JP2005216669A - Image intensifier - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To sufficiently suppress distortion of visible light image due to earth magnetism which induces the distortion. <P>SOLUTION: The image intensifier of this invention includes a magnetic shielding wall due to a main magnetic shielding body 6 as well as a sub-magnetic shielding body 14 which expands the wall up to between a distortion correction coil 8 and the neighborhood PA of the back face fringe of an input face substrate 1. The magnetic shielding wall expanded by the sub-magnetic shielding body 14 locally suppresses the correction magnetism generated by the distortion correction coil 8 from affecting the neighborhood PA of the back face fringe of the input face substrate 1. The local relaxation of the excessive correction due to the distortion correction coil 8 at the neighborhood PA of the back face fringe of the input face substrate 1 which outputs photoelectron images corresponding to incident X-ray images provides more spontaneous correction in distortion of the visible light images outputted to an output fluorescent surface 3 of an image tube 4 and results in sufficient suppression of distortion of the visible light images due to the earth magnetism which induces the distortion. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  In the present invention, an incident X-ray image is converted into a visible light image via a photoelectron image and output to an output phosphor screen, and distortion-induced magnetism that distorts the photoelectron image and causes distortion of the visible light image is generated by a distortion correction coil. The present invention relates to an image intensifier apparatus that cancels with distortion correction magnetism, and more particularly to a technique for sufficiently suppressing distortion of a visible light image caused by geomagnetism as distortion-induced magnetism.

  This type of image intensifier apparatus (hereinafter abbreviated as “II apparatus” as appropriate) includes CsI for outputting a photoelectron image corresponding to an incident X-ray image, as shown in FIGS. An input surface substrate 51 composed of a fluorescent surface and a photocathode, an electron lens system 52 for reducing and forming a photoelectron image emitted from the photocathode of the input surface substrate 51, and reduction by the lens action of the electron lens system 52 A vacuum-sealed image tube 54 that houses an output phosphor screen 53 that converts the formed photoelectron image into a visible light image and outputs it is disposed in a metal outer container 55.

  Such I.D. I. In the device, geomagnetism (strain-induced magnetism) distorts the photoelectron image by Lorentz force and causes distortion of the visible light image. For example, as shown in FIG. 10A, the geomagnetism is changed from an incident X-ray image XA in the form of “+” to a visible light image Xa in the form of “+” correctly as shown in FIG. Without conversion, the image is converted into a visible light image XB having a distortion in which both the vertical and horizontal directions are distorted in an “S” shape. Therefore, in order to avoid distortion of the visible light image due to geomagnetism, a cylindrical magnetic shield body 56 made of a ferromagnetic material is disposed surrounding the electron lens system 52 in the image tube 54 outside the image tube 54. The magnetic shield 56 is magnetically shielded. That is, the magnetic shield 56 serves as a magnetic shielding wall to prevent geomagnetism from being applied from the peripheral side surface of the image tube 54.

  However, it is not preferable to magnetically shield the front surface of the input surface substrate 51, which is an X-ray incident surface, in order to prevent a decrease in the X-ray intensity of the incident X-ray image. For this purpose, a window 57 made of aluminum, titanium, glass or the like is provided on the X-ray incident surface. Therefore, the geomagnetism from the window 57 of the image tube 54 cannot be prevented by the magnetic shield body 56, and the distortion of the visible light image due to the geomagnetism cannot be eliminated by the magnetic shield body 56 alone. Incidentally, as a known technique, I.I. I. A thin permalloy is attached to the front of the device as a magnetic shield.

Therefore, as shown in FIG. 8, a distortion correction coil 58 for generating distortion correction magnetism and a power source 59 for supplying a coil current are disposed in order to cancel the distortion-induced magnetism of the visible light image. Furthermore, a magnetic sensor 60 that detects the strength and direction of the terrestrial magnetism in the vicinity of the input surface substrate 51 and a power supply control unit 61 that controls the power supply 59 according to the output signal of the magnetic sensor 60 are provided. The power supply control unit 61 controls the power supply 59 so that a coil current corresponding to the strength and direction of the geomagnetism detected by the magnetic sensor 60 flows to the distortion correction coil 58, and the distortion correction coil 58 has the strength of the distortion-induced magnetism. Corresponding coil current is supplied from the power source 59 to cancel the distortion-induced magnetism. The distortion of the visible light image due to the geomagnetism as the distortion-induced magnetism from the window 57 of the image tube 54 is suppressed by the action of canceling the geomagnetism by the distortion correction coil 58 (see Patent Document 1).
JP-A-7-65756 (pages 3 to 4, FIGS. 1 to 4)

  However, the conventional I.I. I. In the case of the apparatus, the distortion correction coil 58 cannot sufficiently suppress the distortion of the visible light image caused by the geomagnetism.

