JP3178344B2 - Digital X-ray imaging equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a digital X-ray video apparatus for performing a DSA process.

[0002]

2. Description of the Related Art In a digital X-ray imaging apparatus, an X-ray tube irradiates an object with X-rays from an X-ray tube and transmits the X-rays through the object to an X-ray imaging apparatus comprising a combination of an image intensifier and a television camera. And obtains a video signal of an X-ray transmission image of the subject, digitizes the video signal, and performs various processes. DSA is an image contrasted with a contrast agent, that is, a contrast image, obtained by digitizing an X-ray image (mask image) before injection of the contrast agent and an X-ray image (contrast image) after injection of the contrast agent and performing a subtraction process. An image of a blood vessel or the like filled with the agent is obtained.

[0003] In recent years, a region (a typical example is the entire lower limb from the lower abdomen to the heel) extending over a wide area that cannot be imaged at a time with the visual field size of an X-ray imaging device such as an image intensifier. In order to obtain a DSA image, a step-moving DSA in which the examination table or the imaging system is moved stepwise to capture a mask image, and then the examination table or the imaging system is moved stepwise again to capture a contrast image. Photographing (step DSA) is being performed. According to this, it is possible to obtain a contrast image by moving the injected contrast agent in a stepwise manner as it flows, so that a single imaging can obtain a DSA image of a wide area such as the entire lower limb. And the burden on the subject and the surgeon is reduced.

[0004]

However, in the conventional step DSA, when the X-ray conditions have to be changed at each position such as the entire lower limb, at least three movement steps are required, and the subject and the subject need to move at least three times. There is a problem that there is room for improvement in reducing the burden on the operator.

[0005] That is, in contrast examination of the entire lower limb, the best method is to cover from the lower abdomen to the heel. However, as the field of view is moved from the lower abdomen to the heel, the thickness of the subject is usually reduced. Become thin. Therefore, it is appropriate to set an optimum X-ray condition for each visual field according to the thickness.
This is a necessary condition for obtaining an SA image. Therefore, first, the examination table or the like is moved in a stepwise manner, a test process is performed at each stationary position to irradiate X-rays, a video signal is obtained, and a moving process (test run) for finding an optimum condition is performed. A movement process (mask run) for obtaining a mask image under the optimal conditions of
Finally, a moving step (contrast run) for obtaining a contrast image under each optimum condition is performed while the contrast medium is injected and moved along the flow.

[0006] In this way, moving at least three strokes,
There is a special mental burden for the subject lying on the examination table, and for the surgeon, the condition setting operation for setting the optimum X-ray condition must be performed at each position. This is a troublesome and time-consuming task.

[0007] In view of the above, it is an object of the present invention to provide a digital X-ray imaging apparatus improved so as to further reduce the burden on a subject or an operator.

[0008]

In order to achieve the above object, in a digital X-ray imaging apparatus according to the present invention,
X-ray imaging means for irradiating a subject with X-rays to obtain a video signal of a transmitted X-ray image, and moving the X-ray imaging means stepwise relative to the subject in one direction and then in the opposite direction Moving means for stepwise moving to the same rest position,
The X-ray condition is obtained by experimentally irradiating X-rays at each stationary position of the outward step movement to obtain an image signal, the information is held, and the X-ray is irradiated under the conditions to obtain the image signal of the mask image. A control means for determining an X-ray condition based on the above information in each stationary period of the return path step movement and performing control so as to obtain an image signal of a contrast image at the time of injection of a contrast agent by applying X-rays; Image processing means for storing a mask image at each stationary position, and performing a subtraction process between the contrast images when a contrast image is obtained.

An X-ray condition is obtained by experimentally irradiating X-rays at each stationary position of the outward step movement to obtain an image signal, the information is held, and X-ray irradiation is performed under these conditions to obtain an image of a mask image. Since a signal is obtained, the forward stroke serves as both the conventional test run and mask run. As a result, the step DSA can be performed in two strokes (one round trip). Then, in the return path in which the contrast run is performed, the optimum X-ray conditions at each stationary position can be automatically set based on the stored information, so that the work for setting the X-ray conditions can be omitted.

[0010]

Next, embodiments of the present invention will be described in detail with reference to the drawings. In FIG. 1, a subject 10 is lying on a table 12 of a medical examination table 11. The examination table 11 has a built-in drive unit 13 so that the table 12 can be moved as indicated by an arrow. The X-ray tube 2 sandwiches the subject 10
1 and an image intensifier (II) 22 are arranged opposite to each other, and a television camera 23 is coupled to the image intensifier 22. The video signal obtained by the television camera 23 is sent to the image processing device 24 to be digitized, subjected to various processes, sent to the image monitor device 25 for display, or sent to the recording device 26 for recording. I do.

Here, assuming that a DSA image of the entire lower limb from the lower abdomen to the heel of the subject 10 is obtained, a mask image and a contrast image are obtained at three stationary positions. First, the controller 27 captures these three positions. For example, the operator moves the table 12 to the three positions without exposing the patient to X-rays.
1 is read by the controller 27.

