Abstract
Radioactivity after administration of123I-sodium iodide was measured in breast milk samples obtained from a patient with postpartum thyroiditis. The breast milk was collected over 93 h during the infant’s regular feeding times. The radioactivity in the breast milk was calculated with a123I capsule of the same lot number as the standard source.123I was excreted exponentially with an effective half-life of 5.5 h; 2.5% of the total radioactivity administered was excreted in the breast milk over the 93 h, 95% of which was excreted within the first 24 h, and 98.2% within 36 h.
The first milk sample collected at 7 h after administration of the radiopharmaceutical contained 48.5% of the total radioactivity excreted. We estimated the potential absorption of radioactivity to an infant’s thyroid in uninterrupted breast-feeding to be 30.3 mGy. With a 24-hour interruption, the absorbed radioactivity would be 1.25 mGy; with a 36-hour interruption, it would be 0.24 mGy.
According to our calculations, breast feeding should be curtailed for 36 h to reduce the infant’s exposure to123I radioactivity. By using a correction factor based on maximum radioactivity from another123I capsule of the same lot, we were able to ascertain the appropriate protocol for our patient and establish a measurement method that can be applied in similar clinical situations.
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References
Wyburn JR. Human breast milk excretion of radionuclides following administration of radiopharmaceuticals.J Nucl Med 14: 115–117, 1972.
Romney BM, Nickoloff EL, Esser PD, Alderson PO. Radionuclide administration to nursing mothers: mathematically derived guidelines.Radiology 160: 549–554, 1986.
Rose MR, Prescott MC, Herman KJ. Excretion of iodine 123-hippuran, technetium-99m-red blood cells, and technetium-99m-macroaggregated albumin into breast milk.J Nucl Med 31: 978–984, 1990.
Mountford PJ, Coakley AJ. A review of the secretion of radioactivity in human breast milk: Data, quantitative analysis and recommendations.Nucl Med Commun 10: 15–27, 1989.
Rubow S, Klopper J, Wasserman H, Baard B, van Niekerk M. The excretion of radiopharmaceuticals in human breast milk: additional data and dosimetry.Eur J Nucl Med 21: 144–153, 1994.
Ahlgren L, Ivarsson S, Johansson L, Mattson S, Nosslin B. Excretion of radionuclides in human breast milk after the administration of radiopharmaceuticals.J Nucl Med 26: 1085–1090, 1985.
Hedrick WR, Di Simone RN, Keen RL. Radiation dosimetry from breast milk excretion of radioisotope and pertechnetate.J Nucl Med 27: 1569–1571, 1986.
Nihon Medi-Physics Co., Ltd. private communication.
ICRP. Report of the Task Group on Reference Man. International Commission for Radiological Protection Publication 23, Oxford, England, Pergamon Press, 1975.
Loevinger R, Berman M. A schema for absorbed dose calculation for biologically-distributed radionuclides. MIRD pamphlet No. 1, New York, The Society of Nuclear Medicine, 1968.
ICRP. Radiation dose to patients from radiopharmaceuticals. International Commission for Radiological Protection Publication 53, Annals of the ICPR 18: 266, 1987.
Blue PW, Dydek GJ, Ghaed N. Radiation dosimetry from breast milk excretion of iodine-123.J Nucl Med 28: 544–545, 1987.
Hedrick WR, DiSimone RN, Keen RL. Reply.J Nucl Med 28: 544–545, 1987.
Blue PW, Dydek GJ. Excretion of radioiodine in breast milk.J Nucl Med 30: 127–128, 1989.
The Japan Radioisotope Association. Sodium iodide capsule.Radiopharmaceuticals Hand Book.4th ed. Japan Radioisotope Association, Tokyo, pp. 52–53, 1991.
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Morita, S., Umezaki, N., Ishibashi, M. et al. Determining the breast-feeding interruption schedule after administration of123I-iodide. Ann Nucl Med 12, 303–306 (1998). https://doi.org/10.1007/BF03164918
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DOI: https://doi.org/10.1007/BF03164918