量研学術機関リポジトリ「QST-Repository」は、国立研究開発法人 量子科学技術研究開発機構に所属する職員等が生み出した学術成果（学会誌発表論文、学会発表、研究開発報告書、特許等）を集積しインターネット上で広く公開するサービスです。 Welcome to QST-Repository where we accumulates and discloses the academic research results(Journal Publications, Conference presentation, Research and Development Report, Patent, etc.) of the members of National Institutes for Quantum Science and Technology.
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[Purpose] We proposed an add-on PET system integrated with a birdcage RF-coil for PET/MRI system based on 4-layered depth-of-interaction (DOI) detectors. The PET detectors are placed close to a head to achieve both high sensitivity and high spatial resolution even at the edge of the field of view (FOV). We constructed a new RF-coil for a second prototype of add-on PET, which is combined with 24 DOI-PET detectors and evaluated performance.
[Methods] The second prototype consisted of an RF-coil and 24 PET detector units with two PET detectors each. The detector units were shielded with carbon fiber shielding boxes. Each PET detector consisted of a 14 x 14 x 4-layer array of lutetium fine silicate (LFS) crystals (1.9 mm x 1.9 mm x 4.0 mm), an 8 x 8 multi-pixel photon counter (MPPC, S12641PA-050) array and a readout circuit board with an ASIC. The RF coil was dedicated to a 3T MRI (MAGNETOM Verio, Siemens).
In the evaluation, PET detector performances in simultaneous measurement and spatial resolutions of PET images were measured with a 22Na point-like source and a mini Derenzo phantom. Spin echo (SE) and echo planer imaging (EPI) techniques were used in the evaluation experiment of the simultaneous measurements.
[Results] The influence of the simultaneous measurements with MRI on the PET performance was negligible. All of 1.6 mm hot rods were distinguished in the phantom ezperiment.
[Conclusion] The influence of the simultaneous measurements with MRI on the PET performance was negligible. In addition, the superior spatial resolution of the PET images was obtained.
Development of second add-on PET/MRI prototype: Evaluation of PET imaging performance
