Pediatric Radiology
March 2015, Volume 45, Issue 3, pp 337-344
Radiation dose and image quality in pediatric chest CT: effects of iterative reconstruction in normal weight and overweight children
Haesung Yoon, Myung-Joon Kim, Choon-Sik Yoon, Jiin Choi, Hyun Joo Shin, Hyun Gi Kim, Mi-Jung Lee 

Abstract
Background
New CT reconstruction techniques may help reduce the burden of ionizing radiation.
Objective
To quantify radiation dose reduction when performing pediatric chest CT using a low-dose protocol and 50% adaptive statistical iterative reconstruction (ASIR) compared with age/gender-matched chest CT using a conventional dose protocol and reconstructed with filtered back projection (control group) and to determine its effect on image quality in normal weight and overweight children.
Materials and methods
We retrospectively reviewed 40 pediatric chest CT (M:F = 21:19; range: 0.1–17 years) in both groups. Radiation dose was compared between the two groups using paired Student’s t-test. Image quality including noise, sharpness, artifacts and diagnostic acceptability was subjectively assessed by three pediatric radiologists using a four-point scale (superior, average, suboptimal, unacceptable).
Results
Eight children in the ASIR group and seven in the control group were overweight. All radiation dose parameters were significantly lower in the ASIR group (P < 0.01) with a greater than 57% dose reduction in overweight children. Image noise was higher in the ASIR group in both normal weight and overweight children. Only one scan in the ASIR group (1/40, 2.5%) was rated as diagnostically suboptimal and there was no unacceptable study.
Conclusion
In both normal weight and overweight children, the ASIR technique is associated with a greater than 57% mean dose reduction, without significantly impacting diagnostic image quality in pediatric chest CT examinations. However, CT scans in overweight children may have a greater noise level, even when using the ASIR technique.