  If the distortion of visible light image due to geomagnetism is insufficient, I. For example, when the apparatus is used for transmission X-ray image detection of a medical X-ray fluoroscopic apparatus, an image distortion corresponding to the distortion of a visible light image occurs in an X-ray image obtained by X-ray imaging, and the X-ray image is a lesion site. Problems such as not accurately projecting (affected area) occur.

  The present invention has been made in view of such circumstances, and an object thereof is to provide an image intensifier device capable of sufficiently suppressing distortion of a visible light image caused by geomagnetism as distortion-induced magnetism. And

  In order to achieve such an object, the inventor has intensively studied in order to find out the cause that the distortion of the visible light image cannot be sufficiently suppressed. Then, it was speculated that the distortion of the visible light image could not be sufficiently suppressed because the geomagnetism as the distortion-induced magnetism was not accurately canceled by the distortion correction coil. Then, in the vicinity of the back surface side periphery of the input surface substrate that outputs the photoelectron image corresponding to the incident X-ray image, an overcorrection state is locally generated by the distortion correction coil, and the distortion-induced magnetism is increased by the amount of distortion correction magnetism. As a result, the distortion-induced magnetism is not canceled out properly, and as a result, it has been found that the distortion of the visible light image cannot be sufficiently suppressed. The present invention based on such knowledge has the following configuration.

  That is, the invention described in claim 1 is an input surface substrate that outputs a photoelectron image corresponding to an incident X-ray image, an electron lens system that forms a reduced image of the photoelectron image, and a photoelectron image that is reduced and formed by the electron lens system. An image tube containing an output phosphor screen that converts and outputs a visible light image, a cylindrical main magnetic shield body arranged by enclosing the electron lens system in the image tube outside the image tube, and X-rays of the image tube Distortion correction to generate distortion correction magnetism to counteract the distortion-induced magnetism that wraps around the outer peripheral space of the input surface substrate along the outer periphery of the input surface and distorts the photoelectron image and causes distortion of the visible light image An image intensifier including a coil, and including a ring-shaped sub magnetic shield body that makes one round of the inner surface of the distortion correction coil. The sub magnetic shield body is opposite to the X-ray input side over the entire circumference. ~ side The magnetic shielding wall is constituted by both the main and sub magnetic shield bodies.

  [Operation / Effect] When detecting an incident X-ray image in the image intensifier apparatus of the invention of claim 1 (hereinafter, abbreviated as “II apparatus” as appropriate), the image tube uses a main magnetic shield for magnetic detection. While avoiding the influence of geomagnetism by shielding, the electron lens system reduces the photoelectron image generated by the projection of the incident X-ray image onto the input surface substrate on the output phosphor screen, and the photoelectron image formed as a reduced image is a visible light image. Converted to output. The main magnetic shield body serves as a magnetic shielding wall to prevent geomagnetism as strain-induced magnetism from being applied from the peripheral side surface of the image tube.

  Furthermore, the I.D. I. In parallel with the detection of the incident X-ray image by the image tube, the distortion correction coil wound around the outer peripheral space of the input surface substrate along the outer peripheral edge of the X-ray input surface of the image tube generates the distortion correction magnetism. generate. Distortion of the photoelectron image is suppressed by preventing the geomagnetism from the X-ray input surface side as distortion-induced magnetism that distorts the photoelectron image and causes distortion of the visible light image. As a result, the distortion of the visible light image output to the output phosphor screen is suppressed.

