Which safety measures must be in place to ensure radiation safety?

To ensure radiation safety in any medical facility that utilizes radiation for treatment or imaging, it is critical to implement a comprehensive set of safety measures. The correct answer encompasses all the provided options, each of which plays a vital role in maintaining a safe environment for patients, staff, and visitors.

Warning signs displayed in radiation areas serve as a primary means of communication about potential hazards. These signs alert individuals entering the area to the presence of radiation and the need for precautions, thereby reducing unintentional exposure.

Daily testing of emergency beam off switches is essential for ensuring that these critical safety devices function correctly. In the event of an emergency, the ability to quickly and effectively turn off the radiation source is vital to protect all individuals present.

Additionally, radiation on/off lights at treatment room doors provide a visual indication of whether the radiation source is active. This real-time feedback helps prevent accidental entry into an area where radiation is present, further safeguarding individuals from excessive exposure.

Each of these measures contributes to a robust radiation safety protocol, highlighting the importance of a multi-faceted approach to ensure the well-being of everyone in the vicinity of radiation-producing equipment. Hence, the comprehensive response of "all of the above" appropriately encompasses the necessary safety measures.