Abstract: Objective Discussion on the application value of low dose CT in pulmonary tuberculosis with long-term follow-up examination. Methods Routine follow-up CT scaned 140 anti-TB treated patients with se-condary pulmonary tuberculosis from 2012 January to 2013 June in Guangzhou Chest Hospital, 70 cases of low dose CT scanning (observation group) and 70 cases of routine dose CT scanning (control group). Scored the CT image quality of 2 groups according to 4 standards (edge of tissue or organ, tissue density difference, image artifact and image noise), each standard score 1 points, each patient out of 4 points. Recorded the radiation dose (CTDIvol, DLP) in 2 groups. Write CT diagnosis reports in the 2 case of contrast front piece and the front piece. Analysis and comparison of the changes in 2 diagnostic reports, and scores (Image description and diagnosis conclusion had not changed for 4 points. Image description partly changed and the diagnosis conclusion without change for 3 points. When image description and diagnosis conclusions have changes, the main diagnosis conclusion haven’t changes, it is 2 points while main diagnostic conclusion partly change it is 1 point. The main diagnosis conclusion completely changed for 0 points). To judged if there are significant differences in image quality score, changes score of diagnosis report and radiation dose by t test. Results In observation group and the control group, their image quality score were (3.268±0.463) and (3.507±0.448); changes score of diagnosis report were (2.929±0.983) and (3.186±0.952); radiation dose of CTDIvol were (10.417±1.190)(mGy) and (19.214±1.956)(mGy), DLP were (94.514±13.844)(mGy×cm) and (177.129±17.048)(mGy×cm), respectively. The two groups had significant difference in image quality score and radiation dose CTDIvol and DLP（t=3.106，P=0.002；t=32.149，P<0.001；t=31.474，P<0.001）, had no significant difference in changes score of diagnosis report（t=1.572，P=0.118）. Conclusion Low dose CT can significantly reduce the radiation dose, and has no obviously effect for the diagnosis report. Low dose CT scanning might become a routine application of model CT check follow-up after treatment of tuberculosis.

Key words: Tuberculosis, pulmonary/radiography, Tomography, X-ray computed, Radiation dosage, Follow-up studies