Characterization and Initial Optimization of Reconstruction Performance for Detector Crosstalk of Ultrahigh Performance Brain PET Imager.
6 affiliations
- 1Department of Biomedical Engineering, Yale University, New Haven, CT 06519 USA.
- 2Department of Radiology and Biomedical Imaging, Yale University, New Haven, CT 06519 USA.
- 3United Imaging Healthcare America, Houston, TX 77054 USA.
- 4United Imaging Healthcare, Shanghai 201807, China.
- 5Department of Biomedical Engineering, University of California, Davis, Davis, CA 95616 USA.
- 6Department of Radiology and Biomedical Imaging and the Department of Biomedical Engineering, Yale University, New Haven, CT 06519 USA.
Abstract
The NeuroEXPLORER (NX) is a next-generation, ultrahigh-performance brain positron emission tomography/computed tomography (PET/CT) system designed for both high spatial resolution and sensitivity. To meet high-sensitivity (HS) requirements, the system uses 2-cm-long scintillation crystals, while the novel U-shaped depth-of-interaction (DOI) encoding and small crystal elements enable high resolution. However, using long, small crystals increases signal crosstalk between crystals arising from Compton scattering, photoelectron escape, and incomplete optical isolation, which can degrade spatial resolution. Although the NX electronics detect crosstalk between microblocks and support real-time recovery using measured energy, accurate identification of the first interaction point is not always possible. Incorporating crosstalk events increases coincidence sensitivity by approximately 50% but compromises spatial resolution. Given such a large fraction of detector crosstalk, evaluating its impact on reconstruction performance in the NX is imperative. In this work, we evaluated image resolution in three reconstruction modes: (HS; all events), higher resolution (HR; noncrosstalk events), and lower resolution (LR; crosstalk events), using real phantoms and human studies with multiple tracers. Guided by the resolution characterization of the HYDRA-OLG brain phantom, we introduced a two-Gaussian mixture point spread function (2G-PSF) for HS reconstruction to improve contrast while suppressing noise. At matched iterations, HR yielded the highest image contrast, HS showed slightly reduced contrast, and LR exhibited the largest partial volume effect, as expected. Modeling crosstalk with the 2G-PSF for HS increased contrast toward HR levels without sacrificing sensitivity. Overall, these results provide a practical strategy for including crosstalk events in high-resolution PET systems while mitigating their impact on spatial resolution.
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BibTeX
@article{zhang2026characterization,
title = {{Characterization and Initial Optimization of Reconstruction Performance for Detector Crosstalk of Ultrahigh Performance Brain PET Imager.}},
author = {Jiazhen Zhang and Kathryn Fontaine and Tiantian Li and Paul Gravel and Takuya Toyonaga and Yifan Hu and Jean-Dominique Gallezot and Tianyi Zeng and Tommaso Volpi and Yihuan Lu and Thibault Marin and Jinyi Qi and Richard E Carson},
journal = {IEEE transactions on radiation and plasma medical sciences},
year = {2026},
month = jun,
doi = {10.1109/trpms.2026.3698769},
url = {https://europepmc.org/article/MED/42890279},
note = {CC BY},
}
RIS
TY - JOUR
TI - Characterization and Initial Optimization of Reconstruction Performance for Detector Crosstalk of Ultrahigh Performance Brain PET Imager.
AU - Jiazhen Zhang
AU - Kathryn Fontaine
AU - Tiantian Li
AU - Paul Gravel
AU - Takuya Toyonaga
AU - Yifan Hu
AU - Jean-Dominique Gallezot
AU - Tianyi Zeng
AU - Tommaso Volpi
AU - Yihuan Lu
AU - Thibault Marin
AU - Jinyi Qi
AU - Richard E Carson
PY - 2026
DA - 2026/06/01
JO - IEEE transactions on radiation and plasma medical sciences
DO - 10.1109/trpms.2026.3698769
UR - https://europepmc.org/article/MED/42890279
AB - The NeuroEXPLORER (NX) is a next-generation, ultrahigh-performance brain positron emission tomography/computed tomography (PET/CT) system designed for both high spatial resolution and sensitivity. To meet high-sensitivity (HS) requirements, the system uses 2-cm-long scintillation crystals, while the novel U-shaped depth-of-interaction (DOI) encoding and small crystal elements enable high resolution. However, using long, small crystals increases signal crosstalk between crystals arising from Compton scattering, photoelectron escape, and incomplete optical isolation, which can degrade spatial resolution. Although the NX electronics detect crosstalk between microblocks and support real-time recovery using measured energy, accurate identification of the first interaction point is not always possible. Incorporating crosstalk events increases coincidence sensitivity by approximately 50% but compromises spatial resolution. Given such a large fraction of detector crosstalk, evaluating its impact on reconstruction performance in the NX is imperative. In this work, we evaluated image resolution in three reconstruction modes: (HS; all events), higher resolution (HR; noncrosstalk events), and lower resolution (LR; crosstalk events), using real phantoms and human studies with multiple tracers. Guided by the resolution characterization of the HYDRA-OLG brain phantom, we introduced a two-Gaussian mixture point spread function (2G-PSF) for HS reconstruction to improve contrast while suppressing noise. At matched iterations, HR yielded the highest image contrast, HS showed slightly reduced contrast, and LR exhibited the largest partial volume effect, as expected. Modeling crosstalk with the 2G-PSF for HS increased contrast toward HR levels without sacrificing sensitivity. Overall, these results provide a practical strategy for including crosstalk events in high-resolution PET systems while mitigating their impact on spatial resolution.
SN - 2469-7311
SN - 2469-7303
ER -