@misc{oai:repo.qst.go.jp:00080860,
 author = {Kang, Hangyu and Kang, Hangyu},
 month = {Nov},
 note = {Previously for small animal positron emission tomography (PET), we developed the trapezoid geometry depth-of-interaction (DOI) detector using a sub-surface laser engraving (SSLE) technique. However, the required DOI calibration should be done with collimated beams which takes a long time. This problem can be solved by segmenting the detector crystal in the DOI direction using SSLE. In this study, we present the preliminary results obtained for a DOI detector with a laser processed trapezoid shape LYSO crystal for a small animal DOI PET scanner. The proposed DOI detector consisted of three trapezoid shape LYSO crystal plates.  Each 20 mm long LYSO plate (top =  15.3 mm, bottom = 25.6 mm, thickness = 0.9 mm) was segmented into a 15 × 10 array by using SSLE to yield a top crystal pitch of 1.02 mm, a bottom crystal pitch of 1.71 mm, and DOI bin of 2.0 mm (10 segments). Unlike our previous work, the crystal was segmented in the DOI direction to provide discretized DOI information. The LYSO plates were optically isolated by using an enhanced specular reflector (ESR). A 7×6 array of SiPMs (S13360-2050VE, Hamamatsu Photonics, Japan) with a pixel pitch of 2.4 mm and an 8×4 array of SiPMs (S13361-3050NE-04, Hamamatsu Photonics) with a pixel pitch of 3.2 mm were coupled to the top and bottom surfaces of the trapezoid LYSO array, respectively. The SiPM output signals were multiplexed by using a resistive network, and then digitized using the CAMAC DAQ. We could identify all the 15×3 crystals in the 2D flood map of the back SiPMs. Nine of ten DOI segments could be identified and each had a 2 mm DOI bin. The measured energy resolution was 11.4±1.2%. In the future, we plan to increase the number of crystals in the axial direction to use the full sensitive area of the SiPM., 2020 Virtual IEEE Nuclear Science Symposium and Medical Imaging Conference},
 title = {Discretized DOI Encoding of a Trapezoid Shape PET Detector Made Using 3D Sub-Surface Laser Engraving},
 year = {2020}
}