  On the other hand, the I.D. I. In the case of the apparatus, a ring-shaped sub magnetic shield body that makes one round of the inner surface of the distortion correction coil is configured to be connected to the main magnetic shield body on the opposite side to the X-ray input side over the entire circumference. A magnetic shielding wall is constituted by the sub magnetic shield bodies. Due to the magnetic shielding wall by the sub magnetic shield body, the magnetic shielding wall by the main magnetic shield body spreads between the distortion correction coil and the vicinity of the periphery on the back surface side of the input surface substrate. The magnetic shielding wall added between the distortion correction coil and the vicinity of the back surface side periphery of the input surface board due to the arrangement of the sub magnetic shield body is such that the distortion correction magnetism generated in the distortion correction coil is on the back surface side of the input surface board. It exhibits a magnetic shielding function that locally suppresses the vicinity of the periphery. Then, the overcorrection state of the distortion correction coil is locally relieved in the vicinity of the back surface side periphery of the input surface substrate that outputs a photoelectron image corresponding to the incident X-ray image. As a result, it is possible to suppress unnatural distortion correction by the distortion correction coil that causes distortion of the visible light image output to the output fluorescent screen of the image tube.

  According to a second aspect of the present invention, in the image intensifier according to the first aspect, the distortion correction coil and the main magnetic shield body are disposed inside the outer container in which the image tube is housed. The magnetic shield body is disposed inside the main magnetic shield body, and the peripheral edge of the sub magnetic shield body opposite to the X-ray input side is connected to the inner peripheral surface of the main magnetic shield body. It is.

  [Operation / Effect] The I.V. I. In the case of the apparatus, the distortion correction coil and the main magnetic shield body are disposed inside the outer container in which the image tube is housed, and the sub magnetic shield body is also on the side opposite to the X-ray input side of the sub magnetic shield body. The peripheral edge is connected to the inner peripheral surface of the main magnetic shield body and disposed inside the outer container. Since both the distortion correction coil and the main and sub magnetic shield bodies are housed in the outer container, it is not necessary to expose the distortion correction coil to the outside of the outer container.

  In the case of the image intensifier device according to the first aspect of the present invention, an incident X-ray image is detected by the image tube while preventing the geomagnetism as distortion-induced magnetism from the peripheral side surface of the image tube by the main magnetic shield body, and the output phosphor screen A visible light image is converted into an output. In parallel, a distortion correction coil wound around the outer peripheral space of the input surface substrate along the outer peripheral edge of the X-ray input surface of the image tube generates distortion correction magnetism. The distortion correction coil prevents the geomagnetism from the X-ray input surface side as distortion-induced magnetism that distorts the photoelectron image and causes distortion of the visible light image, so that the distortion of the photoelectron image is suppressed. Visible light distortion is suppressed. Furthermore, a ring-shaped sub magnetic shield body that makes one round of the inner surface of the distortion correction coil is configured to be connected to the main magnetic shield body on the opposite side to the X-ray input side over the entire circumference. A magnetic shielding wall is constituted by both magnetic shield bodies. By the sub magnetic shield body, the magnetic shielding wall by the main magnetic shield body extends to between the distortion correction coil and the vicinity of the periphery on the back surface side of the input surface substrate. The magnetic shielding wall added between the distortion correction coil and the vicinity of the periphery of the back surface of the input surface board due to the arrangement of the sub magnetic shield body causes the distortion correction magnetism generated in the distortion correction coil to be on the back surface side of the input surface board. It exhibits a magnetic shielding function that locally suppresses the vicinity of the periphery. Then, the overcorrection state of the distortion correction coil is locally relieved in the vicinity of the back surface side periphery of the input surface substrate that outputs a photoelectron image corresponding to the incident X-ray image. As a result, the overcorrection state of the distortion correction coil that causes distortion of the visible light image output to the output fluorescent screen of the image tube can be relaxed.

  Therefore, according to the image intensifier device of the first aspect of the invention, it is possible to more naturally correct the distortion of the visible light image due to the geomagnetism as the distortion-induced magnetism.

  Embodiments of the present invention will be described below with reference to the drawings. 1 is an overall configuration diagram of an image intensifier device (II device) according to the embodiment, and FIG. I. FIG. 3 is a plan view showing the arrangement of both main and sub magnetic shields and distortion correction coils in the apparatus. I. It is a side view which shows the arrangement | positioning condition of an apparatus.

