Abstract:

Objective To compare the differences of pulmonary nodule detection rates between iterative reconstruction (sinogram affirmed iterative reconstruction,SAFIRE) algorithm and filtered back projection （FBP）algorithm in chest CT,and to evaluate the detection accuracy.Methods Three groups of tube voltage values of 80,100,and 120 kV were defaulted on the new dual-source CT，with autom
aticmAs care dose 4D technology,the chest phantom with simulated pulmonary nodules was scanned,then the images were reconstructed with FBP and SAFIRE (grade 1-5),respectively.The  detection rates of simulated pulmonary nodules  in the chest CT images reconstructed of SAFIRE (grade 1-5) and FBP were compared，and their diameters and CT values were measured.Results
With the same tube voltage,no significant difference was found in the detection rate of simulated pulmonary nodules between SAFIRE (grade 1-5) and FBP (P>0.05),the diameter deviation of simulated nodules of SAFIRE (grade 3) was less than FBP，and the difference in the average CT value of the simulated nodules between SAFIRE (grade 3) and FBP was not statistically significant (P>0.05);the simulated nodule detection rate of 100 kV was equivalent to the detection rate of 120 kV,the simulated nodule （－800 HU and 3 mm ）detection rate of 80 kV was less than that of 120 kV;as the tube voltage reduced,or simulated nodule diameter decreased，or the density of simulated nodule reduced,the nodule’s diameter deviation was increased.Conclusion Compared with FBP,the capabilities of SAFIRE in pulmonary nodule detection in different densities and different sizes are same,and SAFIRE algorithm is helpful for accurate displaying of pulmonary nodules,and it can be used for low-dose CT lung cancer screening program.

Key words: tomography, X-ray computed；pulmonary nodule；image reconstruction；computer-aided