Application Of Adaptive Statistical Iterative Reconstruction Technique In Reducing Radiation Dose Of Chest CT In Preschool Children

Objective: To explore the application value of adaptive statistical iterative reconstruction(ASiR)in CT scan of preschool children.Methods :Clinical pretest: select 0-<1 chest CT examination 80 children,were randomly divided into 4 groups,each group of 20;1-<3 years old children with chest CT examination in 140,were randomly divided into 7 groups,each group of 20;3-< 6 years old children with chest CT examination in 180,were randomly divided into 9 groups,each group of 20;The preset noise index is in the range of 9-17,adopts Z axis automatic tube current modulation,tube voltage 100 KV,tube current of 20-150 m A,Filter back-projection reconstruction technique,comparative analysis of different noise index under the condition of SNR image,image noise,CTDIvol,DLP and ED,and to evaluate the image quality and meet the diagnostic requirements for each age some children with noise index of maximum critical value.Clinical test: select 0-<1 year old,1-<3 years old,3-<6 year old chest CT plain scan and enhanced examination of 30 children;Plain scan sequence,0-<1 years old children with a preset noise index of 12,1-<3 years old children with a preset noise index of,3-<6 years old children with a preset noise index of 17,using the Z axis Automatic tube current regulation technology,tube voltage 100 KV,tube current 20-150 m A;Enhancedscan sequence,The noise index of 0-6 year old children was preset to 9,and the other parameters were the same as those of plain scan sequence;With enhanced scanning sequence data using Filter back-projection reconstruction algorithm;children with chest plain scan sequence data using the adaptive statistical iterative reconstruction technique(ASiR)for image reconstruction,with 10%step up the value for the 0%-100% 11 group of image reconstruction,which is0% of the conventional Filter back-projection reconstruction algorithm,a comparative analysis of technical conditions of different weights of ASiR reconstruction image under SNR the image noise,and analyze the subjective quality of image comparison,explore the various ages of 0-6 years old children underwent chest CT scan with different weight ASiR reconstruction and chest CT image quality,and to explore the optimal weight range ASiR reconstruction technology.Results: Clinical pretest: 0-<1 years,1-<3 years,3-<6 years old children with noise index were 11,14,16 when scanning the reconstructed image can meet the diagnostic requirements,and significantly reduce the single radiation dose for children,the age of noise index of maximum critical value.Clinical test: The image noise decreased with the increase of the weight of ASiR image reconstruction technology,SNR increased with the increase of the weight of ASiR image reconstruction technology,subjective quality evaluation score increased with adding weight ASiR reconstruction technology,when reaching the optimal weight range will decrease with the increase of ASiR weight and reconstruction technology;0-<1 years old children with images ofASiR optimal weight lung window 50%,mediastinal window was 40%;1-<3years old children with images of ASiR optimal weight lung window 60%,mediastinal window was 50%;3-<6 years old children with images of ASiR optimal weight lung window 70%,mediastinal window 60%.conclusion: In the low dose CT scan of chest in preschool children,the application of ASiR iterative reconstruction technique can significantly improve the image quality,reduce image noise,0-<1 image ASiR years old children with optimal weight lung window was 50%,mediastinal window was 40%;1-<3 years old children with images of ASiR optimal weight lung window 60%,mediastinal window was 50% 3-<6;children at the age of ASiR imaging was 70%,the optimal weight of lung window mediastinal window 60%.