  Example I.I. I. As shown in FIG. 1, the apparatus emits an input surface substrate 1 composed of a phosphor screen such as CsI for outputting a photoelectron image corresponding to an incident X-ray image and a photocathode, and a photocathode of the input surface substrate 1. A vacuum seal containing an electron lens system 2 for reducing the photoelectron image to be formed and an output phosphor screen 3 for converting and outputting the photoelectron image reduced and imaged by the lens action of the electron lens system 2 to a visible light image An image tube 4 of the type is arranged in a metal outer container 5. In FIG. 1, the internal structure of the image tube 4 is shown in a simplified manner to make the drawing easier to see.

  Example I.I. I. In the case of the device, since there is distortion of the photoelectron image due to the influence of geomagnetism (strain-induced magnetism), the electron lens system 2 in the image tube 4 is enclosed outside the image tube 4 in order to avoid distortion of the visible light image due to geomagnetism. The cylindrical magnetic main magnetic shield body 6 is disposed to shield the magnetic field. The main magnetic shield body 6 serves as a magnetic shielding wall to prevent geomagnetism as distortion-induced magnetism from the peripheral side surface of the image tube 4.

  Specifically, the main magnetic shield body 6 is disposed in a state where the inner peripheral surface of the outer container 5 and the outer peripheral surface of the main magnetic shield body 6 are in contact with each other and inserted into the outer container 5. Examples of the ferromagnetic material used for the main magnetic shield body 6 include permalloy.

  Example I.I. I. When detecting an incident X-ray image in the image tube 4 of the apparatus, photoelectrons generated by projecting the incident X-ray image onto the input surface substrate 1 while avoiding the influence of geomagnetism by the magnetic shielding wall by the main magnetic shield body 6. The electron lens system 2 reduces and forms an image on the output phosphor screen 3, and the reduced image is converted into a visible light image and output.

  However, as shown in FIG. 1, the main magnetic shield body 6 is not provided on the front surface of the input surface substrate 1 that is the X-ray incident surface. When magnetic shielding is performed up to the front surface of the input surface substrate 1, the X-ray intensity of the incident X-ray image decreases due to X-ray absorption by the main magnetic shield body 6, and the detection sensitivity decreases. Therefore, it is not preferable to provide a magnetic shield with a ferromagnetic metal on the front surface of the input surface substrate 1, and a window 7 made of aluminum, titanium, glass, or the like is disposed on the X-ray incident surface. Therefore, the geomagnetism applied from the window 7 of the image tube 4 cannot be completely prevented by the main magnetic shield body 6, and the distortion of the visible light image due to the geomagnetism cannot be eliminated by the main magnetic shield body 6 alone.

  Therefore, the I.D. I. As shown in FIG. 2, the apparatus includes a distortion correction coil 8 wound around the outer peripheral space of the input surface substrate 1 along the outer peripheral edge of the window 7 which is the X-ray input surface of the image tube 4. Yes. The distortion correction coil 8 generates distortion correction magnetism in order to cancel distortion-induced magnetism that distorts the photoelectron image and causes distortion of the visible light image. That is, the distortion induced magnetism is canceled by passing a coil current corresponding to the strength of the distortion induced magnetism through the correction coil 8. The number of turns (turns) of the distortion correction coil 8 is not limited to a specific number of turns, but is exemplified by 800 to 1000 turns.

  That is, the I.D. I. In the case of the apparatus, in addition to the distortion correction coil 8, a power source 9 that supplies a coil current of the distortion correction coil 8 is provided. Furthermore, a magnetic sensor 10 that detects the strength and direction of the terrestrial magnetism in the vicinity of the input surface substrate 1 and a power supply control unit 11 that controls the power supply 9 according to the output signal of the magnetic sensor 10 are provided. The power supply controller 11 controls the power supply 9 so that the coil current corresponding to the strength and direction of the geomagnetism detected by the magnetic sensor 10 flows to the distortion correction coil 8. Corresponding coil current is supplied from the power source 9 to cancel the distortion-induced magnetism. Therefore, the geomagnetism as the distortion-induced magnetism from the window 7 of the image tube 4 is prevented by the magnetic canceling action by the distortion correction coil 8, so that the distortion of the visible light image due to the geomagnetism from the window 7 of the image tube 4 is suppressed.

