Positron emission tomography (PET) images and single photon emission computed tomography (SPECT) images have been established quantitatively to some extent. Dosimetry has been proposed to calculate absorbed doses for targets and risk organs in targeted radionuclide therapy based on quantitative nuclear medicine images. It Radionuclides for therapy emit a wide variety of energies and the effects of bremsstrahlung are particularly problematic for to radionuclides used for diagnostics. Patients undergoing targeted radionuclide therapy must be admitted to a dedicated treatment room or special care unit until discharge criteria are met. Medical staff must take appropriate precautions regarding the contamination of rooms and patient excretions to reduce public exposure. The proper management of radiation protection and radiation control in targeted radionuclide therapy facilities is an extremely important issue for medical use and should be addressed in accordance with the actual conditions of each facility, while paying attention to laws and regulations.