@misc{oai:repo.qst.go.jp:00082882,
 author = {Go, Akamatsu and Eiji, Yoshida and Hideaki, Tashima and Shigeki, Ito and Miwako, Takahashi and Taiga, Yamaya and Go, Akamatsu and Eiji, Yoshida and Hideaki, Tashima and Shigeki, Ito and Miwako, Takahashi and Taiga, Yamaya},
 month = {Apr},
 note = {[Purpose] Breast-dedicated PET systems are categorized into two types: a ring-shaped detector arrangement and a dual (top and bottom) flat-panel detector arrangement. Although the flat-panel system allows imaging axillary lymph nodes from the same view as X-ray mammography, PET images are blurred (i.e. spatial resolution is degraded) along the direction connecting the detectors (defined as Z direction) due to the limited angular coverage. To compensate for this issue, we proposed a third type, a dual round-edge detector arrangement. The “round-edge” is a geometry in which the detector blocks at both edge positions were tilted toward the center of the field-of-view (FOV). For proof of concept, we developed a small prototype and evaluated the spatial resolution.
[Methods] The prototype was composed of 32 detector blocks (Top and bottom pairs of 2 rows × 8 columns). A 14×14 array of 1.45×1.45×15 mm3 GFAG scintillator was coupled with an 8×8 array of silicon photomultiplier (SiPM) with a photosensitive area of 3.0×3.0 mm2. A 22Na Derenzo-like multi-rod phantom (rod diameters: 1.6, 2.2, 3.0, 4.0, 5.0 and 6.0 mm) was used for spatial resolution measurement. The phantom was measured in the two directions (XY plane and XZ plane) at the center of the FOV. The flat-panel arrangement was also examined for comparison. 
[Results] In the XY plane, the 1.6 mm rods were clearly resolved in both arrangements. In the XZ plane, the round-edge arrangement significantly improved the spatial resolution compared with the flat-panel arrangement. While the flat-panel arrangement could not resolve the 3.0 mm rods, the round-edge arrangement clearly resolved the 2.2 mm rods. 
[Conclusion] We have demonstrated the dual round-edge detector arrangement can provide a better spatial resolution than the conventional flat-panel arrangement., 第121回日本医学物理学会学術大会},
 title = {Dual round-edge detector arrangement for breast PET: a proof of concept study},
 year = {2021}
}