Sodium Pertechnetate Tc 99m and Breastfeeding

Summary of use during lactation

Information in this record refers to the use of sodium pertechnetate Tc 99m 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] However, other international agencies recommend shorter times for low doses (see table). 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.[2,3] The milk that is pumped by the mother during the time of breastfeeding interruption can either be discarded or stored refrigerated frozen 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.[3] 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]

Drug levels in milk and infant serum

Tc 99m is a gamma emitter with a principal photon energy of 140 keV and a physical half-life of 6.04 hours. With perchlorate blocking, the effective half-life of Tc 99m averages 5.2 hours and 0.82% of an administered dose appears in breastmilk. Without blocking, the effective half-life is 3.4 hours and 10% of an administered dose appears in breastmilk.[1]

Effects in breastfed infants

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

Effects on lactation and breastmilk

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

References

1. Dilsizian V, Metter D, Palestro C, et al. Advisory Committee on Medical Uses of Isotopes (ACMUI) Sub-Committee on Nursing Mother Guidelines for the Medical Administration of Radioactive Material. Final report submitted: January 31, 2019. 2019. https://www.nrc.gov/docs/ML1903/ML19038A498.pdf
2. Mountford PJ, Coakley AJ. A review of the secretion of radioactivity in human breast milk: Data, quantitative analysis and recommendations. Nucl Med Commun 1989;10:15-27.2645546 PubMed
3. ARSAC notes for guidance: Good clinical practice in nuclear medicine. Notes for guidance on the clinical administration of radiopharmaceuticals and use of sealed radioactive sources. 2020. https://www.gov.uk/government/publications/arsac-notes-for-guidance
4. Stabin MG, Breitz HB. Breast milk excretion of radiopharmaceuticals: Mechanisms, findings, and radiation dosimetry. J Nucl Med 2000;41:863-73.10809203 PubMed
5. Almén A, Mattsson S. Radiological protection of foetuses and breast-fed children of occupationally exposed women in nuclear medicine - Challenges for hospitals. Phys Med 2017;43:172-7.28882410 PubMed
6. Stabin MG. Doses from medical radiation sources. https://hps.org/hpspublications/articles/dosesfrommedicalradiation.html. Accessed Nov 6, 2024.
7. International Atomic Energy Agency. Radiation Protection and Safety in Medical Uses of Ionizing Radiation, IAEA Safety Standards Series No. SSG-46, IAEA, Vienna. 2018. https://www.iaea.org/publications/11102/radiation-protection-and-safety-in-medical-uses-of-ionizing-radiation