JPS5823624B2 - Radiographic image creation method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a radiation image creation method using an exoelectron emission image generated when radiation such as X-rays (hereinafter simply referred to as X-rays) is irradiated.

Conventional methods for obtaining radiographic images include exposing a widely used silver halide emulsion film (hereinafter referred to as film) to display changes in the blackening density of reduced silver particles in the silver halide emulsion; Examples include xeroradiography, which utilizes the X-ray sensitivity of a conductor, and ionography, which utilizes ionization development of a gas or insulating liquid sealed between electrodes placed opposite each other.

When photographing with silver halide film, the silver halide film is placed behind the subject and X-rays are irradiated from the opposite side (in front of the subject), then the exposed silver halide film is moved to the developing room and developed in a dark room. It's a method.

This is simple, requiring only an X-ray source when taking pictures and no other special equipment; however, it is complicated, requires a long processing time, and may cause problems as it requires chemical processing in the developing and fixing steps. There are disadvantages such as the generation of waste liquid containing harmful substances.

Additionally, this method is generally suitable for skeletal or hard tissue areas such as the head, thorax, hands, and feet;
This method was not very suitable for photographing soft tissues such as the intestines.

On the other hand, xeroradiography and ionography obtain an X-ray image of the subject as an electrostatic latent image, so when this latent image is developed, the edge effect, which is well known in electrophotography, occurs in low-contrast areas such as soft tissue. It is possible to obtain images with good discrimination.

However, xeroradiography generally has low sensitivity due to the low photon efficiency of the photoconductor, which goes against the request to reduce radiation exposure, and the surface of the photoconductor must be charged prior to imaging, so This method has the disadvantage that it is necessary to take pictures before the dark attenuation becomes large.

In addition, ionography is based on the drift of ion pairs towards the electrodes, which occurs when the gas existing between electrodes arranged opposite each other with a gap absorbs X-rays, and if the gap distance is large, secondary electrons The resolution may decrease due to scattering, or if the scattering is caused by gas, the device becomes bulky in order to maintain airtightness, or if the scattering is made by an insulating liquid, it is necessary to maintain stable insulation. It is not something that can be photographed easily because it requires charging beforehand.

The present invention was made in view of the above circumstances, and it has high resolution and sensitivity, and can be easily photographed like a silver halide film, and can easily visualize X-ray images anytime and anywhere with a heating device or light irradiation device. The purpose of the present invention is to provide an X-ray image creation method that can be used for printing, and offset printing can also be performed if necessary.

The present invention will be explained below.

First, the exoelectron emission phenomenon used in the present invention will be briefly explained.

Mechanical processing such as solid polishing and plastic deformation, radiation irradiation,
Due to chemical reactions on the solid surface, a few eV away from the solid surface.
The following low energy electron emission occurs.

This phenomenon is called exoelectron emission.
This electron emission (abbreviated as EEE) attenuates over time after surface treatment or irradiation of the solid, but even after it has completely attenuated, electron emission can occur again due to stimulation such as light irradiation or heating. occurs.

The former is external emission caused by optical stimulation.
stimulated exoemission (08EE)
ally・stimulated exoemis
sion (abbreviated as TSEE).

As explained above, the present invention utilizes the storage/readout characteristics of solid surface processing and radiation irradiation.

We will also briefly discuss the reversible redox coloring reaction of electrochromic materials that visualizes the emitted electron image.

For example, when an aqueous solution of a viologen compound, which is an electrochromic substance, is sealed between two electrodes and a voltage is applied between the two electrodes, the viologen ions near the cathode develop a blue color and a thin dye layer is formed on the cathode surface.

This reaction is explained as follows.

That is, viologen is dissociated into a siccation and a z>D gen anion in an aqueous solution, and when a potential difference is applied between the electrodes, the viologen scation is attracted to the cathode and receives and removes electrons on the surface of the cathode, producing a blue radical cation.

Then, due to the hydrophobicity of the alkyl group R, it becomes instantaneously insoluble in water and precipitates on the surface of the cathode in the form of a dark brown film.

On this cathode surface, the part where the dye layer is not deposited is hydrophilic, but the part of the dye layer is lipophilic.

The dye layer can be erased by applying a voltage of opposite polarity between the electrodes or by short-circuiting both electrodes.

That is, the viologen ions release electrons to the cathode and return to a colorless state, thus eliminating the reddish-brown color.

The present invention utilizes these phenomena to create an X-ray image that does not require the application of voltage, can be easily visualized anytime and anywhere after X-ray irradiation, and can offset print X-ray images as needed.
Line image creation ability.

Next, the present invention will be explained in detail using the drawings.

