JP2003290202A - Radiographing apparatus, radiographing method, system for radiographic image, program, and computer readable storage medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radiographing apparatus or the like in which the respiratory movement of the chest, of a human body is three-dimensionally grasped. <P>SOLUTION: In the radiographing apparatus in which an X-ray transmitted through the chest of the human body under breathing is periodically detected by a solid-state imaging device and the respiratory movement of the chest of the human body is imaged, the radiographing apparatus is composed of an imaging means for imaging the respiratory movement in a plurality of different directions. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a radiation imaging apparatus, a radiation imaging method, a radiation imaging system, a program, and a computer-readable storage medium in the medical field.

[0002]

2. Description of the Related Art A technique for imaging a transmission intensity distribution by using a substance penetrating ability of radiation represented by X-rays is a basis of modern medical technology development. Since the discovery of X-rays
Imaging of the intensity distribution has been carried out by converting the X-ray intensity distribution into visible light with a phosphor, then forming a latent image with a silver salt film and developing it. In recent years, when digitizing an X-ray image, a stimulable phosphor is used, and a latent image as a stored energy distribution on the stimulable phosphor due to X-ray irradiation is excited by a laser beam and read out to form a digital image. The method using a so-called imaging plate has been generalized. Further, due to the progress of semiconductor technology, a large-sized solid-state image sensor capable of covering the size of a human body, a so-called flat panel detector, has also been developed, and an X-ray image can be directly digitized without forming a latent image so that efficient diagnosis can be performed. It has become.

On the other hand, it is also possible to observe the dynamics inside the human body by imaging the fluorescence from weak X-rays with a high-sensitivity imaging device represented by a photomultiplier tube (image intensifier). Has been used. The latest flat panel detector has sensitivity comparable to that of the image intensifier, and it has become possible to capture the dynamics of a wide range of the human body.

The most effective medical X-ray photography is chest photography of a human body. Chest X-ray photography is indispensable for normal medical examinations because a wide area of the chest including the abdomen is useful for discovering many diseases including lung diseases. Further, in order to efficiently diagnose a huge amount of chest X-ray images taken for health checkups in recent years, image analysis is performed on a chest digital X-ray image using a computer to assist a doctor's initial diagnosis. So-called computer-aided diagnosis (Com
putter-Aided Diagnostic, CA
D) is also being put to practical use.

In recent years, it has become possible to further improve diagnostic accuracy by observing respiratory dynamics of a human body using a flat panel detector having a size capable of photographing the entire chest of the human body. Also, dynamic CAD technology for efficiently processing the enormous amount of image data is being developed.

[0006]

The above-mentioned respiratory dynamics observation is mainly for observing the dynamics of respiration in the lung field, but it is necessary to observe and understand the three-dimensional human body structure originally. It is not for providing three-dimensional information in medical diagnosis.

[0007] Therefore, an object of the present invention is to provide a radiation imaging apparatus, a radiation imaging method, a radiation imaging system, a program, and a computer-readable storage medium capable of three-dimensionally grasping the respiratory dynamics of the human chest. To do.

[0008]

A first aspect of the invention for achieving the above object is to detect radiation transmitted through a chest of a human body in a respiration state periodically by a solid-state image pickup device, and to measure respiratory dynamics of the chest of the human body. The radiation imaging apparatus for imaging the above-mentioned is characterized by comprising imaging means for imaging the respiratory dynamics from a plurality of different directions.

The second aspect of the present invention comprises display means for sequentially displaying the radiation images acquired by the imaging means in the order in which the radiation images were acquired. It is a device.

A third aspect of the present invention is the radiation imaging apparatus according to claim 1, further comprising stereo display means for sequentially stereo-displaying radiation images from the two different directions acquired by the imaging means. .

A fourth aspect of the present invention is the radiographic apparatus according to claim 3, wherein the radiographing means acquires radiographic images from two different directions in substantially the same respiratory phase.

A fifth aspect of the present invention is the radiographic apparatus according to claim 4, wherein the radiographing means acquires radiographic images in different directions depending on whether the breathing state is an exhalation state or an inhalation state.

In a sixth aspect of the present invention, the image capturing means captures images over two breaths, acquires radiographic images from two different directions in substantially the same respiratory phase in two exhalation states, and obtains two inspirations. The radiographic apparatus according to claim 3, wherein radiographic images are acquired from two different directions in substantially the same respiratory phase in a state.

