JPH11234566A - Angiography system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the angiography system that photographs a contrast photo of coronary arteries with high resolution where a deviation of an image by upper side energy and lower side energy is nullified and deterioration in the resolution due to a vibration waveform of a spectroscope is suppressed in the case of having the spectroscope vibrated for the energy difference method. SOLUTION: The angiography system that photographs coronary arteries by using the radiant ray energy difference method is provided with a movement adjustment processing means 21. Thus, a position of image data providing an upper side energy or a lower side energy is moved in parallel prior to difference processing 22 of a difference-processing unit 20 in an image processing means 17.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an angiography apparatus for imaging a coronary artery of a heart, and more particularly to a high-speed energy switching mechanism and an imaging system for realizing an energy difference method using synchrotron radiation. .

[0002]

2. Description of the Related Art In recent years, medical technology has been changing from a technology centered on conventional treatment to a technology centered on prevention. Especially for heart disease, despite the high mortality due to ischemic heart disease such as angina or myocardial infarction, there is no simple and safe diagnostic method as a preventive technology at present,
A diagnostic technique that satisfies such requirements is required.

At present, the final diagnosis of ischemic heart disease is made by selective coronary angiography. In this selective coronary angiography, a thin synthetic resin tube called a catheter is directly inserted into the femoral artery or the brachial artery at the groin and advanced into the blood vessel. An appropriate amount of a contrast medium is injected through a tube to perform imaging of a target site. According to this test, a very clear coronary artery image can be obtained as an image, but there are disadvantages in that the invasion is large and fatal complications due to the test occur. In addition, the test requires hospitalization, requires a large number of medical staff, and has the disadvantage of requiring a great deal of money.

[0004] On the other hand, if the coronary artery can be visualized by a less invasive method of injecting a contrast medium from a vein, the danger to the patient and the burden of hospitalization are significantly reduced, and there is a possibility that it can be used as a mass examination. Come.
However, when a contrast medium is injected from a vein, it is diluted before reaching an artery, and a good image used for diagnosis cannot be obtained. As a method for solving this problem, an energy difference method using a discontinuous change in the mass absorption coefficient of X-rays is used.

[0005] The energy difference method is a method of imaging a coronary artery based on a difference between X-ray images of energies around the K-absorption edge (33.17 keV) of iodine used as a contrast agent.

FIG. 7 is a graph showing the energy dependence of the absorption coefficients of iodine, muscle and bone.

As shown in FIG. 7, the horizontal axis represents photon energy (keV), the vertical axis represents mass absorption coefficient (cm ² / g), and the absorption coefficient of iodine is 33.17 keV (K absorption edge). While it changes abruptly in the vicinity, the absorption coefficient of muscle and bone hardly changes. Therefore, if the difference between the images before and after the K absorption edge is calculated, only the blood vessels in which iodine as a contrast agent flows are captured. However, when the energy difference before and after the K absorption edge is increased, the resolution of the image is reduced.
For example, in order to identify a blood vessel having a diameter of 1 mm, the energy difference needs to be 350 eV or less (for synchrotron radiation, Vol. 3, No. 4, 1990, for medical applications of synchrotron radiation,
Kazuyuki Hyodo and Katsuyuki Nishimura). Further, since the energy width of the K absorption edge itself is about 20 eV, the energy resolution at the upper energy and the lower energy is required to be about 160 eV or less, and a clearer image can be obtained as the energy resolution is smaller.

Conventionally, coronary arteries have been contrasted by the difference between images obtained by X-rays at energies around the K-absorption edge (33.17 keV) of iodine.
Since a monochromatic X-ray having sufficient intensity and energy resolution to obtain a good image cannot be obtained, it has not been put to practical use. Therefore, an angiography apparatus using synchrotron radiation has been proposed.

Synchrotron radiation is synchrotron radiation emitted by the vibration or circular motion of electrons in a deflecting magnet or an angulator, and has a high brightness of 1,000 to tens of thousands of times as compared with a conventional X-ray source. In addition to the fact that it contains X-rays that have properties close to that of laser light, in addition to cardiac function diagnosis using two-dimensional moving images, it will enable quantitative function diagnosis that was considered difficult with conventional X-ray sources. Expected. Therefore, there is high expectation for a diagnostic technique using synchrotron radiation.

