JP2005245761A - X-ray diagnostic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an X-ray diagnostic apparatus which naturally displays a dyed region by a contrast medium and provides a transparent image in real-time at a quick response. <P>SOLUTION: The X-ray diagnostic apparatus is equipped with a system control part 17 which controls an X-ray generating part 13 to perform X-ray irradiation according to a first rate frequency when the X-ray irradiation is performed in a first mode, where trace processing for tracing the maximum value or the minimum value of each pixel in the direction of a time axis for a plurality of X-ray images by an image arithmetic and storage part 16 or averaging processing for adding a plurality of X-ray images is performed, and controls a trigger generating part 12 to implement the X-ray irradiation according to a second rate frequency different from the first rate if the X-ray irradiation is implemented in a second mode where the trace processing or the averaging processing is not implemented. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an X-ray diagnostic apparatus for imaging a circulatory organ or the like using X-rays, and more particularly, perspective peak trace processing for creating a road map mask image for a fluoroscopic road map from a fluoroscopic image, fluoroscopy The present invention relates to an X-ray diagnostic apparatus that executes addition averaging processing and the like.

  An X-ray diagnostic apparatus is an image apparatus that displays the intensity of X-rays transmitted through the body of a subject as a grayscale image, and there are various apparatuses depending on purposes such as diagnosis and treatment. The transmitted X-ray can be visualized by two methods of fluoroscopy and imaging. The former method displays an X-ray image as a moving image on a television monitor in real time, and is excellent in immediacy. In the latter method, an X-ray image is collected by intense X-ray irradiation, reproduced as a moving image and a still image, and further recorded on a film, thereby providing high spatial resolution and sharpness.

  An X-ray image generated by this X-ray diagnostic apparatus includes what is called a perspective road map. This is used for grasping the state of the catheter in the blood vessel when a doctor performs treatment using the catheter, and is generated as follows, for example.

  FIG. 6 is a diagram exemplifying a pulse rate frequency related to X-ray irradiation in a conventional series of perspective road map creation processes. First, a contrast medium is injected into the subject, and thereafter, as shown in FIG. 6, a fluoroscopic image until the contrast medium reaches the diagnostic site is acquired at a predetermined rate frequency. Next, processing for tracing the maximum value (or minimum value) of each pixel value in the time axis direction while obtaining a plurality of time-series fluoroscopic images obtained or acquiring a plurality of time-series fluoroscopic images. That is, a road map mask image is generated by executing peak trace processing (or bottom trace processing). Thereafter, a fluoroscopic image is acquired while performing a catheter operation, and a fluoroscopic road map is created and displayed by executing subtraction processing in real time using this and a road map mask image (for example, Patent Document 1). reference).

  By observing the displayed perspective road map, the doctor can grasp in real time where the operating catheter is. Note that the road map mask image can also be generated by an averaging process that performs an averaging of pixel values (image pixel values) of a plurality of obtained time-series frames instead of the peak trace process.

  By the way, in general, from the viewpoint of reducing the exposure of the patient and the operator (doctor), the pulse rate frequency is reduced to a minimum during fluoroscopy.

  However, in a series of conventional fluoroscopy roadmap creation processes, the pulse rate frequency related to X-ray irradiation in peak trace processing or addition averaging process and the rate frequency related to X-ray irradiation in fluoroscopy are interlocked so as to be the same rate. It is controlled. Therefore, when the pulse rate frequency is lowered to the minimum, the pulse rate frequency is lowered to the minimum even in the fluoroscopy in the peak trace process or the averaging process.

As a result, the flow of the contrast agent can be grasped only discretely in the peak trace processing, etc., and the stained region by the contrast agent becomes an unnatural image with discontinuity, and image information sufficient for diagnosis cannot be provided. . In addition, in addition averaging processing, when it is desired to add more than a certain number of frames to reduce noise, the processing time is increased to secure the necessary number of frames by increasing the addition time, and the response is increased. It will get worse.
Japanese Patent Laid-Open No. 6-165035

  The present invention has been made in view of the above circumstances, and is an X-ray diagnostic apparatus that can display a region stained with a contrast agent naturally and can provide a fluoroscopic image with quick response with high real-time performance. The purpose is to provide.

