1.An investigation of a coincidence detection system for an all-digital small animal PET scanner
Wei LIU ; Yuanbao CHEN ; Anwen LONG ; Xin CHEN ; Zhongyi WU ; Yongxue ZHANG ; Qingguo XIE
Chinese Journal of Nuclear Medicine and Molecular Imaging 2013;(3):223-225
Objective To investigate and design a coincidence detection system for an all-digital small animal PET scanner and evaluate its preliminary performance properties.Methods This coincidence module adopted a coincidence identification mode based on singles data in list-mode.Using digital signal processing technology,energy calibration,crystal identification,timing alignment and coincidence events extraction were performed on singles data in list-mode.The obtained data could be used for image reconstruction.Results The 13 × 13 crystal array was well recognized by the position histogram of one lutetium yttrium orthosilicate (LYSO) crystal block.In the coincidence timing histogram of the micro-Derenzo phantom,1.36 ns full width at half maximum was obtained.The rods with a diameter of 1.2 mm were clearly displayed in the reconstructed image of the micro-Derenzo phantom.Conclusion The coincidence module can provide satisfactory performance to meet the design needs of an all-digital small animal PET scanner.
2. Study of mumps immunity after administrating measles-mumps-rubella vaccine among children aged 2-7 years old in Jiangsu Province in 2015
Yuanbao LIU ; Ying HU ; Xiuying DENG ; Zhiguo WANG ; Xiang SUN ; Peishan LU ; Hongxiong GUO ; Fenyang TANG ; Minghao ZHOU
Chinese Journal of Preventive Medicine 2017;51(7):593-597
Objective:
To investigate the immunity to mumps after administrating measles-mumps-rubella vaccine (MMR) among children aged 2-7 years old in Jiangsu province in 2015.
Methods:
A total of 4 190 healthy children aged 2-7 years old, living in local places for at least 3 months, and having been vaccinated at least 1 dose MMR were recruited to the study from Wujin district of Changzhou city, Gaogang district of Taizhou city and Ganyu district of Lianyungang city by using stratified cluster random sampling method between September and November, 2015. Those who did not accept MMR vaccination, who refused venous blood collection, who had affected mumps according to the memory of parents or teachers and who were diagnosed serious disease by clinical doctors were excluded from study. The self-designed questionnaire was used to collect the general information of the subjects and their MMR immunization history; and 0.5-2.0 ml of venous blood was collected from each subject. ELISA was used to detect the mumps antibody level in the serum of patients. Positive was defined as the antibody level ≥108 mU/ml, and negative as <108 mU/ml. χ2 test was used to compare the difference in positive rates among subjects; and analysis of variance was used to compare the GMC changes in different time points after MMR vaccination.
Results:
Among 4 190 children, 2 280 were males (54.42%) and 1 910 were females(45.58%), and the positive rate of IgG antibody was 81.38% (3 344). There were 3 156 (95.18%) children vaccinated with one dose MMR, 187 (4.80%) children with two dose MMR, and 1 (0.02%) child with three dose MMR. The difference in positive rate of IgG antibody among different aged subjects showed statistical significance (χ2=58.61,