US3849648A

US3849648A - Electron radiograph patient identification system

Info

Publication number: US3849648A
Application number: US00423408A
Authority: US
Inventors: F Allan; M Welkowsky
Original assignee: Xonics Inc
Current assignee: ELSCINT IMAGING Inc; Elscint Ltd; Elscint Inc
Priority date: 1973-12-10
Filing date: 1973-12-10
Publication date: 1974-11-19
Anticipated expiration: 1991-11-19

Abstract

Method and apparatus for placing identification of a patient or other object on an x-ray picture produced on a dielectric receptor sheet by electron radiography. A system for providing a uniform charge on an identification zone of a dielectric receptor, and for discharging selected portions of the charged zone by contact with a photoconductor unit having selected portions thereof made conductive by radiation, with the selected portions providing the identification of the object. A roller mechanism and a flat plate mechanism for providing the contact between charged receptor and photoconductor unit. An optical system and a light emitting diode system for generating the identification pattern.

Description

United States Patent Allan et al.

ELECTRON RADIOGRAPH PATIENT IDENTIFICATION SYSTEM Inventors: Frank V. Allan; Murray S.

Welkowsky, both of Los Angeles, Calif.

Assignee: Xonics, Inc., Van Nuys, Calif.

Filed: Dec. 10, 1973 Appl. No.: 423,408

11.8. CI. 250/315, 250/324 Int. Cl. G03b 41/16 Field of Search 250/315 A, 476

IMAGING CHFVMSER Primary Examiner.lames W. Lawrence Assistant ExaminerDavis L. Willis Attorney, Agent, or FirmHarris, Kern, Wallen & Tinsley 5 7] ABSTRACT Method and apparatus for placing identification of a patient or other object on an x-ray picture produced on a dielectric receptor sheet by electron radiography. A system for providing a uniform charge on an identification zone of a dielectric receptor, and for discharging selected portions of the charged zone by contact with a photoconductor unit having selected portions thereof made conductive by radiation, with the selected portions providing the identification of the object. A roller mechanism and a flat plate mechanism for providing the contact between charged receptor and photoconductor unit. An optical system and a light emitting diode system for generating the identification pattern.

13 Claims, 4 Drawing Figures 4 DATA T-CHRD 20 BACKGROUND OF THE INVENTION This invention relates to the creation of x-ray images without the use of conventional x-ray film, sometimes referred to as electron radiography, such as the technique described in the copending application of Muntz et al, Ser. No. 261,927, filed June 12, 1972, entitled Radiographic Systems with Xerographic Printing and now US. Pat. No. 3,774,029, and assigned to same assignee as the present application.

In such a system, a fluid, typically xenon gas, is used between spaced electrodes in an imaging chamber to produce a photoelectric current within that chamber as 'a function of x-rays entering the chamber. The current is collected on a dielectric receptor sheet, typically Mylar, placed on one of the electrodes, resulting in a latent electrostatic image on the sheet. The latent image is then made visible by conventional xerographic development techniques.

The electron radiographic system is particularly well suited for making medical x-rays and present day medical x-ray systems usually require incorporation of an arrangement for placing patient identification on the resultant picture. Typically the identification information must be placed into the x-ray system prior to making the x-ray exposure, the system having an interlock which prevents exposure until the identification information has been inserted. Actual production of the data pattern on the picture film or receptor may occur prior, during or subsequent to the x-ray exposure.

In the conventional system utilizing photographic film, lead characters are placed on the imaging cassette, resulting in clear characters on a black background in the exposed film. Some alternative arrangements utilize punched cards or other selectivelytransparent devices which rely upon the light sensitive properties of the film.

However, the electron radiography system is insensitive to light and none of the conventional systems using light or x-ray radiation to expose the film can be utili'zed for object identification. One such system for placing markings on x-ray film is shown in US. Pat. No. 3,683,182.

US. Pat. No. 3,244,546 discloses a system for producing characters in a conventional xerographic printer. A data strip is embossed with the desired characters and this embossed strip is brought into contact with the electrostatic charged surface of the drum. The drum is discharged in the regions contacted by the embossed strip, with the raised portions out of contact with the drum. The drum surface is then bathed with toner particles which adhere in the charged regions, and this toner image is transferred to a web in the conventional manner thereby printing the data on the web.

US. Pat. No. 3,472,136 shows an alternative system for generating data characters on a xerographic printer drum. A plurality of belts are mounted side-by-side, each belt carrying a series of the desired characters,

witha data word being produced by appropriately positioning each belt. Light is directed through transparent characters onto the photoconductor drum after which the toner particles are applied to the drum and the toner image is transferred to the web.

Electrostatic type printing systems utilizing stencils for the toner powder are shown in US. Pat. Nos. 3,504,624; 3,635,157; and 3,638,566.

All of these prior art devices require some form of mechanical character generator with type or stencils or wheels or belts which must be individually manipulated by the individual operating the x-ray apparatus. Also, the belt, wheel and stencil styles are inherently limited in the characters available, placing an undue restriction on the type of data which can be used for identification purposes.

SUMMARY OF THE INVENTION The present invention provides object identification in an electron radiographic system using an optical arrangement which in its preferred embodiment can provide any form of identification including characters and pictorial representations, all from a previously prepared data card. The object identification system of the present invention does not require any character manipulation by the operator, who merely inserts the data card into the x-ray machine prior to exposure. In one alternative embodiment, the operator may key in the identification data prior to exposure.

The identification carrying zone of the dielectric receptor is substantially uniformly charged and is then selectively discharged in a pattern corresponding to the identification data. Selective discharge is achieved by contacting the dielectric receptor with a photoconductor unit which is made selectively conductive by an optical system directing radiation to the photoconductor unit. The selective discharge may be performed prior, during or subsequent to the x-ray exposure. After the identification data has been produced on the receptor and after the x-ray exposure, the receptor is then ready for developing of the latent electrostatic image in the conventional manner.

BRIEF DESCRIPTION OF THE DRAWING emitting diodes; and

FIG. 4 illustrates an alternative embodiment of the photoconductor unit of FIG. 1 incorporating a drum.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The apparatus of FIG. 1 includes a charging station 10, an imaging chamber 11 with x-ray tube 12, an identification station 13, and a developing chamber 14. At the charging station 10, a sheet of dielectric receptor 20 rests on a backing plate 21. The backing plate has an electrically conducting upper surface and typically is made of metal. A portion 22 of the backing plate is electrically insulated from the remainder of the plate 21, as shown in FIG. 2. The dielectric receptor 20 has an electrically conducting lower surface in contact with the backing plate. The conducting surface may be obtained in various ways, as by means of a peelable layer of conducting paper or a bonded layer of a transparent conducting plastic or a film of a conducting liquid.- While the conducting surface of the dielectric receptor has a conductivity high relative to that of the opposite surface on which the electrostatic charge image is formed, the conducting surface actually is a poor electrical conductor when compared to a metal, typically having a resistivity in the order of to l0 ohms/- square.

An electrostatic charge is produced on the receptor as by means of a conventional corona generator unit 24 which may be the size of the receptor or which may be smaller, with the unit 24 moving relative to the receptor to cover the entire surface. The major portion of the backing plate 21 is connected to circuit ground and the portion 22 is connected to a dc source 25. With this configuration, the receptor is substantially uniformly discharged to neutral or zero potential all over except for the zone overlying the backing plate portion 22. This zone of the receptor is substantially uniformly charged to a potential dependent upon the potential of the source 25 and the potential of the corona generator unit 24, typically in the order of a few hundred volts.

