APPARATUS AND METHOD FOR PRODUCING a television camera which produces an image for view
IMAGES CORRESPONDING TO PATTERNS OF ing or recording by well known means.
HIGH ENERGY RADIATION Recorded thermal images called thermograms are
FIELD OF THE INVENTION obtainable by the prior art method of optically scan
; 5 ning an infrared detector over a field of view to pro
The instant invention relates to a system for radiogra- duce electrical signals in accordance with the infrared
phy and more particularly to an apparatus and method radiance exhibited by objects in the scanned field of
for converting a pattern of high energy radiation into view The method applies amplified and processed sig
a recorded image using an intermediate energy storing nals from the infrared detector to a glow modulator
medium. 10 tube. The tube output scans a light sensitive surface
BACKGROUND OF THE INVENTION synchronously with the scanning of the field of view to
„. .. „ „ , , . , provide the thermogram. Signals from the infrared de
Since x-rays are practically unfocusable with conven- f . . . .. 5 i . .if i Ji. . u .
. • . . • . • tector intensity modulate the glow modulator tube to
tional optical apparatus, prior art x-ray devices typi- , ,, , , ... . . , . , .,
„ ..r. .c . . \. , , / ., ,. r . produce a black and white picture in which the point
cally utilize contact printing and do not provide direct 15 f. ... . . , ...... <■ .
... i.-r. %u r j • . r intensities of the picture are related to the infrared ra
lmage reduction capability. Therefore, a need exists for ,. , v ,. ...
j .u J u- u -ii -j J- diance of corresponding points in the scanned tie d ot
an apparatus and method which will provide a direct, . y 5 y
small format image representative of a large format v,ew
pattern of high energy radiation without the necessity BRIEF SUMMARY OF THE INVENTION
of a large format radiographic film exposure. 20 ....
In accordance with the present invention, there is
DESCRIPTION OF THE PRIOR ART provided an apparatus and method for recording an Several prior art systems for the storage of an image ima8e representative of an intensity pattern of high enrepresentative of an incident pattern of high energy ra- ergy radiation onto a storage medium. A temporary diation exit. U.S. Pat. Nos. 2,482,813 and 2,482,814 to 25 storage medium, for example, any of certain phosphor F. Urbach disclose devices for storing images produced screens described below, stores energy from a high enby incident ultraviolet light. The stored images are sub- ergy incident pattern of x-rays or other such high ensequently retrieved by stimulation with red or infrared ergy electromagnetic or particulate radiation. An infraradiation or by direct heating of the layer. Scanning, as red or heat source releases the energy stored with the an image readout alternative, is taught in U.S. Pat. No. 30 high energy exposure. An appropriate sensing device 2,482,813, whereas U.S. Pat. No. 2,482,814 shows the receives the emitted energy and produces an electrical uniform flooding of a doubly activated phosphor screen signal therefrom. The electrical signal which is preferawith short wavelength radiation. To form an image with bly amplified is converted into an image for recording the phosphor in printing relation to a photosensitive re- onto the desired storage medium, cording medium, light of a non-exciting wavelength ex- 35 The invention is particularly useful in recording an hausts the excitation of the phosphor in proportion to image representative of a large format high energy radithe intensity distribution of the exposure to record an ati0n intensity pattern, such as a human chest x-ray, image on the recording medium. onto a small format recording medium, such as microU.S. Pat. No. 2,482,815, also to F. Urbach, discloses fiim The invention is practiced without using the large a layer of doubly activated phosphor excited with short 40 format x.ray film required by prior art apparatus and wavelength radiation including x-rays and particulate methods.
radiation. The excited layer is placed in printing rela- In a preferred embodiment, an infrared or heat
tion to a layer of photosensitive material and stimulated source scans the phosphor screen to release the stored
to an image by uniformly distributed infrared light to e as intensit modulated Hghtj the scanned out
release the stored energy and expose the photosensitive Ught vafying m accordance with the image stored on
yf1/ , , ... , . ..on,., the screen. A sensor which is synchronizable with the
Other systems such as that disclosed in U.S. Pat. No. . . , •„•.■*-. u
~ .ei .T ,i, . .• i ui u energy releasing scan, such as an image intensifier tube,
2,468,452 to H. W. Leverenz utihze stimulable phos- ?J .. . ° . , . . ,.6, . . ,
;' .... . . receives the intensity modulated light and produces
phor screens which have the ability to store energy sup- ,„,.., -.ur P.- I.
v.. .... .. ., • j- .i u .u J . 50 eectnca energy in the form of a time varying electron
plied to them directly or indirectly by cathode ray i . • ■ ■ . A i . A ■ A
beams. When stimulated, the screens release energy in eTM8«°n °[ electrical signal modulated in accordance
the form of visible light. Materials such as those dis- the, intensity modulation of the ught.
closed in U.S. Pat. No 2,468,452 will absorb and store The electrical signal is preferably amplified. The s.g
cathode ray energy and give up a portion of this stored „ nal canualso be otherwise modified to obtain a better
energy as visible light when irradiated with infrared 55 lma8e than one obtainable on radiographic film with
light. Hence, phosphors that temporarily store high en- conventional x-ray contact printing methods. Some
ergy incident radiation patterns for retrieval as visible possible signal modifications are image intensification,
images an interval of time later by scanning or flooding signal-to-noise ratio improvement, and edge
with non-visible electromagnetic radiation, such as in- enhancement. Available electrical apparatus afford
frared, are known to those skilled in the art. other image improvements.
Another prior art system is shown in U.S. Pat. No. After modification, if any, the electrical signal is con
3,582,651 to Siedband. The device disclosed therein verted into a time varying modulated light beam which
provides for image storage and display. An image inten- scans a recording medium, such as microfilm, to record
sifier tube converts an incident x-ray pattern into a cor- 65 an image corresponding to the high energy radiation
responding electron image. The tube accelerates the pattern. The image recorded is, in accordance with a
electrons toward the output screen of the intensifier. preferred embodiment, much smaller than the pattern
The visible output screen image is optically coupled to of high energy radiation it represents.