What material is recommended for source tags attached to exposure devices?

The recommended materials for source tags attached to exposure devices are steel or brass because these metals provide a combination of durability and radiopacity, which is essential for safety and effectiveness. Steel and brass are strong enough to withstand the operational environments typically associated with exposure devices while not being easily damaged. Moreover, they are capable of effectively containing the radiation emitted by the source, preventing exposure to personnel.

Using steel or brass ensures that the tags remain securely attached to the device and can endure the wear and tear of frequent handling during the use in radiological applications. Other materials, such as aluminum, may not be robust enough for long-term use in this context, while plastic may lack the necessary strength and stability. Wood, while naturally available, is generally not suitable due to its susceptibility to environmental factors and lack of effective radiopacity. Thus, steel or brass are the ideal choices among the given options for optimizing safety and functionality in exposure devices.