@misc{oai:repo.qst.go.jp:00065056,
 author = {Inadama, Naoko and Hirano, Yoshiyuki and Nishikido, Fumihiko and Murayama, Hideo and Nitta, Munetaka and Yamaya, Taiga and 稲玉 直子 and 平野 祥之 and 錦戸 文彦 and 村山 秀雄 and 新田 宗孝 and 山谷 泰賀},
 month = {Jun},
 note = {Objectives: We are developing a 3D position sensitive PET detector, X'tal cube. Multi-pixel photon counters (MPPCs) are coupled on all surfaces of the scintillation crystal block segmented 3 dimensionally into cubes. No reflector is inserted into the crystal block so that scintillation light spreads to all surfaces and is detected by all MPPCs. Previously, we presented a study comparing a block composed of small cubic scintillator elements and a block consisted of a monolithic scintillator segmented by laser processing technique. In order to analyze optical condition inside the laser processed crystal, we proposed the third approach: a block with stacking scintillator plates segmented 2 dimensionally by laser. This approach involves secondary benefit of increasing a yield rate of laser-processed blocks. Because we got sufficient performance for the segmentation into 2 x 2 x 2 mm3, we examined a higher-resolution X'tal cube using scintillator plates segmented into 1 x 1 x 1 mm3 cubes.
\nMethods: We stacked 18 of LYSO plates with dimensions of 18 mm x 18 mm x 1 mm for the crystal block. Each plate was segmented to 18 x 18 array by the laser processing. The condition between the plates was air. 4 x 4 MPPCs of 50 micrometer type were coupled onto each surface of the crystal block. We used 22Na sources and selected the events caused by 511 keV gamma-rays by setting an appropriate energy window. Segment identification performance was evaluated in a 3D position histogram in which each segment response is appeared as the results of the Anger-type calculation using all MPPC signals. 
\nResults: Although there were a few overlapped segments, most responses were clearly identified. 
\nConclusions: We evaluated performance of the X'tal cube PET detector of 1 mm cubic segments based on a stack of laser-processed scintillator plates., Society of Nuclear Medicine and Molecular Imaging's (SNMMI) 2013 Annual Meeting},
 title = {Performance of the X'tal cube PET detector using 1 mm thick scintillator plates segmented to 1 x 1 mm2 by laser processing},
 year = {2013}
}