Low-Count 89 Zr Imaging Using a Long LSO-Based PET Scanner: A Simulation Study

Abstract

The high sensitivity of long axial field-of-view PET scanners enables effective low-count89Zr imaging. However, intrinsic background from lutetium oxyorthosilicate (LSO) crystals introduces random coincidences. This study evaluated image quality and the impact of LSO background in low-count89Zr PET using GATE Monte Carlo simulations of a NEMA IEC phantom and a patient-based phantom with varying lesion sizes and target-to-background ratios (TBRs). Images were reconstructed with vendor-specific software, both with and without LSO background. Simulated data were compared to experiments based on true and random coincidence statistics. The patient phantom was assessed using standardized uptake values (SUVmax, SUVmean). Activityreduced simulations with dose reduction factors (DRFs) from 2 to 40 showed increasing random fractions at lower activity levels, effectively identified by delayed window method. At high DRFs (20–40), a small negative bias (approx. 5%) in SUV values due to LSO was observed. The simulation framework tends to overestimate random fractions compared to experimental data, indicating the need for further optimization under ultra-low activity conditions. In general, the results suggest that low-count89Zr imaging is technically feasible up to DRF 40, although it involves trade-offs in noise, acquisition time, and detection of small and low-TBR lesions.

Authors 12

1. Philipp Mohr

   University Medical Center Groningen · University of Groningen

   Affiliation as printed

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

2. Peter Klever

   University Medical Center Groningen · University of Groningen

   Affiliation as printed

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

3. Jean Cabello
   Affiliation as printed

   Siemens Medical Solutions USA Inc.,Knoxville,Tennessee,United States of America

4. Z. Li

   University Medical Center Groningen · University of Groningen

   Affiliation as printed

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

5. Viet Dao

   University of Leeds

   Affiliation as printed

   University of Leeds,Department of Applied Mathematics,Leeds,United Kingdom

6. Joost F. Somsen

   University Medical Center Groningen · University of Groningen

   Affiliation as printed

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

7. David Sarrut

   Centre de Recherche en Acquisition et Traitement de l'Image pour la Santé

   Affiliation as printed

   University of Lyon, CREATIS,Lyon,France

8. Joyce van Sluis

   University Medical Center Groningen · University of Groningen

   Affiliation as printed

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

9. Adrienne H. Brouwers

   University Medical Center Groningen · University of Groningen

   Affiliation as printed

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

10. Adriaan A. Lammertsma

    University Medical Center Groningen · University of Groningen

    Affiliation as printed

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

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

    FH Aachen

    Affiliation as printed

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

12. Charalampos Tsoumpas

    University Medical Center Groningen · University of Groningen

    Affiliation as printed

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