Low-dose Ct Lung Screening

objective We probed into the role of LDCT in lung screening. Through compared LDCT images with different tube current, we determined the optimum parameter of scanning and evaluated X-ray dose of low dose spiral CT.Materials and methods 1128 healthy people underwent lung screening with low-dose spiral CT, the age means 44.7years(22～83). All patients were scanned on a GE Light speed ultra 16 CT scanner. all whole lung scanning adopted 1.25mm collimation, p=1.375, 120 Kv, image thickness 7.5mm, 0.8s/360°, bed speed and 27.5mm/360°, all conditions were identical except the tube current in two dosage scanning. We adjusted tube current rang from 10 mA to 40mA depended the figure of patient. The patient, who was found disease, was checked with routine CT(180mA),the images were analyzed with VR,MPVR,MPR,MIP,ALA,et al. Compared LDCT images with normal-dose CT ,we evaluated LDCT images whether can be used in lung screening, and found optimum tube current in lung screening. The X-ray dose what the patients received was recorded one by one.Result Nodules were detected in 109 cases, including 4 lung cancer; phthisis; ground glass opacity phthisis was detected in 3cases; emphysema was detected in 13 cases; inflammation was detected in 11 cases. The optimum tube current: female: I, II, III, IV type were responsible for 15mA, 20mA , 25mA, 30mA; male: I, II, III, IV types were responsible for 20mA, 25mA, 30mA, 35mA. The images of LDCT with lung window can be used in diagnosing disease. When we analysed lung nodules ,we found that sensitivity ,PPV, accuracy respectively is 90.8%,96.1%,83.2%. MPVR, MPR, MIP, ALA, et al technology can help to diagnose and identifying-diagnose lung nodules. Compared with routine CT, X-ray dose of LDCT is lower---about 1/8～1/7 dose of routine CT. There is no difference of two dose images in lung window image quality. There is increasing noise in low-dose mediastina window image.Conclusion In spite of increasing noise, low-dose chest MSCT image can...