DocumentCode :
1849974
Title :
Time-coded apertures for imaging in high-background environments
Author :
Clinthorne, Neal H. ; Rogers, W. Leslie ; He, Zhong ; Wehe, David K.
Author_Institution :
Div. of Nucl. Med., Michigan Univ., Ann Arbor, MI, USA
Volume :
1
fYear :
1995
fDate :
21-28 Oct 1995
Firstpage :
70
Abstract :
There is an increasing need for systems capable of imaging gamma-ray sources at energies up to 1 MeV and beyond. Conventional collimation becomes ineffective at these energies because a significant fraction of the higher energy radiation penetrates the shielding resulting in a high level of background on the detector. To reduce effects of background, the authors examine the use of a time-coded pinhole aperture array. At each step of the temporal code, the source is viewed by a number of pinholes, multiplexing the images onto the detector. Since several holes are open simultaneously, the effective signal-to-background ratio is improved, and furthermore, the array of smaller pinholes preserves spatial resolution over a single, larger pinhole. Using simulations, the authors have compared the performance of a temporal code having 27% mean transmission with both a single pinhole system and a scanning pinhole code (one hole open per time step and a background measurement with all holes closed). Variance in source estimates demonstrates a significant improvement for the 27%, transmission code over the scanning and single pinholes at all background levels
Keywords :
gamma-ray detection; gamma-ray production; image resolution; radioisotope imaging; 1 MeV; diagnostic nuclear medicine; gamma-ray imaging; gamma-ray sources; high-background environments; scanning pinhole code; signal-to-background ratio; simulations; spatial resolution; temporal code; time-coded apertures; time-coded pinhole aperture array; variance; Apertures; Collimators; Gamma ray detection; Gamma ray detectors; Helium; Layout; Nuclear medicine; Optical imaging; Radiation detectors; Spatial resolution;
fLanguage :
English
Publisher :
ieee
Conference_Titel :
Nuclear Science Symposium and Medical Imaging Conference Record, 1995., 1995 IEEE
Conference_Location :
San Francisco, CA
Print_ISBN :
0-7803-3180-X
Type :
conf
DOI :
10.1109/NSSMIC.1995.504179
Filename :
504179
Link To Document :
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