A new reconstruction strategy for image improvement in pinhole SPECT

Tsutomu Zeniya, Hiroshi Watabe, Toshiyuki Aoi, Kyeong Min Kim, Noboru Teramoto, Takuya Hayashi, Antti Sohlberg, Hiroyuki Kudo, Hidehiro Iida

Research output: Contribution to journalArticlepeer-review

29 Citations (Scopus)

Abstract

Pinhole single-photon emission computed tomography (SPECT) is able to provide information on the biodistribution of several radioligands in small laboratory animals, but has limitations associated with non-uniform spatial resolution or axial blurring. We have hypothesised that this blurring is due to incompleteness of the projection data acquired by a single circular pinhole orbit, and have evaluated a new strategy for accurate image reconstruction with better spatial resolution uniformity. A pinhole SPECT system using two circular orbits and a dedicated three-dimensional ordered subsets expectation maximisation (3D-OSEM) reconstruction method were developed. In this system, not the camera but the object rotates, and the two orbits are at 90° and 45° relative to the object's axis. This system satisfies Tuy's condition, and is thus able to provide complete data for 3D pinhole SPECT reconstruction within the whole field of view (FOV). To evaluate this system, a series of experiments was carried out using a multiple-disk phantom filled with 99mTc solution. The feasibility of the proposed method for small animal imaging was tested with a mouse bone study using 99mTc- hydroxymethylene diphosphonate. Feldkamp's filtered back-projection (FBP) method and the 3D-OSEM method were applied to these data sets, and the visual and statistical properties were examined. Axial blurring, which was still visible at the edge of the FOV even after applying the conventional 3D-OSEM instead of FBP for single-orbit data, was not visible after application of 3D-OSEM using two-orbit data. 3D-OSEM using two-orbit data dramatically reduced the resolution non-uniformity and statistical noise, and also demonstrated considerably better image quality in the mouse scan. This system may be of use in quantitative assessment of biophysiological functions in small animals.

Original languageEnglish
Pages (from-to)1166-1172
Number of pages7
JournalEuropean journal of nuclear medicine and molecular imaging
Volume31
Issue number8
DOIs
Publication statusPublished - 2004 Aug
Externally publishedYes

Keywords

  • 3D-OSEM
  • Complete data
  • Pinhole SPECT
  • Small animal
  • Tuy's condition

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging

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