  In order to achieve the above object, the present invention takes the following measures.

  The viewpoint of the present invention is that X-ray generation means for irradiating a subject with X-rays, X-ray detection means for detecting X-rays transmitted through the subject, and X-rays detected by the X-ray detection means An image generation means for generating an X-ray image, and a trace process for tracing the maximum value or the minimum value of each pixel in the time axis direction with respect to a plurality of X-ray images generated by the image generation means, or An image processing means for generating a first image from a plurality of X-ray images by executing an averaging process for adding a plurality of X-ray images, and a control means for controlling the X-ray irradiation timing of the X-ray generation means When the X-ray irradiation is performed in the first mode in which the image processing means executes the trace processing or the averaging process, the control means performs X-ray irradiation according to the first rate frequency. Run When the X-ray irradiation is executed in the second mode in which the X-ray generation means is controlled and the image processing means does not execute the trace process or the addition averaging process, the first rate is different from the first rate. The X-ray diagnostic apparatus is characterized in that the X-ray generation means is controlled to execute X-ray irradiation according to a rate frequency of 2.

  As described above, according to the present invention, it is possible to realize an X-ray diagnostic apparatus that can naturally display a region affected by a contrast medium and that can provide a fluoroscopic image with quick response with high real-time performance.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, components having substantially the same function and configuration are denoted by the same reference numerals, and redundant description will be given only when necessary.

  FIG. 1 shows an external view of the X-ray diagnostic apparatus according to the present embodiment. The configuration of the X-ray diagnostic apparatus will be described using each drawing.

  As shown in FIG. 1, the X-ray diagnostic apparatus includes a ceiling mounting unit 1, a support arm 2, an arm holder 4, a C arm 5, a vertical movement mechanism 6, a top plate 9, a top plate holding unit 10, and a flat panel detector 11. , An X-ray generator 13 is provided.

  The ceiling attaching part 1 is a part for attaching the moving mechanism of the C arm 5 to the ceiling.

  The support arm 2 supports the C arm 5 via the arm holder 4 and can be rotated around the first rotation axis by fixing one end thereof to the ceiling mounting portion 1.

  The arm holder 4 is held on the other end side of the support arm 2 so as to be rotatable around a second rotation axis that is substantially orthogonal to the first rotation axis.

  The C arm 5 is attached to the arm holder 4 so as to be slidable and rotatable around a third rotation axis that is substantially orthogonal to each of the first and second rotation axes. An X-ray generator 13 and a flat detector 11 are attached to both ends of the C-arm 5 so as to sandwich the top 9 and the subject P.

  The vertical movement mechanism 6 is a mechanism that moves the flat detector 11 in a direction approaching or separating from the X-ray generation unit 13.

  The X-ray generator 13 has an X-ray tube and an X-ray restrictor. An X-ray tube is a vacuum tube that generates X-rays, and accelerates electrons emitted from a cathode (filament) by a high voltage to collide with a tungsten anode to generate X-rays. The X-ray restrictor is provided between the X-ray tube and the subject P, shapes the cone-shaped X-ray beam irradiated from the X-ray focal point of the X-ray tube, and converts the X-ray beam having a required solid angle. Form.

  The top plate 9 is a bed for mounting the subject P, and moves in the longitudinal direction or the lateral direction of the subject P. Note that the movement amount, movement timing, and movement speed of the top plate 9 and the C arm 5 are controlled by a C arm / top plate control unit 16 described later.

  The top plate holding unit 10 holds the top plate 9 and moves the top plate 9 in the body axis direction of the subject P.

  The flat detector 11 converts the X-rays that have passed through the subject P into charges and accumulates them. The charges accumulated in the flat detector 11 are read out as an X-ray image signal by the gate driver 21 (see FIG. 2), and converted into image data by the image data generation unit 11a (see FIG. 2).

  The flat detector 11 includes an X-ray that directly converts charges (direct type) and an X-ray that is converted to light and then converted to charges (indirect type). In the present embodiment, the former is described as an example, but the latter may be used.

