The noncontrast-enhanced chest computed tomography (CT) is an emerging diagnostical tool in patient with chronic obstructive pulmonary disease (COPD). As shown in previous studies and pointed out by the Fleischner society, an additional scan in expiration reflects the pathophysiology of this complex disease better and extends the clinical information of the CT.

Nevertheless, this scan is leading to an increase in radiation dose. But currently it is unclear if this increased radiation dose is proportional to the additional clinical value when compared to inspiration-only protocols. Therefore, the aim of this study was to compare the organ specific radiation doses of a combined inspiration-expiration CT on a 3rd generation dual-source scanner with noncontrast-enhanced chest CTs of two clinical routine scanners. Therefore, the radiation doses of nearly 2000 chest CTs have been evaluated.

Inclusion Criteria:

• noncontrast-enhanced chest CT performed on one of the named devices
• imaging performed between August 2014 and September 2017
• CT protocol used as previously specified

Exclusion Criteria:

-

The data was acquired retrospectively, by analyzing CT scans performed between August 2014 and September 2017. Further, the three different study groups have retrospectively been matched using the water equivalent diameter (WED). A difference of 5% was desired to eliminate a size related bias in the effective organ dose calculation.