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 recommends withholding breastfeeding for 60 hours after a diagnostic dose. This length of time is 10 half-lives of the radioisotope, so the nursing infant should not be exposed to radiation if this guideline is followed. However, the effective half-life is 1.8 to 3.1 hours, indicating that resumption of breastfeeding after 30 hours should ensure that the infant is not exposed to any radioactivity via breastmilk. 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.[1,2] 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.[3]
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.[4]