JP2001238875A - X-ray equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide X-ray equipment that are built at a lower cost, have high accuracy in moving motion parts such as an X-ray tube and an X-ray detector, and produce excellent images when taking X-rays using contrast- medium or tomograms, without adjusting the position to normal when turning on electricity. SOLUTION: When the X-rays of an object are taken from many directions by moving an X-ray producing device, an X-ray detecting device, or a table that hold the object, X-ray equipment is provided with a discriminating circuit 11b for pulse which converts two pulse signals output from an incremental encoder 11a and an encoder 11a into signals for turning directions and pulse signals for counting positions, a device 11S for measuring positions with a pulse count and storing circuit 11e which counts pulse signals for counting positions and stores updated, current positions while considering signals for turning directions, and devices 2, 3, 4 that supply power to the device 11S for measuring positions all the times.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an X-ray tube, an X-ray detector, or a support means for supporting a subject.
The present invention relates to an X-ray imaging apparatus that performs radiography.

[0002]

2. Description of the Related Art In a medical field, various X-ray images of a patient (subject) obtained by using an X-ray imaging apparatus are obtained.
It is extremely useful in performing appropriate diagnosis and treatment, especially by taking images of patients from multiple directions.
It is possible to obtain an X-ray image more suitable for diagnosis of a lesion or the like. For example, organs using contrast agents (liver, etc.)
In a fluoroscopic X-ray image of a blood vessel (a so-called angiographic fluoroscopic image), observing the image from multiple directions makes it easier to find a lesion.

FIG. 3A is a schematic diagram showing a schematic configuration of a main part of an X-ray imaging apparatus of this type. In FIG. 3a, X
The X-ray tube 92 and the X-ray image detector 93 are arranged so as to face each other to an arc-shaped support arm (C-shaped support arm) 97, and the support arm 97 extends along the circumferential direction of the arc (around the Z axis). , And can rotate around the direction perpendicular to the body axis of the patient 95 (around the X axis). Then, by combining the rotation operation around the Z axis and the rotation around the X axis, a three-dimensional complicated movement becomes possible, and X-ray imaging of the patient 95 from multiple directions becomes possible.

When performing X-ray imaging from multiple directions using the X-ray imaging apparatus having such a configuration, first, the patient 95 is positioned at a predetermined position as shown in FIG. 3A, and the injector ( While not injecting the contrast agent into the patient 95, the X-ray irradiation by the X-ray tube 92 to the patient 95 is started immediately after the start of the injection of the contrast agent. Z
Two movements about the axis are started simultaneously.

[0005] In addition, tomography for obtaining a tomographic image of the subject in the body axis direction by moving the X-ray tube and the X-ray detector in the body axis direction of the subject and in directions opposite to each other is also known. It will be effective for diagnosis.

The principle of X-ray tomography is as follows.
That is, as shown in FIG. 4, by changing the position of the X-ray tube 82 or the irradiation angle of the X-ray emitted from the X-ray tube 82, the imaging inside the subject M placed on the top plate 81 is performed. Even if the incident direction from the X-ray tube 82 to the target tomographic plane Ma from the X-ray tube 82 is changed, the points A and B located in the imaging target tomographic plane Ma are always the same points on the image receiving surface 3a of the imaging unit 83. a, b
The image receiving surface 3a of the imaging unit 83 is linked to the change in the incident direction of the X-rays to the imaging target tomographic plane Ma so that
Move the position of. Then, the imaging target tomographic plane Ma
Is located outside of X with respect to the imaging target tomographic plane Ma.
As the incident direction of the line changes, the projection position on the image receiving surface 3a changes one by one. For example, while the X-ray tube 82 is projected on the position c1 when the position P1 is set, the point C is set with respect to the incident direction of the X-rays to the imaging tomographic plane Ma when the X-ray tube 82 moves to the position P2. The image is projected onto a point c2 on the image receiving surface 3a.

As described above, the image receiving surface 3a of the image pickup section 83 is changed in the state where the X-ray incidence direction on the tomographic plane Ma to be photographed is changed.
When the respective X-ray fluoroscopic images received in step S are superimposed, in the superimposed image, the transmission X-rays at point C are scattered throughout the image, and point C appears as an unclear blurred point, Since the points A and B are always superimposed on the image receiving surface 3a as the same point, they appear as clear points, and as a result, an X-ray tomographic image obtained by extracting the tomographic plane Ma to be captured is obtained.

