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Objective To estimate the radiation dose and cancer risk of thyroid for children who underwent head CT or chest CT scans.Methods The parameters used in the CT scans were accessed from the DICOM files through PACS used DCMTK software, then the thyroid radiation dose was estimated with the CT-Expo(C) software and the cancer risk induced by CT scan was projected based on BEIR Ⅱ model combined with the Chinese cancer incidence and lifetime table in 2008.Results CT parameters used for different ages were roughly the same, the thyroid equivalent dose for head CT ranged from 1.2-2.0 mGy, the highest thyroid cancer risk occurs for newborn girls, about 9.6/100 thousand population;while for chest CT the thyroid equivalent dose ranged from 8.1 to 38.0 mGy, the highest thyroid cancer risk was also for newborn girls, about 244.7/100 thousand population.The radiation dose and cancer risk for thyroid decreased with the increased age.Conclusions The radiation dose for thyroid from chest CT was relatively higher than head CT, especially for newborn babies;therefore more protection should be given to the thyroid and other radio-sensitive organs during CT scanning.
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Objective To ascertain the frequency distribution of CT examinations in children.Method A wide range of information was collected through the radiology information system (RIS),including ID,sex,birth date,examination time,the examined part of body and other relevant ones related to children who underwent CT examinations between Jan 1,2012 and Dec 31,2012.The SAS software was used for data processing and statistical analysis.Results A total of 1 542 children underwent 1 670 examinations,of which 67％ were male.Head CT examination was the most frequent,accounting for 71.9％ of all CT examinations,and followed by the abdomen/pelvis examinations.The number of examinations of children undergoing the repetitive examination accounted for 6.4％; 51.7％ of the examinations was for trauma.The positive rate of CT examination was 51％,dependent upon the age and examined body parts to some extent.The younger patients had lower positive rate,and the positive rate of head CT examination was lower than those in other parts.Conclusions To reduce the possible cancer risk to be induced by the ionizing radiation from CT,justification of CT examination should be considered for children.
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<p><b>OBJECTIVE</b>To evaluate the effect of exposure to rush-mat dust on the health of workers.</p><p><b>METHODS</b>A cross sectional study of 661 workers (349 men, 312 women) from 35 rush-mat plants was carried out by using occupational health investigation, questionnare and physical examination.</p><p><b>RESULTS</b>The geometric mean total dust concentration in the workshop was up to 20.00 mg/m3, and the geometric mean respirable dust concentration reached 8.22 mg/m3. The mean free SiO2 concentration of accumulated dust was 25.6%. The prevalence of radiographic small opacities profusion category > or = 1/0, according to the China Classification for pneumoconiosis (GB 5906-2000), and compared with the ILO 1980 system, was 2.57%. Even more, one man had category 2 pneumoconiosis with progressive massive fibrosis. However, the incidence of pneumoconiosis (1/0 at least) was correlated with work duration and dust concentration(r = 1.156, P < 0.001; r = 0.106, P = 0.006, respectively). Some positive correlations were found between the incidence of cough or expectoration and occupational exposure (r = 0.085, P = 0.028; r = 0.094, P = 0.016, respectively).</p><p><b>CONCLUSION</b>To our knowledge, this is the first report of rush pneumoconiosis in China. The results have offered the possibility of a dose-response relationship between rush-mat dust and pneumoconiosis. More investigation in this area is need.</p>