Estimated radiation dose to breast feeding infant following maternal administration of 57Co labelled to vitamin B12.

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.