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Investigation of scatter from out of the field of view and multiple scatter in pet using Monte Carlo simulations

Chinese Physics C 2011年第12期35卷 1166-1171页

作者：叶婷柴培高娟贠明凯刘双全单保慈魏龙 Key Laboratory of Nuclear Analysis Techniques Institute of High Energy Physics Chinese Academy of Sciences Graduate University of Chinese Academy of Sciences

In fully three-dimensional （3D） positron emission tomography （pet） imaging, the scatter fraction （SF） is about 40% 60%, which may degrade the imaging quality severely. Scatter correction is important for high quality image reconstruction. Model-based scatter correction has been proved to be accurate and available in clinical pet. However, it does not correct the scatter from out of the field of view （OFOV） and multiple scatters. In this study, we demonstrate the radial and axial distribution of scatters from OFOV when the source is located in different radial positions. In order to apply the above conclusions to different pet systems, we characterize the scatters from OFOV as a function of the ratio of the scanner diameter to the length of the axial field of view （AFOV） by modeling several typical whole-body and micro pet systems. The proportions of true events （S0-0）, single scatter of one photon （S1-0）, single scatter of both photons （S1-1）, double scatter of one photon （S2-0） and multiple scatter （Sm） are also calculated and compared. Here the 3D-pet Monte Carlo simulations are performed with the Geant4 Application for Tomography Emission （GATE）. In summary, the scatters from OFOV tend to be recorded on the lines of response （LOR） far away from the source. They have a much more serious impact on whole-body pet than micro pet depending on the ratio of scanner diameter to the length of AFOV. In whole-body pet, twice scatters including single scatter of both photons （S1-1） and double scatter of one photon （S2-0） add up to about 12% so that twice scatter correction must be taken into account to acquire a high quality reconstruction image.

关键词： pet Monte Carlo simulation GATE scattering

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Dual time point FDG pet imaging in evaluating pulmonary nodules with low FDG avidity

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Nuclear Science and Techniques 2010年第5期21卷 306-311页

作者： CHEN Xiang ZHAO Jinhua SONG Jianhua XING Yan WANG Taisong QIAO Wenli Department of Nuclear Medicine Shanghai First People's Hospital Shanghai Jiaotong University Shanghai China

A standardized uptake value(SUV) of 2.5 is frequently used as criteria to evaluate pulmonary ***,false results may *** studies have shown the usefulness of delayed pet for improving accuracy,while others recently have shown fewer promising *** study was designed to investigate the accuracy of dual time point(DTP) FDG pet imaging in the evaluation of pulmonary lesions with an initial SUV less than *** FDG pet studies were conducted about 1 and 2 hours after FDG injection,and pulmonary lesions with an initial SUV less than 2.5 were *** with pathologic results or imaging follow up were *** differences in SUV and retention index(RI) between benign and malignant pulmonary lesions were *** operating characteristics(ROC) analysis was performed to evaluate the discriminating validity of SUV and RI.51 lesions were finally included.A RI greater than 0% was observed in 64% of the benign lesions;56% had a RI greater than 10%.Among the malignancies,80.8% had a RI greater than 0%,and 61.5% had a RI greater than 10%.We found no significant differences in SUV and RI between benign and malignant *** area under the ROC curve did not differ from 0.5 whether using SUV or the retention *** a SUV increase of 10%,the sensitivity was 61.5%,specificity 44% and accuracy was 52.9%.Dual time point FDG pet may not be of benefit in the evaluation of pulmonary nodules with low FDG avidity.

关键词：肺病变 FDG pet 时间点亲和力评价显像结节

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Remote-controlled module-assisted synthesis of O-(2-[^(18)F]fluoroethyl)-L-tyrosine as tumor pet tracer using two different radiochemical routes

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Nuclear Science and Techniques 2006年第3期17卷 148-153页

作者： WANG Ming-Wei YIN Duan-Zhi ZHANG Lan ZHOU Wei WANG Yong-Xian Radiopharmaceutical Centre Shanghai Institute of Applied Physics the Chinese Academy of Sciences Shanghai 201800 China

The positron-emitter fluorine-18 labeled amino acid O-(2-[18F]fluoroethyl)-L-tyrosine ([18F]FET) has shown very promising perspectives for brain tumor diagnosis with positron emission tomography (pet). There have been two existing preparation routes of [18F]FET named direct nucleophilic radiofluorination of protected L-tyrosine and radiofluoroalkylation of unprotected L-tyrosine, respectively. A general module was designed specifically for the routine synthesis of [18F]FET, which could be suitable for the present two chemical methods with simple modifica- tions. The fluorinated intermediates and the final product were separated and purified using solid phase extraction (SPE) on the Sep-Pak silica plus cartridge instead of the time-consuming high performance liquid chromatography (HPLC) procedures. The total synthesis time was about 50—60 min with good radiochemical yield (about 20—40%, no-decay-corrected) and good radiochemical purity (more than 97%) for both the synthetic methods.

