A dual layer DOI GSO block detector for a small animal PET

Yamamoto, Seiichi

doi:10.1016/j.nima.2008.09.014

Cited by 14 publications

(6 citation statements)

References 8 publications

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“…In this context, BGO and GSO have attracted considerable attention as high-efficiency gammaray absorbers, which stems from their high density. They have been used in various applications such as medical systems (e.g., for positron emission tomography) [21][22][23] and X-ray detectors on board space satellites (e.g., Suzaku and the International Gamma-Ray Astrophysics Laboratory (INTEGRAL)) [24,25]. Regarding activation characteristics, GSO has stronger tolerance to radiation than NaI:Tl and CsI:Tl [26][27][28], and BGO does not exhibit an afterglow [29].…”

Section: Jinst 13 P02023mentioning

confidence: 99%

Evaluation of GAGG:Ce scintillators for future space applications

et al. 2018

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Cerium-doped Gd3(Ga, Al)5O12 (GAGG:Ce) is a promising novel scintillator for gamma-ray detectors. While GAGG:Ce has already been implemented in various commercial products, its detailed characteristics and response to high-energy particles and gamma rays remain unknown. In particular, knowledge is lacking on the radiation tolerance of this scintillator against the gamma-ray and proton irradiation expected in future space satellite mission applications. In this study, we first investigate the light-yield energy dependence, energy resolution, decay time, radiation tolerance, and afterglow of GAGG:Ce scintillators under various temperature conditions. We find excellent linearity of ±3% between light yields and deposited energy over a wide range of 30–1836 keV; however, a light-yield deficit of more than 10% is observed below 30 keV of deposited gamma ray energy. We confirm that the temperature dependence of the light yield, energy resolution, and scintillation decay time is within 5–20% between −20 and 20 ̂C. We also evaluate the GAGG:Ce activation characteristics under proton irradiation and the light-yield degradation by accumulated dose using a 60Co source. Moreover, we successfully identify various gamma-ray lines due to activation. Finally, we find a substantial afterglow for GAGG:Ce scintillators over a few hours; such an afterglow is only minimally observed in other scintillators such as CsI:Tl and Bi4Ge3O12 (BGO). However, the afterglow can be substantially reduced through additional co-doping with divalent metal ions, such as Mg ions. These results suggest that GAGG:Ce is a promising scintillator with potential application in space satellite missions in the near future.

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Section: Jinst 13 P02023mentioning

confidence: 99%

Evaluation of GAGG:Ce scintillators for future space applications

et al. 2018

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“…The third layer made of a thin GSO scintillator with 0.4 mol% Ce (decay time: 70 ns) [17] detects gamma photons. Using pulse shape discrimination [18][19][20][21], the counts of these layers can be separated. The position information is calculated by the Anger principle from 8 Â 8 anode signals from the PSPMT.…”

Section: Methodsmentioning

confidence: 99%

Development of a three-layer phoswich alpha–beta–gamma imaging detector

Yamamoto

Ishibashi

2015

Nuclear Instruments and Methods in Physics Research Section A:

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a b s t r a c tFor radiation monitoring at the sites of such nuclear power plant accidents as Fukushima Daiichi, radiation detectors are needed not only for gamma photons but also for alpha and beta particles because some nuclear fission products emit beta particles and gamma photons and some nuclear fuels contain plutonium that emits alpha particles. In some applications, imaging detectors are required to detect the distribution of plutonium particles that emit alpha particles and radiocesium in foods that emits beta particles and gamma photons. To solve these requirements, we developed an imaging detector that can measure the distribution of alpha and beta particles as well as gamma photons. The imaging detector consists of three-layer scintillators optically coupled to each other and to a position sensitive photomultiplier tube (PSPMT). The first layer, which is made of a thin plastic scintillator (decay time: $ 5 ns), detects alpha particles. The second layer, which is made of a thin Gd 2 SiO 5 (GSO) scintillator with 1.5 mol% Ce (decay time: 35 ns), detects beta particles. The third layer made of a thin GSO scintillator with 0.4 mol% Ce (decay time: 70 ns) detects gamma photons. Using pulse shape discrimination, the images of these layers can be separated. The position information is calculated by the Anger principle from 8 Â 8 anode signals from the PSPMT. The images for the alpha and beta particles and the gamma photons are individually formed by the pulse shape discriminations for each layer. We detected alpha particle images in the first layer and beta particle images in the second layer. Gamma photon images were detected in the second and third layers. The spatial resolution for the alpha and beta particles was $ 1.25 mm FWHM and less than 2 mm FWHM for the gamma photons. We conclude that our developed alpha-beta-gamma imaging detector is promising for imaging applications not only for the environmental monitoring of radionuclides but also for medical and molecular imaging.