As described above, in contrast radiography and tomography in which a subject is imaged from multiple directions, it is necessary to cause an X-ray tube, an X-ray detector, and the like to perform a desired moving operation. This is achieved by controlling the driving means disposed on each of the operating axes so that the output of the position detecting means such as a potentiometer or an encoder provided on each of the operating axes becomes a desired value.

[0009]

However, in the case where a potentiometer is used as the position detecting means, an analog signal is output using a variable resistor, so that fluctuations in the surrounding environment such as temperature drift and the effects of external noise are avoided. Can not do. For this reason, when performing the above-mentioned contrast imaging or tomography in which it is required to move the X-ray tube, the X-ray detector, and the like with extremely high accuracy, a favorable X-ray image cannot be obtained, which hinders diagnosis. It will be.

[0010] On the other hand, when an encoder is used as the position detecting means, the problem of being affected by the surrounding environment and the influence of external noise can be solved because of digital measurement. However, the use of an absolute encoder for performing absolute position detection is extremely expensive, and an X-ray imaging apparatus having a large number of drive shafts requires many expensive encoders.

When an incremental encoder is used, it is relatively inexpensive. However, since the output of information proportional to the amount of rotation of the rotary shaft or the like cannot be detected, the absolute position itself cannot be detected. To get
It is necessary to temporarily move each operation unit to a reference position and calculate the current position of each operation unit based on that point. For this reason, when the power supply of the X-ray imaging apparatus is cut off, all the current positions are erased, and it is necessary for the operator to adjust each operation unit to the reference position every time the apparatus is energized.
Especially for medical equipment, the operator is not involved from the safety point of view.
Since the operation units such as the wire tube cannot be moved, each operation unit cannot be automatically moved to the reference position at the time of energization.

The present invention has been made in order to solve the above-mentioned problems, and has an inexpensive structure and does not perform positioning to a reference position when energized, and thus an X-ray tube or an X-ray detector. It is an object of the present invention to provide an X-ray imaging apparatus capable of moving the operation unit with high accuracy and obtaining a good image in contrast imaging, tomography, and the like.

[0013]

According to the first aspect of the present invention, the X-ray generating means or the X-ray detecting means is moved, or the supporting means for supporting the subject is moved so that the subject can be seen from multiple directions. In an X-ray imaging apparatus that performs X-ray imaging, an incremental encoder and a pulse signal from the encoder are input, and the X-ray generation unit, the X-ray detection unit, or the support unit is input based on an amount of relative movement from a reference position. A position measuring means having a pulse measuring section for measuring and holding the position of the means, and a power supply means for constantly supplying power to the position measuring means separately from the apparatus main body are provided.

According to the first aspect of the present invention, even when the power of the X-ray imaging apparatus is cut off, power is always supplied to the incremental encoder and its measuring unit, so that the encoder is returned to the reference position only at the time of installation. Only by performing the position adjustment described above, it is possible to obtain the absolute position of each operation unit with a low-cost configuration and with high accuracy without being affected by the surrounding environment.

According to a second aspect of the present invention, the power supply means detects a main power supply, an auxiliary power supply charged by the main power supply, and a voltage supplied from the main power supply, and the detected voltage is used as the position measurement means. And a power supply switching means for switching the power supply of the position measuring means to the auxiliary power supply when the voltage value falls below the voltage value required for performing the above operation.

According to the second aspect of the present invention, when the X-ray controller is energized, the power to the X-ray controller is used, and the auxiliary power is used only when the X-ray controller is turned off. And can be used for a long time.

