TY - JOUR
T1 - Studies on sub-millimeter LYSO:Ce, Ce:GAGG, and a new Ce:GFAG block detector for PET using digital silicon photomultiplier
AU - Ullah, Muhammad Nasir
AU - Pratiwi, Eva
AU - Park, Jin Ho
AU - Yamamoto, Seiichi
AU - Kamada, Kei
AU - Yoshikawa, Akira
AU - Yeom, Jung Yeol
N1 - Funding Information:
This study was supported in part by MSIT (Ministry of Science and ICT), Korea, under the ITRC (Information Technology Research Center), Korea support program ( IITP-2018-2016-0-00309-002 ) supervised by the IITP (Institute for Information & communications Technology Promotion), National Research Foundation of Korea ( NRF-2017M2A2A6A02020807 , NRF-2017R1A1A1A05001284 , and NRF-2017M2A2A4A01071240 ), and Korea Health Technology R&D Project through the Korea Health Industry Development Institute (KHIDI) funded by the Ministry of Health & Welfare, Republic of Korea ( HI17C0654 ).
Funding Information:
This study was supported in part by MSIT (Ministry of Science and ICT), Korea, under the ITRC (Information Technology Research Center), Korea support program (IITP-2018-2016-0-00309-002) supervised by the IITP (Institute for Information & communications Technology Promotion), National Research Foundation of Korea (NRF-2017M2A2A6A02020807, NRF-2017R1A1A1A05001284, and NRF-2017M2A2A4A01071240), and Korea Health Technology R&D Project through the Korea Health Industry Development Institute (KHIDI) funded by the Ministry of Health & Welfare, Republic of Korea (HI17C0654).
Publisher Copyright:
© 2018
PY - 2018/12/11
Y1 - 2018/12/11
N2 - The spatial, timing, and energy resolutions of a detector affect the image quality of a positron emission tomography (PET) system. These parameters are in turn dependent on various factors, such as the choice of scintillator, photodetectors, reflector material, and surface treatment (rough or polished) of the scintillators. In this study, we investigated the performances of sub-millimeter scintillator array, LYSO:Ce (polished and rough surfaces with BaSO[Formula presented]reflector or enhanced specular reflector (ESR)), a gadolinium aluminum gallium garnet (Ce:GAGG, rough surface with BaSO[Formula presented]reflector), and a new gadolinium fine aluminum gallate (Ce:GFAG, rough surface with BaSO[Formula presented]reflector) detectors. The outer dimension of each scintillator block was [Formula presented]12 [Formula presented] 12 mm with a 12 [Formula presented] 12 matrix of 0.9 [Formula presented] 6 mm3 crystal elements. These blocks were optically coupled to a digital silicon photomultiplier (dSiPM, DPC-3200-22-44) with a 1 mm thick optical guide. Experiments were conducted at a sensor temperature of [Formula presented]15 °C, and a two-dimensional position histogram for 22Na gamma photons showed that all pixels were clearly resolved for all block detectors (peak-to-valley ratios ranging from 5.3 to 11.1). The average energy resolutions for the LYSO (ESR, rough), LYSO (ESR, polished), LYSO (BaSO4, rough), LYSO (BaSO4, polished), GAGG (BaSO4, rough), and GFAG (BaSO4, rough) arrays were measured as 11.3%, 10.2%, 18.7%, 10.3%, 10.0%, and 13.2% full width at half maximum (FWHM), respectively. The coincidence resolving times (with 3 [Formula presented] 3 [Formula presented] 5 mm3 LYSO crystal as reference) for the LYSO (ESR, rough), LYSO (ESR, polished), LYSO (B aSO4, rough), LYSO (BaSO4, polished), GAGG (BaSO4, rough), and GFAG (BaSO4, rough) arrays were 209 ps, 222 ps, 197 ps, 230 ps, 321 ps, and 276 ps, respectively. In conclusion, the new GFAG scintillator may be a promising candidate for future high-resolution time-of-flight (ToF) PET systems, considering the tradeoff between its performance and potential to be grown at a lower cost.
AB - The spatial, timing, and energy resolutions of a detector affect the image quality of a positron emission tomography (PET) system. These parameters are in turn dependent on various factors, such as the choice of scintillator, photodetectors, reflector material, and surface treatment (rough or polished) of the scintillators. In this study, we investigated the performances of sub-millimeter scintillator array, LYSO:Ce (polished and rough surfaces with BaSO[Formula presented]reflector or enhanced specular reflector (ESR)), a gadolinium aluminum gallium garnet (Ce:GAGG, rough surface with BaSO[Formula presented]reflector), and a new gadolinium fine aluminum gallate (Ce:GFAG, rough surface with BaSO[Formula presented]reflector) detectors. The outer dimension of each scintillator block was [Formula presented]12 [Formula presented] 12 mm with a 12 [Formula presented] 12 matrix of 0.9 [Formula presented] 6 mm3 crystal elements. These blocks were optically coupled to a digital silicon photomultiplier (dSiPM, DPC-3200-22-44) with a 1 mm thick optical guide. Experiments were conducted at a sensor temperature of [Formula presented]15 °C, and a two-dimensional position histogram for 22Na gamma photons showed that all pixels were clearly resolved for all block detectors (peak-to-valley ratios ranging from 5.3 to 11.1). The average energy resolutions for the LYSO (ESR, rough), LYSO (ESR, polished), LYSO (BaSO4, rough), LYSO (BaSO4, polished), GAGG (BaSO4, rough), and GFAG (BaSO4, rough) arrays were measured as 11.3%, 10.2%, 18.7%, 10.3%, 10.0%, and 13.2% full width at half maximum (FWHM), respectively. The coincidence resolving times (with 3 [Formula presented] 3 [Formula presented] 5 mm3 LYSO crystal as reference) for the LYSO (ESR, rough), LYSO (ESR, polished), LYSO (B aSO4, rough), LYSO (BaSO4, polished), GAGG (BaSO4, rough), and GFAG (BaSO4, rough) arrays were 209 ps, 222 ps, 197 ps, 230 ps, 321 ps, and 276 ps, respectively. In conclusion, the new GFAG scintillator may be a promising candidate for future high-resolution time-of-flight (ToF) PET systems, considering the tradeoff between its performance and potential to be grown at a lower cost.
KW - Digital silicon photomultiplier
KW - Scintillation detector
KW - Time-of-flight positron emission tomography
KW - Timing resolution
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U2 - 10.1016/j.nima.2018.09.029
DO - 10.1016/j.nima.2018.09.029
M3 - Article
AN - SCOPUS:85054903032
SN - 0168-9002
VL - 911
SP - 115
EP - 122
JO - Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
JF - Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
ER -