  Further, instead of the flat detector 11, the incident X-ray is converted into an optical image by a fluorescent screen and output as image data. I. A configuration using (Image Intensifier) may be used.

  Next, functions and operations of the X-ray diagnostic apparatus will be described with reference to FIG. FIG. 2 is a block diagram including the internal configuration of the present X-ray diagnostic apparatus. As shown in FIG. 2, the X-ray diagnostic apparatus includes a trigger generation unit 12, an X-ray generation unit 13, an X-ray detection unit 14, a mechanism unit 15, an image calculation / storage unit 16, a system control unit 17, and an operation unit 19. The display unit 30 is provided.

  The trigger generation unit 12 sets X-ray irradiation conditions such as tube current, tube voltage, and irradiation time in accordance with an instruction signal from the system control unit 17. In addition, the trigger generator 12 is a trigger for generating a high voltage to be applied between the anode and the cathode according to the set X-ray irradiation conditions in order to accelerate the thermal electrons generated from the cathode of the X-ray tube 7. Generate a pulse.

  The X-ray generation unit 13 includes an X-ray tube 7 and an X-ray restrictor 8.

  The X-ray detection unit 14 includes a flat panel detector 11, an image data generation unit 11 a, and a gate driver 21. The image data generator 11a includes a charge / voltage converter 23 that converts charges read from the flat detector 11 into a voltage, and an A / D converter that converts the output of the charge / voltage converter 23 into a digital signal. 24 and a parallel / serial converter 25 for converting a digitally converted image signal read out in parallel in line units from the flat detector 11 into a serial signal.

  The mechanism unit 15 includes a C arm / top plate control unit 40, a C arm / top plate position detection unit 42, a second C arm movement mechanism 43, a first C arm movement mechanism 44, and a third C arm movement mechanism 45. have. The C-arm / top controller 40, based on a control signal from the system controller, optimizes the X-ray tube focal point-X-ray detector distance (SID), X-ray cone beam for the diagnosis target region of the subject P. , The incident angle of the X-ray beam with respect to the subject P, and the movement speed of the C arm 5 and the top plate 9 are controlled. The C arm / top plate position detector 42 detects the relative position of the C arm 5 and the top plate 9. The second C-arm moving mechanism 43 is a mechanism that rotates the C-arm around the second rotation axis. The first C-arm moving mechanism 44 is a mechanism that rotates the C-arm around the first rotation axis. The third C-arm moving mechanism 45 is a mechanism that rotates the C-arm around the third rotation axis.

  The image calculation / storage unit 16 includes a mask creation unit 16a, a mask image memory 16b, and an image generation unit 16c, and executes peak trace processing (or bottom trace processing), addition averaging processing, and the like. The operation in each shooting mode of the image calculation / storage unit 16 will be described in detail later with reference to FIG.

  Here, the peak trace processing (or bottom trace processing) is to trace the maximum value (or minimum value) of each pixel in the time direction for images of a plurality of frames, and to see through a road map mask image for a perspective road map. It is generated from an image. In addition, the addition averaging process performs addition averaging of the obtained time-series images of multiple frames, and generates a road map mask image for the perspective road map from the perspective image. To do.

  In the present embodiment, a fluoroscopic mode in which the peak trace process or the averaging process is executed to create a road map mask image is referred to as a “peak trace execution mode”. In addition, for example, the normal fluoroscopy mode for performing normal fluoroscopy regardless of the presence or absence of a contrast agent, real-time fluoroscopy during catheter operation, and subtraction using the obtained fluoroscopy image and roadmap mask image The fluoroscopic mode for executing the processing will be called a road map processing mode.

  The system control unit 17 includes a CPU and a storage circuit (not shown), temporarily stores information such as an operator's instruction and imaging conditions sent from the operation unit 19, and then stores X-ray image data based on these information. Controls the entire system, such as collection and display control, and control related to moving mechanisms.

