JP2005135680A - Radiographic equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radiographic equipment capable of setting satisfactory serial radiographic conditions not exceeding the maximum cooling rate of an X-ray tube device with the use of a just-turn function. <P>SOLUTION: An operator reads out and set X-ray conditions with an operating panel from anatomical radiographic condition data stored in a storage unit 2, and at the same time, sets for photography. A foot switch 5 for fluoroscopy is put 'ON', a fluoroscopic image is confirmed by an image display device 12, a hand switch 6a is put 'ON' to apply an injector 6 to start injection of an imaging agent, and at the same time, the foot switch 5 for fluoroscopy is put 'OFF'. A CPU 3 calculates an average input of a load at fluoroscopy and that at radiography, and sets a radiography current, a pulse load time, and the number of pulse repetition from maximum input characteristics of the serial radiography within a range not exceeding the maximum cooling rate of the X-ray tube device. Then, a C-arm 7 rotates to perform the serial radiography under satisfactory conditions. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an X-ray imaging apparatus, and more particularly to setting of imaging conditions for performing high-speed continuous imaging while seeing through a cardiovascular vessel, a head and abdomen, and rotating a C-arm.

Among the fluoroscopic imaging apparatuses, in particular, the cardiovascular diagnostic apparatus is targeted for diagnosis of cardiovascular and systemic arteriovenous systems such as cranio-abdominal lower limb blood vessels, mainly the arterial system. In order to make a diagnosis by injecting a contrast medium into a blood vessel and observing a blood flow with an X-ray transmission image, it must be possible to perform fluoroscopy and imaging with X-rays from various angles.
The apparatus comprises an X-ray tube device, an image receiving system (image intensifier / TV camera), a holding device for holding them, an examination table (catheter bed), an X-ray high voltage device, and a controller for the device. .
In general, a cardiovascular diagnostic device has a C-arm holding device that can be seen and photographed from various angles, and is combined with an examination table (catheter bed) with a cantilever top. The fluoroscopic / photographing position can be taken at any angle without moving the examiner.

FIG. 5 shows a ceiling-suspended X-ray fluoroscopic apparatus. The C-arm 7 is held from the ceiling via the ceiling suspension part 10, the X-ray tube device 8 is opposed to both ends of the C-arm 7, and the I.D. I. 9 and a TV camera 9a are attached. The C-arm 7 to which the X-ray tube device 8 and the image receiving system are attached slides in a circular arc shape in the channel of the support portion of the C-arm 7, and the support portion has an arrow about the mounting shaft. The angle of the X-ray beam can be changed by rotating the C arm 7 left and right in the direction A. Moreover, the ceiling suspension part 10 can also rotate in the direction of the arrow B, and can also move to an XY direction. In addition, an I.D. I. 9 can be slid up and down by a slide mechanism (not shown). I. I. 9 can be lowered and brought close to the subject side. I. It is also possible to take an enlarged picture by raising 9 upward. The examination table (catheter bed) 11 is composed of a bed table and a bed top plate. The bed table can adjust the height of the bed top plate, and the bed table can be moved in the length direction. it can. In the ceiling-suspended C-arm 7 device, it is possible to photograph at angles from LAO 120 ° to 0 ° (front) and CRA / CAU 45 °.
For example, when the head is inspected, first, the subject is placed on the bed top of the inspection table 11. Then, X-ray conditions are set on the operation panel 1. Next, the C-arm 7 is rotated so that the direction of the X-ray beam is aligned with the direction of the portion of the head to be fluoroscopically imaged. And I.I. I. 9 is brought close to and close to the head of the subject by a slide mechanism. When the fluoroscopic foot switch 5 is stepped on to perform fluoroscopy, the X-ray image is confirmed by the image display device 12, the hand switch 6a is pressed to operate the injector 6, and the contrast medium is injected from a blood vessel such as an artery of the subject. At the same time, X-ray imaging is performed.

There is a technique in which a diagnostic region is continuously imaged three-dimensionally by changing an X-ray incident angle. When photographing the abdomen, the just turn function (when the fluoroscopic foot switch 5 is continuously stepped on and the hand switch 6a is pressed, the injector 6 starts to operate. While the fluoroscopic foot switch 5 is continuously stepped on, the C arm 7 When the fluoroscopic foot switch 5 is released without rotating, the C-arm 7 starts rotating.) Is used to perform high-speed continuous shooting under preset shooting conditions.
Japanese Patent Laid-Open No. 2002-112987 (page 8, FIG. 1)

