TABLE 2.

Estimated uncertainty budget for W2 dose measurements. The largest source of uncertainty is associated with the detector position due to an initial dose fall‐off of approximately 10% per mm from isocenter. The uncertainty associated with the Task Group‐51 dose calibration for the linac¹⁷ is not included since it is a systematic error common to all dosimetric measurements and treatment planning calculations

Dose measurement uncertainties (k = 1) for W2 detector
Type of uncertainty	Source of uncertainty	Effect
Statistical	Detector position	±3%
	Beam output	±0.25%
Systematic	Dose calibration (Eclipse TPR calculation for 4 × 4 cm2 field)	±0.5%
	Measurement in solid water 27	±1%
Total		±3.2%