Research Of The Iterative Algorithm To Improve The Quality Of Abdomen Images By DSCT Low Dose Scan For Patients With Different BMI

Objective: Discuss the effective of iterative reconstruction algorithm(SAFIRE)improve the patients abdominal images quality in low-dose CT scan through lower tube voltage for and the extent of dose reduction.Materials and Methods: According to the principle of random 294 patients with abdominal scan(174 males, 120females) divide into 4 groups. Group A with standard weight scanned using 120 KV, group B with standard weight scanned using 100 KV, group C with overweight scanned using 120 KV, group D with overweight scanned using 100 KV.Record radiation dose CTDIvol, DLP, calculate the ED of four groups. The whole abdomen images were reconstructed by filter back projection algorithm(FBP) images of group B and group D were reconstructed by iterative reconstruction algorithm(SAFIRE).Scored all images quality by two experienced doctors, point 1 is for bad image quality and point 5 is for excellent image quality. In the images of portal level, measure the CT value and standard deviation(SD) of the liver spinal muscular abdominal aorta arterial in arterial phase and portal vein in venous phase. Measured SD of fat can as the noise of the images.To calculate SNR and CNR using the formula SNRorgans = ROIorgans/SD organs CNRorgans=(ROIorgans- ROI muscles)/SDfat. Compare radiation dose(ED) of group A and group B, group C and group D. Compare the SNR and CNR of the images reconstructed by FBP of group A and group B group C and group D both arterial phase and venous phase. For group B and Group D compare SNR and CNR of images which were reconstructed by FBP algorithm and images which were reconstructed by SAFIRE algorithm both arterial phase and venous phase.Results: Radiation dose(CTDIvol, DLP, ED) of group B was lower than that in group A. Group D was lower than group C. To the Scores of images, group D using FBPreconstructed was lower than group C using FBP reconstructed both arterial phase and venous phase, group B using SAFIRE reconstructed is higher than it using FBP reconstructed, so dose for group D both arterial phase and venous phase. For images using FBP reconstruction SNRliver of group A was higher than that of group B, CNRarterial CNRliver of group A were all lower than that of group B in arterial phase and SNRportalvein of group A was higher than group B, CNRportalven CNRliver were all lower than group B in venous phase,SNRportalvein SNRliver of group C were higher than that of group D, CNRarterial CNRliver of group C were all lower than that of group D in arterial phase and SNRportalvein of group C was higher than group D, CNRportalven CNRliver were all lower than group D in venous phase.For group B and group D, the SNRarterial SNRliver CNRarterial CNRliver of images using FBP reconstruction were all lower than that using SAFIRE reconstruction in arterial phase and SNRportalvein SNRliver CNRportalven CNRliver of images using FBP reconstruction were all lower than that using SAFIRE reconstruction in venous phase.Conclusion: Both standard weighted patient and overweighted patient we can use low dose CT scan in abdominal enhanced CT examination through reduce tube voltage. The quality of images will not be bad for patients with standard weighted figure but it will be reduced for patients with overweighted figure. Using the iterative reconstruction algorithm(SAFIRE) can improve the quality of images which was reduced in abdomen low dose CT scan.