For example, as disclosed in Japanese Patent Application Laid-Open No. 9-180900, there has been developed an electron storage ring type radiation light generating device for directly switching the wavelength of synchrotron radiation generated by an insertion light source.

However, since an angiography apparatus using synchrotron radiation is still in the experimental stage, the following experimental apparatus will be described as an example of a conventional technique.

FIG. 8 is a block diagram showing an angiography apparatus.

As shown in FIG. 8, in an angiography apparatus, white light emitted from a wiggler 2 in an electron beam storage ring 1 is converted into pulse light by a rotary shutter 3 of a drum type and oscillated by a cam type. 4, the energy is rapidly switched between the upper energy and the lower energy.
The heart is irradiated. Then, images irradiated by the upper energy and the lower energy are captured by the image sensor 6, and the coronary artery is imaged by the energy difference method.

[0014]

However, in the conventional angiography apparatus, the amount of image shift due to the upper energy and the lower energy is generated, and the resolution is reduced due to the vibration waveform of the spectroscope 4. However, there is a problem that a sufficient resolution cannot be obtained.

More specifically, since the spectroscope 4 rotates the angle θ between the upper energy and the lower energy as shown in FIG. 8, the X-ray incident angle on the subject 5 is shifted by 2θ. Therefore, if the distance between the heart of the subject 5 and the image sensor 6 is L, the position of the blood vessel in the heart moves up and down by 2L (sin θ) when two images are superimposed. If the difference between these two images is obtained, the above-mentioned shift amount becomes blurred, and the resolution of the image is reduced. For example, L = 0.5 mm,
In the case of θ = 1 mrad, the displacement amount is 1 mm, so that a blood vessel of 1 mm or less cannot be identified.

Further, there is a problem that the resolution is reduced due to the vibration waveform of the spectroscope 4.

FIG. 9 is a diagram showing the vibration waveform of the spectroscope and the timing of X-ray irradiation to the subject.

As shown in FIG. 9, since the vibration waveform 7 of the spectroscope is a sine wave, the angle fluctuation of the spectrometer occurs within the irradiation time of the X-ray to the subject shown in the lower part of FIG. . Due to the angle fluctuation of the spectroscope, the bandwidth of the X-ray is widened, that is, the photon energy is changed, and the resolution is deteriorated.

The present invention has been made in order to solve such a problem, and it is intended to reduce the amount of image displacement caused by the upper energy and the lower energy to zero, and to suppress a decrease in resolution due to the vibration waveform of the spectroscope. Accordingly, an object of the present invention is to provide an angiography apparatus capable of obtaining a high-resolution image.

[0020]

According to the first aspect of the present invention,
A radiation light generating means for generating radiation light that is electromagnetic waves from ultraviolet rays to X-rays; and iodine as a contrast agent by monochromaticizing the radiation light generated from the radiation light generation means and vibrating at a specific frequency. A spectroscope that obtains two types of monochromatic radiation having upper and lower energies before and after the K absorption edge, and the two spectrometers having the upper energy and the lower energy separated from the spectroscope.
An image sensor that receives a type of monochromatic radiation, an imager that visualizes a signal from the image sensor, and a difference process between the upper energy and the lower energy using an energy difference method based on a signal from the imager. Image processing means comprising a difference processing unit that obtains an image of a coronary artery by performing an imaging process on the coronary artery using the radiation light. Before performing the processing, there is provided a movement adjustment processing means for performing a parallel movement of one of the image data positions of the upper energy and the lower energy.

According to the present invention, it is possible to eliminate the image shift amount by performing the difference processing after the one image data position is moved in parallel by the two image difference processing unit.

According to a second aspect of the present invention, in the angiography apparatus according to the first aspect, when the vibration swing angle of the spectroscope is θ and the distance between the subject and the image sensor is L, the movement adjustment processing means includes: The parallel movement distance d of one of the image data of the upper energy and the lower energy is set to d = 2L (sin θ).

According to the present invention, the vibration swing angle θ of the spectroscope is
When the distance L between the subject and the image sensor is set, by setting the parallel movement distance d of the image data to d = 2L (sin θ), the image shift amount can be accurately eliminated.

