In the Nuclear medicine process the doses of radiopharmaceutical administered are very small, nuclear medicine procedures result in exposure to a small dose of radiation. Nuclear medicine has been used for more than five decades, and there are no known long-term adverse effects from such low-dose studies.
As with all radiologic procedures, be sure to inform your physician if you are pregnant. In general, exposure to radiation during pregnancy should be kept to a minimum.
Allergic reactions to the radiopharmaceutical can occur, but are extremely rare.