[0017]

FIG. 1 is a schematic diagram showing an entire configuration according to an embodiment of the present invention. In FIG. 1, an X-ray tube 10 for irradiating a subject with X-rays is provided on a horizontal column of an inverted L-shaped X-ray tube support column 20, and the X-rays of the horizontal column of the X-ray tube support column 20 are provided. In the vicinity of the tube 10, a tube expanding and contracting means 11 for moving the X-ray tube 10 in a vertical direction (arrow a),
Tube-side rotating means 12 for rotating the X-ray tube 10 around the longitudinal axis of the top 50 (arrow b), and X around the axis perpendicular to the longitudinal direction of the top 50 (arrow c). Wire tube 10
Is provided with a tube square rotating means 13 for rotating.
The vertical support of the X-ray tube support column 20 includes an X-ray tube support column 2.
A column running means 21 for moving the entirety of the X-ray tube 0 in the longitudinal direction (arrow d) of the top plate 50 is provided.
By moving the entirety 0 in the same direction, the X-ray tube 10 can also move in the longitudinal direction of the top plate 50 (arrow d).

The X-ray tube support column 20 is provided with a compression unit 30 for compressing the abdomen of the subject and a compression unit moving means 31 for rotating the compression unit 30 toward the subject (in the direction of arrow e). ing.

The top plate support column 40 holds the top plate 50, and the top plate support column 40 includes a top plate left-right movement means 51 for moving the top plate 50 in the left-right direction (arrow f), and a top plate 50. Are provided (top arrow g), and a top plate lifting / lowering unit 53 that moves the top plate 50 up and down (arrow h).

An X-ray detector 60 for detecting X-rays emitted from the X-ray tube 10 and transmitted through the subject is provided below the top 50, and the X-ray detector 60 is provided on the top 50. To top plate 5
An image receiving unit traveling moving means 61 for moving in the longitudinal direction of 0 (arrow f) is provided.

Note that, in FIG.
1, tube side direction rotating means 12, tube square rotating means 13,
Compression cylinder moving means 31, top plate left / right moving means 51, top plate rotating means 52, top plate elevating / lowering means 53, and image receiving unit traveling moving means 6
Although the exact locations of the ones are not shown, they are all arranged in a known manner.

FIG. 2 is a block diagram showing an operation control unit such as an X-ray tube, an X-ray detector, and a top plate on which a subject is placed. In FIG. 2, the tube telescopic movement means 11 shown in FIG.
Is composed of a telescopic movement measuring unit 11S for detecting the position when the X-ray tube 10 moves up and down, and a telescopic movement driving unit 11D for moving the X-ray tube 10 up and down. 1
When a desired movement operation is performed with respect to 0, the expansion / contraction drive unit 11D is appropriately controlled based on the position signal detected by the expansion / contraction measurement unit 11S.

An expansion / contraction measuring section 11S is provided on a drive shaft for moving the X-ray tube 10 up and down, and outputs two pulse signals including information on the amount of rotation and the direction of rotation.
a, a pulse discrimination circuit 11b that converts two pulse signals output from the encoder 11a into a rotation direction signal and a pulse signal for position counting, and a rotation direction signal,
It comprises a pulse count / storage circuit 11c which counts pulse signals for position counting, updates the current position and stores it. The update of the current position data is performed by adding or subtracting the newly input count number to or from the current position data in consideration of the rotation direction signal. When the device is installed, each operation unit is positioned to the reference position and the position data of the reference position is stored.The current position data is updated every time the movement of each operation unit is performed from the time of installation of the device. It was obtained by The telescopic drive unit 11D includes a drive / control circuit 11'a.

Although not shown in FIG. 2, the tube side direction rotating means 12, the tube square rotating means 13, the compression cylinder moving means 3
1, the top plate left / right movement unit 51, the top plate rotation movement unit 52, the top plate elevation movement unit 53, and the image receiving unit traveling movement unit 61, similarly, the tube side direction rotation measurement unit 12S, the tube side direction rotation drive unit 12D,... Consists of an image receiving unit traveling measuring unit 61S and an image receiving unit traveling driving unit 61D, and the tube side direction rotation measuring unit 12
From S, the image receiving unit travel measuring unit 61S includes a telescopic movement measuring unit 11S.
Each has an encoder, a pulse discriminating circuit, and a pulse counting / storing circuit in the same manner as described above.

In FIG. 2, a telescopic drive unit 11D, a tube-side rotation drive unit 12D,...
Is supplied with electric power from the DC power supply 2,
1S, tube side direction rotation measuring unit 12S,..., Image receiving unit traveling measuring unit 61S is configured to be supplied with power from the DC power supply 2 or the rechargeable battery 3 via the power supply switching / monitoring circuit 4.