According to a third aspect of the present invention, there is provided a radiant light generating means for generating radiant light which is an electromagnetic wave from ultraviolet rays to X-rays, a monochromatic radiant light generated from the radiant light generating means, and A spectroscope for obtaining two types of monochromatic radiation having upper and lower energies before and after the K absorption edge of iodine as a contrast agent by vibrating at a frequency, and the upper energy and the An image sensor that receives the two types of monochromatic radiation having lower energy, an imager that visualizes a signal from the image sensor, and a signal from the imager using an energy difference method, and the upper energy and Image processing means comprising a difference processing unit that obtains an image of the coronary artery by performing the difference processing of the lower energy. The angiography apparatus for performing an imaging of the coronary artery, wherein a sensor moving means for parallelly moving the image sensor of the image processing means in a direction orthogonal to a light receiving surface thereof in synchronization with a vibration frequency of the spectroscope is provided. It is characterized by.

According to the present invention, by providing a mechanism for parallelly moving the image sensor of the imager in synchronization with the vibration frequency of the spectroscope, it is possible to eliminate the amount of image shift.

According to a fourth aspect of the present invention, in the angiography apparatus according to the third aspect, when the vibration swing angle of the spectroscope is θ and the distance between the subject and the image sensor is L, the moving distance d of the image sensor is Is set to d = 2L (sin θ).

According to the present invention, the vibration swing angle θ of the spectroscope is
When the distance L between the subject and the image sensor is set, by setting the parallel movement distance d of the image sensor to d = 2L (sin θ), the image shift amount can be accurately eliminated.

According to a fifth aspect of the present invention, in the angiography apparatus according to the first to fourth aspects, two shutters are provided for cutting out the radiated light irradiated to the subject, and the radiated light is irradiated per second. Characterized in that radiation light control means for controlling the number of times is provided.

According to the present invention, it is possible to provide two shutters for cutting out the radiated light irradiated to the subject, and to control the number of times of radiated light irradiated per second.

According to a sixth aspect of the present invention, in the angiographic apparatus according to the fifth aspect, the radiation light control means includes two shutters each having a disk provided with a notch, and rotation of the two shutters. And a controller provided to control the synchronization of the number and the notch position.

According to the present invention, two shutters are plates provided with notches on a disk, and a system for controlling the synchronization between the number of rotations and the positions of the notches is provided, whereby radiation emitted per second is provided. The number of times of light can be controlled.

According to a seventh aspect of the present invention, in the angiography apparatus according to the first to sixth aspects, the waveform oscillating the spectroscope is a rectangular wave.

According to the present invention, by making the waveform oscillating the spectroscope a rectangular wave, a decrease in resolution can be suppressed and a high resolution can be obtained.

[0034]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.
This will be described with reference to FIG.

First Embodiment (FIGS. 1 and 2) In this embodiment, either one of the upper energy and the lower energy before performing the difference processing by the energy difference method with reference to FIGS. A description will be given of the provision of the movement adjustment processing means for moving the image data position in parallel.

FIG. 1 is an overall configuration diagram showing an angiography apparatus.

As shown in FIG. 1, the angiography apparatus is provided with a radiated light generating means 10 for generating radiated light which is an electromagnetic wave from ultraviolet rays to X-rays, has a high intensity, and is a high quality light source. I have. This radiation light generating means 10
Is an electron beam storage ring 11 and this storage ring 11
And a wiggler 12 provided therein, and the wiggler 12 emits white light.

The emitted white light is converted by the spectroscope 13 into X light.
The light is diffracted into a single color. A driving unit 14 is connected to the spectroscope 13, and the driving unit 14 controls the spectroscope 1.
3 was vibrated at an angle θ to obtain two types of monochromatic X-rays, i.e., upper energy and lower energy of about 33.17 keV at the K absorption edge of iodine as a contrast agent.

The two types of monochromatic X-rays diffracted by the spectroscope 13 pass through the heart 16 of the subject 15 as a subject and are guided to an image sensor 18 as image processing means 17. At this time, the X-rays incident on the subject 15 have a 2θ angle difference.

The two images collected by the image sensor 18 are taken into an image device 19 as image processing means 17. A difference processing unit 20 is connected to the imager 19, and the difference processing unit 20 stores one image data position in two.
Movement adjustment processing means 2 for performing parallel movement by L (sin θ)
1 is provided. After the image data position is translated by 2 L (sin θ) by the movement adjustment processing means 21, a contrast processing photograph of the coronary artery is output by performing a difference processing 22 for calculating a difference between the two images.

Referring to FIG. 2, a description will be given of a case where the distance for parallelly moving the image data position is set to 2L (sin θ) in the present embodiment.

FIG. 2 is a diagram showing a detailed view of the subject's heart and the image sensor.

As shown in FIG. 2, when the upper energy and the lower energy enter the heart 16 with a 2θ angle difference, the displacement d of the image position on the image sensor 18 becomes
If the distance between the image sensor 6 and the image sensor 18 is L, d = 2L
(Sin θ).

According to the present embodiment, since the shift amount between the two images of the upper energy and the lower energy can be canceled before performing the difference processing, a clear contrast-enhanced photograph of the coronary artery without blurring can be obtained.

Second Embodiment (FIG. 3) In this embodiment, referring to FIG. 3, a sensor moving means in which an image sensor moves in parallel in a direction orthogonal to a light receiving surface thereof in synchronization with a vibration frequency of a spectroscope. A description will be given of the provision of. The same parts as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

FIG. 3 is an overall configuration diagram showing an angiography apparatus.

As shown in FIG. 3, a sensor moving means 23 is connected to the image sensor 18, and the sensor moving means 23 is connected to the image sensor 18,
And a sensor moving wiring 25 connected to the driving unit 24 on one side and connected to the driving unit 14 of the spectroscope 13 on the other side. I have. As a result, the image sensor 18 moves up and down in parallel with the vibration frequency of the spectroscope 13 from the driving unit 14 connected to the spectroscope 13 via the sensor moving wiring 25. The vertical translation distance of the image sensor 18 is set to 2L (sin θ).

According to the present embodiment, FIG.
As shown in the figure, since the displacement d of the position of the two images in the image sensor 18 is 2L (sin θ), the image sensor 1
Since the image 8 itself is moved up and down in synchronization with the vibration frequency of the spectroscope 13, the shift amount between the two images can be canceled before performing the difference processing. Thereby, a sharp contrast photograph of the coronary artery without blur can be obtained.

Third Embodiment (FIGS. 4 to 6) In this embodiment, a description will be given of a case where the rotary shutter and the spectroscope are rectangular waves with reference to FIGS. Note that the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

FIG. 4 is an overall configuration diagram showing an angiography apparatus.

As shown in FIG. 4, between the emission light generating means 10 and the spectroscope 13 of the angiography apparatus, there is provided emission light control means 26 for controlling the number of irradiation light irradiations per second.

The radiant light control means 26 is provided with two rotary shutters 27a and 27b provided for cutting out the radiant light to be irradiated on the subject, and is connected to the rotary shutters 27a and 27b to control the number of rotations and the notch position. And a controller 28 for controlling the synchronization of

FIG. 5 is a diagram showing the shape of the rotary shutter.

As shown in FIGS. 5 (a) and 5 (b), the rotary shutters 27a and 27b are plates provided with notches in the disk, and the rotary shutter 27a is a switch between the upper energy and the lower energy. The cutout corresponds to the time for cutting out two images. On the other hand, the rotary shutter 27b has a cutout for masking two images other than one frame.

In the present embodiment, the spectroscope 13 is used.
Is a rectangular waveform.

FIG. 6 is a diagram showing a vibration waveform of the spectroscope.

As shown in FIG. 6 (a), the vibration waveform of the spectroscope is a rectangular wave which is a periodic waveform that changes between two fixed values alternately and rapidly from one to the other. Controlling. Assuming that the vibration waveform of the spectroscope is a rectangular wave, FIG.
The timing of cutting out the emitted light is as shown in FIG.

According to the present embodiment, the rotary shutter 27
By controlling the synchronization between the rotation speeds a and 27b and the cutout position by the controller 28, two images at a predetermined cutout timing can be photographed by the required number of frames per second.

Further, by making the vibration waveform of the spectroscope 13 a rectangular wave, the spectrometer 1 within the X-ray cut-out time is used.
Since the angle change of No. 3 can be made zero, a high-resolution contrast photograph can be obtained without lowering the resolution.

