Meetings » 10th CTUG Meeting » Abstracts

Investigation into the dose and image quality of Siemens Caredose 4D during clinical use: a comparison of 3 centres

Geraldine Revill

Mount Vernon Hospital


A study was implemented to investigate the function of the AEC (CAREDose 4D) in the Siemens Sensation 16 scanner and to assess the impact of this automatic dose modulation on image quality (noise) and patient dose. The study was performed in two stages. First, measurements were made using the ImPACT conical phantom to assess the system performance in a homogeneous medium. Secondly retrospective patient data was analysed (129 patients) at 3 centres for a chest abdomen pelvis examination. The effective mAs was recorded along with the noise. The noise measurement was taken from a 5mm slice through the bladder and the effective mAs recorded for the same slice.

Conclusion: For this examination the AECs provide up to a 32% reduction in dose compared to a constant mAs setting. The three centres all achieved diagnostic images with similar average amounts of noise (σ = 13.80 ± 1.88, 13.22 ± 2.06, 12.85 ± 2.40). The mean CTDIvol varied between the centres from 8.81mGy to 10.81mGy. This was found to be statistically significant (P<0.05). User chosen parameters chosen at set up were found to have the biggest influence on the dose. From these results recommended levels of image noise are suggested for this examination for three sizes of patient, small medium and large.

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