How often should the accuracy of the built-in thermometer be checked with a calibrated thermometer?

• A. Daily
• B. Weekly
• C. Monthly
• D. Quarterly

Answer: (C)

Regular calibration of measurement devices is essential because sensors can drift over time due to wear, aging, or environmental factors. A built-in thermometer should be checked against a calibrated external thermometer to confirm it still reads accurately. This ensures temperature-dependent readings and compensations remain trustworthy, which is important for consistent image quality and dose-related calculations.

Checking the built-in thermometer on a monthly basis provides a practical balance: it is frequent enough to catch gradual drift before it affects performance, yet not so frequent as to be unnecessarily burdensome. Daily checks would be overly burdensome for a relatively stable sensor, weekly checks are usually more than needed for this type of drift, and quarterly checks risk letting drift go unnoticed for too long. If the comparison shows the built-in reading is out of tolerance, the device should be serviced or recalibrated before continuing use.