Although the conventional X-ray imaging apparatus is configured as described above, when performing imaging, a high-speed continuous imaging is performed under a preset imaging condition using a just turn function, but the imaging time may be long. is there. FIG. 6 shows the load characteristics of the X-ray tube device 8. The amount of heat generated at the anode of the X-ray tube is accumulated in the X-ray tube device 8 in proportion to the product of tube voltage, tube current, and time. The maximum amount of heat stored in the X-ray tube device 8 is referred to as an X-ray tube device storage heat capacity Hm, and the rate of reduction of the residual heat amount in the process of cooling from the state where this amount of heat is applied is the X-ray tube device. The cooling rate, and a curve representing this as a function of time is called an X-ray tube device cooling curve. (A) shows a maximum load state, (b) shows an overload state, and (c) shows a low load state. When the photographing time becomes long, the load curve becomes the state (b), and the photographing must be stopped and cooled. Therefore, the shooting conditions are reset so that the state (a) is obtained, and shooting is performed. Therefore, there is a problem that imaging conditions must be set under sufficient X-ray conditions and so as not to exceed the maximum cooling rate of the X-ray tube apparatus.
The present invention has been made in view of such circumstances, and when performing continuous imaging while rotating the C-arm, the just-turn function is used, the X-ray tube apparatus has the maximum capacity under sufficient X-ray conditions. An object of the present invention is to provide an X-ray imaging apparatus capable of setting imaging conditions so as not to exceed a cooling rate.

  In order to achieve the above object, an X-ray imaging apparatus according to the present invention has an X-ray tube apparatus and an X-ray image receiving unit disposed opposite to both ends of a holding unit, and performs continuous imaging while rotating around a subject. An operation panel for setting X-ray conditions and holding means, a storage device for storing a maximum cooling rate of the X-ray tube device and a continuous imaging maximum input characteristic, and the operation panel while ON Switch means for switching to photographing when fluoroscopy is performed under the X-ray conditions set in (2) and turning OFF, holding means that rotates when the switch means is turned OFF by setting the holding means rotation of the operation panel, and the switch means When the X-ray tube apparatus is turned off, the average input is calculated from the fluoroscopic load and the imaging load of the X-ray tube apparatus, and the imaging conditions are determined from the maximum cooling rate of the X-ray tube apparatus and the continuous imaging maximum input characteristic data stored in the storage device. Calculate While, it is provided with a control means for setting a range that does not exceed the maximum cooling rate shooting current and pulse loading time and the pulse repetition rate of X-ray tube apparatus.

  The X-ray imaging apparatus of the present invention is configured as described above, and the storage device stores data on the maximum cooling rate of the X-ray tube apparatus and the maximum input characteristics of continuous imaging. At the same time as the C-arm is rotated around the subject, the CPU calculates an average input between the load during fluoroscopy and the load during provisional imaging, and the average input is the maximum cooling rate of the X-ray tube apparatus. Within a range that does not exceed, the imaging current, pulse load time, and pulse repetition rate are reset from the maximum continuous imaging input characteristics of the X-ray tube device, and high-speed continuous imaging is performed under sufficient X-ray conditions.

  The X-ray imaging apparatus of the present invention is configured as described above, and when the just-turn function is used and the fluoroscopic foot switch is turned OFF, the CPU averages the fluoroscopic load and the temporarily set imaging load. Since the input is calculated and the average input does not exceed the maximum cooling rate of the X-ray tube device, the imaging current, pulse load time, and pulse repetition rate are set from the maximum continuous input characteristics of the X-ray tube device. Imaging can be performed under the necessary fluoroscopic conditions for confirming the imaging region before imaging and sufficient X-ray conditions allowed for high-speed continuous imaging. Therefore, the performance of the X-ray tube apparatus can be used to the maximum, and the X-ray tube apparatus does not break down due to overload. The operator can record a clear image under automatically set X-ray imaging conditions.

  In the X-ray imaging apparatus of the present invention, at the same time as the end of fluoroscopy, the CPU calculates an average input between the load during fluoroscopy and the set load during imaging, and the average input determines the maximum cooling rate of the X-ray tube apparatus. Within a range that does not exceed, the imaging current, pulse load time, and pulse repetition rate are set from the continuous imaging maximum input characteristics of the X-ray tube device, and high-speed continuous imaging is realized under sufficient X-ray conditions.

