PT - JOURNAL ARTICLE AU - Rodney J. Hicks AU - David Binns AU - Michael G. Stabin TI - Pattern of Uptake and Excretion of <sup>18</sup>F-FDG in the Lactating Breast DP - 2001 Aug 01 TA - Journal of Nuclear Medicine PG - 1238--1242 VI - 42 IP - 8 4099 - http://jnm.snmjournals.org/content/42/8/1238.short 4100 - http://jnm.snmjournals.org/content/42/8/1238.full SO - J Nucl Med2001 Aug 01; 42 AB - Excretion of radiopharmaceuticals into breast milk poses a potential risk to infants and clear recommendations regarding interruption times are required. There are few data available regarding the impact of 18F-FDG on this issue. With increasing use of PET for oncologic imaging and its potential advantages to nursing mothers because of its short physical half-life compared with other commonly used tumor imaging agents such as 67Ga and 201Tl, evaluation of the excretion pattern of this agent in breast milk is important. Methods: We have evaluated the uptake of FDG in the breasts in 7 women, 6 of whom were lactating and 1 of whom was in early postpartum but had not commenced breast-feeding. Milk samples were obtained from 4 of the lactating women, including serial samples from 1. Results: Significantly increased breast uptake was identified in all lactating breasts but not in 1 breast consistently refused by the nursing infant or in the woman who had not begun breast-feeding after delivery of her child. No qualitative change or semiquantitative estimate of radiotracer uptake in the breast was seen after expression of breast milk. Decay-corrected activity measurable in breast milk ranged from 5.54 to 19.3 Bq/mL/MBq injected. Using a standard model of breast-feeding, the calculated maximum cumulative dose to the infant, 0.085 mSv with no interruption of breast-feeding, is well below the recommended limit of 1 mSv. Conclusion: High uptake of FDG in the lactating breast appears to be related to suckling. There is, however, little secretion of activity into breast milk. Accordingly, a higher radiation dose is received by the infant from close contact with the breast than from ingestion of radioactive milk.