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“…Many methods have been developed to design DOI detectors with the single‐ended readout. One method is to use multiple layers of scintillator crystals arranged with offsets . However, the DOI detectors with multiple layer of crystals are difficult to construct and costly.…”

Section: Introductionmentioning

confidence: 99%

“…One method is to use multiple layers of scintillator crystals arranged with offsets. [22][23][24][25] However, the DOI detectors with multiple layer of crystals are difficult to construct and costly. Moreover, their DOI capabilities are limited by the number of layers.…”

Section: Introductionmentioning

confidence: 99%

A depth encoding PET detector using four‐crystals‐to‐one‐SiPM coupling and light‐sharing window method

et al. 2019

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Purpose Depth of interaction (DOI) decoding capability is of great importance for positron emission tomography (PET) requiring high resolution. In this study, we presented a novel low‐cost DOI detector design with four crystals coupling to one SiPM, based on the method of rectangular light‐sharing window (RLSW). A prototype detector was constructed, calibrated, and assessed using the methods of homogeneous radiation and flood map analysis. Methods The DOI detector was constructed with a 4 × 4 array of lutetium‐yttrium oxyorthosilicate (LYSO) crystals (2.95 mm × 2.95 mm × 20 mm3), barium sulfate (BaSO4) reflectors, and optical glues. A RLSW 7 mm in height was deployed in the BaSO4 reflectors. A non‐DOI detector with identical dimensions and without RLSW was also constructed for comparison. The light‐output surface of the detector was air‐coupled with a 4 × 4 array of SiPMs (3 mm × 3 mm2). The signals generated from the 16 SiPMs were read out by a custom‐designed electronic system, and the signals from four adjacent 3 mm SiPMs were summed into one signal to emulate a 2 × 2 array of 6 mm SiPMs. The RLSW caused the DOI‐related position shifts of the crystal spots in the flood map. A homogeneous radiation method was used to establish the transfer functions to convert the spot shifts measured from the flood map into DOI measurements. The accuracy of the DOI measurements was assessed with data acquired using the conventional collimated radiation method. Results All 16 crystals are distinctly separated from each other in the flood map. Twelve crystals, including four central crystals and eight edge crystals, have the DOI capability. The full width half maximum (FWHM) of the DOI measurements of the central crystals and the edge crystals are 3.06 ± 0.08 and 3.79 ± 0.15 mm, respectively, for the configuration with four crystals coupling to one SiPM. By contrast, the FWHMs (3.98 ± 0.16 and 5.12 ± 0.38 mm, respectively) are slightly worse for the configuration with one crystal coupling to one SiPM. The average and standard deviation (STD) of the FWHM energy resolutions of the DOI detector and non‐DOI detector were 10.2% ± 0.7% and 10.7% ± 1.7%, respectively. Their FWHM coincidence timing resolutions were 197.0 ± 9.6 and 206.4 ± 13.3 ps, respectively. The RLSW had no significant impact on the energy resolutions and timing resolutions of the DOI detector. Conclusions The novel four‐crystals‐to‐one‐SiPM coupling technology is a cost‐efficient approach to construct high‐performance detector modules with DOI capability. The methods of homogeneous radiation and flood map analysis are easy to perform and of good performance. Those methods can be adapted in the clinic PET scanners to enable the capability of DOI measurements.

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A dual layer DOI GSO block detector for a small animal PET

Cited by 14 publications

References 8 publications

Evaluation of GAGG:Ce scintillators for future space applications

Evaluation of GAGG:Ce scintillators for future space applications

Development of a three-layer phoswich alpha–beta–gamma imaging detector

A depth encoding PET detector using four‐crystals‐to‐one‐SiPM coupling and light‐sharing window method

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