Final answer:
The operator should stand several meters away from the x-ray tube, more than the minimum of 3, 4, 5, or 6 feet suggested, to reduce radiation exposure effectively, following safety practices that include increasing distance and using shielding like lead-lined barriers.
Step-by-step explanation:
When utilizing digital imaging for x-rays, the operator should increase the distance from the x-ray source to protect against radiation exposure. According to the provided references, the technician commonly stands a few meters away behind a protective barrier.
While the provided options are 3, 4, 5, and 6 feet, these distances would be considered too close, especially when following the standard safety practice of maximizing distance from the x-ray tube. The actual recommended minimum is not explicitly stated, but the implication is that several meters, which would be more than 6 feet, provide a safer distance for the operator, especially when behind protective shielding such as a lead-lined door with a lead glass window. This is in alignment with the principles of radiation safety, which include shielding, increasing distance, and reducing exposure time to achieve a lower effective dose of radiation for the operator.