@misc{oai:repo.qst.go.jp:00086015,
 author = {Go, Akamatsu and Miwako, Takahashi and Yuma, Iwao and Hideaki, Tashima and Eiji, Yoshida and Makoto, Higuchi and Taiga, Yamaya and Go, Akamatsu and Miwako, Takahashi and Yuma, Iwao and Hideaki, Tashima and Eiji, Yoshida and Makoto, Higuchi and Taiga, Yamaya},
 month = {Apr},
 note = {[Purpose] We developed the world’s first helmet-type time-of-flight (TOF) PET, which had a hemispherical detector arrangement. The developed system is characterized as its high-performance and compactness as well as an unusual seat-type design which enables keeping the subject’s eye view wide. Here, we report the basic performance characteristics and the first FDG imaging results of healthy volunteers. 

[Methods] The helmet-type PET consisted of 54 detectors. The 45 detectors were arranged to form a hemisphere and the other 9 detectors were placed to form a half-ring behind the neck. The detector was composed of 12×12 lutetium fine silicate (LFS) scintillators (4×4×10 mm3) connected to a 12×12 silicon photomultiplier (SiPM) array with one-to-one coupling. The energy window was 450–590 keV and the coincidence time window was 3.6 ns. Image reconstruction was performed using 3D-OSEM with 4 iterations and 8 subsets. The performance was characterized based on the NEMA NU2 standards. The coincidence timing resolution was measured using a 22Na point source. 18F-FDG PET and MRI were performed for 11 normal control subjects. The PET data were measured for 10 minutes starting at 45 minutes after injection of 285±23 MBq. 

[Results] The coincidence timing resolution was 235 ps. With the sensitivity gain of 5.7 (= 20-cm-diameter object / 3.5 cm TOF localization), the effective sensitivity was 24 cps/kBq and the effective noise-equivalent count ratio was 120 kcps@9 kBq/mL. The spatial resolution of the FBP image was 2.9 mm at the central position (1 cm offset) of the field-of-view. For the human FDG PET images, the gray matter was clearly visualized with a high contrast to the white matter. Small brain nuclei such as the substantia nigra, the red nucleus, and the superior colliculus were able to be identified.

[Conclusion] We have successfully demonstrated first human imaging on the helmet-type PET., 第78回日本放射線技術学会総会学術大会},
 title = {FDG healthy volunteer imaging with the world’s first helmet-type brain PET},
 year = {2022}
}