Setup Error
The systematic or random deviation between the planned patient position and actual treatment position during radiation delivery.
Full Definition
Setup error encompasses both systematic and random deviations from the intended patient position during radiation therapy treatments. Systematic errors are reproducible shifts that occur consistently throughout a treatment course, often due to immobilization issues or changes in patient anatomy. Random errors are day-to-day variations in patient positioning despite careful setup procedures. Both types of setup error can significantly impact dose distribution and treatment outcomes, making setup verification through imaging protocols and error correction strategies essential components of modern radiation therapy quality assurance.
Usage
Usage note: Distinguish between systematic (reproducible) and random (day-to-day) setup errors in documentation.
In Context
- "Analysis revealed a systematic setup error of 2mm in the lateral direction requiring protocol adjustment." — Quality assurance review
- "Daily imaging helps identify and correct setup errors before treatment delivery." — Protocol guidelines