JP4604845B2 - X-ray receiver - Google Patents

Description

  The present invention converts an input surface substrate that outputs a photoelectron image corresponding to an incident X-ray image, an electron lens system that reduces and forms a photoelectron image, and a photoelectron image that is reduced and formed by the electron lens system to a visible light image. The present invention relates to an X-ray image receiving apparatus including an image tube containing an output fluorescent screen, and more particularly to a technique for canceling distortion-induced magnetism that distorts a photoelectron image and causes distortion of a visible light image.

  As shown in FIGS. 9 and 10, a conventional X-ray image receiving apparatus equipped with this type of image tube includes a fluorescent screen such as CsI for outputting a photoelectron image corresponding to an incident X-ray image, and a photocathode. The input surface substrate 51, the electron lens system 52 for reducing the photoelectron image emitted from the photocathode of the input surface substrate 51, and the photoelectron image reduced by the lens action of the electron lens system 52 visible. A vacuum-sealed image tube 54 that houses an output phosphor screen 53 that converts and outputs a light image is housed in a metal outer container 55.

  In a conventional X-ray image receiving apparatus, normally, geomagnetism distorts a photoelectron image by Lorentz force as distortion-induced magnetism, causing distortion of a visible light image. For example, as shown in FIG. 11 (a), the geomagnetism is not converted from a positive-shaped incident X-ray image XA into a positive-shaped visible light image Xa as shown in FIG. 11 (b). , Both the vertical and horizontal directions are converted into a visible light image Xb having a distortion distorted in an S shape. Therefore, in order to avoid distortion of the visible light image due to geomagnetism, a cylindrical magnetic shield 56 made of a ferromagnetic material is installed so as to surround the electron lens system 52 in the image tube 54 outside the image tube 54. Magnetic shielding. 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, the front surface of the input surface substrate 51, which is an X-ray incident surface, cannot be magnetically shielded in order to prevent a decrease in the X-ray intensity of the incident X-ray image. In addition, a window 57 made of titanium, glass or the like must be provided. Therefore, the geomagnetism applied 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 suppressed by the magnetic shield body 56 alone.

  Therefore, as shown in FIGS. 9 and 10, a distortion correction coil 58 that generates distortion correction magnetism that cancels distortion-induced magnetism of the visible light image, a power supply 59 that supplies a coil current, and the vicinity of the input surface substrate 51 are provided. A magnetic sensor 60 for detecting the geomagnetism and a power control unit 61 for controlling the power source 59 in accordance with the output signal of the magnetic sensor 60 are provided, and the coil current corresponding to the geomagnetism detected by the magnetic sensor 60 is applied to the distortion correction coil 58. The power source 59 is controlled by the power source controller 61 so that the coil current corresponding to the strength of the strain-induced magnetism is supplied from the power source 59 to the strain correction coil 58 to cancel the strain-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, for example, Patent Document 1).

  On the other hand, the visible light image generated on the output fluorescent screen 53 of the image tube 54 is captured by the TV camera 62 and converted into an electrical signal, and then used as an X-ray detection signal for acquiring an X-ray image corresponding to the incident X-ray image. Is output. In the subsequent stage of the TV camera 62, an X-ray image is acquired according to the X-ray detection signal and displayed on the screen of a display monitor (not shown).

On the other hand, in the case of a conventional X-ray image receiving apparatus, the range in which the visible X-ray image actually appears on the output phosphor screen 53 among the input surfaces of the incident X-ray image on the input surface substrate 51 of the image tube 54 is defined as needed. The effective visual field aperture can be changed. For example, assuming that the maximum effective field diameter set in the image tube 54 is 12 inches, the effective field diameter can be changed at any time between two effective field diameters, for example, 12 inches and 9 inches.
The smaller the effective field aperture, the higher the magnification of the visible light image on the output phosphor screen 53. Therefore, the final X-ray image magnification also increases when the effective field aperture is smaller. Therefore, the effective field aperture mode of the image tube 54 having a small diameter is usually referred to as an enlarged field mode.

