Abstract: Objective  The purpose of this study was to evaluate the clinical value of pulmonary biopsy for lung occupying lesions  under low-dose computed tomography(CT)-guidance.  Methods  From January 1 2009  to December 31 2011, 200 consecutive patients with pulmonary occupying lesions prepared for lung biopsy were randomly assigned to either standard dose group or low-dose group that containing 100 patients in each group. Of these patients, 100 patients underwent percutaneous needle lung biopsy under low-dose CT guidance (30 mA, 3 mm reconstruction thickness), while the other 100 patients underwent standard CT-guided procedure (150 mA, 3 mm reconstruction thickness). Following steps of sterilization, puncture and biopsy, data from two groups were analyzed statistically including such parameters as radiation dose (CTDIw, DLP), score of image quality of pulmonary and mediastinal window (range from 1 to 4,＞2 as acceptance), successful puncture rate and histological result as well.  Results  The measured CTDIw (weighted CT dose index) was 1.48 mGy in low-dose CT lung biopsy group and 7.38 mGy in standard dose CT group; mean DLP (dose length product) was (11.52±1.72)mGy×cm and (67.25±4.69)mGy×cm, respectively, indicating significant difference between two groups（t=40.46, P<0.05）. However, acceptance rate in both groups was 100.0% with no significance (all patients’ score ＞2). Also, there was also no statistical difference on successful puncture rate (correction χ²value=0.00, P>0.05) in standard group (98.0%,98/100) compared to low-dose group (99.0%,99/100). In addition, accurate diagnosis rate and false diagnosis rate in malignancy were 82.8%(82/99), 13.7%(13/95) in low-dose group and 89.8%(88/98), 8.3%(8/96) in standard group, showing no differences (χ²_accuracy=2.02，χ²_false=1.39，P>0.05).   Conclusion  Percutaneous needle lung biopsy under low-dose CT-guidance which minimizes the radiation dose could provide high diagnostic accuracy for lung space occupying lesions, deserving to be applied comprehensively to clinical practice.

Key words: Lung diseases, Biopsy, needle, Tomography, X-ray computed, Radiation dosage, Evalution studies