TABLE 2.

Summarized results of algorithm validation for EPID images

Algorithm	Mean agreement (mm)	Standard deviation (mm)	Max difference (mm)
Canny	2.0	0.6	3.3
Peak‐finding	1.8	0.4	2.7
Inflection‐point	0.7	0.5	1.8

For the 10‐patient dataset, the mean agreement, standard deviation of agreement, and maximum disagreement were recorded for each of the three algorithms. The inflection‐point algorithm had the closest mean agreement to manual measurements and the smallest maximum difference and was chosen for subsequent analysis of intrafraction motion and setup errors.