Radiation from a PET scan test is not higher than that from an abdominal CAT scan test. Small quantity and short half life span of radionuclides used for this test make it safe to nurse the baby shortly after the test is done. Overall, it is safe to stop nursing for a 5 to 6 of isotope half life period which is the time require for the complete disappereance of radioactivity from the body. Half life spans . . . . . . . . . . . . . . . . . Breastfeeding interruption time F-18: 110 minutes . . . . . . . . . . . . . . . . . 10 hours (avoid contact for the first 4 hours) C-11: 20 minutes . . . . . . . . . . . . . . . . . . . 2 hours N-13: 10 minutes . . . . . . . . . . . . . . . . . . . 1 hour O-15: 2 minutes . . . . . . . . . . . . . . . . . . . 10 minutes Rb-82: 1,3 minutes . . . . . . . . . . . . . . . . . . 8 minutes Meanwhile the half life span goes by milk pumping and freezing is recommended: it is safe to use the milk after a 10 half life span period.