关键词： pet 氟化作用合成模块正电子发射亲质子

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Quantification of the impact of TOF and PSF on pet images using the noise-matching concept: clinical and phantom study

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Nuclear Science and Techniques 2017年第11期28卷 258-265页

作者： M. Shekari P. Ghafarian S. Ahangari M. R. Ay Department of Medical Physics and Biomedical Engineering Tehran University of Medical Sciences Tehran Iran Research Center for Molecular and Cellular Imaging Tehran University of Medical Sciences Tehran Iran Chronic Respiratory Diseases Research Center National Research Institute of Tuberculosis and Lung Diseases(NRITLD) Shahid Beheshti University of Medical SciencesTehran Iran pet/CT and Cyclotron Center Masih Daneshvari HospitalShahid Beheshti University of Medical Sciences Tehran Iran

This study was to assess quantitatively the accuracy of ^(18)F-FDG pet/CT images reconstructed by TOF+PSF and TOF only, considering the noise-matching concept to minimize probable bias in evaluating algorithm performance caused by noise. pet images of similar noise level were considered. Measurements were made on an inhouse phantom with hot inserts of Φ10–37 mm, and oncological images of 14 patients were analyzed. The pet images were reconstructed using the OSEM, OSEM+TOF and OSEM+TOF+PSF algorithms. Optimal reconstruction parameters including iteration, subset, and FWHM of post-smoothing filter were chosen for both the phantom and patient data. In terms of quantitative accuracy, the recovery coefficient(RC) was calculated for the phantom pet images. The signal-to-noise ratio(SNR),lesion-to-background ratio(LBR), and SUV_(max)were evaluated from the phantom and clinical data. The smallest hot insert(Ф10 mm) with 2:1 activity concentration ratio could be detected in the pet image reconstructed using the TOF and TOF+PSF algorithms, but not the OSEM algorithm. The relative difference for SNR between the TOF+PSF and OSEM showed significantly higher values for smaller sizes, while SNR change was smaller for Ф22–37 mm inserts both 2:1 and 4:1 activity concentration ratio. In the clinical study, SNR gains were 1.6 ± 0.53 and 2.7 ± 0.74 for the TOF and TOF+PSF, while the relative difference of contrast was 17 ± 1.05 and 41.5 ± 1.85% for the TOF only and TOF+PSF, respectively. The impact of TOF+PSF is more significant than that of TOF reconstruction, in smaller inserts with low activity concentration ratio. In the clinical pet/CT images, the use of the TOF+PSF algorithm resulted in better SNR and contrast for lesions, and the highest SUV_(max)was also seen for images reconstructed with the TOF+PSF algorithm.

关键词： Time of flight (TOF) Point spread function(PSF) Lesion detectability pet Quantification Image reconstruction SUV

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Synthesis of O-(2-[^(18)F]fluoroethyl)-L-tyrosine and its biological evaluation in B16 melanoma-bearing mice as pet tracer for tumor imaging

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Science China Chemistry 2007年第2期50卷 276-283页

作者： WANG MingWei,YIN DuanZhi,LI ShiQiang & WANG YongXian Radiopharmaceutical Centre,Shanghai Institute of Applied Physics,Chinese Academy of Sciences,Shanghai 201800,China 1. Radiopharmaceutical Centre Shanghai Institute of Applied Physics Chinese Academy of Sciences Shanghai 201800 China

O-(2-[18F]fluoroethyl) -L-tyrosine([18F]FET) ,a fluorine-18 labeled analogue of tyrosine,has been syn-thesized and biologically evaluated in tumor-bearing mice. The whole synthesis procedure is com-pleted within 50 min. The radiochemical yield is about 40%(no decay corrected) and radiochemical purity more than 97% after simplified solid phase extraction. [18F]FET shows rapid,high uptake and long retention in the tumor as well as low uptake in the brain. The ratios of tumor-to-muscle(T/M) and tumor-to-blood(T/B) of [18F]FET are similar to those of [18F]FDG,but the ratios of tumor-to-brain(T/Br) are 2-3 times higher than that of [18F]FDG. Autoradiography of [18F]FET demonstrates a remarkable accumulation in melanoma with high contrast. It appears to be a probable competitive candidate for melanoma imaging with pet.

