A general-spectral method for improved quantitative SPECT imaging of indium- 111

Stephen C. Moore, Mi Ae Park, Georges El Fakhri, Victor H. Gerbaudo, Robert E. Zimmerman

Research output: Contribution to journalConference articlepeer-review

1 Scopus citations


Improved Indium-111 SPECT imaging should lead to better dose specification in radiotherapy treatment planning; however, photon scatter and down-scatter from the 245- to the 171-keV photopeak represent significant challenges for quantitative SPECT. We have extended to 111In a general-spectral (GS) scatter-compensation method. List-mode acquisitions of a 1.6-cm-diam. sphere containing 111In were obtained with the sphere in three different locations on the major axis of a water-filled elliptical cylinder. The sphere was then removed, the phantom was injected with 111In, repositioned, and scanned repeatedly. High-count, list-mode data from separate sphere and background scans were rebinned into 10-keV windows from 100-280 keV. Attenuated projections, free of scatter and noise, were simulated for use in a least-squares procedure to optimize GS coefficients for a sphere activity-estimation task. Scattered photons in both photopeaks were estimated separately from synthetic noisy projections under different conditions of activity contrast and sphere location; projections were reconstructed with our joint, multi-energy OSEM program. The bias of sphere activity values estimated from projections was less than 7% for both photopeaks and for all contrast values ranging from 2:1 to 8:1; the bias (precision) of sphere activity estimated from OSEM reconstructions was less than 8.5% (3%) for all sphere positions. The GS compensation method is a promising approach for quantitative 111In SPECT.

Original languageEnglish (US)
Article numberM9-347
Pages (from-to)3682-3684
Number of pages3
JournalIEEE Nuclear Science Symposium Conference Record
StatePublished - 2004
Externally publishedYes
Event2004 Nuclear Science Symposium, Medical Imaging Conference, Symposium on Nuclear Power Systems and the 14th International Workshop on Room Temperature Semiconductor X- and Gamma- Ray Detectors - Rome, Italy
Duration: Oct 16 2004Oct 22 2004

ASJC Scopus subject areas

  • Radiation
  • Nuclear and High Energy Physics
  • Radiology Nuclear Medicine and imaging


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