JP-A-7-65756 (pages 3 to 4, FIGS. 1 to 4).

However, the conventional X-ray image receiving apparatus has a problem that the distortion-induced magnetism (geomagnetism) cancellation that causes distortion of the visible light image is not sufficient depending on the aperture size of the effective field aperture set in the image tube 54. .
As shown in FIG. 12, the strength of the distortion correction magnetism generated by the distortion correction coil 58 changes considerably from the center to the periphery of the input surface substrate 51, and the uniformity is weak compared to the geomagnetism to be canceled. The geomagnetism cannot be accurately canceled by the distortion correction magnetism generated by the distortion correction coil 58.

Normally, when the effective field diameter of the image tube 54 is set to the maximum effective field diameter that is frequently used, distortion correction magnetism is applied by the distortion correction coil 58 so that distortion is not conspicuous on a visible light image or an X-ray image. It is configured to generate. In this case, however, the magnification of the visible light image or the X-ray image increases when the mode is changed to the enlarged visual field mode, so that the distortion of the visible light image or the X-ray image becomes conspicuous.
On the contrary, when the effective field diameter of the image tube 54 is set to the effective field diameter of the expanded field mode, the distortion correction magnet 58 generates distortion correction magnetism so that the distortion is not conspicuous on the visible light image or the X-ray image. With this configuration, when the effective field diameter of the image tube 54 is set to the maximum effective field diameter that is frequently used, the visible light image and the X-ray image are greatly distorted at the periphery.

  The present invention has been made in view of such circumstances, and sufficiently cancels distortion-induced magnetism that causes distortion of a visible light image regardless of the aperture size of the effective field aperture set in the image tube. An object of the present invention is to provide an X-ray image receiving apparatus that can perform the above-described process.

In order to achieve the above object, the present invention has the following configuration.
In other words, the X-ray image receiving apparatus according to the first aspect of the present invention is reduced by 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 an electron lens system. A cylindrical magnet arranged in an image tube containing an output phosphor screen that converts the imaged photoelectron image into a visible light image and encloses the electron lens system in the image tube outside the image tube. It is wound around the outer periphery of the input surface substrate along the outer periphery of the shield body and the X-ray input surface of the image tube, and detects distortion-induced magnetism that distorts the photoelectron image and causes distortion of the visible light image. A magnetic detection means; a distortion correction coil for generating distortion correction magnetism that cancels the distortion-induced magnetism based on the detection result of the distortion-induced magnetism by the magnetic detection means; and an output phosphor screen of the input surface of the incident X-ray image on the input surface substrate In fact In an X-ray image receiving apparatus, comprising: a field aperture setting means for setting an effective field aperture that defines a range in which a visible light image appears to be changed between a plurality of effective field apertures having different predetermined aperture dimensions The coil current supply means for supplying the coil current for generating the distortion correction magnetism suitable for each effective field aperture for each effective field aperture to be supplied to the distortion correction coil according to the effective field aperture set in the image tube. The coil current supply means selects a coil current that generates distortion correction magnetism suitable for the effective field diameter set by the field diameter setting means and supplies the selected coil current to the distortion correction coil.

[Operation / Effect] When the incident X-ray image is picked up in the X-ray image receiving apparatus according to the first aspect of the present invention, the image tube generates a photoelectron image generated by the projection of the incident X-ray image onto the input surface substrate. However, as a result of reducing the image on the output phosphor screen while avoiding the influence of geomagnetism by magnetic shielding by the magnetic shield body, the photoelectron image reduced and imaged is converted into a visible light image on the output phosphor screen. In other words, the magnetic shield body serves as a magnetic shielding wall to prevent the geomagnetism as distortion-induced magnetism that distorts the photoelectron image from the peripheral side surface of the image tube and causes distortion of the visible light image.
In addition, in the X-ray image receiving apparatus according to the first aspect of the present invention, it is wound in such a manner as to surround the outer peripheral space of the input surface substrate along the outer peripheral edge of the X-ray input surface of the image tube in parallel with the imaging of the incident X-ray image. When the rotated distortion correction coil generates distortion correction magnetism, the geomagnetism is canceled 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, distortion of the photoelectron image is prevented, and distortion of the visible light image output to the output phosphor screen is suppressed.