[0060]

As described above, according to the present invention, the shift amount of the image due to the upper energy and the lower energy obtained by vibrating the spectroscope for the energy difference method is reduced to zero, and A high-resolution contrast-enhanced photograph of the coronary artery can be taken while suppressing a decrease in the resolution due to the vibration waveform of.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram showing an angiography apparatus according to a first embodiment.

FIG. 2 is a diagram showing a detailed view of a subject's heart and an image sensor in the first embodiment.

FIG. 3 is an overall configuration diagram showing an angiography apparatus according to a second embodiment.

FIG. 4 is an overall configuration diagram showing an angiography apparatus according to a third embodiment.

FIG. 5 is a diagram illustrating a rotary shutter according to a third embodiment.

FIG. 6 is a diagram showing a vibration waveform of a spectroscope in a third embodiment.

FIG. 7 is a configuration diagram showing a conventional experimental example.

FIG. 8 is a diagram showing a K absorption edge of iodine.

FIG. 9 is a diagram showing a vibration waveform of a spectroscope.

[Explanation of symbols]

 Reference Signs List 10 synchrotron radiation generating means 11 storage ring 12 wiggler 13 spectroscope 14 drive unit 15 subject 16 heart 17 image processing means 18 image sensor 19 image unit 20 difference processing unit 21 movement adjustment processing means 22 difference processing 23 sensor movement means 24 drive unit 25 Sensor moving wiring 26 Synchrotron radiation control means 27a, 27b Rotary shutter 28 Controller

Claims (7)

[Claims] 1. A radiation light generating means for generating radiation light, which is an electromagnetic wave from ultraviolet rays to X-rays, and a monochromatic radiation light generated from said radiation light generation means and vibrated at a specific frequency. 2 having upper and lower energies before and after the K-absorption edge of iodine as a contrast agent
A spectroscope that obtains two types of monochromatic radiation, an image sensor that receives the two types of monochromatic radiation having the upper energy and the lower energy separated from the spectroscope, and a signal from the image sensor. Image processing means comprising an imager to be visualized and a difference processing unit for performing a difference process between the upper energy and the lower energy by using an energy difference method based on a signal from the imager to obtain an image of a coronary artery. In the angiography apparatus that performs the imaging of the coronary artery using the emitted light, before performing the difference processing of the difference processing unit in the image processing unit, one of the upper energy and the lower energy An angiograph comprising a movement adjustment processing means for performing parallel movement of image data positions. It chromatography apparatus. 2. An angiography apparatus according to claim 1, wherein when the vibration swing angle of the spectroscope is θ and the distance between the subject and the image sensor is L, the movement adjustment processing means performs the upper energy and the lower energy. Is set to d = 2L (sin
θ), an angiographic apparatus characterized in that: 3. A radiation light generating means for generating radiation light, which is electromagnetic waves from ultraviolet rays to X-rays, and a radiation light generated from the radiation light generation means being monochromatic and vibrating at a specific frequency. 2 having upper and lower energies before and after the K-absorption edge of iodine as a contrast agent
A spectroscope that obtains two types of monochromatic radiation, an image sensor that receives the two types of monochromatic radiation having the upper energy and the lower energy separated from the spectroscope, and a signal from the image sensor. Image processing means comprising an imager to be visualized and a difference processing unit for performing a difference process between the upper energy and the lower energy by using an energy difference method based on a signal from the imager to obtain an image of a coronary artery. In the angiography apparatus for imaging the coronary artery using the emitted light, the image sensor of the image processing means is translated in a direction orthogonal to the light receiving surface in synchronization with the oscillation frequency of the spectroscope. An angiography apparatus provided with a sensor moving means for causing the sensor to move. 4. The angiography apparatus according to claim 3, wherein when the vibration swing angle of the spectroscope is θ and the distance between the subject and the image sensor is L, the moving distance d of the image sensor is set.
Is set to d = 2L (sin θ). 5. The angiography apparatus according to claim 1, further comprising two shutters for cutting out the radiation emitted to the subject, and controlling the number of radiations emitted per second. An angiographic apparatus comprising a radiation light control means. 6. The angiography apparatus according to claim 5, wherein the radiation light control means includes two shutters each of which is a plate provided with a notch in a disk, a rotation speed of the two shutters, and the notch position. And a controller for controlling synchronization of the angiography apparatus. 7. An angiographic apparatus according to claim 1, wherein the waveform oscillating the spectroscope is a rectangular wave.