What is the annual table travel maximum range tolerance (all directions)?

• A. ±1 mm
• B. ±3 mm
• C. ±2 mm
• D. ±2.5 mm

Answer: (C)

Over a year, the patient table can experience small drifts due to wear and calibration changes. The annual maximum range tolerance in every direction is two millimeters, meaning the table’s position should stay within plus or minus two millimeters along each axis relative to where it was planned. This level balances practical mechanical stability with the need to keep patient alignment accurate for treatment. If the couch wanders more than two millimeters in any direction, maintenance or recalibration is warranted. The smaller value would be overly strict for an annual check, while larger values would permit misalignments that could affect dose delivery.