Multi-energy, single-isotope imaging using stacked detectors

B. S. McDonald, S. Shokouhi, H. H. Barrett, T. E. Peterson

Research output: Contribution to journalArticlepeer-review

6 Scopus citations


We investigated a scheme for concurrently detecting low- and high-energy emissions from 123I with a stacked silicon double-sided strip detector (DSSD) and modular scintillation camera (Modcam) from the FastSPECT II design. We sequentially acquired both low- and high-energy emission images of an 123I object with a prototype DSSD and a Modcam. A sandwich aperture increases spatial resolution in the low-magnification DSSD image via a smaller pinhole diameter and allows a higher magnification image on the Modcam. Molybdenum, the insert material, efficiently stops 20-30 keV photons due to its ∼20 keV K-edge. Theoretically, less than 10% of 159 keV photons interact in 0.035 cm thick sheet of molybdenum, while this thickness stops virtually all ∼30 keV photons. Thus, photons from both energy regions will be incident upon their respective detectors with little cross talk. With a multi-pinhole collimator, we can decode multiplexed images on the Modcam by making use of the lower-magnification DSSD image. This approach can provide an increase in system sensitivity compared to single-detector configurations. Using MCNP5 we examined the potential benefits and drawbacks of stacked detectors and the sandwich aperture for small-animal pinhole SPECT via the synthetic-collimator method. Simulation results encourage us to construct the novel aperture and use it with our new DSSDs designed for mounting in a transmission configuration.

Original languageEnglish (US)
Pages (from-to)196-199
Number of pages4
JournalNuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
Issue number1
StatePublished - Aug 21 2007


  • I
  • Monte Carlo
  • Pinhole collimator
  • Small-animal imaging

ASJC Scopus subject areas

  • Nuclear and High Energy Physics
  • Instrumentation


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