JP2004283365A - Radiographic imaging system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radiographic imaging system for imaging an radiographic iamge of high image quality. <P>SOLUTION: The radiographic imaging system for imaging the image of a testee body by radiation comprises: a radiographic image acquisition part for acquiring the radiographic image of the testee body by using the radiation; a plurality of optical image acquisition parts for detecting light emitted from the testee body and respectively acquiring the optical image of the testee body from different directions; a stereoscopic image generation part for generating the stereoscopic image of the testee body by using the plurality of optical images respectively acquired by the plurality of optical image acquisition parts; and a radiographic imaging control part for judging the propriety of radiographic imaging on the basis of the stereoscopic image generated by the stereoscopic image generation part and making the radiographic image acquisition part acquire the radiographic image of the testee body. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a radiation imaging system. In particular, the present invention relates to a radiation imaging system that controls radiation imaging according to the movement of a subject.
[0002]
[Prior art]
Radiation images captured using radiation such as X-rays are widely used as medical images. Conventionally, a radiographic image has been obtained by irradiating a silver salt film with visible light generated by irradiating a phosphor with radiation that has passed through a subject and developing the same as in a normal photograph.
[0003]
However, in recent years, a method for detecting an image using a stimulable phosphor without using a silver salt film has been developed (for example, see Patent Document 1). In such a method, the radiation that has passed through the subject is absorbed by the stimulable phosphor, and then the stimulable phosphor is excited with light energy or thermal energy, so that the radiation energy is converted into light from the stimulable phosphor. The light is radiated and the light is photoelectrically converted to obtain an image signal. A method for detecting a radiation image using a large number of semiconductor elements has also been developed (see, for example, Non-Patent Document 1).
[0004]
[Patent Document 1]
Japanese Patent Laid-Open No. 55-12429 [Non-Patent Document 1]
“Phys. Med. Biol.”, Vol. 42, 1997, p. 1-39
[0005]
[Problems to be solved by the invention]
In the radiographic image capturing as described above, if the patient moves for some reason during the time when X-rays are irradiated (usually several msec to several hundred msec), the radiographic image is blurred and accurate diagnosis is performed. May not be possible. In general, in imaging of the chest, since it is necessary to perform imaging with the lungs expanded, the subject needs to stop moving during radiographic imaging. Therefore, radiation imaging is performed after the doctor instructs the patient to inhale after breathing.
[0006]
However, actually, there are cases where the patient does not hold his breath as instructed by the doctor, or the timing for holding his breath may be shifted. In such a case, radiographic imaging is performed while the subject is moving, so that the radiographic image is likely to be shaken, and when the lungs are not captured in a state where the lungs are sufficiently expanded without breathing in There is a problem that a desired radiation image cannot be obtained. Furthermore, when a desired image cannot be obtained in this way, a radiographic image is captured again, and the accumulation of radiation exposure on the subject becomes a problem.
[0007]
Then, an object of this invention is to provide the radiation imaging system which can solve said subject. This object is achieved by a combination of features described in the independent claims. The dependent claims define further advantageous specific examples of the present invention.
[0008]
[Means for Solving the Problems]
That is, according to an embodiment of the present invention, a radiation imaging system that images a subject with radiation, the radiation image acquiring unit that acquires a radiation image of the subject using radiation, and the light emitted from the subject are detected. A plurality of optical image acquisition units that respectively acquire optical images of the subject from different directions, and a stereoscopic image that generates a stereoscopic image of the subject using the plurality of optical images respectively acquired by the plurality of optical image acquisition units A generation unit; and a radiation imaging control unit that determines whether radiation imaging is appropriate based on the stereoscopic image generated by the stereoscopic image generation unit and causes the radiation image acquisition unit to acquire a radiation image of the subject.
[0009]
The radiation imaging control unit includes a subject motion detection unit that detects the motion of the subject based on the stereoscopic image generated by the stereoscopic image generation unit, and the motion of the subject detected by the subject motion detection unit is substantially stationary. In this case, the radiographic image acquisition unit may acquire a radiographic image of the subject.
[0010]
The radiation imaging control unit includes a subject volume detection unit that detects a change in the volume of the subject based on the stereoscopic image generated by the stereoscopic image generation unit, and the volume of the subject detected by the subject volume detection unit When the change is equal to or less than the reference value, the radiographic image acquisition unit may acquire the radiographic image of the subject. The optical image acquisition unit may acquire an optical image in a range including the outer periphery of the subject.
[0011]
The radiation imaging control unit includes a subject depth detection unit that detects a depth of the subject in the radiation irradiation direction based on the stereoscopic image generated by the stereoscopic image generation unit, and a depth of the subject detected by the subject depth detection unit. And a radiation dose adjusting unit that adjusts the amount of radiation applied to the subject. The optical image acquisition unit may acquire an optical image in a wider range than the radiological image to be acquired by the radiological image acquisition unit.
