Studies on the application of adaptive statistical iterative reconstruction algorithm combined with automatic tube current modulation in chest low dose CT

Objective: To study the application of the adaptive statistical iterative reconstruction(ASiR) combined with automatic tube current modulation scanning in chest CT scan on GE Discovery CTHD 750 and to evaluate the feasiblity of low dose scan in chest CT. Methods:100 continual patients underwent chest CT scan on GE Discovery CTHD 750 were randomly divided into two groups(A and B,each containing 50 patients).Automatic tube current modulation scanning was performed,with noise index 15 HU in group A and 25 HU in group B.Images were reconstructed with different settings of ASiR(0~100%).CT dose index volumes(CTDI vol),dose length product(DLP) were recorded,and effective dose(ED) was calculated.The imaging quality was evaluated by three radiologists blindly and independently with a 5-point scoring method. Results:CTDI vol and ED were 4.22 mGy and 2.51 mSv in group A,while 1.51 mGy and 0.89 mSv in group B,which decreased by 64.22% and 64.54% respectively.Image quality in both groups met the diagnostic requirements. Conclusion:Radiation dose can be significantly decreased with image quality maintained using automatic tube current modulation scanning combined with ASiR reconstruction in chest CT scan on GE Discovery CTHD 750.