DE2360966A1 - METHOD AND DEVICE FOR PRODUCING A RADIOGRAM OR ROENTGEN IMAGE - Google Patents

Description

PATENT Attorneys ^ :. ' .

DIPL-ING. P. WlRTH · - DI PL.-ING.G. THEN MOUNTAIN

DR. V. SCHMIED-KLOWARZIK ■ DR. P. WEINHOLD · D ^ R. D. GUDEL

6 FRANKFURT AM MAIN 9 ^ R Π Q R R

OR. ESCHENHEIMER STRASSE ^ 9 ^ jOUjUU

December 7, 1973
Gu / gm

Horizons Research Incorporated 23 Soο Mercantile Road Cleveland, Ohio, 44 122

Method and device for producing a radiogram or x-ray image.

The invention relates to a method and a device for the electrophotographic production of a radiogram or an X-ray image. '.

For producing radiograms or x-rays is a ^ electrostatic printing process ("xerography") became known. In this process, a plate coated with selenium is electrostatically charged and exposed to an X-ray image (the charge is removed from the surface directed into the area of the plate that is irradiated by X-rays), and then the latent becomes electrostatic Image developed by fine dust coloring. The fine dust image is then transferred onto white paper and then on the paper surface by the action of heat fixed. The selenium plate must be heated to slightly elevated temperatures after each exposure in order to achieve the Prepare new plate and existing shadow - desolate To eliminate haze images. This method is complicated and has the disadvantage that disturbances occur in the X-ray image in small areas after

exposures have been carried out on the individual plates, so that the service life is impaired. _7th

Furthermore, the electrostatic dust dyeing leads to your said method so that the edge areas of the electrostatic image are favored during the filling of continuously irradiated areas is neglected, since the colorant depends on the stress gradients on the surface of the plate, and not according to the real potential present at every point on the surface « In certain applications, this edge is favored one usually with halogen silver radiographs or x-rays non-appearing information supplied. However, this visual appearance is different from what radiologists use or normally observe personnel engaged in such investigations.

The invention relates to the generation of a radiogram or an X-ray image using a simple electrostatic Process that eliminates the complicated procedures of "xerography" or halosilver radiography.

The invention also proposes an inexpensive device for producing radiograms or x-ray images.

In the method according to the invention for producing a radio gram or X-ray image, the colored image density is proportional to the exposure to the X-rays.

Further important features of the present invention are explained in more detail below on the basis of exemplary embodiments. It shows: -

Fig. 1 schematically shows an apparatus for carrying out the invention Procedure;

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2 shows an enlarged section for the top position of a

Detail of the device according to Fig. 1; -

FIGS. 3 and k representations similar to FIG. 2 to illustrate """" · of modified ones ^{; FIG.} Embodiments «<- ■

In Fig / 1 is a device for performing the inventive Procedure shown. A conventional X-ray source Io generates X-rays to examine an object 12, which is to be represented '. One not shown Means is for holding the object 12 between the source Io and a recording sheet 17 are provided. A f ee ishish Screen or a screen. I ^ isct with a: substance l6y. usually an insulating agent, coated which. Medium becomes partially conductive, when X-rays are on it fall; the screen 14 is with the recording sheet in contact, of a thin., charge-carrying insulating layer l8 on the surface, which at a partial conductive support layer 2o. is held. The recording sheets 17 can of a partially conductive .transparenten holding element 20 "are worn. The, recording sheet 17 is located auf.einer electrically conductive plate 22. A

Voltage source 26 is between the electrically conductive picture 16 connected to the "electrically conductive support plate 22, namely "via a" switch 2 * t. -

The electrical, fine-grained screen 14 can consist of a Variety of metals or alloys can be produced; suitable metals are brass, stainless steel, aluminum and phosphor bronze .; The number of stitches, i.e. the number of Wires per s running inch "(" Mesh ") can be between loo and looo vary; the finer masehen ensure one higher resolution·. Otherwise, the screen can be made of woven individual fibers 13 ″, for example made of polypropylene, polyester or polyamide. Umbrellas made of such woven art

..,, sizes
Resins are available in mesh / to over 325 mesh; they are extremely strong and somewhat less expensive than corresponding screens of Metallgewebe.Wird a screen of an insulating plastics einzelfaserigen _f -Uses so must a