  In addition, as shown in FIG. I. The apparatus A is disposed on one end side of the overhead traveling C-arm 12 for the X-ray fluoroscopic apparatus and faces the X-ray tube B disposed on the other end side of the C-arm 12. As the C-arm 12 rotates about the rotation shaft 13 provided at the center of the back surface of the C-arm 12, the I.I. I. The device rotates in the direction indicated by arrow RA. Further, as the C arm 12 slides within a predetermined range along the arc of the C arm 12, the I.D. I. Device A moves in the direction indicated by arrow RB. With such rotation and movement, the effective intensity of the strain-induced magnetism varies from the window of the image tube 4, and this variation is reflected in the detected intensity of the magnetic sensor 10. Therefore, it is incorporated in the control loop (control loop) of the power source 9 performed by the power source control unit 11. I. The function of canceling the strain-induced magnetism of the strain correction coil 8 is not disturbed by the variation of the effective strength of the strain-induced magnetism accompanying the movement of the device A.

  Furthermore, the I.V. I. In the case of the apparatus, as shown in FIG. 1 and FIG. 2, the sub-magnetic shield body 14 made of a ring-shaped ferromagnetic material that goes around the inner surface of the distortion correction coil 8 is opposite to the X-ray input side over the entire circumference. The main magnetic shield body 14 is connected to the main magnetic shield body 14 on the side, and the main and sub magnetic shield bodies 6 and 14 form a magnetic shielding wall. Since the sub magnetic shield body 14 is configured to relieve the overcorrection state of the distortion correction coil locally in the vicinity of the back surface side periphery of the input surface substrate 1 of the image tube 4, this point will be described below.

  Specifically, as shown in FIG. 1, the sub magnetic shield body 14 has a “L” shape in cross-sectional shape, and an overall planar shape is a true circle. The main and sub magnetic shield bodies 6 and 14 are fitted so as to be coaxial via a non-magnetic attachment ring 15, and the sub magnetic shield body 14 is attached to the main magnetic shield at the tip of the lateral side of the “L” shape. It is connected to the inner peripheral surface of the body 6. As shown in FIG. 2, when viewed from the front of the window 7 of the image tube 4, a distortion correction coil 8 is sandwiched between the main magnetic shield body 6 and the sub magnetic shield body 14, so that a ring-shaped sub magnetic shield is formed. The body 14 is in a state of making one round of the inner surface of the distortion correction coil 8. As the ferromagnetic body of the sub magnetic shield body 14, for example, permalloy or the like can be cited as with the main magnetic shield body 6. Examples of the nonmagnetic material of the attachment ring 15 include aluminum.

  Thus, the I.D. I. In the case of the apparatus, a ring-shaped sub magnetic shield body 14 that goes around the inner surface of the distortion correction coil 8 is connected to the main magnetic shield body 14 on the opposite side to the X-ray input side over the entire circumference. The main and sub magnetic shield bodies 6 and 14 constitute a magnetic shielding wall. Due to the magnetic shielding wall by the sub magnetic shield body 14, the magnetic shielding wall by the main magnetic shield body 6 extends between the distortion correction coil 8 and the vicinity of the rear surface side peripheral edge PA of the input surface substrate 1.

  The magnetic shielding wall added between the distortion correction coil 8 and the vicinity of the peripheral edge of the back surface of the input surface substrate 1 due to the arrangement of the sub magnetic shield body 14 has the distortion correction magnetism generated by the distortion correction coil 8 on the input surface. It exhibits a magnetic shielding function that locally suppresses the vicinity of the peripheral edge PA on the back surface side of the substrate 1. Then, the overcorrection state of the distortion correction coil 8 is locally relieved in the vicinity of the back surface side periphery PA of the input surface substrate 1 that outputs a photoelectron image corresponding to the incident X-ray image. As a result, the distortion of the visible light image output to the output phosphor screen 3 of the image tube 4 can be corrected more naturally.

  In order to verify the action of eliminating the sub magnetic shield body 14 with respect to the overcorrection state of the distortion correction coil 8, the simulation method based on Maxwell's equations in electromagnetics was obtained under the following conditions. That is, the I.D. I. A comparative example having the same configuration as that of the example except that the apparatus and the sub magnetic shield body 14 are not provided and only the main magnetic shield body 6 is provided. I. The device was compared. The application state of the distortion correction magnetism by the distortion correction coil 8 in the vicinity of the rear surface side peripheral edge PA and the front surface side peripheral edge PB of the input surface substrate 1 of each of the examples and the comparative examples, and a 36 AT coil current is passed through the distortion correction coil 8. The simulation was performed under the condition that the PC type with an initial relative permeability of 40000 is used as the ferromagnetic material of the sub magnetic shield body 14.

