Last update Feb. 14, 2024

Fluorine-18 (18F)

Very Low Risk

Safe. Compatible. Minimal risk for breastfeeding and infant.

Fluorine-18 (18F) is a radioactive isotope of fluorine that emits positrons. It is used in positron emission tomography.

There are several substances labeled with fluorine-18 for diagnostic purposes: fluorodeoxyglucose 18F or fluorodeoxyglucose 18F (FDG-18F), fluorodopa (18F-FD), fluorocholine 18F, thymidine 18F, florbetapir 18F, florbetaben 18F, sodium fluoride 18F.

They are administered by intravenous injection to assess cerebral and myocardial or other tissue glucose metabolism. They are used in the diagnosis of oncological, cardiac (coronary heart disease) and neurological (epilepsy and Alzheimer's disease), renal and bone diseases.

FDG is not excreted in breast milk, but radiation from 18F accumulates in the lactating breast tissue. (Mitchell 2019)

Most agencies and expert authors consider that, due to their short physical half-life, no interruption of lactation is required after PET with 18F(Mattsson 2021, Mitchell 2019, ICRP 2015 p320, Jamar 2013, Leide 2010)

Others recommend an interruption of 1 to 4 hours (ARSAC 2023, ACMUI 2019, IAEA 2018 p283) and avoidance of contact with the infant for 12 hours to nullify the radiation accumulated in the lactating breast (Jamar 2013, Leide 2010, Hendler 2010, Hicks 2001). During that time, milk can be expressed, not discarded, and given to the infant. (Mitchell 2019, Jamar 2013, Hicks 2001)

Nuclear medicine services can measure the radioactivity of milk so that breastfeeding can be safely resumed. (Stabin 2000)

Breastfeeding can lead to excessive uptake of 18FDG diffusely in the breast, sometimes unilaterally, depending on the breastfeeding practice, which can lead to misdiagnoses of breast cancer or lymphoma or mastitis. (Ko 2013, Abhyankar 2012, Hendler 2010, Hicks 2001)

See below the information of this related product:

Suggestions made at e-lactancia are done by APILAM team of health professionals, and are based on updated scientific publications. It is not intended to replace the relationship you have with your doctor but to compound it. The pharmaceutical industry contraindicates breastfeeding, mistakenly and without scientific reasons, in most of the drug data sheets.

Jose Maria Paricio, Founder & President of APILAM/e-Lactancia

Your contribution is essential for this service to continue to exist. We need the generosity of people like you who believe in the benefits of breastfeeding.

Thank you for helping to protect and promote breastfeeding.

José María Paricio, founder of e-lactancia.


Main tradenames from several countries containing Fluorine-18 (18F) in its composition:


Variable Value Unit
Oral Bioavail. 100 %
Tmax 0.5 hours
1.2 hours


  1. ARSAC. Administration of Radioactive Substances Advisory Committee. Notes for Guidance on the Clinical Administration of Radiopharmaceuticals and Use of Sealed Radioactive Sources. Section 7 Conception, Pregnancy and Breastfeeding, p. 53-58. ARSAC Support Unit. Centre for Radiation, Chemical and Environmental Hazards. Public Health England. 2020 Consulted on Dec. 4, 2023 Abstract Full text (link to original source) Full text (in our servers)
  2. Mattsson S, Leide-Svegborn S, Andersson M. X-RAY AND MOLECULAR IMAGING DURING PREGNANCY AND BREASTFEEDING-WHEN SHOULD WE BE WORRIED? Radiat Prot Dosimetry. 2021 Oct 12;195(3-4):339-348. Abstract Full text (link to original source)
  3. IAEA - International Atomic Energy Agency. Radiation Protection and Safety in Medical Uses of Ionizing Radiation IAEA Safety Standards Series No. SSG-46, 2018 Abstract Full text (link to original source)
  4. Leide-Svegborn S, Ahlgren L, Johansson L, Mattsson S. Excretion of radionuclides in human breast milk after nuclear medicine examinations. Biokinetic and dosimetric data and recommendations on breastfeeding interruption. Eur J Nucl Med Mol Imaging. 2016 Abstract
  5. ICRP 2015: Mattsson S, Johansson L, Leide Svegborn S, Liniecki J, Noßke D, Riklund KÅ, Stabin M, Taylor D, Bolch W, Carlsson S, Eckerman K, Giussani A, Söderberg L, Valind S; ICRP.. Radiation Dose to Patients from Radiopharmaceuticals: a Compendium of Current Information Related to Frequently Used Substances. ANNEX D. RECOMMENDATIONS ON BREAST-FEEDING INTERRUPTIONS. ICRP Publication 128. Ann. ICRP 44(2S). 2015. Table D1 p320-21. Abstract Full text (link to original source)
  6. Jamar F, Buscombe J, Chiti A, Christian PE, Delbeke D, Donohoe KJ, Israel O, Martin-Comin J, Signore A. EANM/SNMMI guideline for 18F-FDG use in inflammation and infection. J Nucl Med. 2013 Abstract Full text (link to original source) Full text (in our servers)
  7. Ko KH, Jung HK, Jeon TJ. Diffuse intense 18F-FDG uptake at PET in unilateral breast related to breastfeeding practice. Korean J Radiol. 2013 Abstract Full text (in our servers)
  8. Abhyankar A, Joshi J, Basu S. FDG uptake in unilateral breast related to breastfeeding practice in a patient of pulmonary hydatid cyst. Clin Nucl Med. 2012 Abstract
  9. Hendler D, Stemmer SM. Uncommon reason for high fluorodeoxyglucose positron emission tomography uptake. J Clin Oncol. 2010 Abstract Full text (in our servers)
  10. Leide-Svegborn S. Radiation exposure of patients and personnel from a PET/CT procedure with 18F-FDG. Radiat Prot Dosimetry. 2010 Abstract
  11. ICRP. Radiation dose to patients from radiopharmaceuticals. Addendum 3 to ICRP Publication 53. ICRP Publication 106. Annex D. Recommendations on breast-feeding interruptions, p. 163-165. Ann ICRP. 2008 Abstract Full text (link to original source) Full text (in our servers)
  12. Hicks RJ, Binns D, Stabin MG. Pattern of uptake and excretion of (18)F-FDG in the lactating breast. J Nucl Med. 2001 Abstract Full text (in our servers)

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