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conductive coating 15 can be applied to the surface of the single fibers (see Fig. 2). A preferred method of applying such a conductive layer is vacuum evaporation, in which a thin layer of a conductive agent, for example aluminum, is applied to the surface of the screen. However, other methods of applying electrically conductive layers to the individual synthetic resin fibers can also be used, for example non-electrical plating. The screen coating consists of a substance which normally has a high resistance, typically greater than 10 ohms, cm, and which becomes slightly conductive when exposed to X-rays. The material may or may not become conductive when illuminated by illumination from the visible or ultraviolet regions of the spectrum. Therefore, this material can be viewed as an X-ray sensitive photoconductor. If the X-ray photoconductor ΐβ is not sensitive to visible lighting or irradiation, the method according to the invention can be carried out with normal room lighting. If the X-ray sensitive photoconductor is sensitive to visible light, the photoconductive screen must be enclosed in a light-tight cassette or otherwise shielded from the light,

Typical X-ray sensitive photoconductors that have been used in this process are selenium, selenium alloys containing small amounts of one or more of the following elements: tellurium, sulfur, arsenic, antimony, bismuth and iodine; Cadmium sulphide, cadmium selenium and lead oxide, the thickness of the coating 16 is not critical, to make X-rays of greater intensity visible, it is desirable to provide sufficient thickness so that a perceptible portion of the incident X-rays is absorbed, typical coating thicknesses are sufficient from l / 4 mil (= Ο, 0θ6 mm) to 5 mil (= 0.127 mm). The coating shown in Fig. 1 must be applied to the screen l4 in such a way that the coating t & between the conductive screen lA and the insulating ^

layer -1.8 lies. The coating l6 can cover the wires of the Umbrella completely 'surrounded or it can with respect to this ■ Wires can be arranged asymmetrically. It can be any known Coating processes are used, e.g. vacuum evaporation, Layers or tie layers. Spraying of material, for example selenium, onto the screen during this temperature at elevated temperatures is held, etc.

The recording sheet 17 »that consists of the insulating layer 18 and consists partially of the conductive layer 2o, can advantageously made of dielectric paper (also electrographic Paper · called) exist. Such a thing

Paper is characterized in that. there is a partial Senior Grtin.ds.cb.icht 2o> possesses which is coated with a very thin insulating polymer layer l8. the insulating polymer layer usually has a good dispersed white pigment for good feel and surface properties to manufacture. The thickness of the insulating dielectric layer is usually in the range of 1/5 to 1 m " (= 0.005-0.0254 mm). Such paper is commercially available.

If transparency is desired, the dielectric paper 17 can be replaced by a thin polymer film, for example acetate, polyester or polystyrene, which has a transparent or semi-transparent conductor 20 on the back. Such a film can consist of copper iodate and can be formed by spreading a thin layer of copper on the surface of the film, after which the copper layer is treated with iodine pans. The thickness of the plastic insulating layer 18 is preferably not more than 3 mil (= Q> v / P mm), and is preferably in the range of 1 mil (= v0.0254 mm). If it should be desirable, a greater transparency «For easier handling, this element can consist of a base part made of polyester with a thickness of 5 mil (= .0.127mm), on which a semiconducting copper-iodine layer is applied, over which a layer with a thickness of t / 2 to 1 rail (= 0.0127-0.025 mm) from one

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thermoplastic insulating material, e.g. polystyrene.

When the method according to the invention is carried out, the switch 24 is closed and the X-ray source to is activated.

the x-ray
After exposure by / / the switch 24 is opened and the recording sheet 17 is taken out of the sandwich-like layer arrangement; the image held latently on the insulating element 18 is colored electrostatically, for which purpose conventional electrostatic coloring devices, for example liquid coloring, cascades, magnetic brushes or fine dust, can be used. The colored image is then fixed with heat using any heat means.

