Setting of Noise Index in Low-dose Chest CT Examination / 中国医学影像学杂志

Purpose To explore the optimal value of noise index (NI) of adaptive statistical iterative reconstruction (ASIR) in low-dose chest examination,so as to reduce the radiation dose of patients.Materials and Methods 1200 mid-age and elderly healthy individuals were randomly divided into 4 groups according to the NI difference,with 300 in each group,group A:NI=20;group B:NI=25;group C:NI=30;group D (the normal control group):NI=14.Combined with AS IR technology,the quality of the axial image was reviewed and evaluated,and the score of each subject was given and recorded based on the quality of the image and the matching degree with the disease it indicated.Results The subjective scores of images in each group were:group A (3.53±0.43),group B (3.28±0.32),group C (3.12±0.18) and group D (5.00±0),respectively.The scores of these 4 groups were all above 3,which could be used for diagnosis.The body mass index was (24.39 ± 3.09) kg/m2,(25.49 ± 2.45) kg/m2,(25.53 ± 3.21) kg/m2 and (25.55 ± 2.28) kg/m2,respectively.The number of layers was 60.64 ± 6.38,64.42 ± 5.71,61.77 ± 6.45 and 62.32±6.15,respectively,and there was no statistically significant difference between these 4 groups (P＞0.05).The effective dose (ED) was (1.66± 0.84) mSv,(1.11 ± 0.34) mSv,(0.88±0.30) mSv and (5.99± 1.37) mSv,respectively,and the differences between any two groups were all statistically significant (P＜0.05).ED of group C was the lowest,85％ lower than group D,47％ lower than group A,and 21％ lower than group B.Conclusion Using ASIR technology,setting NI=30 can ensure that the image quality meet the needs of diagnosis,and also effectively reduce the radiation dose,which is a preferable scanning scheme.

Effect of power-frequency electromagnetic fields on antioxidant indexes in operation personnel / 中国职业医学

OBJECTIVE: To investigate the effect of the power-frequency electromagnetic field on antioxidant indexes in operation personnel. METHODS: By random sampling method,a total of 58 workers who work in 500 kV transformer substations for at least 5. 0 years were selected as the exposure group,and 60 administrative staffs in the same enterprise were included as the control group. The power frequency electromagnetic fields in the 2 groups were measured. The cumulative exposure dose of individual magnetic field was calculated. Peripheral venous blood was collected in these 2groups and was examined with the superoxide dismutase( SOD) activity,malondialdehyde( MDA) level and the relative gene expression level of manganese superoxide dismutase( MnSOD). RESULTS: There was no statistical significance in the SOD activity,MDA level and the relative gene expression level of MnSOD between the exposure group and the control group( P > 0. 05). The logistic regression analysis results indicated that cumulative exposure dose was not correlated with the SOD activity,MDA level and the relative gene expression level of MnSOD after adjusting confounding factors such as age,smoking,alcohol and tea drinking( P > 0. 05). CONCLUSION: Power-frequency electromagnetic field exposure has no significant effects on the SOD activity,MDA level and the relative gene expression level of MnSOD of operation workers.

Epidemiological investigation of welder's pneumoconiosis in two container manufacturing industries in Guangdong province / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To investigate the incidence of welder's pneumoconiosis in container manufacturing industries in Guangdong province and present some preventive and curative strategy.</p><p><b>METHODS</b>Occupational epidemiology study methods were used to study the incidence of welder's pneumoconiosis in two container manufacturing enterprises (enterprise A and enterprise B).</p><p><b>RESULTS</b>Before 2004, the rate of up-to-standard of weld fume concentration in the workplaces was relatively low (< or = 40%), and the maximum value of time weighted average (TWA) was 26.7 mg/m(3). After 2004, with the system of dust control, the rate of up-to-standard was 85% in the enterprise A. Of the 813 weld workers examined, 19 were diagnosed as welder's pneumoconiosis (stage I was 15, while I (+) was 4 ) and the incidence was 2.34% (19/813). The age of electric welders suffering from welder's pneumoconiosis and the duration of dust exposure were (33.45 + 4.64) and (8.04 + 1.97) years respectively. Chest radiographic examination showed mainly small round opacities "p". The value of MVV, FEF25%, FEF50% and FEF75% in lung function tests were significantly lower than those of the control group (P < 0.05 or P < 0.01).</p><p><b>CONCLUSION</b>The main features of welder's pneumoconiosis in container manufacturing industries are the short duration of dust exposure, and small round opacities "p" in the chest radiographs. Therefore, it should be the key point of the prevention and treatment of occupational diseases in this industry to control the harmful weld fume.</p>

Epidemiological study of gem worker's silicosis / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To study the hazards of gem dusts and the epidemiological features of the occurrence of gem worker's silicosis (GWS).</p><p><b>METHODS</b>Epidemiological investigation in a gem factory in Guangdong province was carried out.</p><p><b>RESULTS</b>The average dusts concentration in workshop was 2.3 mg/m(3), average free silica content was 94.64%. There were 47 patients diagnosed as silicosis. The prevalence of GWS was 4.58% (47/ 1,027). The age of patients suffering from silicosis and the duration of dust exposure were (27.04 +/- 3.25) years and (4.67 +/- 1.17) years respectively. Chest radiographic examination showed mainly small round opacities "q". The incidences of GWS complicated by pulmonary tuberculosis, spontaneous pneumothorax and pulmonary emphysema were 10.64%, 10.64%, 44.68% respectively.</p><p><b>CONCLUSION</b>The hazards of gem dust to workers might be serious. Higher incidence, younger age suffered from silicosis, shorter duration of dust exposure, more complications, and poorer prognosis in gem workers appeared to be the main epidemiological features of GWS in Guangdong.</p>

Diagnostic Value of MSCT Longitudinal-reconstruction in the Ureteral Obstruction / 实用放射学杂志

Objective To evaluate the diagnostic value of MSCT longitudinal reconstruction in the ureteral obstruction.Methods 34 patients with ureteral obstruction were scaned transversely and longitudinally by GE Lightspeed 16 CT scanner and the images were reconstructed with three-dimensional software.All cases were proved by operation and pathology except for 2 cases of uretal obstruction compressed by retroperitoneal lymph nodes.Results In 34 cases,there were 22 cases of ureteral calculi,2 cases of ureteritis,3 cases of carcinoma of ureter,3 cases of pelvisureteral conjunction stricture,1 case of ureteral cyst,1 case of retrocaval ureter and 2 cases of ureter compressed by retroperitoneal metastatic lymph nodes.On longitudinal reconstruction images,22 lesions of calculi in the ureter and thickened uretal wall were showed.Contrast-enhanced CT scan was preformed in 5 cases,the CT values of lesions were increased about 20~35 HU,after administration of contrast medium,and light hydronephrosis in 18 cases,medium hydronephrosis in 6,serious hydronephrosis in 2 and no hydronephrosis in one case were showed on delayed contrast-enhanced scan.Conclusion Longitudinal reconstruction image is of significant value in diagnosis of ureteral obstruction.