Is Technetium Tc 99m Sulfur Colloid safe while breastfeeding?

Summary of use during breastfeeding

Information in this record refers to the intravenous use of technetium Tc 99m sulfur colloid as a diagnostic agent. A US Nuclear Regulatory Commission subcommittee has recommended that nursing be discontinued for 24 hours after administration of all technetium Tc 99m diagnostic products to simplify guidance recommendations, although this time interval may be longer than necessary.[1] The International Commission on Radiological Protection and others recommend that breastfeeding need not be interrupted after administration technetium Tc 99m sulfur colloid.[2,3] In order to follow the principle of keeping exposure "as low as reasonably achievable", the International Atomic Energy Administration recommends withholding breastfeeding for 4 hours.[4] The mother can nurse the infant just before administration of the radiopharmaceutical. During the period of interruption, the breasts should be emptied regularly and completely. 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.[5,6] The milk that is pumped by the mother during the time of breastfeeding interruption can either be discarded or stored refrigerated and given to the infant after 10 physical half-lives, or about 60 hours, have elapsed. Mothers need not refrain from close contact with their infants after usual clinical doses; but following injection doses greater than 370 MBq (10 mCi), patients should minimize close contact with infants for 6 hours.[7,8]

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.[9]

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.[10]

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 effective half-life of technetium Tc 99m sulfur colloid averages 5.1 hours after intravenous administration.[9]