On the other hand, in the case of the X-ray image receiving apparatus according to the first aspect of the present invention, a visible light image actually appears on the output fluorescent screen among the input surfaces of the incident X-ray image on the input surface substrate by the field aperture setting means. The effective field diameter of the image tube that defines the range can be changed between a plurality of effective field diameters having different predetermined diameter dimensions. The magnification of the visible light image on the output phosphor screen of the image tube changes with the change of the effective field aperture by the field aperture setting means.
On the other hand, in the X-ray image receiving apparatus according to the first aspect of the present invention, a coil current for generating a distortion correction magnetism suitable for each effective field aperture for each effective field aperture is supplied to the strain correction coil so as to be selectable for each effective field aperture. Coil current for generating distortion correction magnetism suitable for the effective field aperture set by the field aperture setting means when the supply field means is provided and the effective field aperture is changed by the field aperture setting unit Is selected and supplied to the distortion correction coil, so even if the aperture size of the effective field of view set in the image tube is changed, the distortion correction coil can accurately cancel the distortion-induced magnetism that causes distortion of the visible light image. it can.

  According to a second aspect of the present invention, in the X-ray image receiving apparatus according to the first aspect, the field aperture setting means changes the effective field aperture of the image tube by electrical control of the electron lens system. .

[Operation and Effect] In the case of the X-ray image receiving apparatus according to the second aspect of the present invention, the effective field diameter of the image tube can be easily changed because the effective field diameter can be changed by the electric field system. Can be changed.

  In the case of the X-ray image receiving apparatus according to the first aspect of the present invention, a cylinder disposed in parallel with the detection of the incident X-ray image by the image tube and surrounding the electron lens system in the image tube outside the image tube. In addition to preventing geomagnetism as distortion-induced magnetism that distorts the photoelectron image from the peripheral side of the image tube and causes distortion of the visible light image by the magnetic shield body in the form of a magnetic shield, the image tube The distortion correction coil wound around the outer periphery of the input surface substrate along the outer peripheral edge of the X-ray input surface generates distortion correction magnetism, which distorts the photoelectron image and distorts the visible light image. It is configured to cancel the geomagnetism from the X-ray input surface side as the strain-induced magnetism that causes the distortion, and the distortion of the photoelectron image is prevented, so that the distortion of the visible light image output to the output phosphor screen is suppressed, An effective field aperture of the image tube that prescribes the range in which the visible fluorescent image appears on the output phosphor screen of the input surface of the incident X-ray image on the input surface substrate by the field aperture setting means is determined in advance. Therefore, the magnification of the visible light image on the output fluorescent screen of the image tube can be changed.

In addition, in the case of the X-ray image receiving apparatus according to the first aspect of the present invention, a coil current for generating distortion correction magnetism suitable for each effective field diameter is supplied to the distortion correction coil so as to be selectable for each effective field diameter. In the case where the coil current supply means is provided and the effective field aperture is changed by the field aperture setting means, the coil current supply means generates distortion correction magnetism suitable for the effective field aperture set by the field aperture setting means. Since the coil current is selected and supplied to the distortion correction coil, even if the effective visual field aperture set in the image tube is changed, the distortion correction coil can accurately cancel the distortion-induced magnetism that causes the distortion of the visible light image. .
Therefore, according to the X-ray image receiving apparatus of the first aspect of the present invention, it is possible to sufficiently cancel the distortion-induced magnetism that causes the distortion of the visible light image regardless of the aperture size of the effective field aperture set in the image tube. it can.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an overall configuration diagram of an X-ray fluoroscopic apparatus in which an X-ray receiver (X-ray image receiving apparatus) according to an embodiment is incorporated, and FIG. 2 is an explanatory diagram illustrating the configuration of the X-ray receiver according to the embodiment. FIG. 4 is a plan view showing an arrangement state of a magnetic shield body and a distortion correction coil of the X-ray receiver according to the embodiment, and FIG. 4 is a perspective view showing an X-ray imaging system in the X-ray fluoroscopic apparatus.

  The X-ray fluoroscopic apparatus of FIG. 1 includes an X-ray tube 1 that irradiates a subject M placed on a top board BD with X-rays for X-ray fluoroscopy according to control by the X-ray irradiation control unit 10, and a subject M. An image intensifier type X-ray receiver 2 that captures a transmission X-ray image of the X-ray as an incident X-ray image, converts it into an electrical signal, and outputs it as an X-ray detection signal for X-ray fluoroscopy, and an X-ray receiver 2 Necessary for X-ray fluoroscopic images acquired by the fluoroscopic image acquisition unit 3 for acquiring X-ray fluoroscopic images based on X-ray detection signals for X-ray fluoroscopy output from A display monitor 4 for displaying an operation menu and the like, and an operation unit 5 for inputting data and commands necessary for fluoroscopic imaging are provided.

  As shown in FIGS. 2 and 3, an X-ray receiver 2 of the embodiment includes an input surface substrate 11 composed of a fluorescent screen such as CsI and a photocathode for outputting a photoelectron image corresponding to an incident X-ray image, and a photocathode. The electron lens system 12 for reducing the photoelectron image emitted from the photocathode of the input surface substrate 11 and the photoelectron image reduced and formed by the lens action of the electron lens system 12 are converted into a visible light image and output. A vacuum-sealed image tube 14 that houses the output phosphor screen 13 is housed in a metal outer container 15.

  In the case of the X-ray receiver 2 of the embodiment, in order to suppress the distortion of the visible light image on the output phosphor screen 13 as the photoelectron image is distorted due to the influence of geomagnetism (strain-induced magnetism), A cylindrical magnetic shield body 16 is installed to surround the electron lens system 12 on the outside of the image tube 14 for magnetic shielding. The magnetic shield body 16 is made of a ferromagnetic material such as permalloy, and the magnetic shield body 16 serves as a magnetic shielding wall to prevent geomagnetism as strain-induced magnetism from the peripheral side surface of the image tube 14. The magnetic shield body 16 is arranged to be inserted into the outer container 15 with the inner peripheral surface of the outer container 15 and the outer peripheral surface of the magnetic shield body 16 in contact with each other.

  When an incident X-ray image is taken by the X-ray receiver 2 of the embodiment, the electron lens system 12 converts the photoelectron image generated by the projection of the incident X-ray image onto the input surface substrate 11 of the image tube 14 into a magnetic shield. While the magnetic shielding wall by the body 16 avoids the influence of geomagnetism, the reduced fluorescent image is formed on the output fluorescent screen 13, and the reduced focused photoelectron image is converted into a visible light image on the output fluorescent screen 13. The The visible light image generated on the output fluorescent screen 13 of the image tube 14 is captured by the TV camera 19 and converted into an electrical signal, and then output as an X-ray detection signal.

  However, in the case of the image tube 14, as shown in FIG. 2, the magnetic shield body 16 is not provided on the front surface of the input surface substrate 11 which 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 magnetic shield 16, and the X-ray detection sensitivity decreases. Therefore, the front surface of the input surface substrate 11 cannot be magnetically shielded with a ferromagnetic metal, and a window 17 made of aluminum, titanium, glass or the like must be provided on the X-ray incident surface. Therefore, the geomagnetism applied from the window 17 of the image tube 14 cannot be prevented by the magnetic shield body 16, and the distortion of the visible light image due to the geomagnetism cannot be suppressed by the magnetic shield body 16 alone.