  Example I.I. I. The simulation results for the apparatus are shown in FIG. I. The simulation results for the apparatus are shown in FIG. “G” in the figure indicates Gaussian.

  In the vicinity of the rear surface side peripheral edge PA of the input surface substrate 1, the intensity of distortion correction magnetism by the distortion correction coil 8 is the same as that of the embodiment shown in FIG. I. In the case of the apparatus, the I.D. of the comparative example shown in FIG. I. Less than in the case of the device.

  Similarly, in the vicinity of the surface side peripheral edge PB of the input surface substrate 1, the intensity of distortion correction magnetism by the distortion correction coil 8 is the same as that of the embodiment shown in FIG. I. In the case of the apparatus, the I.D. of the comparative example shown in FIG. I. Less than in the case of the device.

  That is, in the simulation result, the I.D. I. In the case of a device, the I.D. I. Compared with the apparatus, the strength of the distortion correction magnetism by the distortion correction coil 8 is greatly reduced in the vicinity of the rear surface side periphery PA of the input surface substrate 1, and the sub magnetic shield body 14 is in an overcorrected state of the distortion correction coil 8. Indicates that the problem is resolved.

  Thus, the I.D. I. In the case of the apparatus, the distortion correction coil 8 includes the sub magnetic shield body 14 that extends the magnetic shielding wall by the main magnetic shield body 6 to between the distortion correction coil 8 and the vicinity of the rear surface side periphery PA of the input surface substrate 1. The distortion correction magnetism which generate | occur | produces suppresses locally on the back surface side periphery vicinity PA of the input surface board | substrate 1 locally. Then, the overcorrection state of the distortion correction coil 8 is locally relieved in the vicinity of the back surface side periphery PA of the input surface substrate 1 that outputs a photoelectron image corresponding to the incident X-ray image. As a result, the distortion of the visible light image output to the output phosphor screen 3 of the image tube 4 can be corrected more naturally.

  It should be noted that the I.V. I. I. of the device and the comparative example. I. As shown in FIG. 3, when X-ray images obtained by performing X-ray imaging with each apparatus mounted on an X-ray fluoroscopic imaging apparatus were comparatively observed, the I.D. I. The X-ray image when the apparatus is used is the I.D. I. It was confirmed that there was less image distortion than the X-ray image when the apparatus was used.

  In addition, the I.D. I. In the case of the apparatus, the distortion correction coil 8 and the main magnetic shield body 6 are disposed inside the outer container 5 in which the image tube 4 is housed, and the sub magnetic shield body 14 is also an X-ray in the sub magnetic shield body 14. The peripheral edge opposite to the input side is connected to the inner peripheral surface of the main magnetic shield body 6 and is arranged inside the outer container 5. Since both the distortion correction coil 8 and the main magnetic shield bodies 6 and 14 are housed in the outer container 5, it is not necessary to expose the distortion correction coil 8 to the outside of the outer container 5.

  The present invention is not limited to the above embodiment, and can be modified as follows.

  (1) I. of Example I. In the apparatus, as shown in FIG. 6, the main magnetic shield body 6A is slightly shorter on the X-ray incident surface side, and there is no magnetic shielding wall by the main magnetic shield body 6A on the outer peripheral side of the distortion correction coil 8. An apparatus having the same configuration as that of the embodiment can be given as a modification. Even if there is no magnetic shielding wall by the main magnetic shield body 6A on the outer peripheral side of the distortion correction coil 8, the magnetic shielding function of the sub magnetic shield body 14 with respect to the vicinity PA on the rear surface side of the input surface substrate 1 is not impaired. Further, the absence of the magnetic shielding wall by the main magnetic shield body 6A on the outer peripheral side of the distortion correction coil 8 is because the magnetic shielding wall by the sub magnetic shield body 14 serves as a substitute. I. The apparatus is substantially the same as the I.D. I. The same effect as the device is achieved.

