Within this subtask, a method will be developed to determine image quality combining state-of-the-art objective and subjective image analysis, thus maximising optimisation without compromising diagnosis.

Experienced clinical radiologists from 5 university hospitals using 300 patient chest CT examinations from adult patients will use the Delphi technique to a) establish a list of specific clinical indications b) establish clinical criteria of image quality for chest CT and c) perform subjective image quality assessment. Objective image quality assessment on chest CT images will also be developed and then applied to the same set of examinations.

Thus, for the first time, objective and subjective image quality analysis will be combined and compared to assess image quality levels of selected chest CT protocols in well-defined clinical indications. Noise, noise structure, contrast and structure sharpness will be characterized directly in patient images. The impact of tube potential, tube current, tube current modulation, noise suppression, filtering and reconstruction methods on image quality will be studied, objectively and subjectively, on simulated images.