  Therefore, in the X-ray receiver 2 of the embodiment, as shown in FIGS. 2 and 3, a magnetic sensor (magnetic detection means) 20 for detecting the strength and direction of the terrestrial magnetism in the vicinity of the input surface substrate 11, and an image tube 14 is wound around the outer peripheral space of the input surface substrate 11 along the outer peripheral edge of the window 17 which is the X-ray input surface 14, and the photoelectron image is distorted based on the detection result of the distortion-induced magnetism by the magnetic sensor 20. A distortion correction coil 18 that generates distortion correction magnetism that cancels distortion-induced magnetism that causes distortion of a visible light image is provided, and distortion is induced by flowing a coil current that matches the strength of distortion-induced magnetism through the distortion correction coil 18. It is configured to cancel the magnetism. The number of turns (number of turns) of the distortion correction coil 18 is not limited to a specific number of turns, but is exemplified by 800 to 1000 turns.

  That is, simultaneously with the imaging of the incident X-ray image, the distortion correction coil 18 generates distortion correction magnetism, thereby distorting the photoelectron image and causing distortion of the visible light image from the X-ray input surface side. Since the geomagnetism is cancelled, the distortion of the photoelectron image is prevented, so that the distortion of the visible light image output to the output phosphor screen 13 is suppressed.

On the other hand, in the case of the X-ray receiver 2, as shown in FIG. 2, a visible light image actually appears on the output fluorescent screen 13 out of the input surface of the incident X-ray image on the input surface substrate 11 of the image tube 14. A visual field aperture setting mechanism 21 is provided for setting the effective visual field aperture of the image tube 14 that defines the range so that it can be changed at any time among a plurality of effective visual field apertures having different predetermined aperture dimensions.
The aperture size and number of a plurality of effective field apertures that can be set in the image tube 14 are not limited to a specific size or number. However, for the sake of convenience, the maximum effective field aperture set in the image tube 14 will be described below. It is assumed that the effective field diameter can be changed at any time between the large and small effective field diameters of 12 inches and the small diameter of 9 inches by the visual field diameter setting mechanism 21. The smaller the effective field aperture, the higher the magnification of the visible light image on the output phosphor screen 13, so the final X-ray fluoroscopic image magnification also increases with a smaller effective field aperture. In the following, as shown in FIG. 3, the setting mode of the large-diameter 12-inch effective field aperture 14a, which is frequently used, is referred to as the standard viewing mode, and the small-diameter 9-inch effective field aperture 14b is set with a high image magnification. The mode is referred to as an enlarged view mode.

  In the case of the X-ray receiver 2 of the apparatus of the embodiment, a field-of-view mode designation signal corresponding to the designated field-of-view mode is generated when either the standard field-of-view mode or the enlarged field-of-view mode is designated by the operation unit 5. A field-of-view mode control unit 22 for outputting and a lens electrode power source 23 for applying a voltage to the electrodes of the electron lens system 12 are provided, and the lens electrode power source 23 is controlled according to a field-of-view mode designation signal output from the field-of-view mode control unit 22. By changing the voltage applied to the electrode of the electron lens system 12, the effective field diameter is changed between the standard field mode and the enlarged field mode. That is, the visual field aperture setting mechanism 21 is mainly configured by the visual field mode control unit 22 and the lens electrode power source 23, and the electrical control that the change of the effective visual field aperture changes the voltage applied to the electrodes of the electron lens system 12. Easy to do.

  On the other hand, in the case of the X-ray receiver 2 of the embodiment, as shown in FIG. 2, the coil current that generates the distortion correction magnetism suitable for each effective field aperture is set for each effective field aperture set by the image tube 14. A coil current supply unit 24 that is supplied to the distortion correction coil 18 so as to be selectable every time, and the coil current supply unit 24 generates a distortion correction magnetism suitable for the effective field aperture set by the field aperture setting mechanism 21. Since the feature is that the current is selected and supplied to the distortion correction coil 18, this point will be described in detail below.

  The coil current supply unit 24 selects a coil current that generates a distortion-corrected magnetism suitable for the 12-inch effective field aperture 14a that is the standard field-of-view mode of the image tube 14 in accordance with a distortion-induced magnetism detection signal from the magnetic sensor 20 and performs distortion. In accordance with a standard visual field mode current supply unit 24A supplied to the correction coil 18 and a detection signal of distortion-induced magnetism by the magnetic sensor 20, a distortion correction magnetism suitable for the 9-inch effective visual field aperture 14b which is an enlarged visual field mode of the image tube 14 is generated. The field-of-view mode current supply unit 24B that selects a coil current to be supplied and supplies the selected coil current to the distortion correction coil 18, and the output of the magnetic sensor 20 is expanded to a standard field-of-view mode current supply unit 24A according to the field-of-view mode specified by the field-of-view mode designation signal Switching to selectively connect to either one of the visual field mode current supply units 24B And it has a switch section 24C.

In the case of the coil current supply unit 24, when the standard visual field mode is designated, the contact of the changeover switch unit 24C is in a connection state indicated by a solid line, and the output of the magnetic sensor 20 is connected to the standard visual field mode current supply unit 24A. At the same time, when the standard visual field mode current supply unit 24A supplies the coil current to the distortion correction coil 18 and the enlarged visual field mode is designated, the contact of the changeover switch unit 24C is in the connection state indicated by the alternate long and short dash line. Are connected to the enlarged visual field mode current supply unit 24B, and the enlarged visual field mode current supply unit 24B supplies a coil current to the distortion correction coil 18.
In the case of the standard visual field mode current supply unit 24A and the enlarged visual field mode current supply unit 24B, the distortion is corrected by an open loop method. However, the standard visual field mode current supply unit 24A and the enlarged visual field mode current supply unit 24B A configuration in which distortion correction is performed by a feedback method may be used.

  More specifically, in the case of the standard visual field mode current supply unit 24A, a 12-inch effective visual field aperture set by the image tube 14 as shown in FIG. As shown in FIG. 6, an incident X-ray image YA of + shape projected on 14a appears as an approximately + visible light image Ya on the output phosphor screen 13, and a coil current that generates distortion correction magnetism is used as a distortion correction coil. 18, the amplification degree and the polarity of the coil current for the strain-induced magnetism detection signal by the magnetic sensor 20 are adjusted and set in advance. In other words, the visible light image Ya with a small apparent distortion is obtained at the 12-inch effective field aperture 14a by performing excessive correction by the magnetic field distribution of FIG. 12 generated by the correction coil 18. A visible light image ya without distortion correction by the distortion correction coil 18 is shown in FIG. 6 by a broken line for comparison.

In the case of the enlarged visual field mode current supply unit 24B, the detection signal of the distortion-induced magnetism by the magnetic sensor 20 is used as an input signal and projected onto the 9 inch effective visual field aperture 14b set in the image tube 14 as shown in FIG. The incident X-ray image YB in the form of FIG. 8 is supplied to the distortion correction coil 18 with a coil current for generating distortion correction magnetism that appears on the output phosphor screen 13 as a positive visible light image Yb as shown in FIG. The amplification degree and the polarity of the coil current for the detection signal of the strain-induced magnetism by the magnetic sensor 20 are adjusted and set in advance.
A visible light image Ya at the time of distortion correction by the standard visual field mode current supply unit 24A is shown by a broken line in FIG. 8 for comparison.

  In the distortion correction by the standard visual field mode current supply unit 24A, as shown in FIGS. 6 and 8, the overall distortion of the area of the 12-inch effective visual field aperture 14a is suppressed, but the area of the 9-inch effective visual field aperture is Distortion cannot be suppressed exactly. However, if the distortion correction is performed by the enlarged visual field mode current supply unit 24B, as shown in FIG. 8, the distortion in the area of the 9-inch effective visual field aperture 14b can be suppressed. In the case of the enlarged visual field mode current supply unit 24B, it is difficult to suppress distortion in an area exceeding the 9-inch effective visual field aperture 14b, but in the enlarged visual mode, the area exceeding the 9-inch effective visual field aperture 14b is not used. There is no problem because it is an area.

