JPS6180097A - One-dimensional x-ray fluorescent screen element - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a fluorescent surface element that converts a one-dimensional X-ray image into a light image.

[Technical background of the invention]

For X-ray images in the medical field, images with a two-dimensional spread are usually used, but contrast can be improved by reducing X-ray image scattering by the subject C2 and scattering of X-rays and their light within the image receiving element. In order to obtain good images, a photographing system that extends in the -dimensional direction may be used.

In these systems, particle fluorophores such as dolinicum oxysulfide fluorophore particles are conventionally hardened into a sheet with a binder to form an X-ray fluorophore surface.

Further, as an input phosphor surface of the X-ray image tube, a sesicum iodide phosphor is vacuum-deposited on an aluminum substrate to serve as the input phosphor surface.

[Problems with background technology]

As mentioned above, in the case of an X-ray fluorescent surface made of particle phosphors hardened with a binder and made into a sheet, if the sheet is made thicker to improve XvA absorption, the resolution will deteriorate significantly, and if the sheet is made thinner to increase the resolution, the X There is a relationship in which linear absorption is poor and the S/C ratio is significantly lowered.

On the other hand, when a cesium iodide fluorescent surface is deposited on an aluminum substrate, columnar crystals are obtained with good resolution, but the cesium iodide fluorescent surface is extremely hygroscopic and requires a moisture-proof cover. , this cover has the disadvantage that by blocking light, the contrast is significantly reduced due to the reflection of light on the cover.

Furthermore, when used as an input fluorescent surface of an X-ray image tube, the unevenness of the surface makes it difficult to form a uniform photocathode and reduces the sensitivity of the photocathode.

[Object of the Invention] - The object of the present invention is to improve the above-mentioned drawbacks and to obtain a one-dimensional X-ray phosphor element with high resolution and a good S/R ratio.

[Summary of the invention]

The present invention provides an optical fiber plate in which a large number of optical fibers each consisting of a core and a cladding part are bundled and solidified so as to extend in the lateral direction; an exposed core part formed on the light introduction side of the optical fiber plate; The one-dimensional X-ray phosphor element includes a columnar crystal mainly composed of cesium iodide formed to prevent a core, and has a long side direction of the optical fiber plate as a one-dimensional direction, and has high resolution and 8/8 An improvement in the N ratio can be obtained.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be described with reference to FIGS. 1 to 3.

Note that common parts are given common symbols.

The optical fiber used in this embodiment may be made of glass or plastic, but a glass optical fiber will be described.

As shown in Fig. 1, the -dimensional X-ray fluorophore element consists of a rectangular support frame (1), an optical fiber plate (2), a columnar crystal whose main component is cecium iodide (3), and a cover (
4).

The rectangular support frame (1) accommodates and supports therein an optical fiber (2) which is formed by bundling optical fibers consisting of a core portion 4 and a cladding portion and solidifying them so as to extend in the lateral direction. The X-ray source side of the plate (2) has a structure that slightly protrudes from the support frame (1), and the protruding lower cladding part of the optical fiber plate (2) has been removed to expose the core member. A columnar crystal (3) whose main component is cesium iodide is formed in the part t2e, and the light emitted from this columnar crystal (3) passes through the core part OE9 and moves from the left to the right in FIG. be guided towards However, the surface of the columnar crystal (3) is covered with an aluminum reflective film (
5). Further, in order to shield the columnar crystal (3) from external light and prevent moisture absorption, a cover (4) is also provided which is fixed to the support frame (1) so as to cover the columnar crystal (3).

The one-dimensional X-ray phosphor element thus constructed is incorporated into a projection system as shown in FIG.

