RT Journal Article SR Electronic T1 Absorbed 18F-FDG Dose to the Fetus During Early Pregnancy JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP 803 OP 805 DO 10.2967/jnumed.109.071878 VO 51 IS 5 A1 Zanotti-Fregonara, Paolo A1 Jan, Sébastien A1 Taieb, David A1 Cammilleri, Serge A1 Trébossen, Régine A1 Hindié, Elif A1 Mundler, Olivier YR 2010 UL http://jnm.snmjournals.org/content/51/5/803.abstract AB We describe a rare case of a woman who underwent 18F-FDG PET/CT during early pregnancy (fetus age, 10 wk). The fetal absorbed dose was calculated by taking into account the 18F-FDG fetal self-dose, photon dose coming from the maternal tissues, and CT dose received by both mother and fetus. Methods: The patient (weight, 71 kg) had received 296 MBq of 18F-FDG. Imaging started at 1 h, with unenhanced CT acquisition, followed by PET acquisition. From the standardized uptake value measured in fetal tissues, we calculated the total number of disintegrations per unit of injected activity. Monte Carlo analysis was then used to derive the fetal 18F-FDG self-dose, including positrons and self-absorbed photons. Photon dose from maternal tissues and CT dose were added to obtain the final dose. Results: The maximum standardized uptake value in fetal tissues was 4.5. Monte Carlo simulation showed that the fetal self-dose was 3.0 × 10−2 mGy/MBq (2.7 × 10−2 mGy/MBq from positrons and 0.3 × 10−2 mGy/MBq from photons). The estimated photon dose to the fetus from maternal tissues was 1.04 × 10−2 mGy/MBq. Accordingly, the specific 18F-FDG dose to the fetus was about 4.0 × 10−2 mGy/MBq (11.8 mGy in this patient). The CT scan added a further 10 mGy. Conclusion: The dose to the fetus during early pregnancy can be as high as 4.0 × 10−2 mGy/MBq of 18F-FDG. Current dosimetric standards in early pregnancy may need to be revised.