The possible applications and specific devices for carrying out the method according to the invention are described in the ' the following examples clarified, which, however, in no way limit the application of the invention.

example 1

A screen made of simple, cross-woven stainless steel

WGi * fc ©

Weave with a mesh / of 4oo mesh was made over a square Stretched aluminum frame, the inner 'dimension of which:

12 inches (= 30.48 cm) on one side and its outer dimension

13 inches (= 33jO2 cm). The stainless steel screen was attached to the frame with epoxy glue. The frame assembly so fabricated was mounted in a vacuum vapor deposition at an average distance of 24 inches from a quartz evaporation block mounted in a tantalum heater. -A load of 100 g of high purity selenium was placed in the evaporation block. The steam coater was subjected to Io Torr pressure and the selenium evaporated from the block onto the screen over a period of 1 hour. During the evaporation, the screen was kept at an elevated temperature of 7 ο C, and two by an electric heater. The thickness of the selenium layer obtained was approx. 1 mil (= 0.253 mm).

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A sheet of dielectrically coated paper (electrographic Paper) was dielectrically coated with the Placed side up on an aluminum plate, the one Dimensions of 8 χ Io inch (= 20.5 χ 25.4 cm) possessed. The selenium coated screen was placed on the dielectric paper (selenium coated side down) placed. A power source with a capacity of 8oo V. was placed between the conductive screen and the aluminum plate connected in series.

A medical x-ray machine with an automatic Rectifier * which had an X-ray tube with a tungsten layer, was placed at a distance of 60 cm above the coated screen,

X-rays of human extremities, for example one hand were holding a tube with an operating voltage

, Flushing the voltage. ,

manufactured by coKV /, with an exposure in the area from 2o to So mas. X-ray images of light aluminum castings

Sjai, tension

were obtained at 9oKv / and Io to loo mas. During the

X-rays

The exposure through which the switch was closed, so that a voltage existed between the conductive screen and the paper cold plate. After exposure, the switch was opened, the dielectric paper was removed and developed in a dry inking unit with a magnetic brush ("Adressograph Multigraph Corporation ¹¹ ). The developed image was then fixed in a commercially available heat emitter (" Sun Chemical Corporation Model 12ο ¹¹ ). By this method, a negative image is obtained, the charge being transferred from the photoconductor to the surface of the dielectric layer on the paper in areas exposed to the X-rays. Since the photoconductor does not evenly touch the dielectric layer, the image is self-screened.

In this way the image (la a mass range is developed, and a full area of continuous color reproduction

6 / Ό9

is received.

When using the screen used in this example, the sensitivity obtained depends on the voltage used away. At voltages of well over 900 V. the background appears: as a carrier and is transmitted to areas of the screen that are not exposed to the X-rays. It has also found that equivalent results were obtained regardless of the polarity of the power supply. It was however, it is necessary to use dyes which have differently developed pigment carrier particles, and accordingly the carrier transferred to the dielectric paper » For example, if the polarity of the power source polarized the screen negatively with respect to the back of the sheet of paper, thus the negative charge was transferred to the surface of the dielectric paper. In this case it was necessary with a magnetic ink carrier system, in which the dye particles have a positive charge with respect to the magnetic Receive the carrier.

Example 2

with a
An X-ray sensitive photoconductor coated screen was treated as in the previous example except that the photoconductor used was an alloy of arsenic and selenium consisting of 25 atomic percent arsenic and 75 atomic percent selenium. The alloy was prepared by weighing the high purity arsenic and selenium, placing the two components together in a toughened glass tube. The tube was evacuated and sealed, and the materials were fired by heating the compressed tube in an electric furnace at a temperature slightly above the melting point of the materials for a period of several hours. The alloy was then spread on the screen in the same way as described in Example 1. The X-ray

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Radiation sensitivity has been slightly improved, namely by using a Se-As alloy instead of using from selenium alone.

Example 3

The same procedure was used as in Example 1, except that the x-rays, photosensitive coating was made from lead oxide »In this example lead oxide was made with vacuum evaporation on a stainless steel

-. . . , wide "■ _ .. Steel screen with a mesh size of 400 mesh. at the evaporation caused a lead of the lead oxide, and a gray suboxide was formed. The -pTioto-conductive coating therefore had to be burned in the air at a higher temperature, to reoxidize the photoconductor up to one Point at which the dark conductivity to a suitable one. Value had dropped. This image indicated lower X-ray sensitivity at lower voltage of the X-ray tube, i.e. in the range of 50-6.0 KV / Peak tension, and higher photosensitivity, was observed when the tubes were under tension greater than 90 KV / peak voltage.