The imaging system shown in Fig. 6 consists of a fan beam X projected from an X-ray source (62) through an X-ray slit (68).
The ray (66) passes through the object (63) and enters the one-dimensional X-ray fluorescent element (61), where it is converted into light that diverges in all directions by the columnar crystal (3) shown in Figure 1. The light is collected toward the core part (c) by the reflective film (5), and is emitted from the surface of the core part (to) opposite to the surface on which the phosphor II (31) is arranged. 67) is formed into a two-stage image sensor (65) by a lens (64), and an image is captured.

The manufacturing method of the above-mentioned one-dimensional X-ray fluorescent surface element (I will explain it in two steps. First, one side of the positive fiber plate (2) extending in the -dimensional direction is coated with photoresist, and light is irradiated from the opposite side. Burn the photoresist on the top of the core of the glass fiber plate (2).Next, wash off the unburned part of the photoresist, that is, the photoresist that is double coated on top of the cladding, and wash it with concentrated acid. Next, the photoresist baked on the core part Ce is scraped off.Then, the core part (e) protrudes from the cladding part (5) or the optical fiber plate (2) as shown in Fig. 2. A cesium iodide phosphor is deposited on this surface by vacuum FMN method.

When the cesium iodide phosphor is vacuum-deposited, columnar crystals grow in the projection portion 1; therefore, even if the columnar crystals grow sufficiently long, they will not coalesce with adjacent columnar crystals.

Therefore, the light emitted from x W c within the columnar crystal is confined within the columnar crystal and guided to the core portion (5). As a result, light usage efficiency increases and resolution deterioration is prevented. The contact surface between the core part and the columnar crystal (3) is flat and perpendicular to the columnar crystal (3), so light can efficiently pass through the columnar crystal (3).
) leads to the core (to). Also columnar crystals (3)
A reflective film (5) is formed on the surface of the reflective film (5) by thinly depositing aluminum. Due to this reflection [ikr (5) l2, the light emitted from the columnar crystal (3) in directions other than the core part @ is reflected back into the columnar crystal (3), increasing the efficiency of the light reaching the core part (a). At the same time, light leakage to the adjacent columnar crystals (3) is prevented to more reliably prevent a decrease in resolution. In addition, even if the fluorescent surface made of columnar crystals containing cesium iodide as its main component is sufficiently thick, a surface with no deterioration in resolution can be obtained. A light surface is obtained. The absolute value of resolution is determined by the size of the columnar crystal (3), and the size of the columnar crystal is determined by the size of the core portion. The core portion (a) can be made large or small as required, and usually has a diameter of several microns to several hundred microns, and in this example, it is 200 microns. Therefore, the resolution is 2.
It became 51pA4m. Columnar crystals of cesium iodide are highly hygroscopic, and if they absorb moisture, they will no longer emit light and the crystals will collapse, so a cover (4) is attached to the interior (I) to prevent moisture by letting dry air in. The cover (4) is made of thin plastic so as not to attenuate the X-rays. Next, another embodiment will be described with reference to FIGS. 4 to 6.

This upward one-dimensional X-ray fluorescent element (61) is arranged as shown in Figure 6, and the X-ray tube (
A two-dimensional image is formed by moving the -dimensional fluorescent element (62) and the -dimensional fluorescent element (61) relative to the subject (63). In this case, since the subject (63) is a human body, the gap between the X-ray tube (62) and the -dimensional X-ray fluorescent element (61) is approximately 1 crFL, which is a large device 1; It is very difficult to scan the position of the beam (66) with an accuracy of less than o,its, and the xl fan beam (
66) is irradiated onto the -dimensional X-ray fluorescent element (61). Therefore, the position at which the -dimensional X-ray fluorescent element (61) is irradiated is shifted. Therefore, -dimensional X-ray fluorescent element (61)
As shown in FIG. 4, this can be easily solved by expanding the irradiation position in the direction of deviation. In other words, in FIG. Columnar crystal (3) 1 reflection m f5), cover (4
), the cross section of the core rock and the columnar crystal (3) is made flat (for example, 200μ x 1000μ).

By doing this again, it is possible to have a deviation of 800μ. Therefore, the configuration of the device is greatly simplified and the economical effect is large.