关键词： [18F]FET [18F]FDG pet imaging melanoma autoradiography

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Advancing Al-doped ZnO thin films structural,optical and electrical properties of low temperature pet substrates via flash lamp annealing

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Journal of Semiconductors 2024年第12期45卷 47-60页

作者： Juwon Lee Chang-Hyeon Jo Gwangseop Lee Min-Sung Bae Slawomir Prucnal Shengqiang Zhou Muhammad Zubair Khan Osama Gohar Mohsin Saleem Jung-Hyuk Koh Graduate School of Intelligent Energy and Industry Chung-Ang UniversityHeukseok-roSeoulRepublic of Korea School of Electrical and Electronic Engineering Chung-Ang UniversitySeoulRepublic of Korea Helmholtz-Zentrum Dresden-Rossendorf Institute of Ion Beam Physics and Materials ResearchBautzner Landstraße 40001328DresdenGermany Department of Materials Science and Engineering Pak-Austria Fachhochschule:Institute of Applied Sciences and TechnologyMangHaripur22621Khyber PakhtunkhwaPakistan Department of Mechanical and Electrical Systems Engineering Graduate School of EngineeringKyoto University of Advanced ScienceGotanda-choYamanouchiUkyo-kuKyoto 615-8577Japan School of Chemical and Materials Engineering(SCME) National University of Sciences&Technology(NUST)-H12Islamabad 44000Pakistan

In this study,aluminum-doped zinc oxide(AZO)thin films were deposited onto a low-temperature polyethylene terephthalate(pet)substrate using DC magnetron *** parameters included power range of 100-300 W,a working pressure of 15 mTorr,and a substrate temperature of 50°***-deposition,flash lamp annealing(FLA)was employed as a rapid thermal processing method with a pulse duration of 1.7 ms and energy density of 7 J·cm-2,aimed at enhancing the film's quality while preserving the temperature-sensitive pet *** offers advantages over conventional annealing,including shorter processing times and improved material *** structural,optical,and electrical characteristics of the AZO films were assessed using X-ray diffraction,field emission scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy,ultraviolet-visible spectroscopy,and Hall effect *** results demonstrated that properties of AZO films varied with deposition and annealing *** deposited at 200 W and subjected to FLA exhibited superior crystallinity,with average visible light transmittance exceeding 80%and resistivity as low as 0.38Ω·cm representing 95%improvement in *** analysis revealed that carrier concentration,mobility,and resistivity were influenced by both sputtering and annealing *** findings underscore the effectiveness of FLA in optimizing AZO thin film properties,highlighting potential in optoelectronics applications.

关键词： flash lamp annealing AZO thin film pet sputtering

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Prognostic significance of interim ^(18)F-FDG pet/CT SUV reduction associated with Ki67 in patients with diffuse large B-cell lymphoma

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Nuclear Science and Techniques 2014年第2期25卷 40-46页

作者：孙一文赵晋华乔文礼邢岩陈香宋建华 Department of Nuclear Medicine Shanghai First Poeple's HospitalShanghai Jiaotong University

To detect the prognostic significance of interim F-FDG pet/CT SUV(standard uptake value) reduction(△SUV_(max)) associated with Ki67 in patients with diffuse large B cell lymphoma(DLBCL).47 DLBCL patients underwent pet/CT before initiation and after 2-4 cycles of chemotherapy were *** SUV_(max)of the dominant lesions were ***67 positive indices were provided by enzyme-labeled ***17.0 was used for statistical ***_(max) of different groups were compared by t ***-operator characteristic analysis was performed to determine the optimal cutoff *** analyses of PFS(Progression-free survival) were compared using log-rank *** average of △SUV_(max)and △SUV_(max)%were 11.53 and 69.10%,*** optimal cutoff values of △SUV_(max)x and △SUV_(max)%were 11.45 and 82.92%,*** △SUV_(max) and △SUV_(max)%indicated longer PFS(p 55%was revealed to be an indicator of shorter PFS(p = 0.019).Either △SUV_(max)≤11.45 or Ki67>55%was defined as an indicator to poor outcome and scored 1 *** PFS rate was 100%in patients scored 0 point,yet 0%in patients scored 2 *** tended to be shorter along with the score getting higher(p = 0.006).△SUV_(max) and Ki67 positive index were both of significance in DLBCL *** prognostic value may be confirmed when △SUV_(max) was accordant with Ki67.

关键词： B细胞淋巴瘤 pet SUV 预后患者 CT 弥漫性中期

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NUCLEATION ACTION OF THERMOTROPIC LIQUID CRYSTAL POLYMERS IN THE BLENDS WITH pet

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Chinese Journal of Polymer Science 1991年第3期9卷 260-265页

作者：谢萍尹伟金永泽李革 Institute of Chemistry Academia Sinica Beijing 100080

The present work concerns the crystallization of pet accelerated by addition of thermotropic liquid crystalline polymers (TLCP)based on two aromatic copolyesters: PHB/pet (60:40 ) and PHB/HDA/2,6-DNA /IPA ( 50:25 : 12.5 : 12.5 ). The investigation has been made by measurements of the cold-crystallization and melt-crystallization temperatures by DSC and of the changes of density and depolarizing light intensity during the isothermal process. In addition, the morphology of selectively etched surface of compressing pellets proved the presence of crystalline fibrillar structure, it can be supposed to have grown up from the micelle nucleus based on bundle of rigid TLCP chains.

