According to regulations, how long must records of written directives be maintained?

The correct answer is that records of written directives must be maintained for a minimum of three years. This requirement is grounded in regulatory standards that aim to ensure proper documentation and accountability in the practice of nuclear medicine. Maintaining records for this period allows for adequate review and compliance checks, which are crucial for quality assurance, patient safety, and adherence to legal standards.

The choice of three years strikes a balance, ensuring that facilities have the necessary history of directives accessible for any potential audits, investigations, or clinical reviews that may arise. This timeframe also aligns with practices in other healthcare disciplines, promoting a consistency in documentation retention.

In contrast, the other durations listed either exceed the minimum requirement or do not comply with the established regulations. Maintenance for periods longer than three years, such as ten or five years, while beneficial for comprehensive records management, is not mandated unless specified by institutional policies or for specific cases.