nipple markers
Nipple markers can be a useful technique in the evaluation of small radiodensities overlying the expected position of the nipple on a chest radiograph. Not uncommonly a small round opacity projects over the lower thorax on a chest radiograph (see: solitary pulmonary nodule).
Often, especially in women, this is a nipple shadow - a dense nipple projected over the lung. However, one must be cautious that this is not pathology - in particular, a low-grade lung malignancy (with potential surgical cure).
If in doubt, recall the patient and repeat the study with nipple markers. These can be small ball-bearings, paperclips reformed in triangle shapes around the nipple or other radiopaque markers, which are stuck to the chest with the nipple within or with the marker directly on the nipple. Markers are usually placed on both sides of the chest, even though the concern is usually on one side only.
On the repeat film:
