Objective To evaluate the application value of low-dose CT (LDCT) in physical examination for coal miners with different exposure time.Methods The consecutive three-year imaging data of 972 coal miners with over 20-year exposure were retrospectively reviewed.All miners were divided into 3 groups according to different exposure time,including 317 cases with less than 10 years,299 cases with 10-20 years and 356 cases with more than 20 years.All subjects underwent LDCT examination every year during three consecutive years.Results Baseline LDCT:As the exposure time was prolonged (with less than 10 years,10-20 years and more than 20 years),the number of coal miners has increased with non-calcified pulmonary nodules,interstitial pulmonary lesions,clinically cured or stable stage of pulmonary tuberculosis,pulmonary calcification and pulmonary fibrous stripes,but without statistically significant difference.The detection rates of lung bullae,aorta and coronary artery sclerosis were also increased mildly,with the prolonged exposure time.There was no significant correlation between exposure time and detection rates of bronchiectasis,pulmonary inflammatory lesions,lymph node enlargement or calcification,pleural lesions.The exposure time of 6 cases of malignant nodules and 2 cases of active tuberculosis was more than 10 years.During a two-year follow-up using LDCT scan,there were no significant changes in most of intrapulmonary,pleural and mediastinal lesions.Neither were in pulmonary nodules less than or equal to 4 mm.Three pulmonary nodules with 4-8 mm diameters were enlarged.Most of the inflammatory lesions have changed in size.Conclusion The LDCT scan has a certain value for chest physical examination of the coal miners with different exposure time.It is very necessary to screen the high-risk population of coal miners with exposure time of more than 10 years using LDCT.LDCT reexamination has significant value for pulmonary nodules and inflammatory lesions with diameter of more than 4 mm.Most of intrapulmonary,pleural and mediastinal lesions have no obvious change in the short term,and make an annual reexamination unnecessary,neither does a negative baseline LDCT.

Objective: To investigate the clinical significance of low-dose CT (LDCT) in coal mine workers with relatively long working years. Methods: A total of 907 coal mine workers with ≥20 working years were enrolled, among whom there were 863 male and 44 female workers with a mean age of 49.5 years. Digital radiography (DR) was performed for these workers in 2013, and LDCT was performed for three consecutive years from 2014 to 2016. Results: A total of 32 workers were found to have lung nodules by DR in 2013, while in 2014, 269 workers were found to have non-calcified lung nodules by LDCT, and there was a significant difference in the number of workers with lung nodules (χ²=233.73, P<0.005) . There was also a significant difference in the detection rate of nodules between the workers with different working years of dust exposure (χ²=6.648, P=0.00) . The male workers had a significantly higher detection rate of nodules than the female workers (χ²=5.690, P=0.017) . There was no significant difference in the number of nodules between workers with different types of work (χ²=16.985, P=0.05) . There were 443 lung nodules in total, among which 71.56% were solid nodules and 55.75% had a size of ≤4mm; malignant nodules were confirmed by surgery in 6 (0.66%) of the 907 workers after baseline LDCT. LDCT reexamination in 2015 and 2016 found new nodules in 8 workers and enlarged nodules in 3 workers, and there was no significant change in the number of nodules with a size of ≤4 mm. Conclusions It is necessary to perform high-risk population screening for coal mine workers by LDCT. The follow-up strategies for nodules with a size of ≤4mm are the same as those for negative results; annual reexamination is recommended for nodules with a size of >4-8 mm, and clinical treatment should be considered for nodules with a size of >8 mm.