Impact of SAFIRE reconstruction algorithm on image quality and radiation dose of chest CT

Objective To investigate the differences of image quality and radiation dose of chest CT between sinogram affirmed iterative reconstruction(SAFIRE)algorithm and filtered back projection(FBP)algorithm.Methods Three sets of tube voltage values of 80,100,120kV were defaulted.Using automatic mAs care dose 4Dtechnology,aphantom was scanned with new dual-source CT(Somatom definition flash).Data sets were reconstructed with FBP and SAFIRE(level 1—5),and the noise and CT values of different structures of chest were compared.Two radiologists evaluated the image quality independently.After each scanning,the dose weighted index(CTDIvol)and dose-length product(DLP)were recorded,then effective dose was calculated and compared.Results With the same scan condition,image noise of SAFIRE of chest CT was significantly lower than that of FBP(P0.05).Among different scan conditions,regardless of FBP algorithm or SAFIRE algorithm,image noise of chest CT went lower when tube voltage increased.Image noise of different structures of chest changed with different reconstruction algorithm and tube voltage.Both subjective and objective image quality indicators of 100kV/SAFIRE(level 3)were better than those of 120kV/FBP,and radiation dose reduced by 37.61%.Conclusion SAFIRE reconstruction algorithm can effectively improve image quality and reduce radiation dose in chest CT.