Is Technetium Tc 99m Tilmanocept safe while breastfeeding?

Summary of use during breastfeeding

Information in this record refers to the use of technetium Tc 99m tilmanocept as a diagnostic agent. No information is available on the use of technetium Tc 99m tilmanocept during breastfeeding. The manufacturer and guidelines recommend withholding breastfeeding for 24 hours after a diagnostic dose.[1] The mother can nurse just before administration of the radiopharmaceutical. 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.[2,3] The milk that is pumped by the mother during the time of breastfeeding interruption can either be discarded or stored frozen and given to the infant after 10 physical half-lives, or about 60 hours, have elapsed.

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.[4]

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.[5]

Effects on the breastfed infant

Relevant published information was not found as of the revision date.

Effects on milk supply

Relevant published information was not found as of the revision date.

Levels in milk

Tc 99m is a gamma emitter with a principal photon energy of 140 keV and a physical half-life of 6.04 hours.[1] The biological half-life is 1.8 to 3.1 hours, giving an effective half-life from 1.4 to 2 hours.