Analysis and evaluation of radioactive material transport monitoring in Beijing from 2006 to 2020 / 中国辐射卫生

Transport monitoring is an important link in the transport process of radioactive materials, involving the whole process, that is, before departure, during transportation and after arrival. To do well in transport monitoring, radiation monitoring organizations need to actively participate in the work, and also need to do a good job in the supervision of radioactive materials transport monitoring. Beijing is one of the radioactive materials distribution centers in China, the monitoring workload is large, the number of monitoring reports is large, the number of packages by air transportation is relatively large, and the transportation and monitoring for medical use is dominant. Through the introduction of radioactive materials transportation monitoring work, and analysis of 2006—2020 radioactive materials transportation monitoring situation, this paper discusses the problems that need to be paid attention to in the monitoring work and the ways to deal with them, so as to provide ideas for radiation monitoring organizations to carry out monitoring work and manage the transport of radioactive materials well.

Study on outdoor radon and its progeny concentration level and variation pattern in Beijing area / 中华放射医学与防护杂志

Objective:To understand the concentration level of radon and its progeny in outdoor air in Beijing area and to analyze the related variation pattern and influencing factors.Methods:The continuous measurement device for radon and its progeny concentration is used for the one-year continuous measurement at three points in different directions in Beijing area.Results:The annual concentration average value was (10.9±4.9) Bq/m 3 for radon and (5.8±3.4) Bq/m 3 for its progeny (equilibrium equivalent radon concentration EEC) in outdoor air in Beijing with the annual average value of 0.52±0.19 for equilibrium factor F. Clear diurnal variations of the concentrations of radon and its progeny was observed. Conclusions:The result of one-year continuous measurement show that the concentrations of radon and its progeny in the outdoor air in Beijing area are close to the world average, lower than the typical values in China given by grab sampling measurement. The daily variation pattern of radon and its progeny concentrations is similar to those at home and abroad. The seasonal variation pattern features local climate in Beijing.

Brain dynamic functional connectivity between default mode network and executive control network by resting state functional MRI in patients with alcohol use disorder / 中华放射学杂志

Objective:To investigate the changes of dynamic functional connectivity between the default mode network (DMN) and executive control network (ECN) in the resting state in patients with alcohol use disorder (AUD).Methods:From September 2018 to June 2019, 23 cases of AUD group and 24 cases of healthy control (HC) group matched with age, gender, education level and handedness were collected at Renmin Hospital of Wuhan University. Mini-mental state examination (MMSE) and Michigan alcoholism screening test (MAST) were performed in all subjects for cognition and alcohol dependence score. All the subjects underwent T 1WI-3D structural imaging and resting state functional MRI (rs-fMRI) examination. Group spatial independent component analysis (ICA) was used to select the independent components of DMN and ECN. Then dynamic changes in the functional connectivity between the DMN and the DMN were obtained by sliding window approach and clustering method. Finally, the independent sample t test was used to compare the difference of general clinical data between the two groups, the linear correlation analysis was conducted in the parameter value and MMSE and MAST scores. Results:Compared with the HC group, the static functional connectivity analysis showed that the precuneus and posterior cingulate gyrus of the DMN were enhanced in the AUD group ( P=0.016, t=2.496). The DMN and ECN functional connectivity showed four different brain activity states, the proportion of state1 increased by 6.81% and state2 decreased by 6.83% in the AUD group, state3 and state4 were relatively stable. In state1, the internal functional connectivity of the DMN in the AUD group was enhanced, while the functional connectivity between DMN and ECN was mainly enhanced. In state2, the internal functional connectivity of the ECN was enhanced, and the connectivity between the DMN and ECN was mainly weakened. The mean dwell of state2 in the AUD group was negatively correlated with the MAST score ( r=-0.433, P=0.039). Conclusions:Dynamic functional connectivity patterns between DMN and ECN have been changed in patients with AUD. Dynamic functional connectivity can reveal transient changes in brain activity, which can provide certain imaging evidence for finding changes in AUD deep brain activity.