The receptor with the charged zone is now ready for insertion into the imaging chamber 11 where the electrostatic image of the patient or other object is produced in the manner described in the aforesaid copending application. After exposure, the receptor is moved to the identification station 13 which includes a conductive backing plate and a photoconductor unit 31. The backing plate 30 has an electrical conducting upper surface for contacting the conducting surface of the receptor, and typically it is made of sheet metal. The photo conductor unit 31 comprises a plate of a dielectric photoconductive material with an electrical conducting upper surface 32. The photoconductive material may be one of the conventional materials available, and the conducting layer 32 may be a thin transparent metallic film. A mechanism indicated generally at 34 serves to move the unit 31 downward into contact with the receptor 20 and upward away from the receptor. The unit 31 is the size of the portion 22 and the components are arranged so that the unit 31 engages the charged zone of the receptor. The backing plate 30 and the conducting surface 32 are electrically interconnected, as by being connected to circuit ground.

An optical system provides for directing radiation in a predetermined pattern onto the photoconductor unit 31, with the pattern providing the identification information for the object x-rayed. Radiation, typically visible light, is directed from a source onto a data card 41, which is imaged at the unit 31 through the transparent electrical conducting upper surface, with lenses 43 as needed. The identification information may be typed, written or otherwise placed on the data card as desired, with the radiation pattern arriving at the photoconductor unit being a function of the information on the data card. The regions of the photoconductor unit receiving the radiation becomeelectrically conductive. When the photoconductor unit with the electrical conductive pattern therein is brought into contact with the charged zone of the receptor, the receptor is locally discharged through the conducting photoconductive material, the conducting layer 32 and the backing plate 30, leaving a charge pattern corresponding to the pattern on the data card.

The photoconductor unit 31 is moved out of engagement with the receptor and the receptor is moved onto the developing chamber 14. The receptor is bathed in toner particles which adhere to the charged portions and produce the visible image, including the identification 45.

The sequence of operation illustrated in H0. 1 may be varied as desired. As example, the zone on the receptor may be charged and the identification discharge pattern produced prior to x-ray exposure. Alternatively the x-ray exposure may be made, after which the zone is charged and selectively discharged. Of course. the zone must be protected from x-ray radiation in the imaging chamber if it is charged prior to x-ray exposure. At the identification station, the image of the data card may be projected onto the photoconductor unit at the time of engagement with the receptor or prior to engagement, since the photoconductive material remains conductive for a period of time after exposure.

An alternative embodiment of the photoconductor unit which utilizes light emitting elements such as light emitting diodes for the optical system is illustrated in FIG. 3. An array of light emitting diodes 48 may be positioned directly on the photoconductive material of the photoconductor unit. The light emitting elements 48 may be utilized to provide any desired image, typically a plurality of seven bar numbers. The patient identification or other data may be introduced into a data processor 49 via a keyboard 50, with the data processor determining which elements 48 are to be energized to generate the desired information. The energized elements 48 make the corresponding portions of the photoconductor unit 32 electrically conductive, permitting operation in the manner described in conjuction with the embodiment of FIG. 1.

1n the alternative embodiment of FIG. 4, a drum 60 is utilized in place of the photoconductor unit plate 31. The drum has an outer layer 61 of photoconductive material and an inner electrical conducting layer 62 connected to circuit ground by suitable means such as resilient wipers (not shown). The photoconductive material of the drum is made locally conductive by an optical system such as the described in conjuction with the embodiment of P10. 1. The drum configuration is particularly suited for use with a system where the receptor moves through the identification station without stopping, with the drum in rolling contact with the re ceptor. The operation of the embodiment of FIG. 4 may be the same as the embodiment of FIG. 1.

We claim:

1. A method of placing object identification on an x-ray picture formed on a dielectric receptor by electronradiography, including the steps of:

producing an electrostatic charge image on a dielectric receptor by exposing the object to x-ray radiation;

producing a substantially uniform electrostatic charge on a zone of the dielectric receptor; contacting the receptor at the charged zone by a photoconductor with the receptor and photoconductor having contiguous nonconducting surfaces and spaced interconnected conducting surfaces; directing radiation to the photoconductor in a pattern which identifies the object and making selected portions of the photoconductor conductive;

discharging the portions of the charged zone of the receptor in contact with said selected photoconductor portions; and

developing a visual image on the receptor corresponding to the charges thereon.

