Is Tc99-m sestamibi Safe in Breastfeeding

I am a breastfeeding mother and i want to know if it is safe to use Tc99-m sestamibi? Is Tc99-m sestamibi safe for nursing mother and child? Does Tc99-m sestamibi extracts into breast milk? Does Tc99-m sestamibi has any long term or short term side effects on infants? Can Tc99-m sestamibi influence milk supply or can Tc99-m sestamibi decrease milk supply in lactating mothers?

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 (ICRP 2008, Howe 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 occur immediately after a diagnostic test with Tc 99m sestamibi (ARSAC 2016, ICRP 2008, Howe 2008, Stabin 2000, Rubow 1994 and 1991). Some agencies (ARSAC 2016, ICRP 2008) consider it more prudent to discontinue breastfeeding for about 4 hours, expressing breast milk and instead offering milk previously expressed and stored in a refrigerator prior to testing.Milk expressed after feeding 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).

Information in this record refers to the use of Tc99-m sestamibi (Tc 99m-methoxyisobutylisonitrile; Tc 99m MIBI) as a diagnostic agent. The United States Nuclear Regulatory Commission and other agencies state that breastfeeding need not be interrupted after administration of Tc99-m sestamibi in doses up to 1000 MBq (30 mCi) to a nursing mother.[1][2][3] However, to follow the principle of keeping exposure "as low as reasonably achievable", some experts recommend nursing the infant just before administration of the radiopharmaceutical and interrupting breastfeeding for 3 to 6 hours after the dose, then expressing the milk completely once and discarding it. If the mother has expressed and saved milk prior to the examination, she can feed it to the infant during the period of nursing interruption.[2][4][5] Mothers need not refrain from close contact with their infants after usual clinical doses.[6] Mothers concerned about the level of radioactivity in their milk could ask to have it tested at a nuclear medicine facility at their hospital. When the radioactivity is at a safe level she may resume breastfeeding. A method for measuring milk radioactivity and determining the time when a mother can safely resume breastfeeding has been published.[7] For nursing mothers who work with Tc 99m substances in their workplace, there is no need to take any precautions other than those appropriate for general radiation protection.[8]