Last update June 10, 2018


Limited compatibility

Unsafe. Moderate/severe adverse effects. Compatible under certain circumstances. Follow-up recommended. Use safer alternative or discontinue breastfeeding from 5 to 7 T ½ . Read Commentary.

Copper 64 (Cu-64) is an unstable isotope of copper which emits positrons.
It is used in medicine for diagnostic purposes (positron emission tomography, PET) and radiation therapy for cancer treatment (Pfeifer 2012, Holland 2009).

Although copper has an average biological life of 18 to 24 days, the radioactive decay half-life of the Cu-64 is 12.7 hours.
Other copper isotopes are also used for diagnostic purposes: Cu-60, Cu-61 and Cu-62 with a radioactive decay half-life of 24 minutes, 3.3 hours and 10 minutes respectively, and in radiotherapy: Cu-67 with a radioactive decay half-life of 62 hours (Follacchio 2017).

Since the last update date we have not found published data on its excretion in breastmilk.

Timings for halting breastfeeding or avoiding close contact are calculated so that the infant is not exposed to more than 1 millisievert (1 mSv = 0.1 rem) of radiation (ICRP 2008, Howe 2008, Stabin 2000). An adult receives between 5 and 10 mSv per year from environmental radiation.
After a period of 10 half-lives of the isotope, all traces of radioactivity will have disappeared in the body.

If you want to continue breastfeeding it is advisable to express and conserve breastmilk in a freezer during the days or weeks prior to administering Cu-64. After the test, express milk for 10 half-lives (127 hours, 5 days), feeding in the meantime using the milk previously stored. Milk expressed after the test can be stored in a separate drawer in the freezer and re-used once 10 half-lives (5 days) have passed.

Try using the radionuclide which has the shortest life.

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.

Other names

Cu-64 is Cooper 64 in Abbreviation.

Is written in other languages:


Variable Value Unit
Oral Bioavail. 71 %
Molecular weight 64 daltons
432 - 576 hours


  1. Follacchio GA, De Feo MS, Monteleone F, De Vincentis G, Liberatore M. Radiopharmaceuticals labelled with copper radionuclides: clinical results in human beings. Curr Radiopharm. 2017 Abstract
  2. Pfeifer A, Knigge U, Mortensen J, Oturai P, Berthelsen AK, Loft A, Binderup T, Rasmussen P, Elema D, Klausen TL, Holm S, von Benzon E, Højgaard L, Kjaer A. Clinical PET of neuroendocrine tumors using 64Cu-DOTATATE: first-in-humans study. J Nucl Med. 2012 Abstract
  3. Holland JP, Ferdani R, Anderson CJ, Lewis JS. Copper-64 Radiopharmaceuticals for Oncologic Imaging. PET Clin. 2009 Abstract
  4. US.NRC - Howe DB, Beardsley M, Bakhsh S. U.S. Nuclear Regulatory Commission Office of Nuclear Material Safety and Safeguards. Apéndice U, Tabla U.3. Consolidated guidance about materials licenses. Program-specific guidance about medical use licenses. Final report. Appendix U, Table U.3. NUREG-556. Vol.9, Rev 2. 2008 Full text (link to original source) Full text (in our servers)
  5. Johnson PE, Milne DB, Lykken GI. Effects of age and sex on copper absorption, biological half-life, and status in humans. Am J Clin Nutr. 1992 Abstract Full text (link to original source) Full text (in our servers)

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