US2885560A - X-ray method - Google Patents
X-ray method Download PDFInfo
- Publication number
- US2885560A US2885560A US645742A US64574257A US2885560A US 2885560 A US2885560 A US 2885560A US 645742 A US645742 A US 645742A US 64574257 A US64574257 A US 64574257A US 2885560 A US2885560 A US 2885560A
- Authority
- US
- United States
- Prior art keywords
- screen
- ray
- rays
- ray signal
- contrast
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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Classifications
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05G—X-RAY TECHNIQUE
- H05G1/00—X-ray apparatus involving X-ray tubes; Circuits therefor
- H05G1/08—Electrical details
- H05G1/64—Circuit arrangements for X-ray apparatus incorporating image intensifiers
-
- G—PHYSICS
- G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
- G21K—TECHNIQUES FOR HANDLING PARTICLES OR IONISING RADIATION NOT OTHERWISE PROVIDED FOR; IRRADIATION DEVICES; GAMMA RAY OR X-RAY MICROSCOPES
- G21K4/00—Conversion screens for the conversion of the spatial distribution of X-rays or particle radiation into visible images, e.g. fluoroscopic screens
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B33/00—Electroluminescent light sources
Definitions
- theimages are produced by contrast differences between individual portions of such images. It is desirable in some cases to increase the contrast obtainable in the images. Also, it may be desirable for some limited applications to decrease the contrast in the images. In addition, it is desirable to enhance the brightness of the images produced on a uoroscopic screen without substantially increasing the quantity of X-ray irradiation used to generate the X-ray signal.
- the screen is thereafter irradiated with the same X-ray signal pattern as previously, but preferably with an increased X-ray intensity. This causes the screen to produce a luminous image corresponding to the applied X-ray signals, but with a varied and preferably enhanced contrast between the brightest and the darkest portions of the luminous image.
- Fig. 1 is a sectional elevation of the preferred X-rayelectroluminescent fluoroscopic screen
- Fig. 2 is a schematic diagram of the X-ray unit andv operating circuit therefor, illustrating the phosphor screen presensitizing operation
- Fig. 3 is a schematic diagram similar to Fig. 2 illustrating the second phase of the equipment operation,-
- Fig. l is illustrated the preferred embodiment of vable bus bars 20 and to the electroluminescent field-voltage supply described ICC wherein the image is produced on the tluoroscopic screen with improved contrast;
- Fig. 4 is a graph of the ratio of enhanced output vs. X-ray irradiation of a presensitized fluoroscopic screen
- Fig. 5 is a graph of brightness in arbitrary units vs. time illustrating the operation of the unit so that the contrast between the brightest and darkest portions of the iluoroscopic image is varied.
- the phosphor materials which may be used in this copending application are those which will display an enhanced luminous output when excited by X-rays and simultaneously placed within the inuence of an alternating electric field. This is contrary to the action of most phosphors which will display a quenching effect under similar conditions.
- the phosphors which may be used in the instant system are those which may be used in the so-called X-ray enhancement as disclosed in the heretofore-mentioned copending Destriau application, namely, those phosphors which display an enhanced output when irradiated with X-rays and simultaneously placed within the inuence of an alternating electric eld.
- Specific phosphors which will be suitable for the instant purpose are mixtures of zinc sulde and cadmium sulde wherein the molar ratio of zinc to cadmium is from nine mole parts zinc, one mole part cadmium to three mole parts zinc, seven mole parts cadmium and activated by from 0.01)(10-2 to 6.0)(10-2 mole of manganese per mole of luminescent material.
- the phosphor material may be activated by a mixture of manganese and silver, with the silver being present in amounts of from traces (0.001 X 10*2 mole silver per mole manganese) up to about 1.0 l02 mole silver per mole manganese.
- zinc sulfide phosphors which are activated with manganese or mixtures of manganese and silver in the heretofore-disclosed amounts are also suitable.
- the phosphor material may comprise 1CdS3.5ZnS, activated by 1x10-4 mole manganese per mole of luminescent material, such a phosphor having been fired during preparation at a C. t0 1150 C.
- the electroluminescent-uoroscopic screen 10 which comprises a substantially planar layer of luminescent material 12 adjacent a substantially planar layer of di- 'electric material 14 with the luminescent and dielectric materials being sandwiched beween two thin, conducting layers or electrodes 16 and 18.
- Each of the electrode layers 16 and 18 may be connected through suitsuitable electrical connection 22 hereinafter.
- a foundation-viewing plate 24 is placed over one of the conducting layers, for example electrode layer 18 and an insulating layer 26 may be placed over the other conducting electrode layer 16 in order to miniassignee mize shock hazard.
- a protecting and handling shield 28 may be provided around 'the entire periphery of the screen in order to facilitate storage, handling, etc.
- the luminescent material layer 12 is preferably positioned ⁇ next to the 'foundation-viewing plate 24, although for some applications it .may be preferable to place the dielectric layer 14 next 'to the viewing plate 24.
- 'T he thickness of the luminescent material layer ⁇ L12 is not particularly critical, but as a specific example it may ⁇ have :a thickness of 0.2 mm.
- the dielectric layer 14 ' may comprise any 'suitable dielectric which has a high dielectric constant, is transparent :to either visible light or to '.X-rays dependingupon its position within thescreen, and :will not rapidly deteriorate under the action of X- rays.
- the dielectric material layer ⁇ 14 may .comprise a mica sheet about 10.05 mm. thick, although this thickness is in ⁇ no "way critical and may be increased or decreased as indicated by the application.
- a suitable light-transmissive dielectric material such as polyvinyl-chloride acetate may be admixed with the phosphor and the separate layer of dielectric material .dispensed with, if desired, or the dielectric material may be dispensed with entirely in some special applications and only the phosphor layer 12 placed between Vthe electrodes 16 and 18. It should be pointed out that the purpose of the dielectric material is to prevent electrical breakdown through the phosphor and between the electrodes '16 and 18 and the electric fields as may be used herein need not be particularly intense.
- the usable electric fields may vary over a wide range as in the heretofore-mentioned copending Destriau application and as a specific example, the electric iield which is applied across the screen during screen presensitization may have an intensity of 20 kv. per cm.
- the conducting electrodes 16 and 18 may be fabricated of any conducting materials which may be coated as a thin sheet and are transmissive to visible light in the case of the lower layer 18 and transmissive to X-rays in the case of the upper layer 16. Of course these electrodes should not deteriorate appreciably under the action of X-rays.
- the electrode 18 may be fabricated of a thin layer of tin oxide on a glass base, such as sold under the trademark NESA by Pittsburgh Plate Glass Co., Pittsburgh, Pa.
- Other suitable thin, conducting coatings such as oxides of zinc, cadmium, aluminum or bismuth, for example, may also be used.
- the electrode 16 may be fabricated of tin oxide, for example, or it may be a thin coating of aluminum which may be applied by the well-known vacuum-metalizing techniques.
- the thin, protective layer 26, which is intended to insure against shock hazard and to facilitate handling, may be fabricated of any X-ray-transrnissive material which has relatively good electrical insulation properties and plastics such as polytetrauoroethylene are suitable.
- the protective layer 26 may be dispensed with, if desired, and the shock hazard eliminated by grounding the electrode 16.
- the foundation glass-viewing plate is normally fabricated of any glass which contains heavy atoms which will absorb the X-rays and thus protect the viewer or the photographic plate, as the case may be. As an example, any of the well-known lead or cerium glass may be used.
- the protecting and handling shield 2S may be fabricated of a plastic similar to the layer 26 and this shield may be dispensed with, if des-ired.
- Fig. 2 is illustrated, in block diagram, one embodiment of a suitable X-ray apparatus which in this showing is set for initial exposure of the object being X- rayed in order to presensitize the uoroscopic screen 10.
- This apparatus 30 comprises an X-ray rectifier and transformer unit 32, X-ray and lm shutter timer 34, X-ray tube 36, feld-voltage-control unit 38, field-timer unit 40, the X-ray uoroscopic screen 10, exposure switch 42, field-electric switch 44, camera film 46, camera shutter tripping unit 43 and camera shutter 50.
- Fig. 3 is shown in block diagram the sameX-ray apparatus Aas shown in Fig. 2, but with the electric lield switch -44 in an openposition.
- the apparatus With the X-ray uoroscopic screen presensitized, the apparatus is thus set to again irradiate theobject being X-raye'd in order to produce on the iiuoroscopic screen a corresponding image with excellent contrast.
- the details of the operation of this apparatus will be considered as Vthe description proceeds.
- '1:"orjpurposes of explanation the object'fSZ'being X-rayed has been shown as having one portion with twice the X-ray permeability as the remaining portion.
- Fig. 4 is shown a graph of enhancing ratio vs. second X-ray irradiation, expressed as milliamperes of current drawn by the X-ray tube 36.
- thescreen 10 waspresensitized and the screen brightness was measured with no object between the screen and the X-ray tube 36 when it drew indicated currents.
- inclusive of an object on the X-ray table requires a greater quantity or intensity of X-ray irradiation, to deliver to the screen 10 an equivalent quantity of X-rays (in the case of the presensitizing step) or an equivalent intensity of X-rays (in the case of the second irradiation).
- the X-ray tube 36 as used herein had a hard glass window and was operated at a voltageof kv. with a self-rectified circuit.
- the target material was tungsten and the distance from the centerline of the tube 36 to thescreen 10 was 2() cm. Under these conditions of operation, the tube ⁇ current and time were measured'to the indicated values of Q. It should be understood that these conditions of operation may be varied considerably, depending on the application.
- the brightness ratio is also dependent upon the intensity of the second X-ray-signal irradiation of the screenfandthisisplotted las the -abscissa ⁇ in -these curves.
- Bm is the maximum brightness in arbitrary units for a presensitized screen and Bo is the maximum brightness in arbitrary units for an unsensitized screen irradiated with equal-intensity X-rays.
- Fig. 5 is illustrated the operation of the equipment in order to improve the contrast of the resulting image.
- the object being X-rayed is represented as comprising two portions, one of which has twice the permeability to X-rays as the other portion.
- the object 52 is placed on the X-ray table and, as an example, is irradiated with X-rays of such intensity that the portions of the screen adjacent the more X-raytransmissive portion of the object will receive a quantity of X-ray irradiation equivalent to a total Q of 160 pa. min.
- the electric field as indicated hereinbefore is applied across the screen since the switch 44 is in the closed position, see Fig.
- the X-ray irradiation is removed just before the field is removed.
- the brightness of the screen with the simultaneously-applied X-rays and field will follow the general line O-T-U for the screen portions adjacent the more X-ray transmissive portions of the object.
- the screen brightness will follow the line O-T-U for the screen portions adjacent the more X-ray opaque portion of the object being X-rayed, which screen portions will receive a quantity of X-ray irradiation equivalent to a Q of 80 na. min.
- This procedure presensitizes the screen 10. It should be noted that the screen prcsensitization is not effected by the field alone, nor will the field alone, as specified, develop any appreciable pure electroluminescence in the screen 10.
- a generally-linear response of X-ray intensity to screen brightness is realized and the brightest portions of the screen will be twice as bright as the darkest portions of the screen, as indicated by the relative brightness of the ordinates at points U and U. It should be noted that Without the simultaneous application of the electric field across the screen, the screen brightnesses may be approximately one-fifth those which are represented.
- the field is shown as being discontinued at point V, and this may be ten seconds, for example, after the presensitizng X-ray irradiation is stopped. Immediately thereafter, while the object is still remaining stationary on the viewing table, the object 52 may be again irradiated with much more intense X-rays. Of course, the initial X-ray irradiation could be removed simultaneously with the field, or shortly thereafter. The latter procedure, however, would sacrifice some screen presensitization.
- the second X-ray irradiation (j) is of such intensity that the screen portion adjacent the more X-ray-transmissive portion of the object will receive an X-ray intensity equivalent to that produced when the tube i is drawing 1.4 milliamperes with no object in place
- the contrast in the image. produced on the screen will be improved from the ratio of 2:1, which would be realized with no screen presensitization, to the ratio of 2.8:1 which is actually realized.
- decreasing contrast may be achieved by limiting the presensitizing X-ray irradiation of the screen so that the brighter portions are presensitized to a of 20 tta. min., and the darker portions are presensitized to the Q of 10 fra. min.
- the enhancing ratios will be 1.06:1 for the brighter portions and 1.14:1 for the darker'portions, which will decrease the contrast realized in the image.
- the field has been removed after removal of the first X-ray signal irradiation, but it should be understood that the field and the X-ray signal irradiation may be removed simultaneously with out impairing the operation and the second X-ray signal may be applied immediately thereafter. This of course could be accomplished by increasing the X-ray intensity and simultaneously removing the field.
- the transient image which achieves a maximtun of contrast at points X and X in Fig. 5, is'preferably relater. Referring to Fig. 3 when the switch 44 is raised to an elevated position to open the field timer unit 40, ⁇
- the camera-shutter tripping unit 48 When the exposure switch 42 is closed, the timer unit 34 is actuated and at a predetermined time thereafter and the shutter-tripping unit 48 actuates the film shutter 50 to record the brightestportions of the transient image. Immediately thereafter the second X-ray irradiation may be stopped. This may be effected by opening exposure switch 42 or by setting the timer unit 34. As an example, the camera may record the image five seconds after the second X-ray signal irradiation of the screen 10 is started.
- the screen presensitization can be effected with a relatively small quantity of X-rays. Thereafter, the X- ray intensitymay be greatly increased in order to obtain maximum luminosity and contrast in the image.
- This stronger-intensity X-ray signal need only be of relatively short duration as the peak in luminosity is reached in a matter of seconds and once this peak is recorded photographically, the second and more intense X-ray irradiationrnay be stopped.
- the brightness of the image produced on the screen during the second X-rayvirradiation is not as great as would be obtained with the simultaneous application of an electric field across the screen while the screen was irradiated with equivalent intensity X-rays.
- the build-up in luminosity of the lenhanced brightness is relatively slow and accordingly, the quantity of X-rays required to produce such ultimate enhanced luminosity is correspondingly great.
- the buildup in luminosity of the screen, upon application of the second and more intense X-ray signal is quite rapid and immediately after the peak in luminosity has been reached, the second X-ray irradiation may be stopped.
- the total quantity of X-rays to which the object is exposed need only be relatively small in order to obtain a bright image.
- the foregoing method may be utilized in X-raying both animate and inanimate objects. If a living object is to be X-rayed and difficulty is anticipated in keeping the object stationary, the presensitization period may be shortened by increasing the X-ray intensity and decreasing the exposure time to achieve the desired value of Q (X-ray intensity times time). lmmediately thereafter the field may be removed and the X-ray irradiation simultaneously increased to the desired value in order to achieve the peak in luminosity, such as shown by point X in Fig. 5. Thereafter, the second X-ray irradiation is stopped.
- the time interval between presensitization and the application of the second applied X-ray signal may be extended considerably, if desired, and even after 17 hours the presensitized screen still retains a considerable portion of the stored or memorized image. Also, irradiation of the presensitized screen with visiblel light or ultraviolet will impair the presensitization.
- the objects of the invention have been achieved by providing a method for varying the contrast in the luminous response to an X-ray signal of an X-ray responsive phosphor screen.
- the brightness of the screen may be enhanced simultaneously with the contrast, without appreciably increasing the quantity of X-ray signal irradiation which is used to excite the screen.
