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Proceedings Paper

Coded Aperture Gamma-Ray Imaging With Stochastic Apertures
Author(s): A. Z. Akcasu; R . S. May; G. F. Knoll; W. L. Rogers; K. F. Koral; L. W. Jones
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Paper Abstract

Tracer doses of y-emitting, radio-labeled pharmaceuticals have been used for a number of years for tumor localization and to provide the clinician with regional information concerning organ function and blood flow. An image of the radio-pharmaceutical distribution is formed by means of the emitted y-rays. Elevated or depressed concentration of the tracer agent as reflected by hot or cold spots in the image is indicative of abnormalities. The y-rays, which must be of sufficient energy to penetrate tissue with minimum scattering and absorption, cannot be refracted or reflected so the image must be formed by aperture limitation; (i.e. a pinhole in lead or multi-channel collimators). Such an aperture is extremely inefficient with solid angle efficiencies on the order of 10-4; efficiency may be increased but only at the sacrifice of resolution or field of view. This, coupled with the need to minimize the radiation dose to the patient and to maintain reasonably short imaging times, results in low resolution images corrupted by noise arising from the statistical fluctuation of the y-photon emission. A typical 25 cm diameter image field seldom contains more than 1000 resolved image elements and the information is often carried by fewer than 100,000 photons.

Paper Details

Date Published: 1 May 1974
PDF: 12 pages
Proc. SPIE 0043, Application of Optical Instrumentation in Medicine II, (1 May 1974); doi: 10.1117/12.953885
Show Author Affiliations
A. Z. Akcasu, The University of Michigan (United States)
R . S. May, The University of Michigan (United States)
G. F. Knoll, The University of Michigan (United States)
W. L. Rogers, The University of Michigan (United States)
K. F. Koral, The University of Michigan (United States)
L. W. Jones, The University of Michigan (United States)

Published in SPIE Proceedings Vol. 0043:
Application of Optical Instrumentation in Medicine II
William R. Hendee; William C. Zarnstorff, Editor(s)

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