an image display means for displaying subtraction-processed images at each angle sequentially output from the arithmetic means.