What is the annual electron applicator interlocks tolerance?

• A. non-functional
• B. partial
• C. conditional
• D. functional

Answer: (D)

Interlocks are safety features that prevent radiation delivery when conditions aren’t safe, such as a door open or an incorrect applicator in place. For the annual QA of an electron applicator, the acceptance criterion is that all interlocks operate properly—they must be functional. This means the interlock system reliably shuts off or prevents the beam whenever a fault condition is detected, the door is opened, or the wrong applicator is used.

If the interlocks are non-functional, only partially working, or conditional, safety cannot be guaranteed, so the system would fail the tolerance. Therefore, the best answer is that the annual electron applicator interlocks tolerance is functional—all interlocks are fully operational.