In the case of the X-ray fluoroscopic apparatus shown in FIG. 1, the main part of the X-ray tube 1 and the X-ray receiver 2 (centering on the image tube 14 and the TV camera 19) is a ceiling traveling type C as shown in FIG. The mold arm 6 is attached to one end and the other end of the mold arm 6 so as to face each other with the subject M interposed therebetween, and the C-arm 6 rotates around the rotation shaft 7 provided in the center of the back surface of the C-arm 6. As a result, the main parts of the X-ray tube 1 and the X-ray receiver 2 are rotated in the direction indicated by the arrow 8 while the C-arm 6 is rotated along the arc of the C-arm 6 while the main portions of the X-ray tube 1 and the X-ray receiver 2 are opposed. As the predetermined range is slid, the X-ray tube 1 and the X-ray receiver 2 are moved in the direction indicated by the arrow 9 while being opposed to each other, and the X-ray fluoroscopic direction is changed. Yes.
Further, when the X-ray tube 1 and the main part of the X-ray receiver 2 move as the C-arm 6 rotates and the X-ray fluoroscopic direction changes, the effective strength of the strain-induced magnetism applied from the window of the image tube 14 However, since the fluctuation is reflected in the intensity of the detection signal of the magnetic sensor 20, even if the fluoroscopic direction changes, the distortion correction function of the distortion correction coil 18 is inhibited. There is no.

  The main control unit 25 is mainly composed of a computer (CPU) and its operation program. An appropriate command signal is input according to the input of data and commands from the operation unit 5 or the progress of fluoroscopy. It performs a general control function to send data and data in a timely manner and always operate the entire device appropriately.

  As described in detail above, in the case of the X-ray receiver 2 of the embodiment, the magnetic shield body 16 becomes a magnetic shielding wall in parallel with the detection of the incident X-ray image by the image tube 14, and the peripheral side surface of the image tube 14. In addition to preventing geomagnetism as distortion-induced magnetism that distorts the photoelectron image and causes distortion of the visible light image, the distortion correction coil 18 generates distortion correction magnetism to cause distortion-induced magnetism on the X-ray input surface side. Therefore, since the distortion of the photoelectron image is suppressed, the distortion of the visible light image output to the output phosphor screen 13 is suppressed, and the field aperture setting mechanism 21 allows the input surface substrate 11 to be corrected. Among the input surfaces of the incident X-ray image, the effective visual field aperture of the image tube 14 that defines the range that actually appears as a visible light image on the output fluorescent screen 13 is a plurality of different aperture sizes. Since the configuration can be changed between the effective field diameter, it is possible to change the magnification of the visible light image at the output phosphor screen 13 of the image tube 14.

In addition, in the case of the X-ray receiver 2 of the embodiment, the coil current that generates the distortion correction magnetism suitable for each effective field aperture for each effective field aperture set in the image tube 14 can be selected for each effective field aperture. When the effective current aperture is changed by the visual field aperture setting mechanism 21 provided with the coil current supply unit 24 that supplies the correction coil, the effective visual field aperture set by the visual field aperture setting mechanism 21 is set by the coil current supply unit 24. Is selected and supplied to the distortion correction coil 18, so that even if the effective visual field aperture set in the image tube 14 is changed, the distortion correction coil 18 distorts the visible light image. It is possible to accurately cancel the strain-induced magnetism that causes
Therefore, according to the X-ray receiver 2 of the embodiment, the distortion-induced magnetism that causes distortion of the visible light image can be sufficiently canceled regardless of the aperture size of the effective field aperture set in the image tube 14. .

The present invention is not limited to the above embodiment, and can be modified as follows.
(1) In the case of the X-ray receiver 2 in the apparatus of the embodiment, the installation position of the magnetic sensor 20 is in the vicinity of the outer edge on the front surface (input surface) side of the image tube 14, but the installation position of the magnetic sensor 20 is For example, the magnetic sensor 20 may be installed on the side (side peripheral surface) of the image tube 14.

(2) In the case of the X-ray receiver 2 in the apparatus of the embodiment, the lens electrode power source 23 is provided side by side with the image tube 14, but the lens electrode power source 23 is provided separately from the image tube 14. There may be.
In the case of the X-ray receiver 2 in the apparatus of the embodiment, the visual field mode control unit 22 is arranged on the control console side separately from the image tube 14, but the visual field mode control unit 22 is provided in the image tube 14. It may be.