  The operation unit 19 is an interactive interface including a display panel, a keyboard, various switches, a mouse, and the like. The operator of the apparatus uses the operation unit 19 to display subject (patient) information, the optimum X-ray irradiation conditions for the subject P or the diagnostic target part, the X-ray tube focus-X-ray detector distance, the X-ray cone. Setting of various imaging conditions such as the shape of the beam, the incident angle of the X-ray beam with respect to the subject P, the moving speed of the C-arm 5 and the top plate 9, the movement control of the mechanism unit 15, or the command signal for starting imaging Perform input etc. These setting signals and command signals are sent to each unit via the system control unit 17. The X-ray irradiation conditions include a tube voltage applied to the X-ray tube 7, a tube current, an X-ray irradiation time, etc., and the examination information, examination method, physique of the subject, past diagnosis history, etc. as the subject information There is.

  In addition, by inputting a subject ID (patient ID) from the operation unit 19, the subject information or various imaging conditions based on the subject information are stored in a network from a storage medium external to the device that is stored in advance. When the operator needs to change these information and setting conditions displayed on the monitor 34 of the display unit 30 or the display panel of the operation unit 19, the operation unit 19 is automatically read out. You may perform the input for a change more.

  The display unit 30 displays a mask image, a roadmap mask image, a DSA image, and the like output from the image calculation / storage unit 16. The display unit 30 synthesizes the various image data and the display image storage circuit 31 that temporarily stores the image data and the accompanying information such as numbers and various characters, and the X-ray image data and the accompanying information. It comprises a D / A converter 32 for converting to an analog signal, a format conversion circuit 33 for converting the analog signal to a TV format to generate a video signal, and a liquid crystal or CRT monitor 34 for displaying the video signal. .

  The present X-ray diagnostic apparatus described above further includes an interface (not shown) in addition to the basic configuration described above, and various image data are stored in an external hard disk, a recording medium such as a DVD or MOD via this interface, Further, it is output on a film by a laser imager or the like. The interface is connected to a network, and image data and examination information are stored in a data recording system inside and outside the hospital via this network, and further transferred to and displayed on an observation system inside and outside the hospital for use in diagnosis by a doctor.

(Pulse rate frequency change processing)
Next, the pulse rate frequency changing process executed by the X-ray diagnostic apparatus will be described. This control process employs different pulse frequency rates when executing image acquisition in an execution mode such as peak trace and when executing image acquisition in other imaging modes. In the present embodiment, as an example, a case will be described in which the pulse frequency rate in the execution mode such as peak trace is changed higher than the pulse frequency rate in the other fluoroscopic modes so that the contrast state can be observed more naturally.

  Examples of the fluoroscopic mode other than the execution mode such as peak trace include a normal fluoroscopic mode and a road map processing mode.

  FIG. 3 is a conceptual diagram showing the flow of control data and image data in fluoroscopic execution in each mode of execution mode such as peak trace, normal fluoroscopic mode, and roadmap processing mode.

  First, the pulse rate frequency of X-ray irradiation for each mode is input and set from the operation unit 19 by an operator's manual operation. This setting is set to 30 p / s for the execution mode such as peak trace, 7.5 p / s for the normal fluoroscopic mode, and 7.5 p / s for the road map processing mode.

  The X-ray irradiation pulse rate frequency for each mode is set by the operator selecting desired setting data from several setting data stored in advance in the setting data storage unit 170 of the system control unit 17. The configuration may be set.

  FIG. 4A is an example of setting data based on a combination of specific numerical values of the pulse rate frequency for each mode. For example, the operator can set the pulse rate frequency of the X-ray irradiation for each mode by selecting a setting data number based on a desired combination from the table of FIG. 4A displayed on the monitor 34.

  FIG. 4B is an example of setting data based on a combination of a normal perspective mode rate value and a magnification from the rate value. When the operator selects a setting data number in a desired combination, the system control unit 17 adds the corresponding magnifications to the normal fluoroscopic mode rate value, and uses the result to perform X-ray irradiation for each mode. Set the pulse rate frequency automatically.

