needs to put nipple markers to ensure that indeed the 'shadows' or what he thinks it is are the nipples. This is standard procedure but your doctor can easily identify this even though markers were not used as both 'shadows' will be at the same level.
Xray exposure does expose you to radiation
but of very little significance
Most viral induced coughs do last up to 2 months, and also important that you stop smoking
if you do.