Design and development of a high resolution animal SPECT scanner dedicated for rat and mouse imaging

Salar Sajedi, Navid Zeraatkar, Vahideh Moji, Mohammad Hossein Farahani, Saeed Sarkar, Hossein Arabi, Behnoosh Teymoorian, Pardis Ghafarian, Arman Rahmim, Mohammad Reza Ay

Research output: Contribution to journalArticlepeer-review

24 Scopus citations


A dedicated small-animal SPECT system, HiReSPECT, was designed and developed to provide a high resolution molecular imaging modality in response to growing research demands. HiReSPECT is a dual-head system mounted on a rotating gantry. The detection system is based on pixelated CsI(Na) scintillator crystals coupled to two Hamamatsu H8500 Position Sensitive Photomultiplier Tubes in each head. Also, a high resolution parallel-hole collimator is applied to every head. The dimensions of each head are 50 mm×100 mm, enabling sufficient transaxial and axial fields-of-view (TFOV and AFOV), respectively, for coverage of the entire mouse in single-bed position imaging. However, a 50 mm TFOV is not sufficient for transaxial coverage of rats. To address this, each head can be rotated by 90 degrees in order to align the larger dimension of the heads with the short body axis, allowing tomographic data acquisition for rats. An innovative non-linear recursive filter was used for signal processing/detection. Resolution recovery was also embedded in the modified Maximum-Likelihood Expectation Maximization (MLEM) image reconstruction code to compensate for Collimator-Detector Response (CDR). Moreover, an innovative interpolation algorithm was developed to speed up the reconstruction code. The planar spatial resolution at the head surface and the image spatial resolutions were 1.7 mm and 1.2-1.6 mm, respectively. The measurements followed by post-processing showed that the observed count rate at 20% count loss is about 42 kcps. The system sensitivity at the collimator surface for heads 1 and 2 were 1.32 cps/μCi and 1.25 cps/μCi, respectively. The corresponding values were 1.18 cps/μCi and 1.02 cps/μCi at 8 cm distance from the collimator surfaces. In addition, whole-body scans of mice demonstrated appropriate imaging capability of the HiReSPECT.

Original languageEnglish (US)
Pages (from-to)169-176
Number of pages8
JournalNuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
StatePublished - Mar 21 2014


  • Instrumentation
  • Small animal imaging

ASJC Scopus subject areas

  • Nuclear and High Energy Physics
  • Instrumentation


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