Humerus photon starvation streak artefact.

INTRODUCTION

The reduced (attenuated) number of photons passing through the arm can result in a combination of fine and thick streak artefacts, particularly with the use of thin CT slices and lower radiation dose parameters. This phenomenon is known as photon starvation. We noted an abnormal appearance of the humerus when imaged with certain arm position. This appearance was thought to be artefact due to photon starvation.

METHODS

A human radius bone was imaged in different positions and the kV and mA were varied in an attempt to reproduce the artefact, which would support the hypothesis that the artefact may be caused by bone attenuation.

RESULTS

Scanning the bone in a different angle and radiation dose parameters reproduced the artefactual appearance of the bone.

CONCLUSION

Performing a chest CT scan with arms up can occasionally result in an abnormal appearance to the humerus due to photon starvation artefact. Familiarity with this artefact is essential to avoid misinterpretation.