FIG. 1 is a block diagram showing an X-ray imaging apparatus according to an embodiment of the present invention.
The X-ray imaging apparatus of the present invention includes an X-ray imaging device 13 (operation panel 1, storage device 2, CPU 3), an operation panel 1 for setting X-ray conditions and imaging, an anatomical imaging condition, an X-ray tube. The average input calculation program of the apparatus 8, the maximum cooling rate of the X-ray tube apparatus 8, the maximum input characteristics of continuous imaging, the storage device 2 for storing the program for setting the imaging conditions, and the average input of the X-ray tube apparatus 8 are calculated and imaged. The CPU 3 for setting the current, the pulse load time, and the number of repetitive pulses, the X-ray tube device 8 and the X-ray image receiving unit 9b are attached to both ends of the C arm 7 suspended from the ceiling suspension unit 10, and the subject on the examination table is centered A C-arm type fluoroscopic imaging device 4 that rotates in a straight line, an image display device 12 that displays an X-ray image, an examination table on which a subject is placed, and an injector 6 that has a hand switch 6a for injecting a contrast medium. .

  The difference between the present X-ray imaging apparatus and the conventional apparatus is that in the conventional apparatus, the fluoroscopic conditions and the imaging conditions are set by the operation panel 1 of the controller, and the fluoroscopy is first performed in accordance with the X-ray conditions. However, after that, continuous imaging is performed, and the initial input is set with a margin so that the average input of the X-ray tube apparatus 8 does not exceed the maximum cooling rate. On the other hand, in the present X-ray imaging apparatus, after the fluoroscopy is completed, the CPU 3 reads the calculation program from the storage device 2, calculates the average input between the fluoroscopic load and the temporarily set radiographic load, and the average input As long as the maximum cooling rate of the X-ray tube device does not exceed the maximum cooling rate of the X-ray tube device, the imaging current, pulse load time, and pulse repetition rate are reset from the maximum continuous input characteristics of the X-ray tube device, and sufficient X-ray conditions are set. High-speed continuous shooting with.

This X-ray imaging apparatus performs fluoroscopy and imaging using an imaging just turn function. In the just turn function, the fluoroscopic foot switch 5 is continuously depressed to perform fluoroscopy, and when the hand switch 6a is pressed, the injector 6 starts operating. The C-arm 7 does not rotate while continuing to step on the fluoroscopic foot switch 5, and when the fluoroscopic foot switch 5 is released, the C-arm 7 starts to rotate and performs shooting.
FIG. 2 is a diagram showing a fluoroscopy / photographing process using the photographing just turn function (the horizontal axis represents time). While the operator continues to step on the fluoroscopic foot switch 5, X-rays are emitted under the fluoroscopic condition. In order to prevent the average input including the time of imaging to the X-ray tube apparatus 8 from exceeding the maximum cooling rate of the X-ray tube apparatus 8, the fluoroscopic condition initially set on the operation panel 1 is several mA or less. Limit to (low collection rate). In addition, the time for which the fluoroscopic foot switch 5 is continuously depressed is set to a predetermined time (fixed value) or less in consideration of the photographing time. The operator confirms the imaging region of the subject with the image display device 12, presses the hand switch 6a, operates the injector 6, injects the contrast medium into the subject, and releases the foot switch 5 for fluoroscopy. At this point, the C-arm 7 starts to rotate. The CPU 3 reads the calculation program from the storage device 2, calculates the average input of the load during fluoroscopy and the load during radiography, and continuously captures maximum input characteristic data so as not to exceed the maximum cooling rate of the X-ray tube device 8. The shooting conditions (high collection rate) are reset, and shooting starts. Photographing is performed while the C-arm is rotating, and the photographing time is a predetermined time (fixed value). Then, the C-arm stops and shooting is finished. Here, {(limit time for continuing to step on the fluoroscopic foot switch 5) + (imaging time)} = a constant value, and the average input (average collection rate) of the load during fluoroscopy performed by the CPU 3 and the load during radiographing. As shown in equation (1) of the program of the CPU 3 in FIG. 1, {(low collection rate during fluoroscopy) × (time for which the fluoroscopic foot switch 5 is depressed) + (high collection set during shooting) (Rate) × (shooting time)} / {(time for which the foot switch 5 for fluoroscopy is stepped on) + (shooting time)}.

  FIG. 3 shows an operation flowchart of the X-ray imaging apparatus. On the operation panel 1, the fluoroscopic conditions (fluoroscopic tube voltage, tube current), imaging conditions (imaging tube voltage, tube current, pulse load time, pulse repetition rate), and rotation of the C-arm 7 are set. Then, the foot switch 5 for fluoroscopy is stepped on (ON). Then, the fluoroscopic foot switch 5 is continuously stepped on, the fluoroscopic image of the subject displayed on the image display device 12 is confirmed, the imaging region is determined, and the hand switch 6a is pressed. The injector 6 starts operating. While continuing to step on the fluoroscopic foot switch 5, fluoroscopy is performed at a low collection rate (several mA). A fluoroscopic image of the subject displayed on the image display device 12 is observed, and the fluoroscopic foot switch 5 is released (OFF) at the timing when the contrast agent is filled. The rotation of the C-arm 7 starts, the CPU 3 calculates the average input of the X-ray tube device 8, and the imaging conditions (high collection rate) are reset from the continuous imaging maximum input characteristic data so as not to exceed the maximum cooling rate. Continuous shooting is performed at a high collection rate. When a predetermined time elapses, the C-arm 7 is stopped and the photographing is finished.