A seventh aspect of the present invention further includes a breathing state detecting means for detecting the breathing state, and the photographing means has substantially the same breathing based on the phase of the breathing detected by the breathing state detecting means. The radiation imaging apparatus according to claim 4, wherein the radiation imaging apparatus is configured to acquire radiation images from two different directions in phase.

An eighth invention is a radiation image system in which a plurality of devices are communicably connected to each other, and each element constituting the radiation imaging apparatus according to any one of claims 1 to 7. It is a system for radiographic images characterized by having.

A ninth invention is a program for causing a computer to function as a predetermined means, wherein the predetermined means constitutes each of the radiation imaging apparatuses according to any one of claims 1 to 7. It is a program including means.

A tenth aspect of the present invention is a computer-readable storage medium having the program according to the ninth aspect stored therein.

An eleventh aspect of the present invention is a radiographic method for detecting radiation transmitted through a chest of a human body in a respiratory state by a solid-state image pickup device to photograph the respiratory dynamics of the chest of the human body. It is a radiation imaging method characterized by having an imaging process of imaging from different directions.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) A preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a block diagram schematically showing a first embodiment of the present invention, in which 1 represents an X-ray generator (X-ray source), and X-rays are shown in the direction of the broken line arrow in the figure. Radiates. Reference numeral 2 denotes a human body (patient) which is a subject. In this case, in order to image the chest, an X-ray is incident from the back surface to capture an image of the chest. Reference numeral 3 denotes a flat panel detector for imaging the X-ray intensity distribution, and a plurality of image receiving elements (also simply referred to as pixels) corresponding to a plurality of pixels forming an image are arranged in a matrix on the image receiving surface. And this X-ray source 1
The flat panel detector 3 and the flat panel detector 3 are connected to each other by a rotary arm schematically shown by 31. This rotating arm 31
Rotation of the X-ray source 1 and flat panel detector 3
While always facing each other, it operates so as to shoot the subject 2 from different directions. Normal flat panel detector 3
The pixel matrix of is arranged at equal intervals of 100 μm to 200 μm pitch. 4 is a device called a photo timer that monitors the X-ray dose transmitted through the human body in order to control the X-ray dose emitted to the human body to be the optimum X-ray dose, and is placed in the rear or front part of the flat panel detector. ing. Since each pixel value output from the flat panel detector is an analog voltage signal at an initial stage, it is converted into a digital value which is a numerical value by an A / D converter indicated by 5. Usually, at least this A / D converter is built in the same housing as the flat panel detector, and it is apparently recognized that a digital value (image data) is directly output from the flat panel detector. 6 and 7
Is a buffer memory for temporarily storing image data, each of which functions as a so-called double buffer, and is configured such that one side is reading while the other is reading, and the function of maintaining the continuity of the reading process is performed by using the switch 16. 9
Is a differentiator, but X stored in the memory 8 in advance
It has a function of subtracting the image data (offset image) acquired from the sensor without emitting a line from the image data of the actual subject. Specifically, push the switch 17 to the B side,
The image data is stored in the memory 8 without emitting X-rays, and the switch 17 is tilted to the A side for actual use. 10
Is a reference table (Look Up Table) and has a function of converting the image data value. Specifically, this lookup table is set to convert the input value into a value proportional to its logarithmic value. The block 11 is a differencer, which stores the image data, which is obtained by radiating only X-rays without converting the subject in advance and converted into a logarithmic value, into the memory 12, and stores the image data in the actual subject image. This is for correcting the variation in gain of each pixel of the flat panel detector. Specifically, radiation is emitted in the absence of a subject, the switch 17 is tilted to the A side, and the switch 18 is tilted to the B side to store image data representing gain variations in the memory 12, and in the case of an actual subject image, Switch 17 and switch 18
Turn it down and use it. Reference numeral 19 is a block having a function of correcting a defective pixel, and the defective pixel of the flat panel sensor used, which is stored in advance in the memory indicated by 20, is estimated from normal pixel data around the defective pixel, and the defective pixel is detected. This is for correction. For this correction, an average value of surrounding normal pixel data values is generally used. The image thus variously corrected is once stored in the image memory 13 and then recorded in the filing device 14. The plurality of pieces of image data are read out by the display device 21 and continuously displayed and presented to the observer.

