Objective To investigate the optimal combination of different noise levels and ASIR-V weights in low dose chest scanning with Revolution 256CT.Methods A total of 320 healthy subjects were randomly divided into four groups:conventional dose group(NI15)and low dose group(NI25,30,35),80 people in each group,which were combined with different weights(0-100％)of ASIR-V.Region of interest(ROI)noise(SD),signal-to-noise ratio(SNR),contrast to noise ratio(CNR),dose volume index(CTDIvol),dose length product(DLP)and effective radiation dose(ED)were measured and calculated.The image was scored subjectively to obtain the combination of optimal noise index(NI)and ASIR-V weight.Objective indicators were compared by ANOVA,and subjective indicators were compared by Kappa consis-tency test.P＜0.05 indicates statistical significance.Results(1)With the increase of ASIR,the SD value gradually decreased,and the SNR and CNR values gradually increased,and the differences were statistically significant(F=1.216-39.410,P＜0.05).(2)With the increase of NI value,SD value gradually increased,SNR and CNR values gradually de-creased,and the differences were statistically significant(F=1.216-39.410,P＜0.05).(3)With the increase of NI value,the values of CTDIvol,DLP and ED gradually decreased,and the differences were statistically significant(F=140.221-153.169,P＜0.05).Compared with the conventional dose group,the effective radiation doses of the three low-dose groups were reduced by about 68％,79％and 84％,respectively.(4)Subjective score in NI15 combined with 30％ASIR-V weight,NI25 combined with 40％ASIR-V weight;NI30 combined with 50％ASIR-V weight;NI35 combined with 60％ASIR-V weight was the highest.The optimal combination of NI and ASIR-V weights was NI1 5 combined with 30％ASIR-V weight,NI25 combined with 40％ASIR-V weight,NI30 combined with 50％ASIR-V weight,and NI35 combined with 60％ASIR-V weight in the Revolution 256CT chest low-dose scan.
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NSTL
维普
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