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Objective:To analyze the changes in the epidemiological characteristics of scarlet fever cases in Shanghai City before and after the outbreak of coronavirus disease 2019 (COVID-19), and to provide a reference for scientific prevention and control of scarlet fever.Methods:The information of scarlet fever reported cases in Shanghai City from January 2016 to June 2021 in the information system of Chinese Disease Prevention and Control was collected, and the differences in time trend, regional distribution, age and gender distribution of cases before and after the outbreak of COVID-19 in Shanghai City were analyzed by descriptive epidemiologic method.Results:The incidence rate of scarlet fever reported in 2016-2019 was (0.22-4.02)/100 000 in each month, with a median of 1.13/100 000. During January 2020 (the outbreak began in Shanghai City) and June 2021, the incidence rate of scarlet fever was (0.01-1.64)/100 000, with a median of 0.14/100 000, which was 12.39% of that before the outbreak of COVID-19. During February and June 2020, the monthly reported incidence rate of scarlet fever was (0.18-0.58)/100 000, showing an upward trend compared with the same period in 2020 ((0.01-0.05)/100 000). From 2016 to 2019, the annual reported incidence rate of each district was (0.55-65.48)/100 000, with a median of 9.57/100 000; while in 2020, the annual reported incidence rate of each district was (0.29-9.85)/100 000, with a median of 2.18/100 000, which was 22.78% of that before the outbreak of COVID-19. The incidence of scarlet fever dropped significantly. The incidence rate in Minhang District was still the highest. The cases were mainly four to eight years old, and there was no substantial difference of the proportions before and after COVID-19 pandemic, with the incidence rate of six years old group the highest. The proportion of male was more than female in reported case, while the male ratio in reported cases was not significantly different before and after COVID-19 pandemic.Conclusions:The incidence rate of scarlet fever in Shanghai City has dropped sharply after COVID-19 pandemic. The main epidemiological characteristics of the regional and population distribution of cases remain unchanged.
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Objective To investigate the differences in tumor volume and metastatic tumors of the liver and regional lymph nodes between contrast-enhanced computed tomography (CT) and diffusion-weighted magnetic resonance imaging (DWMRI) through a comparative analysis,as well the useful information for target volume delineation,and to guide radiotherapy in clinical practice.Methods A total of 40 patients with pancreatic cancer were enrolled and underwent contrast-enhanced CT and DWMRI in the same position.The target volume was delineated,the major axis of the maximum tumor section was measured,and the numbers of liver metastatic tumors and metastatic tumors of the lymph nodes with a diameter of 5-8 mm or＞8 mm were measured based on the CT and DWMRI images.The analysis was performed by using paired t-test or paired Wilcoxon rank sum test.Results The mean gross tumor volume (GTV) delineated by contrast-enhanced CT and DWMRI was 54.95 cm3 and 41.67 cm3(P =0.000),and the mean value-different value was 13.28 cm3.The major axis of the maximum tumor section measured by contrast-enhanced CT and DWMRI were 4.18 cm and 3.94 cm (P=0.000),respectively,and in two patients,dCT was smaller than dDWMRI.A total of 83 liver metastatic tumors were identified by contrast-enhanced CT,and 112 were identified by DWMRI;the liver metastatic tumors detected by contrast-enhanced CT accounted for 74％ of those detected by DWMRI.As for the metastatic tumors of the lymph nodes with a diameter of 5-8 mm or＞8 mm,103 or 46 were detected by contrast-enhanced CT,and 200 or 56 were detected by DWMRI,and the tumors detected contrast-enhanced CT accounted for 52％ or 82％ of those detected by DWMRI.There were significant differences in all data between contrast-enhanced CT and DWMRI.Conclusions GTV and the major axis of the maximum tumor section measured by DWMRI are lower than those measured by contrast-enhanced CT,and contrast-enhanced CT is sensitive in detecting the metastatic tumors of the liver and lymph nodes.However,it is necessary to conduct further controlled experiments with reference to pathology.
ABSTRACT
In recent years, the incidence of pancreatic cancer shows rising trend and higher mortality. Pancreatic cancer lacks early diagnostic methods with high sensitivity and specificity, and the surgical resection rate is 10 %-20 % with high operation mortality, poor long-term curative effect and less than 5 %survival rate within 5 years. At present, researchers indicate that radiotherapy can improve the quality of life, increase tumor local control rate and prolong the overall survival time of patients with pancreatic cancer in different levels. Diffusion weighted imaging (DWI), as a functional imaging technology of magnetic resonance imaging (MRI), is the only way to react cell levels. This paper will summarize the application of DWI in radiotherapy of pancreatic cancer.
