Radiation dose of 18F-FDG to lactating breasts, its effect on the effective dose and a more accurate effective dose from 18F-FDG

Lactating breasts have greater uptake of fluorine-18 fluorodeoxyglucose (F-FDG) than nonlactating breasts; however, there are no published data on the radiation dose from F-FDG to lactating breasts or this effect on the effective dose (ED). In addition, the International Commission on Radiological Protection's (ICRP) most recently published ED of 1.9×10 mSv/MBq from F-FDG was calculated using weighting factors that have since been superseded. We therefore calculated the F-FDG radiation dose to the lactating breast, its effect on the ED and calculated more up-to-date EDs from F-FDG for nonlactating patients.

Breast uptake of F-FDG and volume were determined from PET/CT images of a lactating patient. These data, together with previously published biokinetic data on F-FDG, were used to calculate a radiation dose to the lactating breasts and its effect on the ED. In addition, tissue weighting factors and organ doses from the ICRP publications 103 and 106 were used to calculate more up-to-date EDs from F-FDG in nonlactating patients.

The absorbed dose to the lactating breast from F-FDG is 1.75×10 mGy/MBq, which results in an increase in the ED of 6%. In nonlactating patients, a more up-to-date ED from F-FDG is 1.77×10 mSv/MBq for women and 1.64×10 mSv/MBq for men.

This is the first reported dosimetry of F-FDG in lactating breasts, data that are required when justifying the radiation dose from an F-FDG PET scan in lactating patients. In addition, we calculated more up-to-date EDs from F-FDG that are lower than the current widely reported ED and should be used in future publications on F-FDG.