Which statement about dose calibrator calibration is NOT true?

• A. It ensures accuracy of activity measurements; calibrations with traceable standards; daily constancy checks and periodic calibration per guidelines.
• B. It should be performed only when the device is suspected to be out of spec.
• C. It is performed to maintain traceability of activity measurements.
• D. It should follow vendor or regulatory guidelines for frequency.

Answer: (B)

Dose calibrator calibration is part of a regular quality assurance program to ensure that measured radioactivity accurately reflects the true activity. This relies on calibrations with standards that are traceable to recognized national or international references, and it uses a routine schedule that includes daily constancy checks and periodic calibrations according to manufacturer and regulatory guidelines. The purpose is to detect drift, changes in detector response, or other alterations that could affect patient dose or assay results, so measurements stay reliable over time.

The statement that should be performed only when the device is suspected to be out of spec is not correct because routine calibrations and daily constancy checks are the standard practice. Problems can develop gradually and may not be obvious without regular checks, and guidelines require maintaining accuracy through ongoing calibration. The other points—ensuring accuracy with traceable standards, maintaining traceability of activity measurements, and following vendor or regulatory guidelines for frequency—are all consistent with proper dose calibrator calibration.