Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1822532 | Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment | 2015 | 8 Pages |
Abstract
PET for small animal, IRI-microPET, was designed and built at the NSTRI. The scanner is made of four detectors positioned on a rotating gantry at a distance 50Â mm from the center. Each detector consists of a 10Ã10 crystal matrix of 2Ã2Ã10Â mm3 directly coupled to a PS-PMT. A position encoding circuit for specific PS-PMT has been designed, built and tested with a PD-MFS-2MS/s-8/14 data acquisition board. After implementing reconstruction algorithms (FBP, MLEM and SART) on sinograms, images quality and system performance were evaluated by energy resolution, timing resolution, spatial resolution, scatter fraction, sensitivity, RMS contrast and SNR parameters. The energy spectra were obtained for the crystals with an energy window of 300-700Â keV. The energy resolution in 511Â keV averaged over all modules, detectors, and crystals, was 23.5%. A timing resolution of 2.4Â ns FWHM obtained by coincidence timing spectrum was measured with crystal LYSO. The radial and tangential resolutions for 18F (1.15-mm inner diameter) at the center of the field of view were 1.81Â mm and 1.90Â mm, respectively. At a radial offset of 5Â mm, the FWHM values were 1.96 and 2.06Â mm. The system scatter fraction was 7.1% for the mouse phantom. The sensitivity was measured for different energy windows, leading to a sensitivity of 1.74% at the center of FOV. Also, images quality was evaluated by RMS contrast and SNR factors, and the results show that the reconstructed images by MLEM algorithm have the best RMS contrast, and SNR. The IRI-microPET presents high image resolution, low scatter fraction values and improved SNR for animal studies.
Related Topics
Physical Sciences and Engineering
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Instrumentation
Authors
S.Z. Islami rad, R. Gholipour Peyvandi, M. Askari lehdarboni, A.A. Ghafari,