[0012]
The above summary of the invention does not enumerate all the necessary features of the present invention, and sub-combinations of these feature groups can also be the invention.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described through embodiments of the invention. However, the following embodiments do not limit the invention according to the claims, and all combinations of features described in the embodiments are included. It is not necessarily essential for the solution of the invention.
[0014]
FIG. 1 shows an example of an overview of a radiation imaging system 100 according to an embodiment of the present invention. The radiation imaging system 100 includes a radiation source 106 that generates radiation 102 and irradiates the subject 104, a radiation image of the subject 104 using the radiation 102 emitted from the radiation source 106, and a subject And a plurality of optical image acquisition units 110 that detect the light emitted from 104 and acquire optical images of the subject 102 from different directions, respectively. The radiation image acquisition unit 108 is, for example, an imaging table. The radiation 102 is X-ray, α-ray, β-ray, γ-ray or the like.
[0015]
The optical image acquisition unit 110 may be a CCD camera that detects visible light and acquires an image, or may be an infrared camera that detects infrared light and acquires an image. The radiation imaging system 100 illustrated in FIG. 1 includes two optical image acquisition units 110, but may include three or more optical image acquisition units 110. Further, the subject 104 may be irradiated with appropriate visible light or infrared light illumination as necessary. Since it is invisible to the photographer if it is infrared light, it does not become an obstacle for the photographer to visually recognize the irradiation light for confirming the irradiation field.
[0016]
In the radiation imaging system 100, the movement, physique, orientation, and the like of the subject 104 are detected by the plurality of optical image acquisition units 110. For example, the respiration state of the subject 104 is detected based on the light images acquired by the plurality of light image acquisition units 110. Further, whether the subject 104 is fat or thin, or in which direction the subject 104 is directed, is detected based on the optical images acquired by the plurality of optical image acquisition units 110. Then, the radiation source 106 and the radiation image acquisition unit 108 obtain a radiation image of the subject 104 under appropriate imaging conditions based on the state of the subject 104 detected from the optical images acquired by the plurality of optical image acquisition units 110. get. For example, an appropriate imaging timing is determined based on the respiratory state of the subject 104, and an appropriate radiation dose is determined based on the physique and orientation of the subject 104.
[0017]
By using a high-performance CCD camera or the like as the optical image acquisition unit 108, an optimal imaging condition can be determined for each subject 104, and a radiographic image of the subject 104 can be acquired under the optimal imaging condition. Therefore, since it is possible to reduce re-imaging of the radiation image, it is possible to suppress accumulation of exposure of the radiation 102 to the subject 104.
[0018]
FIG. 2 shows an example of the configuration of the radiation image acquisition unit 108 according to this embodiment. The radiation image acquisition unit 108 includes a photo timer 112 that controls the amount of radiation incident on the radiation image acquisition unit 108, a grid 114 that removes scattered radiation, and a photo timer 112 and a grid 114 that transmit radiation that has passed through the subject 104. A storage phosphor sheet 116 for recording radiation image information; a reading unit 118 for reading radiation image information from the storage phosphor sheet 116; and radiation image information held by the storage phosphor sheet 116. And an erasing unit 120 for erasing.
[0019]
The reading unit 118 includes an excitation light source 122 that generates excitation light, an imaging optical system 124 that forms the excitation light on the stimulable phosphor sheet 116, and a stimulant emitted from the stimulable phosphor sheet 116 by the excitation light. A plurality of line sensors 126 for detecting the emitted light and a plurality of condensing optical systems 128 for condensing the stimulated emission light on each of the plurality of line sensors 126 are provided. The erasing unit 120 includes a plurality of erasing light sources 130 that generate erasing light.
[0020]
The stimulable phosphor sheet 116 is provided so as to be movable in the direction of arrow C between the imaging position A and the reading position B by a moving mechanism (not shown). When the stimulable phosphor sheet 116 is held at the imaging position A, the radiation that has passed through the subject 104 is absorbed through the phototimer 112 and the grid 114 to record a radiation image.
[0021]
The reading unit 118 and the erasing unit 120 are provided to be movable in the direction of arrow D by a moving mechanism (not shown). The reading unit 118 irradiates the stimulable phosphor sheet 116 with excitation light while moving along the stimulable phosphor sheet 116 when the stimulable phosphor sheet 116 is held at the reading position B. Radiation image information is read by detecting the stimulated emission light emitted from the phosphor sheet 116. The radiation image read from the stimulable phosphor sheet 116 by the reading unit 118 is recorded as digital data. Further, the erasing unit 120 irradiates the storable phosphor sheet 116 with erasing light while moving along the storable phosphor sheet 116 together with the reading unit 118, and releases the radiation energy remaining in the storable phosphor sheet 116. This erases the radiation image information.
