What type of package is 18F shipped in when empty?

The correct answer involves recognizing the specific regulations concerning the shipment of radioactive materials, particularly in terms of the packaging requirements for radioactive substances like fluorine-18 (^18F).

^18F is a radioactive isotope used commonly in PET imaging, and when it is shipped in an empty state, it must still comply with safety standards established for the transport of radioactive materials. Type A containers are specifically designed for the transport of radioactive materials, providing a high level of safety and protection against leakage or contamination during transport.

Class 7 refers to radioactive materials according to the United Nations' classification system for hazardous materials. Class 7 packaging is appropriate for materials that pose radiation hazards, which is the case with ^18F. Thus, the combination of Type A certification and Class 7 designation confirms that an empty package previously containing ^18F must adhere to strict safety regulations to ensure that it does not pose a risk during its transport.

Hence, when considering the requirements for the shipment of empty containers previously holding radioactive materials, Type A, Class 7 packages accurately fulfill the requisite standards for safety and compliance.