A block designated by 15 represents a controller (control mechanism) for controlling imaging, drives the flat panel detector 3 at a predetermined timing, and triggers the X-ray generator 1 to radiate the X-ray pulse. Output.

FIG. 2 illustrates the imaging sequence. The left column A is the motion of the patient, the subject, column B is the operation of the radiologist who is the operator, and column C is the X-ray imaging apparatus. The column of mode D indicates the movement of the rotary arm 31. First (A
At the time of 1), the patient stands in front of the imaging table (position 2 in FIG. 1) according to the instruction of the operator. At the next time point (B1), the operator gives an instruction to inhale, and then gives an instruction to slowly exhale from the time point (B2). The patient inhales according to the instruction (A2), and then slowly exhales (A3), but the operator operates the imaging device and the rotating arm of FIG. 1 to continuously capture the respiratory dynamics of the patient ( C1). The rotating arm rotates at a predetermined speed during shooting (D1). Normally, the rotation angle of one shooting is about ± 30 °. Further, this photographing interval is about 3 to 10 images per second according to the speed of the breathing motion. The operator gives an instruction to inhale slowly after a lapse of an appropriate time (several seconds) while observing the state of the patient (B3). Even at this point, continuous X-ray photography is continuing. The operator, while watching the state of the patient, notifies the end of the photographing when the patient breathes out (B4). Then, the photographing and the rotation of the rotating arm are stopped (C2, D2). Figure 3
Is a timing chart schematically showing the state at this time, the upper stage shows the patient's state, the middle stage shows the X-ray pulse, and the lower stage shows the movement of the sensor system including the flat panel detector 3. An X-ray pulse indicated by A is emitted while the patient exhales or inhales according to the instruction of the operator. The pulse width of A may be a fixed constant value, and
It is also possible to control using the photo timer 4 shown in FIG. 1, and in the latter case, the total X measured by the photo timer 4 is used.
When the dose (integrated value) reaches a predetermined set value, the controller 15 sends an X-ray emission stop signal to the X-ray generator 1 to stop the X-ray emission (stop the pulse). Normally, the time sampling interval required for slow breathing is about 3 to 10 frames per second, and here, the patient is allowed to breathe relatively slowly, and imaging of about 3 frames per second is performed.

By the above-described operation, respiratory dynamics photography can be performed by asking the patient to perform an operation that is not much different from the conventional physical examination by slowing deep breathing.

The order of exhalation / inhalation and the number of times in this embodiment are not limited to those described above.

By such an operation, a plurality of images corresponding to each phase of the patient's respiration can be obtained.

FIG. 4 shows a display state on the display device 21 shown in FIG. Here, F1 from the maximum inspiratory state to the maximum expiratory state until returning to the maximum inspiratory state again
32 images of F32 to F32 are displayed. The schematic diagram attached to each frame (the middle of which is omitted) in FIG. 4 shows the subject 2 and the X that change due to the rotation of the rotating arm 31 at the time of shooting.
The positional relationship between the radiation source 1 and the flat panel detector 3 is schematically shown. In F1, the subject is photographed from the rear left, F16 is photographed almost in the front, and F32 is photographed from the rear right. An observer who continuously observes this image can observe the respiratory dynamics of the lung field, and at the same time, can observe the three-dimensional structure inside the subject by observing the moving image in which the imaging direction rotates.

In this embodiment, the rotary arm 31 is used to
Although the radiation source 1 and the flat panel detector 3 are rotated at the same time, it is naturally possible to fix the flat panel detector and move only the X-ray source while always directing the photographing direction to the subject and the flat panel detector. is there.

(Second Embodiment) FIG. 5 shows a block diagram of the second embodiment. The same components as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted. In FIG. 5, 33
The block indicated by is a stereo X-ray generator, which has two targets for the cathode ray with respect to the rotating anode as shown in FIG. 6, and alternates from the distant right eye focus and left eye focus. It can emit X-rays. Also, in the final stage, 22
The block indicated by is a 3D monitor, specifically, a monitor capable of stereo display. There are various types of this monitor, but independent left and right eye images are presented to the left and right eyes of the observer to induce fusion in the observer's brain.
Anything that allows the dimensional structure to be grasped is sufficient. The method of independently presenting the left and right images to the left and right eyes is that the observer wears glasses with left and right lenses having different polarization characteristics and displays images with the corresponding polarization, using the lenticular lens to display the left and right images. There is a method of spatially separating and independently presenting them to the left and right eyes of the observer.

