Evaluation of PET imaging resolution using 350 μm pixelated CZT as a VP-PET insert detector

Yongzhi Yin, Ximeng Chen, Chongzheng Li, Heyu Wu, Sergey Komarov, Qingzhen Guo, Henric Krawczynski, Ling Jian Meng, Yuan Chuan Tai

Research output: Contribution to journalArticlepeer-review

Abstract

A cadmium-zinc-telluride (CZT) detector with 20 × 20 pitch pixels was studied in high-resolution positron emission tomography (PET) imaging applications. The PET imaging system was based on coincidence detection between a CZT detector and a lutetium oxyorthosilicate (LSO)-based Inveon PET detector in virtual-pinhole PET geometry. The LSO detector is a 20 × 20 array, with 1.6 mm pitches, and 10 mm thickness. The CZT detector uses ac 20 × 20 × 5 mm substrate, with 350 μm pitch pixelated anodes and a coplanar cathode. A NEMA NU4 Na-22 point source of 250 μm in diameter was imaged by this system. Experiments show that the image resolution of single-pixel photopeak events was 590 μm FWHM while the image resolution of double-pixel photopeak events was 640 μm FWHM. The inclusion of double-pixel full-energy events increased the sensitivity of the imaging system. To validate the imaging experiment, we conducted a Monte Carlo (MC) simulation for the same PET system in Geant4 Application for Emission Tomography. We defined LSO detectors as a scanner ring and 350 μm pixelated CZT detectors as an insert ring. GATE simulated coincidence data were sorted into an insert-scanner sinogram and reconstructed. The image resolution of MC-simulated data (which did not factor in positron range and acolinearity effect) was 460 mu;m at FWHM for single-pixel events. The image resolutions of experimental data, MC simulated data, and theoretical calculation are all close to 500 μm FWHM when the proposed 350 μm pixelated CZT detector is used as a PET insert. The interpolation algorithm for the charge sharing events was also investigated. The PET image that was reconstructed using the interpolation algorithm shows improved image resolution compared with the image resolution without interpolation algorithm.

Original languageEnglish (US)
Article number6710182
Pages (from-to)154-161
Number of pages8
JournalIEEE Transactions on Nuclear Science
Volume61
Issue number1
DOIs
StatePublished - Feb 2014

Keywords

  • Cadmium-zinc-telluride (CZT) detectors
  • Coincidence techniques
  • Imaging applications
  • Positron emission tomography (PET)

ASJC Scopus subject areas

  • Nuclear and High Energy Physics
  • Nuclear Energy and Engineering
  • Electrical and Electronic Engineering

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