I-131 IN BREAST-MILK FOLLOWING THERAPY FOR THYROID-CARCINOMA

This study evaluates breast milk secretion of I-131 following therapeutic administration of 4000 MBq of I-131-iodide during lactation. Methods: Breast milk I-131 activity concentration was measured over a 32-day period. Dosimetry calculations were undertaken to estimate the period for discontinuation of breast feeding and the equivalent dose to the breasts. Results: To achieve an infant effective dose < 1 mSv and an infant thyroid dose < 10 mSv, breast feeding would need to be discontinued for at least 52 days. The estimated equivalent dose to the breasts was 1.6 Gy. Conclusion: It is suggested that I-131-iodide administration is not undertaken during lactation and that breast feeding is discontinued several days prior to administration.