High-transparency coded apertures in planar nuclear medicine imaging: experimental results

David M. Starfield, David M. Rubin, Tshilidzi Marwala, Rex J. Keddy

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

1 Citation (Scopus)

Abstract

Coded apertures provide an alternative to collimators in gamma-ray imaging. Advances in the field of coded apertures have lessened the artifacts that are associated with the near-field geometry of nuclear medicine. Nevertheless, image resolution and the manufacturing techniques that are available are constrained by the thickness of the aperture material. Thickness artifacts result. Thin apertures are theoretically desirable, but high transparency results in a loss of contrast. Together with detector quantization effects, this leads to noise in the reconstructed image. Provided that the gamma camera has a sufficient bit-depth, and an appropriate number of counts of radioactivity are obtained, high transparency need not reduce the signal-to-noise ratio. An opaque coded aperture, with an attenuation of 97 %, was constructed by laser drilling a tungsten sheet. A highly transparent coded aperture, with an attenuation of 29 %, was obtained by laser ablating tungsten foil. A specialized aluminium gamma camera frame matches the coded aperture to the mounting mechanism of the gamma camera, and facilitates both alignment and rotation of the coded aperture - the latter for the application of a near-field artifact reduction technique. This paper includes simulation of the effect of count statistics on high-transparency coded aperture images, and presents experimental planar phantom-based results for both the opaque and the highly transparent coded apertures. The results are comparable to the simulations, and support the concept of high-transparency coded apertures in diagnostic nuclear medicine.

Original languageEnglish
Title of host publication2007 IEEE Nuclear Science Symposium and Medical Imaging Conference, NSS-MIC
Pages3151-3154
Number of pages4
DOIs
Publication statusPublished - 2007
Externally publishedYes
Event2007 IEEE Nuclear Science Symposium and Medical Imaging Conference, NSS-MIC - Honolulu, HI, United States
Duration: 27 Oct 20073 Nov 2007

Publication series

NameIEEE Nuclear Science Symposium Conference Record
Volume4
ISSN (Print)1095-7863

Conference

Conference2007 IEEE Nuclear Science Symposium and Medical Imaging Conference, NSS-MIC
Country/TerritoryUnited States
CityHonolulu, HI
Period27/10/073/11/07

ASJC Scopus subject areas

  • Radiation
  • Nuclear and High Energy Physics
  • Radiology, Nuclear Medicine and Imaging

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