[0022]
FIG. 3 shows an example of the configuration of the radiation imaging system 100 according to the present embodiment. The radiation imaging system 100 generates a radiation 102 and irradiates the subject 104, a radiation image acquisition unit 108 that acquires a radiation image of the subject 104 using the radiation 102, and the radiation 104 emitted from the subject 104. A plurality of optical image acquisition units 110 that detect light and acquire optical images of the subject 104, respectively, and a plurality of optical images acquired by the optical image acquisition units 110, respectively, to form a stereoscopic image of the subject 104. Based on a plurality of light images respectively acquired by the generated stereoscopic image generation unit 132 and the plurality of light image acquisition units 110, it is determined whether or not radiation imaging is appropriate, and the radiation image acquisition unit 108 acquires a radiation image of the subject 104. A radiation imaging control unit 134.
[0023]
The radiation imaging control unit 134 includes a subject motion detection unit 136 that detects the motion of the subject 104 based on a plurality of optical images acquired by the plurality of optical image acquisition units 110, and a plurality of optical image acquisition units 110. A subject volume detector 138 that detects a change in the volume of the subject 104 based on the plurality of optical images acquired, and a radiation 102 based on the plurality of optical images acquired by the plurality of optical image acquisition units 110, respectively. The subject depth detection unit 140 that detects the depth of the subject 104 in the direction of irradiation of the subject, and the radiation 102 that the radiation source 106 irradiates the subject 104 based on the depth of the subject 104 detected by the subject depth detection unit 140 And a radiation dose adjusting unit 142 that adjusts the amount of.
[0024]
The apparatus further includes a stereoscopic image generation unit 132 that generates a stereoscopic image of the subject 104 using the plurality of optical images acquired by the plurality of optical image acquisition units 110, respectively. The radiation imaging control unit 134 may determine whether radiation imaging is appropriate based on the stereoscopic image generated by the stereoscopic image generation unit 132, and may cause the radiation image acquisition unit 108 to acquire a radiation image of the subject 104. That is, the subject motion detection unit 136, the subject volume detection unit 138, and the subject depth detection unit 140 are generated by the stereoscopic image generation unit 132 using a plurality of light images respectively acquired by the plurality of light image acquisition units 110. The movement of the subject 104, the volume of the subject 104, and the depth of the subject 104 may be detected based on the obtained optical image.
[0025]
When the movement of the subject 104 detected by the subject motion detection unit 136 is substantially stationary, the radiation imaging control unit 134 generates radiation to the radiation source 106 and causes the radiation image acquisition unit 108 to receive the radiation image of the subject 104. Get it. Specifically, the subject motion detection unit 136 detects the motion of the subject 104 due to breathing, beating, etc., and the radiation imaging control unit 134 detects the radiographic image when the motion of the subject 104 is stabilized below a reference value. To get. By using a stereoscopic image of the subject 104 generated from a plurality of light images acquired by the plurality of light image acquisition units 110, the movement of the subject 104 can be detected with higher accuracy. Therefore, it is possible to acquire a high-quality radiation image with little blur.
[0026]
The radiation imaging control unit 134 causes the radiation source 106 to generate radiation when the change in the volume of the subject 104 detected by the subject volume detection unit 138 is equal to or less than a reference value, and causes the radiation image acquisition unit 108 to cause the subject 104 to emit radiation. Let's get a radiographic image. Specifically, the subject volume detection unit 138 detects a change in the subject 104 due to breathing or the like, and the radiation imaging control unit 134 acquires a radiographic image when the subject 104 stops breathing. By using a stereoscopic image of the subject 104 generated from a plurality of light images acquired by the plurality of light image acquisition units 110, a change in the volume of the subject 104 can be accurately detected, and the respiratory state of the subject can be determined. It can be detected more accurately. Therefore, a radiographic image can be acquired at an appropriate timing such as when the lung is expanded.
[0027]
The subject depth detection unit 140 detects the depth of the subject 104 based on the physique and orientation of the subject 104. The depth here is the thickness of the subject 104 existing between the radiation source 106 and the radiation image acquisition unit 108. The fat subject 104 has a greater depth than the lean subject 104, and the subject 104 facing the direction perpendicular to the irradiation direction of the radiation 102 is more than the subject 104 facing the radiation 102 irradiation direction. The depth is great. The radiation adjustment unit 142 adjusts the amount of radiation more for the subject 104 having a greater depth than the subject 104 having a smaller depth. The radiation dose adjustment unit 142 adjusts the irradiation time, wavelength, intensity, and the like of the radiation 102 according to the depth of the subject 104, so that the subject 104 can be irradiated with an appropriate amount of radiation 102. Therefore, a high-quality radiographic image can be acquired, and the cumulative exposure of the radiation 102 to the subject 104 can be suppressed.