  (3) In the case of the embodiment, the X-ray receiver 2 is configured to be applied to the overhead traveling C-arm 6 as shown in FIG. The present invention can also be applied to a stationary C-arm incorporated in an X-ray imaging table.

  (4) In the case of the embodiment, the X-ray image receiving apparatus of the present invention is used in an X-ray fluoroscopic apparatus, but the X-ray image receiving apparatus of the present invention may be applied to an X-ray imaging apparatus other than the X-ray fluoroscopic apparatus. it can.

1 is an overall configuration diagram of an X-ray fluoroscopic apparatus in which an X-ray receiver of an embodiment is incorporated. It is explanatory drawing which shows the structure of the X-ray receiver of an Example. It is a top view which shows the arrangement | positioning condition of the magnetic shield body and distortion correction coil of the X-ray receiver of an Example. It is a perspective view which shows the X-ray imaging system in a X-ray fluoroscope. It is a schematic diagram which shows an example of the incident X-ray image in the standard visual field mode of the X-ray receiver of an Example. It is a schematic diagram which shows an example of the visible light image in the standard visual field mode of the X-ray receiver of an Example. It is a schematic diagram which shows an example of the incident X-ray image in the expansion visual field mode of the X-ray receiver of an Example. It is a schematic diagram which shows an example of the visible light image in the expansion visual field mode of the X-ray receiver of an Example. It is a whole block diagram of the conventional X-ray receiver. It is a top view which shows the arrangement | positioning condition of the magnetic shield body and distortion correction coil in the conventional X-ray receiver. It is a schematic diagram which shows an example of the incident X-ray image and visible light image in the conventional X-ray receiver. It is a magnetic intensity display chart which shows the application condition of the distortion correction magnetism by the distortion correction coil in the periphery vicinity of the input surface board | substrate of a X-ray receiver.

Explanation of symbols

2 ... X-ray receiver (X-ray receiver)
DESCRIPTION OF SYMBOLS 11 ... Input surface board | substrate 12 ... Electron lens system 13 ... Output fluorescent screen 14 ... Image tube 14a ... 12-inch effective visual field aperture (effective visual field aperture)
14b: 9 inch effective field aperture (effective field aperture)
16 ... Magnetic shield 18 ... Distortion correction coil 20 ... Magnetic sensor 21 ... Field size setting mechanism (field size setting means)
24 ... Coil current supply section (coil current supply means)
YA, YB ... Incident X-ray image Ya, Yb ... 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 and forming the photoelectron image, and an output phosphor screen for converting and outputting the photoelectron image reduced and imaged by the electron lens system to a visible light image; An image tube containing a tube, a cylindrical magnetic shield disposed around the electron lens system inside the image tube, and a photoelectron image that distorts the visible light image. Based on the detection result of the strain-induced magnetism by the magnetic detection means for detecting the strain-induced magnetism and 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 A distortion correction coil that generates distortion correction magnetism that cancels out the strain-induced magnetism, and an effective field of view that defines a range in which an actual visible light image appears on the output phosphor screen of the input surface of the incident X-ray image on the input surface substrate Caliber In an X-ray image receiving apparatus having a field aperture setting means that can be changed between a plurality of effective field apertures having different predetermined aperture sizes, each effective field aperture is set for each effective field aperture set in the image tube. A coil current supply means for supplying a coil current for generating a distortion correction magnetism suitable for each effective field aperture to the strain correction coil is provided, and the coil current supply means is set by the field aperture setting means. An X-ray image receiving apparatus comprising: selecting a coil current that generates distortion-corrected magnetism suitable for the above-mentioned and supplying the selected coil current to the distortion-correcting coil. 2. The X-ray image receiving apparatus according to claim 1, wherein the field aperture setting means changes the effective field aperture of the image tube by electrical control of an electron lens system.

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