The DC power supply 2 receives the power supplied to the X-ray imaging apparatus and supplies a DC current. When the power supplied to the X-ray imaging apparatus is cut off, the power supply is also stopped. When the DC power supply 2 operates, the rechargeable battery 3
It is charged by the electric power from the C power supply 2 and is connected to the power supply switching / monitoring circuit 4.

The output of the rechargeable battery 3 and the output of the DC power supply 2 are connected to the power supply switching / monitoring circuit 4. The circuit operates by the power of the rechargeable battery 3 and constantly monitors the voltage output from the DC power supply 2. When the voltage of the DC power supply 2 is reduced to such an extent that the expansion / contraction measurement unit 11S, the tube-side rotation measurement unit 12S,... , Tube side direction rotation measuring unit 12S,...
The power supplied from the DC power supply 2 to the image receiving unit traveling measurement unit 61S is changed to the power supplied from the rechargeable battery 3.

Thus, when the apparatus is not used, such as at night,
Even when the power supply to the X-ray imaging apparatus is cut off, the encoder 11a, the pulse discrimination circuit 11b, and the pulse count and storage circuit 1
1c and other tube-side direction rotation measuring units 12S,..., The image receiving unit traveling measuring unit 61S are also continuously supplied with electric power. Therefore, even when an increment type encoder is used, a reference is made when the device is energized. The absolute position can always be detected without performing position adjustment. In particular, by continuously supplying power to the entire encoder, counter discrimination circuit, and pulse count / memory circuit,
Even when the X-ray tube 10, the top panel 50, the X-ray detection unit 60, etc. can operate unexpectedly when the power to the apparatus is cut off, it is possible to reliably detect the movement of the X-ray tube 10, the top panel 50, the X-ray detection unit 60, By detecting an accurate absolute position, it is possible to obtain a high-accuracy captured image in tomography or contrast imaging.

[0029]

According to the present invention, even when the power supply to the X-ray imaging apparatus is cut off, the power is always supplied to the incremental encoder and the entire measuring unit, so that the increment type Even if the encoder is used, the absolute position can be detected without performing positioning to the reference position every time the device is energized. In particular, by continuously supplying power to the increment type encoder and the entire measurement unit, even when the X-ray tube, the top plate, the X-ray detection unit, etc. may operate unexpectedly when power to the device is cut off. These movements can be reliably detected, and a high-accuracy captured image can be obtained in tomographic imaging or contrast imaging by always knowing the exact absolute position of each part.

Further, when the X-ray control device is energized, the power to the X-ray control device is used, and the auxiliary power supply is used only when the X-ray control device is turned off. The auxiliary power supply can be used for a long time.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an X-ray imaging apparatus according to an embodiment of the present invention.

FIG. 2 is a block diagram showing an operation control unit such as an X-ray tube, an X-ray detector, and a top plate on which a subject is placed according to an embodiment of the present invention.

FIG. 3 is a diagram for explaining contrast imaging.

FIG. 4 is a diagram for explaining tomography.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... X-ray tube 20 ... X-ray tube support column 30 ... Compression cylinder 40 ... Top plate support column 50 ... Top plate 60 ... X-ray detection part

Claims (2)

[Claims] 1. An X-ray imaging apparatus that performs X-ray imaging of a subject from multiple directions by moving an X-ray generating unit or an X-ray detecting unit, or moving a supporting unit that supports the subject. An incremental encoder and a pulse measuring unit that receives a pulse signal from the encoder and measures and holds the position of the X-ray generation unit, X-ray detection unit or the support unit based on the relative movement amount from a reference position An X-ray imaging apparatus comprising: a position measuring unit having: a power supply unit that constantly supplies power to the position measuring unit separately from the apparatus main body. 2. The X-ray imaging apparatus according to claim 1, wherein the power supply unit detects and detects a main power supply, an auxiliary power supply charged by the main power supply, and a voltage supplied from the main power supply. An X-ray imaging apparatus comprising: a power supply switching unit that switches a power supply of the position measurement unit to the auxiliary power supply when a voltage falls below a voltage value necessary for performing an operation of the position measurement unit.