Next, still another embodiment will be described with reference to FIG.

As shown in FIG. 6, the one-dimensional X-ray fluorescent surface element (61)
The incident X is irradiated by the line fan beam (66)
The focus of @ is on the X-ray tube (62), and it is irradiated from that point through the X-ray slit (6g) in a fan shape.

Therefore, the direction of incidence of X-rays on the -dimensional X-ray fluorophore element (61) differs from its position (two directions). As the X-rays pass through adjacent columnar crystals (3), the emission point of one X-ray spreads and the resolution deteriorates.Therefore, the growth direction of the columnar crystals (3) is tilted to the incident direction of the X-rays ( Therefore, 1: When vacuum evaporating a cesium iodide phosphor, the purpose can be achieved by placing the evaporation source obliquely to the evaporation surface I. The required inclination of the columnar crystals is Since it is symmetrical with respect to the center of the one-dimensional X-ray fluorophore, it is possible to obtain the evaporation source by concentrating the evaporation source in two directions perpendicular to the center of the one-dimensional X-ray fluorophore.In this way, the resolution can be improved. A one-dimensional fluorescent surface element with excellent properties can be obtained.

Further: As another embodiment, in order to further intensify the optical image conversion of this -dimensional X-ray image, these -dimensional X-ray fluorescent surface elements are used as the input surface of an image tube and an optical fiber is used. A photocathode is formed on the side surface to constitute a close focusing type image tube. In this way, a one-dimensional X-ray fluorescent surface element with significantly improved ζ-sensitivity can be obtained. Due to the strength of the vacuum container, a large two-dimensional image tube would be very expensive, but one-dimensional image tubes do not have this limitation and can easily be made long.

〔Effect of the invention〕

In this way, it is possible to obtain a one-dimensional X-ray fluorescent surface that does not easily deteriorate resolution even with a thick film, so that it has good X-ray absorption efficiency, that is, S
An excellent primary X-ray fluorophore element with good C and resolution can be obtained, and an extremely C2 excellent X-ray imaging device can be provided.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing a one-dimensional X-ray fluorescent surface element according to an embodiment of the present invention, FIG. 2 is a sectional view taken along line A-A in FIG. 1, and FIG. 4 is a sectional view showing another embodiment of the present invention; FIG. 5 is a sectional view taken along line C-C in FIG. 4; FIG. 6 is a conceptual diagram explaining how to use the element of the present invention. 1... Support frame 2... Optical fiber plate 26... Core part γ... Clad part 3... Cesium iodide columnar crystal 5... Reflective film 4... Cover 62...
X-ray tube 64... Lens 65... Optical imaging element 68... X-ray slit agent Patent attorney
Noriyuki Chika (Ii) SoA) Fig. 1 Fig. 2 Fig. 8 Fig. 4 Fig. 5 SL. Figure 6

Claims (4)

[Claims] (1) An optical fiber plate formed by bundling and solidifying a large number of optical fibers consisting of a core part and a cladding part so as to extend in the lateral direction; an exposed core part formed on the light introduction side of the optical fiber plate; 1. A one-dimensional X-ray phosphor element comprising a columnar crystal mainly composed of cesium iodide formed on an exposed core portion, the one-dimensional direction being the long side direction of the optical fiber plate. (2) A one-dimensional X-ray fluorophore element according to claim 1, characterized in that the core portion has a flat cross-section and is arranged so that its minor axis coincides with a one-dimensional direction. . (3) The one-dimensional X-ray fluorescent surface element according to any one of claims 1 to 2, wherein the columnar crystal has a light reflecting layer or a light blocking layer on the uppermost layer. (4) The primary crystal according to any one of claims 1 to 4, wherein the columnar crystal is formed so that the growth direction is inclined from the center of the columnar crystal array to a single point in the vertical direction. Original X-ray fluorescent surface element.