  The table of setting data shown in FIGS. 4 (a) and 4 (b) is classified according to the diagnosis site from the viewpoint of operability, such as head examination, abdominal examination, and lower limb examination. It is preferable that the configuration is set.

  Further, in the following, it is assumed that the setting data of number 1 in FIG.

  When the pulse rate frequency of X-ray irradiation for each mode is set, the system control unit 17 controls the trigger generation unit 12 according to each pulse rate frequency to execute X-ray irradiation. That is, X-ray irradiation is executed at 30 p / s in the peak trace execution mode, 7.5 p / s in the DSA processing mode, and 7.5 p / s in the normal fluoroscopic mode.

  Transmitted X-rays from the subject obtained by each X-ray irradiation are detected by the X-ray detection unit 14 and sent to the image calculation / storage unit 16 as X-ray image data.

  In the image calculation / storage unit 16, when the fluoroscopic mode is the normal fluoroscopic mode, the X-ray image data is sent to the display unit 30 and displayed as a fluoroscopic image in real time. When the fluoroscopic mode is an execution mode such as peak trace, a mask image for each frame is created in the mask creating unit 16a. The generated mask image for each frame is sequentially output to the display unit 30 and displayed in real time, and sent to the mask image memory 16b. In the mask image memory 16b, a peak trace process for tracing the minimum value of each pixel in the time direction is performed on an image for each frame that is sequentially input, and a road map mask image is generated. Further, when the fluoroscopic mode is the roadmap processing mode, the image generation unit 16c uses the roadmap mask image generated in the mask image memory 16b and the fluoroscopic image sequentially input from the X-ray detection unit 14. A DSA image is generated.

  The image generated in this way is displayed on the display unit 30 in a predetermined form. In particular, for an image created in an execution mode such as peak trace, a natural mask image is displayed as if it was continuously flowing, rather than a discrete flow of contrast medium. Furthermore, a road map mask image obtained by performing an averaging process on such a mask image is a high quality image with little noise because of many addition targets, and is displayed with a fast response because of a high pulse rate frequency. be able to.

(Perspective operation)
Next, the fluoroscopic operation of the X-ray diagnostic apparatus will be described.

  FIG. 5 is a diagram showing an X-ray irradiation sequence executed when a fluoroscopic road map is generated and displayed in real time by the X-ray diagnostic apparatus. When the setting data is selected by the operator, as shown in FIG. 5, first, in the normal fluoroscopic mode, acquisition of a fluoroscopic image is executed at a predetermined pulse rate (in this case, 7.5 p / s). . The obtained image is displayed on the display unit 30 in real time. In normal fluoroscopy mode, the catheter is advanced to the vicinity of the target vessel.

  Next, the fluoroscopic mode is switched to an execution mode such as peak trace by a predetermined operation. The fluoroscopic image is acquired at a pulse rate higher than that in the normal fluoroscopic mode (in this case, 30 p / s). From the X-ray image obtained by injecting the contrast medium, a road map mask image is generated by the peak trace process and displayed on the display unit 30.

  Next, when the road map mask image is obtained, the fluoroscopic mode is switched to the road map processing mode by a predetermined operation or automatically, and a pulse rate lower than the execution mode such as peak trace (in this case, 7.5 p. / S), X-ray irradiation for obtaining a fluoroscopic image is executed. A perspective road map is created by road map processing for subtracting the road map mask image from the perspective image obtained at the rate, and is displayed on the display unit 30 in real time. The doctor can grasp the state of the catheter being operated in real time by observing the displayed perspective road map.

  According to the configuration described above, the following effects can be obtained.

  According to the present X-ray diagnostic apparatus, it is possible to set different pulse rate frequencies when executing an execution mode such as peak trace and when performing other fluoroscopic modes. Therefore, by setting the pulse rate frequency in the execution mode such as peak trace higher than the pulse rate frequency in the other imaging modes, it is possible to naturally display the region affected by the contrast agent, and a high-quality diagnostic image. Can be provided easily and quickly. In addition, when the averaging process is executed, a high-quality diagnostic image can be provided with high real-time characteristics and quick response.

  Further, according to the X-ray diagnostic apparatus, the pulse rate frequency for each fluoroscopic mode can be automatically set by selecting from preset setting data in addition to manual setting. As a result, the pulse rate frequency setting for each fluoroscopic mode can be realized easily in a short time.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

FIG. 1 shows an external view of the X-ray diagnostic apparatus according to the present embodiment. FIG. 2 is a block diagram including the internal configuration of the present X-ray diagnostic apparatus. FIG. 3 is a conceptual diagram showing the flow of control data and image data in shooting execution in each of the execution mode such as the peak trace mode, the normal fluoroscopic mode, and the road map processing mode. FIG. 4A is an example of setting data based on a combination of specific numerical values of the pulse rate frequency for each mode. FIG. 4B is an example of setting data based on a combination of a normal perspective mode rate value and a magnification from the rate value. FIG. 5 is a diagram showing an X-ray irradiation sequence executed when a fluoroscopic road map is generated and displayed in real time by the X-ray diagnostic apparatus. FIG. 6 is a diagram illustrating a pulse rate frequency related to X-ray irradiation in the creation of a conventional perspective road map.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Ceiling attaching part, 2 ... Support arm, 4 ... Arm holder, 5 ... C arm, 6 ... Vertical movement mechanism, 9 ... Top plate, 10 ... Top plate holding part, 11 ... Planar detector, 12 ... Trigger generating part , 13 ... X-ray generation unit, 14 ... X-ray detection unit, 15 ... Mechanism unit, 16 ... Image calculation / storage unit, 16a ... Mask creation unit, 16b ... Mask image memory, 16c ... Image generation unit, 17 ... System control , 19 ... operation section, 30 ... display section, 31 ... display image storage circuit, 32 ... D / A converter, 33 ... format conversion circuit, 34 ... monitor, 40 ... C arm / top panel control section, 42 ... C arm / top plate position detection unit, 43 ... second first C arm moving mechanism 44 ... C arm moving mechanism, 45 ... C arm rotating mechanism

Claims (5)

X-ray generation means for irradiating the subject with X-rays;
X-ray detection means for detecting X-rays transmitted through the subject;
Image generating means for generating an X-ray image based on the X-rays detected by the X-ray detecting means;
For a plurality of X-ray images generated by the image generating means, a trace process for tracing the maximum value or the minimum value of each pixel in the time axis direction or an addition averaging process for adding the plurality of X-ray images is executed. And image processing means for generating a first image from a plurality of X-ray images,
Control means for controlling the X-ray irradiation timing of the X-ray generation means;
Comprising
When the X-ray irradiation is executed in the first mode in which the image processing means executes the trace process or the addition average process, the control means performs the X-ray irradiation according to a first rate frequency. When X-ray irradiation is performed in the second mode in which the X-ray generation unit is controlled and the image processing unit does not perform the trace process or the addition averaging process, a second rate different from the first rate is used. Controlling the X-ray generation means to perform X-ray irradiation according to a frequency;
X-ray diagnostic apparatus characterized by the above.   The X-ray diagnostic apparatus according to claim 1, wherein the first rate frequency is higher than the second rate frequency.   The second mode is a normal fluoroscopy mode in which fluoroscopy is performed regardless of the presence or absence of contrast medium injection, and a subtraction process is performed using an image that can be fluoroscopically performed during catheter operation and the first image. The X-ray diagnostic apparatus according to claim 1, wherein at least one of the road map processing modes is included. Storage means for storing a plurality of setting data comprising combinations of the first rate frequency and the second rate frequency;
A selection means for selecting desired setting data from the storage means;
Further comprising
The control means controls the X-ray generation means based on the setting data selected by the selection means;
The X-ray diagnostic apparatus according to any one of claims 1 to 3, wherein: Storage means for storing a plurality of setting data comprising a combination of the second rate frequency and a magnification for the second rate frequency;
A selection means for selecting desired setting data from the storage means;
Further comprising
The control means controls the X-ray generation means based on the setting data selected by the selection means;
The X-ray diagnostic apparatus according to any one of claims 1 to 3, wherein:

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