Evaluation of a silicon photomultiplier PET insert for simultaneous PET and MR imaging

Authors

  • Ko Guen Bae,

    1. Department of Nuclear Medicine, Seoul National University College of Medicine, Seoul 110-799, South Korea and Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul 110-799, South Korea
    Search for more papers by this author
  • Kim Kyeong Yun,

    1. Department of Nuclear Medicine, Seoul National University College of Medicine, Seoul 110-799, South Korea and Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul 110-799, South Korea
    Search for more papers by this author
  • Yoon Hyun Suk,

    1. Department of Nuclear Medicine, Seoul National University College of Medicine, Seoul 110-799, South Korea and Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul 110-799, South Korea
    Search for more papers by this author
  • Lee Min Sun,

    1. Department of Nuclear Medicine, Seoul National University College of Medicine, Seoul 110-799, South Korea and Interdisciplinary Program in Radiation Applied Life Science, Seoul National University College of Medicine, Seoul 110-799, South Korea
    Search for more papers by this author
  • Son Jeong-Whan,

    1. Department of Nuclear Medicine, Seoul National University College of Medicine, Seoul 110-799, South Korea and Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul 110-799, South Korea
    Search for more papers by this author
  • Im Hyung-Jun,

    1. Department of Nuclear Medicine, Seoul National University College of Medicine, Seoul 110-799, South Korea
    Search for more papers by this author
  • Lee Jae Sung

    1. Department of Nuclear Medicine, Seoul National University College of Medicine, Seoul 110-799, South Korea; Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul 110-799, South Korea; Interdisciplinary Program in Radiation Applied Life Science, Seoul National University College of Medicine, Seoul 110-799, South Korea; and Institute of Radiation Medicine, Medical Research Center, Seoul National University College of Medicine, Seoul 110-799, South Korea
    Search for more papers by this author
    • a)

      Author to whom correspondence should be addressed. Electronic mail: jaes@snu.ac.kr; Telephone: +82-2-2072-2938; Fax: +82-2-745-2938.


Abstract

Purpose:

In this study, the authors present a silicon photomultiplier (SiPM)-based positron emission tomography (PET) insert dedicated to small animal imaging with high system performance and robustness to temperature change.

Methods:

The insert consists of 64 LYSO-SiPM detector blocks arranged in 4 rings of 16 detector blocks to yield a ring diameter of 64 mm and axial field of view of 55 mm. Each detector block consists of a 9 × 9 array of LYSO crystals (1.2 × 1.2 × 10 mm3) and a monolithic 4 × 4 SiPM array. The temperature of each monolithic SiPM is monitored, and the proper bias voltage is applied according to the temperature reading in real time to maintain uniform performance. The performance of this PET insert was characterized using National Electrical Manufacturers Association NU 4-2008 standards, and its feasibility was evaluated through in vivo mouse imaging studies.

Results:

The PET insert had a peak sensitivity of 3.4% and volumetric spatial resolutions of 1.92 (filtered back projection) and 0.53 (ordered subset expectation maximization) mm3 at center. The peak noise equivalent count rate and scatter fraction were 42.4 kcps at 15.08 MBq and 16.5%, respectively. By applying the real-time bias voltage adjustment, an energy resolution of 14.2% ± 0.3% was maintained and the count rate varied ≤1.2%, despite severe temperature changes (10–30 °C). The mouse imaging studies demonstrate that this PET insert can produce high-quality images useful for imaging studies on the small animals.

Conclusions:

The developed MR-compatible PET insert is designed for insertion into a narrow-bore magnetic resonance imaging scanner, and it provides excellent imaging performance for PET/MR preclinical studies.

Ancillary