FIG. 7 is a timing chart in this case, in which the upper part is the X-ray pulse and the lower part is the flat panel sensor 3.
Is the operation. At the timing of A1 in FIG. 7, control is performed so that X-rays are emitted from the right eye focus of the stereo X-ray tube, and at the timing of A2, X-rays are controlled to be emitted from the left eye focus of the stereo X-ray tube. The interval T1 between the A1 pulse and the A2 pulse is set to be relatively short at about 50 mSec. This T
During the period 1, the X-ray intensity distribution is accumulated in the flat panel detector 3 and read out. The time required for this accumulation is about 3 to 4 mSec, and data is read from the flat panel detector 3 in the remaining time. That is, the flat panel detector 3 accumulates image information while the X-ray pulse is emitted, and then reads the image information. The pulse widths of A1 and A2 may use a predetermined constant value, and may be controlled by using the photo timer 4, and in the latter case, the total X-ray dose measured by the photo timer 4 ( When the integrated value) reaches a predetermined set value, the controller 15 sends an X-ray emission stop signal to the X-ray generator 1 to stop the X-ray emission (stop the pulse). Also,
Approximately 300 ms for the time interval T2 until the shooting of the next cycle
It is set as a relatively long time of about ec. Normally, the time sampling interval required for slow breathing is about 3 to 10 frames per second, and here, the patient is allowed to breathe relatively slowly, and imaging of about 3 frames per second is performed.

The lung field must be moving and moving during the time when the A1 and A2 pulses are emitted,
When observing with a stereo viewer, some movement of the left and right images does not interfere with the observation for the observer, fusion is possible within the brain, and the three-dimensional structure can be grasped.

Therefore, by displaying the two sets of left and right moving images photographed in this way on the 3D monitor 21, the observer can grasp the three-dimensional structure of the respiratory dynamics while observing them.

In the present embodiment, the stereo tube 33 is used, but in some cases, the normal X-ray tube is physically moved, or two or more X-ray tubes are used. It is also possible to realize the function of.

(Third Embodiment) In exhalation / inhalation of the breathing motion, there is a timing at which the lung shape becomes similar. Therefore, it can be configured such that there is a pair of corresponding images between the plurality of images during the expiratory operation and the plurality of images during the inspiratory operation.

In the present embodiment, the three-dimensional structure of the three-dimensional structure is obtained by observing from the 3D monitor 22 the images of the same respiratory phase photographed from different directions depending on the state of exhalation and the state of inspiration. It becomes possible to grasp.

That is, the rotating arm 31 of FIG. 1 or the rotating arm 31 of FIG.
It is possible to use any of the stereo tubes 33 of
When the patient is in an exhaled state, an X-ray is taken diagonally from the left rear,
When in the intake state, shoot from diagonally right rear. Next, the corresponding image pair is found from the obtained images and 3D
The monitor 22 displays in stereo. At this time, as a method of finding the corresponding image pair, a method of finding the pair based on the size and shape of the lung field portion from the image data, or a patient's respiratory state at the time of image acquisition using a bellows or an impedance measuring device, etc. A method of monitoring and capturing images at substantially the same breathing phase and setting an image pair can be considered.

In addition, the patient is made to perform the breathing action more than once,
It is also possible to perform X-ray imaging from different directions and observe on a 3D monitor at the same phase of two expiratory and inspiratory operations.

(Other Embodiments) The present invention can be applied to a plurality of devices (for example, one or more image processing devices, one or more interfaces, one or more radiation imaging devices, and one or more X-ray generation devices). It goes without saying that the present invention can be applied to any of the configured system, the configuration in which the image processing apparatus and the radiation imaging apparatus are integrated, and the like.

Further, an object of the present invention is to supply a storage medium storing a program code of software for realizing the functions of the above-described embodiment to a system or an apparatus, and a computer (CPU or CPU of the system or the apparatus) of the system or the apparatus. It is needless to say that it is also achieved by the MPU or the like) reading and executing the program code stored in the storage medium.

