went thru radiation following lumpectomy in April and May of this year. Since then I have noticed the odor of the flatulence is sort of metallic smelling. Years ago I worked in a hospital and noticed the same smell coming from patients, thinking it might be due to chemotherapy or some other treatment. Having no pain or excess bloating, but a bit more flatulence then previous to the surgery. I see a gastroenterologist on a regular basis and have had colonoscopies done.