关键词： Blend Thermotropic Liquid Crystalline Polymer pet Nucleation

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Animal biodistribution, safety and validation study of dopamine transporter pet imaging agent ^(18)F-FECNT

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Nuclear Science and Techniques 2009年第1期20卷 11-16页

作者： WANG Songpei CHEN Zhengping LI Xiaomin TANG Jie LIU Chunyi ZOU Meifen PAN Donghui LU Chunxiong XU Yuping XU Xijie ZHOU Xingqin JIN Jian The Key Laboratory of Nuclear Medicine Ministry of Health PRC Jiangsu Institute of Nuclear Medicine Wuxi 214063 PR China School of Medicine and Pharmaceutics Jiangnan University Wuxi 214122 PR China

This work was to investigate the pharmacologic characteristics of 18F-FECNT (2β-carbomethoxy-3β- (4-chlorophenyl)-8-(2-[18F]fluoroethyl)nortropane) as a dopamine transporter (DAT) pet imaging agent. Its partition coefficients were determined in n-octanol and phosphate buffer (PB) (pH 7.0 and pH 7.4). 6-Hydroxydopamine (6-OHDA) left-sided lesioned Parkinsonian rats were established and validated by rotational behavior tests. Biodistribution in vivo in mice, autoradiography in normal and hemi-Parkinsonian rat brains, and toxicity test were performed. The results showed that partition coefficients were 34.14 (pH 7.0) and 56.41 (pH 7.4), respectively. Biodistribution exhibited rapid uptake and favorable retention in the mice brains. The major radioactivity was metabolized by the hepatic system. The autoradiography showed that 18F-FECNT was highly concentrated in striatum, and that the left and the right striatal uptake were symmetrical in normal SD rat brains. In left-sided lesioned PD rat brains, the striatal uptake of 18F-FECNT bilaterally decreased in comparison with normal rats. No significant uptake was visible in the 6-OHDA lesioned-sided striatal areas. The results demonstrated that 18F-FECNT binds to DAT was specific. Toxicity trial displayed that the acceptable dose per kilogram to mice was 625 times greater than that to human. These indicate that 18F-FECNT is a potentially safe and useful DAT pet imaging agent in the brain.

关键词： DAT pet ^18F-FECNT PD 原子核

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Novel radioligands for imaging sigma-1 receptor in brain using positron emission tomography(pet)

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Acta Pharmaceutica Sinica B 2019年第6期9卷 1204-1215页

作者： Yu Lan Ping Bai Zude Chen Ramesh Neelamegam Michael SPlaczek Hao Wang Stephanie AFiedler Jing Yang Gengyang Yuan Xiying Qu Hayden RSchmidt Jinchun Song Marc DNormandin Chongzhao Ran Changning Wang Athinoula A.Martinos Center for Biomedical Imaging Department of RadiologyMassachusetts General HospitalHarvard Medical SchoolCharlestownMA 02129USA Gordon Center for Medical Imaging Department of RadiologyMassachusetts General HospitalHarvard Medical SchoolCharlestownMA 02129USA Department of Biological Chemistry and Molecular Pharmacology Harvard Medical SchoolBostonMA 02129USA Department of Pharmacy Renmin Hospital of Wuhan UniversityWuhan 430060China

The sigma-1 receptor(σ1R)is a unique intracellular protein.σ1R plays a major role in various pathological conditions in the central nervous system(CNS),implicated in several neuropsychiatric *** ofσ1R in the brain using positron emission tomography(pet)could serve as a noninvasively tool for enhancing the understanding of the disease’s ***,σ1R pet tracers can be used for target validation and quantification in ***,we describe the radiosynthesis,in vivo pet/CT imaging of novelσ1R11C-labeled radioligands based on 6-hydroxypyridazinone,[11C]HCC0923 and[11C]*** radioligands have high affinities toσ1R,with good *** mice pet/CT imaging,both radioligands showed appropriate kinetics and ***,the specific interactions of two radioligands were reduced by compounds 13 and 15(self-blocking).Ofthe two,[11C]HCC0929 was further investigated in positive ligands blocking studies,using classicσ1R agonist SA 4503 andσ1R antagonist PD ***σ1R ligands could extensively decreased the uptake of[11C]HCC0929 in mice ***,the biodistribution of major brain regions and organs of mice were determined in *** studies demonstrated that two radioligands,especially[11C]HCC0929,possessed ideal imaging properties and might be valuable tools for non-invasive quantification ofσ1R in brain.

关键词： σ1R pet Brain imaging 6-Hydroxypyridazinone 11C-labeled radioligand

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