[0028]
Further, as shown in FIG. 1, the optical image acquisition unit 110 preferably acquires an optical image in a wider range than the radiological image that should be acquired by the radiological image acquisition unit 108. The subject motion detection unit 136 detects the motion of the subject 104 at the edge of the radiographic image by generating a three-dimensional image having a wider range than the radiographic image to be acquired by the radiographic image acquisition unit 108. In addition, the subject depth detection unit 140 can easily detect the distance from the radiation source 106 of the subject 104 at the edge of the radiographic image. Therefore, the radiation imaging control unit 134 can acquire a radiation image at a more appropriate timing and a more appropriate radiation dose.
[0029]
Moreover, it is preferable that the optical image acquisition unit 110 acquires an optical image in a range including the outer periphery of the subject 104 as shown in FIG. Since the stereoscopic image generation unit 132 generates a stereoscopic image including the outer periphery of the subject 104, the subject volume detection unit 138 can easily detect a change in the volume of the subject 104. Therefore, the radiation imaging control unit 134 can acquire a radiation image at a more appropriate timing.
[0030]
As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. Various modifications or improvements can be added to the above embodiment. It is apparent from the scope of the claims that the embodiments added with such changes or improvements can be included in the technical scope of the present invention.
[0031]
【The invention's effect】
As is clear from the above description, according to the radiation imaging system of the present invention, a high-quality radiation image can be captured.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating an example of an overview of a radiation imaging system 100. FIG.
FIG. 2 is a diagram illustrating an example of a configuration of a radiation image acquisition unit.
3 is a diagram illustrating an example of a configuration of a radiation imaging system 100. FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 100 Radiation imaging system 102 Radiation 104 Subject 106 Radiation source 108 Radiation image acquisition part 110 Optical image acquisition part 112 Photo timer 114 Grid 116 Storage phosphor sheet 118 Reading unit 120 Erase unit 122 Excitation light source 124 Imaging optical system 126 Line sensor 128 Condensing optical system 130 Erasing light source 132 Stereo image generating unit 134 Radiation imaging control unit 136 Subject motion detection unit 138 Subject volume detection unit 140 Subject depth detection unit 142 Radiation dose detection unit

Claims (6)

A radiation imaging system for imaging a subject with radiation,
A radiological image acquisition unit that acquires a radiographic image of the subject using the radiation;
A plurality of optical image acquisition units that detect light emitted from the subject and acquire optical images of the subject from different directions; and
A subject motion detection unit that detects the motion of the subject based on the plurality of optical images respectively acquired by the plurality of optical image acquisition units; and the subject motion detection unit detects the subject A radiation imaging system comprising: a radiation imaging control unit that causes the radiation image acquisition unit to acquire the radiation image of the subject when the movement is substantially stationary. A radiation imaging system for imaging a subject with radiation,
A radiological image acquisition unit that acquires a radiographic image of the subject using the radiation;
A plurality of optical image acquisition units that detect light emitted from the subject and acquire optical images of the subject from different directions; and
A subject volume detection unit configured to detect a change in the volume of the subject based on the plurality of optical images respectively acquired by the plurality of optical image acquisition units, and the subject detected by the subject volume detection unit; A radiation imaging system comprising: a radiation imaging control unit that causes the radiation image acquisition unit to acquire the radiation image of the subject when the change in the volume of the specimen is equal to or less than a reference value. Using a plurality of the light images respectively acquired by the plurality of light image acquisition units, further comprising a stereoscopic image generation unit for generating a stereoscopic image of the subject,
The radiation imaging control unit determines whether the radiation imaging is appropriate based on the stereoscopic image generated by the stereoscopic image generation unit, and causes the radiological image acquisition unit to acquire the radiation image of the subject. The radiation imaging system according to 2. A radiation imaging system for imaging a subject with radiation,
A radiological image acquisition unit that acquires a radiographic image of the subject using the radiation;
A plurality of optical image acquisition units for detecting light emitted from the subject and acquiring optical images of the subject from different directions;
A three-dimensional image generation unit that generates a three-dimensional image of the subject using the plurality of light images respectively acquired by the plurality of light image acquisition units;
A subject depth detection unit that detects the depth of the subject in the radiation direction based on the stereoscopic image generated by the stereoscopic image generation unit;
A radiation imaging system comprising: a radiation dose adjusting unit that adjusts an amount of the radiation applied to the subject based on the depth of the subject detected by the subject depth detecting unit. The radiation imaging system according to claim 3 or 4, wherein the optical image acquisition unit acquires the optical image in a range including an outer periphery of the subject. The radiographic imaging system according to claim 3 or 4, wherein the optical image acquisition unit acquires the optical image in a wider range than the radiographic image to be acquired by the radiological image acquisition unit.

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