  (2) I. of Example I. In the apparatus, as shown in FIG. 7, the distortion correction coil 8A is wound in a triangular cross section, and the sub magnetic shield body 14A and the mounting ring 15A have a cross section of the distortion correction coil 8A. An apparatus having the same configuration as that of the embodiment other than the oblique line extending along the inclined inner surface can be given as a modification. Even if the distortion correction coil 8A has a triangular cross section, the function of canceling the distortion-induced magnetism is not impaired. Further, even if the cross sections of the sub magnetic shield body 14A and the mounting ring 15A are simple oblique lines, the magnetic shielding function for the vicinity of the peripheral edge PA on the back surface side of the input surface substrate 1 is not impaired. I. The apparatus is substantially the same as the I.D. I. The same effect as the device is achieved.

  (3) I. of Example I. The apparatus has a configuration including the power supply 9 and the power supply control unit 11, but the present invention is an I.D. configuration in which the power supply 9 and the power supply control unit 11 are not provided. I. It also applies to the device.

  (4) I. of Example I. The apparatus is not limited to the overhead traveling C-arm 12 as shown in FIG. 3, but can be disposed on the floor traveling C-arm, or on a stationary C-arm incorporated in the X-ray imaging table. You can also. It can also be arranged in an X-ray imaging apparatus other than the C-arm.

Example I.I. I. It is a whole block diagram of an apparatus. Example I.I. I. It is a top view which shows the arrangement | positioning condition of both the main and sub magnetic shield bodies and distortion correction coils in the apparatus. I. of the embodiment in the X-ray fluoroscopic apparatus I. It is a side view which shows the arrangement | positioning condition of an apparatus. Example I.I. I. It is a magnetic strength display chart which shows the application condition of the distortion correction magnetism by the distortion correction coil in the peripheral edge vicinity of the input surface board | substrate of an apparatus. I. Comparative Example I. It is a magnetic strength display chart which shows the application condition of the distortion correction magnetism by the distortion correction coil in the peripheral edge vicinity of the input surface board | substrate of an apparatus. I. of the modified example I. It is a fragmentary sectional view which shows the arrangement | positioning condition of both the main and sub magnetic shield bodies of an apparatus, and a distortion correction coil. I. of another modified example. I. It is a fragmentary sectional view which shows the arrangement | positioning condition of both the main and sub magnetic shield bodies of an apparatus, and a distortion correction coil. Conventional I.D. I. It is a whole block diagram of an apparatus. Conventional I.D. I. It is a top view which shows the arrangement | positioning condition of the magnetic shield body and distortion correction coil in an apparatus. I. I. It is a schematic diagram which shows an example of the incident X-ray image and visible light image in an apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Input surface board 2 ... Electron lens system 3 ... Output fluorescent screen 4 ... Image tube 5 ... Outer container 6 ... Main magnetic shield body 8 ... Distortion correction coil 14 ... Sub magnetic shield body XA ... Incident X-ray image Xa ... Visible light image

Claims (2)

  An input surface substrate for outputting a photoelectron image corresponding to an incident X-ray image, an electron lens system for reducing the photoelectron image, and an output phosphor screen for converting the photoelectron image reduced and imaged by the electron lens system into a visible light image. The stored image tube, a cylindrical main magnetic shield body arranged by enclosing the electron lens system in the image tube outside the image tube, and the input surface substrate along the outer peripheral edge of the X-ray input surface of the image tube An image intensifier that includes a distortion correction coil that generates a distortion correction magnetism to distort the photoelectron image and cause distortion of the visible light image. And a ring-shaped sub magnetic shield body that goes around the inner surface of the distortion correction coil, and this sub magnetic shield body is connected to the main magnetic shield body on the opposite side to the X-ray input side over the entire circumference. It is configured, an image intensifier device, wherein the magnetic shielding wall is composed of a double magnetic shield of the main sub. The image intensifier according to claim 1, wherein the distortion correction coil and the main magnetic shield body are disposed inside the outer container in which the image tube is accommodated, and the sub magnetic shield body is disposed inside the main magnetic shield body. An image intensifier device, wherein the peripheral edge of the sub magnetic shield body opposite to the X-ray input side is connected to the inner peripheral surface of the main magnetic shield body.

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