As shown in FIG. 1, an exoelectron emitting material 2 is placed on a substrate 1.
A subject 5 is placed between a radiation source 4 and an exoelectron emitting member 3 laminated with X-rays.

As the exoelectron emitting material 2, beryllium oxide with a trace amount of lithium or sodium added is effective.

For example, for beryllium oxide raw materials with a purity of 99% or more,
Add and mix 5 mol/s of lithium compound or sodium compound.

The lithium compound or sodium compound may be a sulfate, a hydrochloride, a nitrate or the like.

Mixing may be carried out wet or dry, but wet mixing is preferable since uniform mixing is possible.

The compound thus obtained is calcined at a temperature of 1200-1800'C for one hour or more.

At this time, air or 02 gas is flowed into the furnace to maintain an oxidizing atmosphere.

After baking, let it cool naturally and take it out. The fired product is in the form of a white powder or a white ceramic depending on the type of compound, and the latter is pulverized into a fine powder.

The exoelectron emitting substance is Bed; Li or Bed:
Not limited to Na, La 804 e B a 804 +
Any material that exhibits an exoelectron emission phenomenon such as LiF may be used.

The exoelectron emitting member 3 used in the present invention is made by coating the above-mentioned fine powder mixed with a conductive binder such as carbon paste or Alpaste on a suitable substrate 1 such as aluminum or Bakelite.

The exoelectron emitting member 3 that has been irradiated with X-rays is taken out, and an electrochromic substance 4 is applied while irradiating the exoelectron emitting member 3 with light, as shown in FIG. The member 3 is irradiated with light using the light irradiation device 1.

Figure 5 shows the number of exoelectron counts per unit time as a function of light irradiation time.As can be seen from Figure 5, it is almost constant within 3 minutes of light irradiation time, and thereafter. Therefore, especially when used for creating X-ray images as in the present invention, it is desirable to stimulate with strong light such as a laser beam and emit exoelectrons in a short period of time.

When intense light is irradiated in this way, exoelectrons are emitted from the surface of the exoelectron-emitting material 2 according to the amount of X-ray irradiation.
The reaction as described above occurs in the electrochromic material 6, and a dye layer 8 is deposited on the surface of the exoelectron emitting material 2.

An X-ray image can be obtained simply by coating the electrochromic substance 6 on the surface of the exoelectron emitting member 3 that has been irradiated with X-rays in this manner and irradiating the exoelectron emitting member with light.

To transfer this image to paper or other final imaging material,
Dampening water 9 is further applied to the exoelectron emitting member 3 visualized with the electrochromic substance 6.

As explained above, the parts that are not visualized are hydrophilic, so the dampening solution 9 adheres to them.

Next, when the offset ink 10 is applied, the pigment layer visualized by the electrochromic substance 4 is lipophilic, so the offset ink 10 adheres to the image (
Figure 3).

The image created by this offset ink 10 is transferred to a normal rubber cylinder 1.
1 and then transferred to a final image forming member 13 such as paper by the action of impression cylinder 12 (FIG. 4).

In order to improve the exoelectron emission efficiency of the present invention, the substrate 1 may be made conductive, coated with the electrochromic substance 6, a transparent electrode may be stacked on top, and the transparent electrode side may be used as an anode to apply voltage and irradiate light. .

This voltage may be as low as several volts, and no holding power is required for display.

When erasing an image, this voltage may be applied with the opposite polarity.

The present invention has been described in detail above, and after irradiating the exoelectron emitting member 3 in which the exoelectron emitting substance 2 is laminated on the substrate 1 with X-rays through the subject 5, the surface of the exoelectron emitting member 3 is By applying electrochromic material to the surface and irradiating it with light, both resolution and sensitivity were increased, and
After X-ray irradiation, the exoelectron-emitting member can be carried freely, and the X-ray image can be visualized simply by coating an electrochromic substance while irradiating it with light in a place where there is a light irradiation device. It does not require a developing chamber capable of wastewater treatment or a charging or voltage application device such as in xeroradiography or ionography.

[Brief explanation of drawings]

FIGS. 1 and 2 are explanatory diagrams of the radiation image creation method of the present invention, FIGS. 3 and 4 are explanatory diagrams of the offset printing method of radiation images, and FIG. 5 is an explanatory diagram of the exoelectron emission used in the present invention. It is a diagram. - 1 is a substrate, 2 is an exoelectron emitting material, 4 is an electrochromic material, 6 is a dampening solution, 7 is an offset ink, and 11 is a light irradiation device.

Claims (1)

[Claims] 1 After irradiating X-rays through the subject 5 to an exoelectron emitting member 3 in which an exoelectron emitting substance 2 is laminated on a substrate 1, an electrochromic substance is applied to the surface of the exoelectron emitting member 3 and irradiated with light. A radiation image creation method characterized by: