Information in this record refers to the use of indium In 111 white blood cells (In 111 leukocytes) as a diagnostic agent. Breastfeeding should be interrupted temporarily after administration of high doses of In 111 leukocytes to a nursing mother. British authorities state that doses greater than10MBq should not be administered to breastfeeding patients, and at that dose and below, no interruption of breastfeeding is required.[1] US recommendations state that a period of 6 days of interruption of breastfeeding is recommended, irrespective of dose.[2] The duration of breastfeeding interruption depends on the dose administered (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.[1,3] 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 28 days, have elapsed. After doses greater than 10 MBq, consideration of temporarily limiting close contact between the mother and infant.[1]
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]