Effect of chest low-dose spiral CT scan for lung cancer screening among asymptomatic adults / 中国辐射卫生

@#<b>Objective</b> To evaluate the effect of chest low-dose spiral computed tomography (LDCT) scan for lung cancer screening among asymptomatic adults. <b>Methods</b> Asymptomatic adults at the age of 18 years and older receiving LDCT scans for lung cancer screening in Shanghai Pudong New Area People’s Hospital from January 2019 to December 2021 were recruited, and those with positive pulmonary nodules underwent percutaneous needle biopsy or bronchoscopic biopsy for pathological examination of pulmonary nodules. The effect of LDCT scan for lung cancer screening was compared between never-smokers and ever-smokers. <b>Results</b> A total of 9359 eligible individuals meeting inclusion and exclusion criteria were enrolled, including 4492 never-smokers and 4867 ever-smokers, and the overall detection rate of positive pulmonary nodules was 16.2%. There were significant differences between never-smokers and ever-smokers in terms of age at the first LDCT screening, gender composition, body mass index, and cumulative follow-up period (<i>P</i> < 0.05), and no significant differences were seen in terms of types of pulmonary nodules at the first LDCT screening and proportion of subjects with positive pulmonary nodules (<i>P</i> > 0.05). There were no significant differences between never-smokers and ever-smokers with positive pulmonary nodules in terms of proportion of subjects with positive pulmonary nodules at the first LDCT screening, proportion of subjects with positive pulmonary nodules during the follow-up, types of pulmonary nodules at the first LDCT screening, proportion of subjects with multiple pulmonary nodules, and mean size of pulmonary nodules at the first LDCT screening (<i>P</i> > 0.05); however, there was a significant difference in the nature of pulmonary nodules (<i>χ</i>² = 47.23, <i>P</i> < 0.01). In addition, the incidence rate of lung cancer was significantly lower among never-smokers with positive pulmonary nodules than among ever-smokers with positive pulmonary nodules (<i>χ</i>²=6.42, <i>P</i> < 0.01). <b>Conclusion</b> Chest LDCT scan may significantly improve the detection rate of pulmonary nodules among never-smokers. Although the detection rate of lung cancer is significantly lower among never-smokers with positive pulmonary nodules than among ever-smokers with positive pulmonary nodules, there is no significant difference between never-smokers and ever-smokers in the false-positive rate of lung cancer screening with chest LDCT scan. Chest LDCT scan is recommended for lung cancer screening among asymptomatic adults.

The Application of Heating Effect in Breeding of Microorganism / 微生物学通报

Advances in mechanism and application of the heating effect in breeding of microorganism are reviewed in this paper. Heat produces mutagenesis effect and screening effect. Heating mutagenesis effect is occurred through the substitution of G-C base pair induced by heat, and heating screening effect produces higher forward mutation rate induced by other mutagens.