  The continuous imaging means includes high-speed continuous imaging for performing contrast imaging of a circulatory system that continuously repeats a load of several milliseconds, or a pulse load of several milliseconds at a rate of 30 to 60 FPS (frame / s). Cine-mode image acquisition (30 FPS is mainstream), DSA, etc., usually lasting in seconds and combined with fluoroscopy. In the storage device 2 of the apparatus, an input diagram is prepared with respect to a load for high-speed continuous shooting. FIG. 4 shows the input characteristics of the X-ray tube apparatus 8 during high-speed continuous imaging. The vertical axis represents the input value of the product of the tube voltage and the tube current, and the horizontal axis represents the pulse load time of the tube current. Nn (n = 1, 2, 3) indicates the total number of shots. The PULSE DUTY and the pulse load time during continuous shooting are, for example, 0.04 s at 6 frames / s, 0.10 s at 3 sheets / s, 0.16 s at 2 sheets / s, and 0.16 at 1 sheet / s. Set to 25 s. The load condition is set so that the average input does not exceed the maximum cooling rate of the X-ray tube device from the input characteristic diagram of the X-ray tube device 8.

In the above-described embodiment, the description has been given of performing the fluoroscopy and the high-speed continuous shooting at the low collection rate using the shooting just turn function, and performing the shooting at the high collection rate. The same applies to shooting.
Although the rotation time of the C-arm 7 is constant, in order to collect images while rotating the C-arm 7 in one injection of the contrast medium, the contrast medium rotates while it reaches the target site. In addition, high speed rotation of the C-arm 7 is required. The present invention can be similarly applied to an apparatus that can set a rotation speed fast and set a slow rotation.

  As an application example of the present invention, the present invention can be used in a 3DX imaging apparatus that acquires images by rotating the C-arm 7 around the body axis during imaging in the head region or the like. Subtraction images obtained by the DF device can also be obtained for rotational imaging, which is useful for reducing the contrast agent, collecting images while rotating for as long as possible, and performing accurate three-dimensional grasping.

It is explanatory drawing which showed the implementation method of the X-ray imaging apparatus of this invention. It is a figure for demonstrating the imaging | photography just turn function of the X-ray imaging apparatus of this invention. It is a figure which shows the operation flow of the X-ray imaging apparatus of this invention. It is a figure which shows the relationship between the imaging | photography input of the X-ray tube apparatus at the time of high-speed continuous imaging | photography, and pulse load time. It is a figure which shows the X-ray imaging apparatus of the fluoroscopic imaging stand which has C arm. It is a figure which shows the load curve and cooling curve of an X-ray tube apparatus.

Explanation of symbols

1 Operation panel 2 Storage device 3 CPU
4 C-arm type fluoroscopic imaging device 5 Fluoroscopy foot switch 6 Injector 6a Hand switch 7 C-arm 8 X-ray tube device 9 I.
9a TV camera 9b X-ray image receiving unit 10 Ceiling suspension unit 11 Inspection table 12 Image display device 13 X-ray image capturing device

Claims (1)

  An X-ray imaging apparatus for performing continuous imaging while rotating an X-ray tube device and an X-ray image receiving unit opposite to both ends of a holding unit and rotating the subject around the subject, and sets X-ray conditions and holding unit An operation panel, a storage device that stores the maximum cooling rate of the X-ray tube device and the maximum input characteristics of continuous imaging, and the X-ray conditions set on the operation panel are turned on while the device is turned on. Switch means for switching, holding means that rotates when the switch means is turned off by setting the rotation of the holding means of the operation panel, and the load and radiographing of the X-ray tube apparatus when the switch means is turned off The average input is calculated from the load of the X-ray tube device, the maximum cooling rate of the X-ray tube device stored in the storage device, the imaging conditions are calculated from the continuous imaging maximum input characteristic data, and the range not exceeding the maximum cooling rate of the X-ray tube device X-ray imaging apparatus characterized in that a control means for setting a photographing current and pulse loading time and the pulse repetition rate.

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