Next, the operator moves the table 12 to the position where the step DSA is started, and then presses the hand switch 29 for X-ray irradiation. Then, as shown in FIG. 2, first, a test X-ray irradiation 31 is performed at the position. The video signal obtained in this way is taken into the image processing device 24, and the controller 27 calculates the optimum X-ray conditions, and stores the information in an internal memory or the like. At the same time, the controller 27 controls the X-ray power supply device 28 to set the conditions, and performs X-ray irradiation 32 for a mask image to obtain a mask image. This mask image is stored in the image processing device 24.
Are stored in an image memory (not shown) built in the image processing device 24.

When the storage of the mask image is completed, a movement signal (FIG. 2) is supplied from the controller 27 to the driving device 13, the table 12 moves, and the subject 10 reaches the position, and stops there. . At this position, as in the case of the position, the test X-ray irradiation 3 for obtaining the optimum X-ray condition is performed.
Step 3 is performed to store the information of the obtained condition, and to perform the setting for the condition and the exposure 34 for imaging the mask image.

When the storage of the mask image at the position is completed,
The movement signal is again output from the controller 27 and the subject 1
0 is moved to the position and stands still. In this position as well, a trial exposure 35 is performed and the optimum X
Line conditions are determined and the information is stored. At the same time, the setting for the condition is performed.
6 is performed, and the mask image at the position is
Is stored in the image memory.

Although the mask run is completed in this way, it should be noted that this mask run also serves as a conventional test run and is completed in one stroke.

After the completion of the mask run, a contrast agent is injected into the subject 10, and the process proceeds to a contrast run. First,
The optimal X-ray condition at this position
7, the controller 27 sets the conditions for the X-ray power supply 28 to the X-ray power supply 28, and performs several X-ray exposures 37 for a contrast image. When the video signal of the contrast image is sent to the image processing device 24, a subtraction process with the mask image at that position is performed, and a DSA image at that position is obtained.

When the imaging of the specified number of contrast images is completed, a movement signal is automatically issued from the controller 27, the table 12 moves in the opposite direction, and the subject 10 reaches the position. Also at this position, similarly to the position, the optimum X-ray condition at the position is read from the memory in the controller 27, and the controller 27 sets the X-ray power supply device 28 to the condition, and the contrast image is obtained. X-ray exposures 38 are performed. When the video signal of the contrast image is sent to the image processing device 24,
Subtraction processing with the mask image at that position is performed, and a DSA image at that position is obtained.

When the imaging of the specified number of contrast images at this position is completed, a movement signal is output from the controller 27, the table 12 moves, and the subject 10 reaches the position. Similarly, at this position, the optimum X-ray conditions at the position are read out, set therefor, and the exposure 39 for the contrast image is performed thereunder, thereby obtaining a specified number of contrast images. Subtraction with the mask image at this position is performed, and a DSA image at the position is obtained.

In this contrast run, the visual field of the image intensifier 22 is moved in accordance with the flow of the contrast agent from the lower abdomen to the toes.
For this reason, the field of view is moved from the tip of the foot toward the lower abdomen in the first stroke (outward path), and conversely from the lower abdomen toward the tip of the foot in the next step (return path). Since the mask run also serves as a test run as described above, after all, the step DSA can be realized in two strokes (one round trip).

Although the movement signal from the controller 27 is automatically output in the above description, the movement signal may be output at an arbitrary timing by operating the switch or the like separately by the operator. According to this, particularly in the contrast run, the operator can determine the movement timing while observing the flow of the contrast agent according to the flow. In addition, although the subject 10 is held on the examination table 11,
For example, the subject 10 may be held by hanging from the ceiling. Further, instead of moving the subject 10, the subject 10 is fixed and the X-ray tube 21,
Needless to say, the image intensifier 22 and the television camera 23 can be moved. In addition, the specific configuration and the like can be variously changed.

[0021]

As described above, according to the digital X-ray imaging apparatus of the present invention, the step DSA that previously required three strokes (1.5 reciprocations) can be completed in two strokes (one reciprocation). Since the X-ray condition setting is automatically performed, the mental and physical burden on the subject can be reduced, and the operability can be improved by reducing the operator's labor. In particular, because the travel distance is reduced, the table may collide with something,
The probability of occurrence of a potential danger that the subject may suffer due to recoil or the like can be reliably reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a time chart for explaining the operation.

[Explanation of symbols]

 REFERENCE SIGNS LIST 10 subject 11 examination table 12 table 13 drive device 21 X-ray tube 22 image intensifier 23 television camera 24 image processing device 25 image monitor device 26 recording device 27 controller 28 X-ray power supply 29 hand switch

Claims (1)

(57) [Claims] 1. An object is irradiated with X-rays and transmitted therethrough.
X-ray imaging means for obtaining a video signal of a line image, and moving means for stepwise moving the X-ray imaging means relative to a subject in one direction and then stepwise to the same stationary position in the opposite direction X-rays are tentatively irradiated at each stationary position of the forward step movement to obtain a video signal, X-ray conditions are obtained and the information is held, and X-rays are irradiated under the conditions to obtain a video signal of a mask image. Control means for determining the X-ray conditions based on the above information in each stationary period of the return path step movement and performing X-ray irradiation to obtain an image signal of a contrast image when a contrast agent is injected; and Digital X-ray imaging apparatus comprising: a digital X-ray imaging apparatus that stores a mask image at each stationary position after digitizing the image and performs subtraction processing between the contrast images when a contrast image is obtained.