Example 4 ■ ·

The procedure of Example 1 was repeated except that the dielectric paper was replaced with a transparent receiving sheet. The transparent recording sheet was prepared by first applying a thin copper layer to a clean film base made of polyester in a thickness of 5 mil (= 9 »012 ¹ ^ nIq) by evaporation. The copper was then converted to copper iodine by holding the copper clad film in a stream of vaporizing iodine. Finally, a thin dielectric film was placed over the now transparent semiconducting copper-iodine layer using a coating process with a "Bird" applicator and adding a 10% solution of polystyrene in a solution of benzene toluene in

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a mixing ratio of 50:50. The dry layer thickness of the polystyrene layer was about 1/2 mil (= 0.0127 mm). The same procedure as in Example 1 was used and almost the same results were obtained, except that the X-ray image is viewed by fluoroscopy could.

Example 5

The procedure of Example 2 was repeated except that the photoconductor used consisted of an alloy of selenium, arsenic and antimony, the mixing ratio being about 70 atomic percent selenium, 20 atomic percent arsenic and 10 atomic percent Antimony fraud. The conditions of the X-ray Radiation exposure was used as described in Example 1 and radiographs of good quality in about half the time as described in Example 1.

Example 6

Example 5 was repeated except that the photoconductor was composed of 72 atomic percent selenium, 22 atomic percent arsenic and 6 atomic percent Bismuth passed · Again were the 'conditions used exposure to X-rays as described in Example 1 and good quality radiograms obtained in about a third of the time described in Example 1.

It is important for the invention that radiograms or x-ray images are produced in a disgusting device, which is a fine-grained one Has a screen that is sensitive to X-rays Photoconductor is coated, whereby the screen is exposed to X-ray exposure, while the coated screen is in physical contact "with an insulating support holder, and while an electrical voltage between the screen and an electrically conductive one Plate is exercised with the plate on the side

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of the insulating element is located, the opposite of the side is provided on which the coated screen is located, and then passing through the latent image that is on the carrier holding member as a result of the exposure. X-rays is formed, is colored electrostatically.

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Claims (6)

Expectations · / Device for generating a radiogram or x-ray image of an object, characterized by an x-ray source (10) arranged on one side of an object (12) from which a radiogram or x-ray image is to be produced, furthermore by an arrangement (14) for Generating an X-ray image or radiogram on the other side of the object (12), this arrangement (Ik) ■ an electrically conductive base layer (16) and a recording sheet (17) located thereon with an electrically conductive layer (18) and an insulating layer Support holder lenient (20), the layer (l8) rests on the base layer (l6), and wherein a conductive screen (20) made of a fabric grid rests on the insulating layer (l8), namely at least the part of the fabric screen which is physically Is in contact with the holding layer (18), which has a coating (22) made of a photoconductive material which becomes electrically conductive when exposed to X-rays, and wherein ei ne means (24) for exerting a tension between the conductive base layer and the screen fabric is provided. 2. Apparatus according to claim 1, characterized in that the photoconductive material is selected from the group which consists of selenium, cadmium sulfide, cadmium selenium, lead oxide and selenium alloys, with at least 1 element of selected from the group consisting of telur, sulfur, arsenic, Antimony, bismuth, iodine, and mixtures of the photoconductive material. 3 · Device according to claim 1, characterized in that the screen is made of metal and that the photoconductor is selenium. 4. Device according to claim 1, characterized in that LO 9 82 6/0996 the screen made of single-fiber synthetic resin; exists that is coated with a conductor. 5. Apparatus according to claim I ₁ . characterized in that the imaging element is dielectric coated paper. 6. Method for producing a radiogram or x-ray image using a device according to claim 1, characterized in that an object (12) is X-rays exposing a pattern of x-rays passing through the object to a sensitive one Element is thrown, and exposure takes place while tension is between a screen (.14) and a metal base to form a latent electrostatic image on an insulating layer (18) and then developing a visual representation of the latent image. The patent attorney Dr. D. Gudel 409826/0996 Blank page