J Nucl Med 2001 Aug;42(8):1238-42
Pattern of uptake and excretion of (18)F-FDG in the lactating breast.
Hicks RJ, Binns D, Stabin MG.
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 (18)F-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 (67)Ga and (201)Tl, 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.
