CTs and MRIs
Nursing mothers occasionally need to under radiologic procedures such as CT scans, MRIs, angiography, or urograms. These scans typically use intravenous and/or oral contrast, either iodinated contrast or gadolinium-containing contrast.
The American College of Radiology has determined that less than 1% of these agents are excreted into breastmilk, and less than 1% of any contrast medium in breastmilk would be absorbed thru the infant's GI tract.
Therefore, breastfeeding does not need to be interrupted when a mother undergoes an MRI, CT, angiogram or urogram when these contrast agents are used.
Nuclear Medicine- procedures that use radioactive materials
Elective diagnostic nuclear medicine procedures should be delayed until the patient is no longer breastfeeding.
When a nursing woman receives radioactive compounds, the radioactive material will be excreted into breastmilk and will irradiate the breasts. The radioactive material will also leak out thru the breastmilk.
If a nuclear procedure cannot be delayed until weaning, recommendations for pumping and dumping or storage of breastmilk are specific to each nuclear substance. Please search for the nuclear compound in the National Library of Medicine Toxnet to find the latest recommendations on management.
Breastmilk expressed while moms are exposed to radioactive materials can be stored in the freezer. Over time, the breastmilk will no longer be radioactive. The breastmilk should be kept in a freezer that is infrequently opened and is away from frequent contact with people, to avoid irradiating others.
National Library of Medicine Toxnet, Lactmed database.