Last update May 28, 2019
Metastable Technetium 99 (99mTc) is a radioactive isotope that emits gamma radiation. Its radioactive decay half-life is 6.0 hours.
After radioactive labelling with sodium pertechnetate (99mTc) solution, the technetium (99mTc) sestamibi solution obtained is used in single photon emission computed tomography (SPECT) for the diagnosis of myocardial, mammary and parathyroid disease.
0.05% of the administered dose is excreted in breast milk (Leide 2016, Liepe 2016).
Breastfeeding interruption or close contact avoidance times are calculated so that the infant is not exposed to more than 1 millisievert (1 mSv = 0.1 rem) of radiation (ARSAC 2019, US.NCR 2016, ICRP 2008, Stabin 2000). An adult receives between 5 and 10 mSv annually from environmental radiation.
The main regulatory agencies which manage radioactive substances and experts consider that breastfeeding can be resumed immediately after a diagnostic test with Tc 99m sestamibi (Mitchell 2019, ARSAC 2019 p51, US.NCR 2016 tab U.3, ICRP 2008 p163, Stabin 2000, Rubow 1994 y 1991).
If the dose administered was ≥ 900 MBq, a 3-hour interruption is recommended (ARSAC 2019 p51).
Some agencies (ARSAC 2019, ICRP 2008) consider it more prudent to discontinue breastfeeding for about 4 hours, expressing breast milk once and instead offering milk previously expressed and stored in a refrigerator prior to testing.
Milk expressed after the SPECT can be frozen and used after 10 radioactive half lives: 10 x 6.0 = 60 hours = 3 days (Hale 2017, p.1919).
Close contact with the infant need not be avoided (Mountford 1999).
We do not have alternatives for Technetium 99m Sestamibi (MIBI).
Suggestions made at e-lactancia are done by APILAM team, and are based on updated scientific publications. It is not intended to replace the relationship you have with your doctor but to compound it.
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