Nipple markers can be a useful technique in the evaluation of densities 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. This can be a small ball-bearing, unraveled paperclip reformed in a triangle around the nipple or other radio-opaque marker, which is stuck to the chest with the nipple within or the marker on the nipple. On the repeat film: