Image Reconstruction Analysis for Positron Emission Tomography With Heterostructured Scintillators

IEEE Transactions on Radiation and Plasma Medical Sciences, vol. 7, pp. 41–51

Abstract

The concept of structure engineering has been proposed for exploring the next generation of radiation detectors with improved performance. A TOF-PET geometry with heterostructured scintillators with a pixel size of$3.0 \times 3.1 \times 15\,\,\mathrm {mm^{3}}$was simulated using Monte Carlo. The heterostructures consisted of alternating layers of BGO as a dense material with high stopping power and plastic (EJ232) as a fast light emitter. The detector time resolution was calculated as a function of the deposited and shared energy in both materials on an event-by-event basis. While sensitivity was reduced to 32% for 100-$\mu \text{m}$thick plastic layers and 52% for$50~\mathrm {\mu m}$, the coincidence time resolution (CTR) distribution improved to 204 ± 49 and 220±41 ps, respectively, compared to 276 ps that we considered for bulk BGO. The complex distribution of timing resolutions was accounted for in the reconstruction. We divided the events into three groups based on their CTR and modeled them with different Gaussian TOF kernels. On an NEMA IQ phantom, the heterostructures had better contrast recovery in early iterations. On the other hand, BGO achieved a better contrast-to-noise ratio (CNR) after the 15th iteration due to the higher sensitivity. The developed simulation and reconstruction methods constitute new tools for evaluating different detector designs with complex time responses.

Authors 8

1. Philipp Mohr Aachen Factuly of Chemistry and Biotechnology

   University Medical Center Groningen · University of Groningen · European Organization for Nuclear Research · FH Aachen

   Affiliation as printed

   Factuly of Chemistry and Biotechnology, FH Aachen University of Applied Sciences, Jülich, Germany

   Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands

   Experimental Physics Department, European Organization for Nuclear Research (CERN), Geneva, Switzerland

2. Nikos Efthimiou

   University of Pennsylvania

   Affiliation as printed

   Department Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA

3. Fiammetta Pagano

   University of Milano-Bicocca · European Organization for Nuclear Research

   Affiliation as printed

   Experimental Physics Department, European Organization for Nuclear Research (CERN), Geneva, Switzerland

   Physics Department, University of Milano-Bicocca, Milan, Italy

4. N. Kratochwil

   European Organization for Nuclear Research

   Affiliation as printed

   Experimental Physics Department, European Organization for Nuclear Research (CERN), Geneva, Switzerland

5. Marco Pizzichemi

   University of Milano-Bicocca · European Organization for Nuclear Research

   Affiliation as printed

   Experimental Physics Department, European Organization for Nuclear Research (CERN), Geneva, Switzerland

   Physics Department, University of Milano-Bicocca, Milan, Italy

6. Charalampos Tsoumpas

   University of Leeds · University Medical Center Groningen · University of Groningen

   Affiliation as printed

   Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands

   Biomedical Imaging Science Department, Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, Leeds, U.K

7. E. Auffray

   European Organization for Nuclear Research

   Affiliation as printed

   Experimental Physics Department, European Organization for Nuclear Research (CERN), Geneva, Switzerland

8. K. Ziemons Aachen Faculty of Biomedical Engineering and Technomathematics

   FH Aachen

   Affiliation as printed

   Faculty of Biomedical Engineering and Technomathematics, FH Aachen University of Applied Sciences, Jülich, Germany