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- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- High Energy & Nuclear Physics (AREA)
- Image-Pickup Tubes, Image-Amplification Tubes, And Storage Tubes (AREA)
- Apparatus For Radiation Diagnosis (AREA)
- Luminescent Compositions (AREA)
Priority Applications (5)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US645742A US2885560A (en) | 1957-03-13 | 1957-03-13 | X-ray method |
FR1189995D FR1189995A (fr) | 1957-03-13 | 1957-10-11 | Mode de fonctionnement d'un appareil électroluminescent à rayons chi |
DE1958W0022831 DE1048645C2 (it) | 1957-03-13 | 1958-02-22 | |
GB7051/58A GB837172A (en) | 1957-03-13 | 1958-03-05 | Improvements in or relating to x-ray apparatus |
JP642858A JPS3411028B1 (it) | 1957-03-13 | 1958-03-12 |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US645742A US2885560A (en) | 1957-03-13 | 1957-03-13 | X-ray method |
Publications (1)
Publication Number | Publication Date |
---|---|
US2885560A true US2885560A (en) | 1959-05-05 |
Family
ID=24590288
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US645742A Expired - Lifetime US2885560A (en) | 1957-03-13 | 1957-03-13 | X-ray method |
Country Status (5)
Country | Link |
---|---|
US (1) | US2885560A (it) |
JP (1) | JPS3411028B1 (it) |
DE (1) | DE1048645C2 (it) |
FR (1) | FR1189995A (it) |
GB (1) | GB837172A (it) |
Cited By (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3096458A (en) * | 1960-07-19 | 1963-07-02 | Rca Corp | Electroluminescent device |
US3148276A (en) * | 1960-10-17 | 1964-09-08 | Edgerton Germeshausen & Grier | Method of increasing the response of photographic emulsions to radiation |
US3155861A (en) * | 1961-02-08 | 1964-11-03 | Westinghouse Electric Corp | Method for operating electroluminescent device |
US3233247A (en) * | 1963-08-28 | 1966-02-01 | Sylvania Electric Prod | Electroluminescent photographic reproduction device |
US3344300A (en) * | 1965-03-23 | 1967-09-26 | Hughes Aircraft Co | Field sustained conductivity devices with cds barrier layer |
US3346756A (en) * | 1965-04-13 | 1967-10-10 | Robert J Doyle | Electrode support for an optical fiber disc |
US3430088A (en) * | 1966-09-30 | 1969-02-25 | Gen Electric | Wire terminal electroluminescent device and manufacture |
US3673450A (en) * | 1970-01-30 | 1972-06-27 | Spectra Tech Corp | Electroluminescent techniques and devices |
-
1957
- 1957-03-13 US US645742A patent/US2885560A/en not_active Expired - Lifetime
- 1957-10-11 FR FR1189995D patent/FR1189995A/fr not_active Expired
-
1958
- 1958-02-22 DE DE1958W0022831 patent/DE1048645C2/de not_active Expired
- 1958-03-05 GB GB7051/58A patent/GB837172A/en not_active Expired
- 1958-03-12 JP JP642858A patent/JPS3411028B1/ja active Pending
Non-Patent Citations (1)
Title |
---|
None * |
Cited By (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3096458A (en) * | 1960-07-19 | 1963-07-02 | Rca Corp | Electroluminescent device |
US3148276A (en) * | 1960-10-17 | 1964-09-08 | Edgerton Germeshausen & Grier | Method of increasing the response of photographic emulsions to radiation |
US3155861A (en) * | 1961-02-08 | 1964-11-03 | Westinghouse Electric Corp | Method for operating electroluminescent device |
US3233247A (en) * | 1963-08-28 | 1966-02-01 | Sylvania Electric Prod | Electroluminescent photographic reproduction device |
US3344300A (en) * | 1965-03-23 | 1967-09-26 | Hughes Aircraft Co | Field sustained conductivity devices with cds barrier layer |
US3346756A (en) * | 1965-04-13 | 1967-10-10 | Robert J Doyle | Electrode support for an optical fiber disc |
US3430088A (en) * | 1966-09-30 | 1969-02-25 | Gen Electric | Wire terminal electroluminescent device and manufacture |
US3673450A (en) * | 1970-01-30 | 1972-06-27 | Spectra Tech Corp | Electroluminescent techniques and devices |
Also Published As
Publication number | Publication date |
---|---|
GB837172A (en) | 1960-06-09 |
DE1048645B (it) | 1959-01-15 |
JPS3411028B1 (it) | 1959-12-26 |
FR1189995A (fr) | 1959-10-08 |
DE1048645C2 (it) | 1959-07-09 |
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