title: Estimated radiation dose to breast feeding infant following maternal administration of 57Co labelled to vitamin B12.
abstract: Administration of a radiopharmaceutical may result in a radiation dose to an infant due to ingestion of the radiopharmaceutical secreted in the breast milk. Following a maternal administration of Co labelled to vitamin B12 (cyanocobalamin) as part of a Schilling test an estimate of the absorbed dose to a breast feeding infant was calculated. Milk samples were collected from every feed in the first 24 h, and at approximately 48 and 72 h post-administration. The absorbed dose to the infant's liver (the organ receiving the highest dose) was calculated to be 0.23 mGy. The effective dose to the infant was calculated to be 0.025 mSv, which is considerably lower than the current regulatory limit of 1 mSv. The Administration of Radioactive Substances Advisory Committee advise that the first feed, at approximately 4 h after administration, be discarded. The data show that this was unwarranted, and that the peak concentration of Co in the breast milk occurred at around 24 h.
authors.affiliation: Department of Medical Physics, Royal United Hospital, Bath, UK. kay.pomeroy@orh.nhs.uk
authors.forename: Kay M
authors.initials: KM
authors.lastname: Pomeroy
authors.forename: Laura J
authors.initials: LJ
authors.lastname: Sawyer
authors.forename: Martyn J
authors.initials: MJ
authors.lastname: Evans
mesh_terms: D001942:Breast Feeding / Q000009:adverse effects; D003037:Cobalt Radioisotopes / Q000009:adverse effects / Q000032:analysis*; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D008895:Milk, Human / Q000737:chemistry*; D011829:Radiation Dosage; D011832:Radiation Injuries / Q000209:etiology / Q000517:prevention & control; D011874:Radiometry / Q000379:methods*; D018570:Risk Assessment / Q000379:methods*; D012307:Risk Factors; D012546:Schilling Test / Q000009:adverse effects / Q000379:methods*; D014805:Vitamin B 12
chemical_list: D003037:Cobalt Radioisotopes; D014805:Vitamin B 12