X-ray intensifying screen may make possible radiographic procedures where detection speed and X-ray tube power have been the limiting factors. Device will reduce total population exposure to harmful radiation in the United States

Buchanan, R. A.

English

NASA Technical Reports Server

. 
May 1972	
R1 1313
K3C HQS	 B72-10232 
•	
US 
 
Stye 
AEC-NASA Tech Briefs announce new technology derived from the research and development program of the U.S. 
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Improved Intensifying Screen Reduces X-Ray Exposure 
I 
IX 
 
%4_ 
L Medical X-Ray Film(Blue Sensitive)
- (Green Sensitive)
\\ 
CoW04 Emission 
(Scale Expanded) 
- --'- - 
1 
U) 
C 
C 
C 
0 
'I) U) 
E 
Lii 
0 
0. 
0 
a.
Gd2O2S:Tb 
Emission
U-
0 
U) C 
U, 
0 
-j 
4000	 5000	 6000
	
7000 
Wavelength (A ) 
Spectral Emission of CaW0 4 and Gd 202S:Tb 
A terbium-activated gadolinium oxysulfide 
(Gd2O2S:Tb) intensifying screen increases the sensitivi-
ty of x-ray film by a factor of 2 when compared to a 
standard calcium tungstate (CaW04) screen. Optimizing 
the film to this new x-ray phosphor can increase film 
sensitivity by a factor of 20. Consequently, x-ray ex-
posure can be reduced comparably without changing 
the quality of present images.
Terbium-activated gadolinium oxysulfide has over 
five times the intrinsic luminescense efficiency of 
CaW04 , with its emissions primarily in the green spec-
tral range near 5400 A. Calcium tungstate, on the other 
hand, emits a broadband which peaks in the blue spec-
0 tral range near 4200 A. The figure compares the two 
spectra; the CaW04 intensity scale is expanded for 
clarity.
(continued overleaf) 
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The spectral sensitivity of medical x-ray film (see 
figure) has developed over the years to match the blue 
emission from CaW04 . The sensitivity range of this 
blue-sensitive film does not include the principle emis-
sion from Gd202S:Tb. There does exist, however, a 
green-sensitive film with the spectral sensitivity range 
shown. Using the green-sensitive film with a Gd2O2S:Tb 
screen, 1/18 of the x-ray exposure is needed to get film 
darkening equivalent to that obtained using a CaWO4 
screen. Using the blue-sensitive film with a Gd202S:Tb 
screen, 1/2 the exposure is neededfor equivalent dark-
ening. An even larger exposure reduction (about 1/20 
of that presently required) will be possible when a new 
photographic film with maximum sensitivity near 5400 A 
is developed for the new screens. 
The new x-ray intensifying screen may make 
possible new radiographic procedures where detection 
speed and x-ray tube power have previously been the 
limiting factors. It will also significantly reduce the 
total population exposure to harmful radiation in the 
United States.
Note:
Requests for further information may be directed 
to:
Mr. Glenn K. Ellis 
Technology Utilization Officer 
Office of Information Services 
U.S. Atomic Energy Commission 
Washington, D.C. 20545 
Reference: TSP72- 10232 
Patent status: 
Inquiries concerning rights for commercial use of 
this information may be made to: 
Mr. George H. Lee, Chief 
Chicago Patent Group 
U.S. Atomic Energy Commission 
Chicago Operations Office 
9800 South Cass Avenue 
Argonne, Illinois 60439 
Source: R. A. Buchanan 
Lockheed Aircraft Corporation

under contract to

Atomic Energy Commission 
(AEC-10090) 
a 
B72-10232	 Category 03


Improved intensifying screen reduces X-ray exposure

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