2. A method as defined in claim 1 including simultaneously producing the substantially uniform electrostatic charge on the zone of the dielectric receptor and a substantially neutral charge on the remainder of the receptor prior to the exposure step.

3. A method as defined in claim 1 wherein said zone is charged prior to said exposure.

4. A method as defined in claim 1 wherein said zone is charged subsequent to said exposure.

5. A method as defined in claim 1 wherein the radiation is directed to the photoconductor while the photoconductor is in contact with the receptor.

6. A method as defined in claim 1 wherein radiation is directed to the photoconductor prior to contacting the receptor.

7. Apparatus for providing object identification on an x-ray picture formed on a dielectric receptor by electronradiography, including in combination:

first means for producing a substantially uniform electrostatic charge on a zone of a first nonconducting surface of a dielectric receptor having a second conducting surface;

a photoconductor unit having a first nonconducting suface and a second conducting surface;

second means for interconnecting the second surfaces;

third means for bringing the first surfaces into contact with each other; an

fourth means for directing radiation to said photoconductor unit in a predetermined pattern making predetermined portions of said photoconductor unit conductive, with the contact of said first surfaces discharging said charged zone in the predetermined pattern. 8. Apparatus as defined in claim 7 wherein said photoconductor unit includes a drum with a photoconductive layer, and said third means includes means for rolling said drum along the receptor.

9. Apparatus as defined in claim 7 wherein said photoconductor unit includes a plate with a photoconductive layer, and said third means includes means for moving said plate and receptor toward and away from each other.

10. Apparatus as defined in claim 7 wherein said fourth means includes a radiation source and an optical system for directing radiation from said source to a pattern defining element and then to said photoconductor unit.

11. Apparatus as defined in claim 7 wherein said fourth means includes an array of radiation emitting elements positioned at said photoconductor unit and means for energizing selected radiation emitting elements in said predetermined pattern.

12. Apparatus as defined in claim 7 wherein said first means includes;

a corona generator; a conducting backing plate for supporting a dielectric receptor spaced from said generator, said plate having first and second sections electrically insulated from each other;

means for connecting said first section to circuit ground; and

means for connecting said section to a dc potential.

13. Apparatus as defined in claim 7 wherein said second conducting surface of said photoconductor unit is transparent to said radiation.

Claims

1. A method of placing object identification on an x-ray picture formed on a dielectric receptor by electronradiography, including the steps of: producing an electrostatic charge image on a dielectric receptor by exposing the object to x-ray radiation; producing a substantially uniform electrostatic charge on a zone of the dielectric receptor; contacting the receptor at the charged zone by a photoconductor with the receptor and photoconductor having contiguous nonconducting surfaces and spaced interconnected conducting surfaces; directing radiation to the photoconductor in a pattern which identifies the object and making selected portions of the photoconductor conductive; discharging the portions of the charged zone of the receptor in contact with said selected photoconductor portions; and developing a visual image on the receptor corresponding to the charges thereon.

7. Apparatus for providing object identification on an x-ray picture formed on a dielectric receptor by electronradiography, including in combination: first means for producing a substantially uniform electrostatic charge on a zone of a first nonconducting surface of a dielectric receptor having a second conducting surface; a photoconductor unit having a first nonconducting suface and a second conducting surface; second means for interconnecting the second surfaces; third means for bringing the first surfaces into contact with each other; an fourth means for directing radiation to said photoconductor unit in a predetermined pattern making predetermined portions of said photoconductor unit conductive, with the contact of said first surfaces discharging said charged zone in the predetermined pattern. 8. Apparatus as defined in claim 7 wherein said photoconductor unit includes a drum with a photoconductive layer, and said third means includes means for rolling said drum along the receptor.

12. Apparatus as defined in claim 7 wherein said first means includes; a corona generator; a conducting backing plate for supporting a dielectric receptor spaced from said generator, said plate having first and second sections electrically insulated from each other; means for connecting said first section to circuit ground; and means for connecting said section to a dc potential.