In this case, the program code itself read from the storage medium realizes the function of the above-described embodiment, and the program code and the storage medium storing the program code constitute the present invention. Becomes

As a storage medium for supplying the program code, ROM, floppy (R) disk, hard disk, optical disk, magneto-optical disk, CD-RO
M, CD-R, a magnetic tape, a non-volatile memory card, etc. can be used.

Further, by executing the program code read by the computer, not only the functions of the above-described embodiments are realized, but also the OS or the like running on the computer is executed based on the instruction of the program code. It goes without saying that the present invention is also configured when a part or all of the actual processing is performed and the functions of the above-described embodiments are realized by the processing.

Further, after the program code read from the storage medium is written in the memory provided in the extended function board inserted in the computer or the extended function unit connected to the computer, based on the instruction of the program code. Needless to say, the present invention is configured even when the CPU or the like provided in the function expansion board or the function expansion unit performs a part or all of the actual processing, and the processing realizes the functions of the above-described embodiments. Yes.

As described above, according to this embodiment,
By photographing, displaying, and observing respiratory dynamics from a plurality of different directions, it has become possible to grasp the respiratory dynamics of a patient three-dimensionally.

[0044]

According to the present invention, it is possible to provide a radiographic apparatus, a radiographic method, a radiographic system, a program, and a computer-readable storage medium that enable three-dimensional grasping of respiratory dynamics of the human chest. it can.

[Brief description of drawings]

FIG. 1 Block diagram

FIG. 2 is a diagram showing an example of a shooting sequence.

FIG. 3 is a timing chart regarding shooting.

FIG. 4 is a diagram schematically showing a displayed image.

FIG. 5: Block diagram

FIG. 6 is a diagram schematically showing the structure of a stereo X-ray tube.

FIG. 7 is a timing chart regarding shooting.

[Explanation of symbols]

3 flat panel detector 5 controller 21 Display 31 rotating arm

Claims (11)

[Claims] 1. A radiation imaging apparatus for periodically detecting radiation transmitted through a chest of a human body in a breathing state by a solid-state imaging device to photograph respiratory dynamics of the human chest, and photographing the respiratory dynamics from a plurality of different directions. A radiation imaging apparatus, comprising: 2. The radiation imaging apparatus according to claim 1, further comprising a display unit that sequentially displays the radiation images acquired by the imaging unit in the order in which the radiation images were acquired. 3. The radiation imaging apparatus according to claim 1, further comprising a stereo display unit that sequentially stereo-displays the radiation images from the two different directions acquired by the imaging unit. 4. The radiation imaging apparatus according to claim 3, wherein the imaging means acquires radiation images from two different directions at substantially the same respiratory phase. 5. The radiation imaging apparatus according to claim 4, wherein the imaging unit acquires radiation images in different directions in an exhalation state and an inhalation state in the breathing state. 6. The imaging means captures images over two breaths, acquires radiographic images from two different directions in substantially the same respiratory phase in two expiratory states, and substantially in two inspiratory states. The radiographic apparatus according to claim 3, wherein radiographic images are acquired from two different directions in the same respiratory phase. 7. A breathing state detecting means for detecting the breathing state is further provided, and the photographing means has two breathing phases at substantially the same breathing phase based on a phase of breathing detected by the breathing state detecting means. The radiation imaging apparatus according to claim 4, wherein the radiation imaging apparatus is configured to acquire radiation images from different directions. 8. A radiographic system comprising a plurality of devices communicatively connected to each other, comprising:
A radiation imaging system, comprising: each element that constitutes the radiation imaging apparatus according to any one of 1 above. 9. A program for causing a computer to function as a predetermined unit, wherein the predetermined unit includes each unit constituting the radiation imaging apparatus according to any one of claims 1 to 7. A program characterized by. 10. A computer-readable storage medium in which the program according to claim 9 is stored. 11. A radiography method for periodically detecting radiation transmitted through a chest of a human body in a respiratory state by a solid-state imaging device to photograph respiratory dynamics of the human chest, wherein the respiratory dynamics are photographed from a plurality of different directions. A radiation imaging method, comprising: