Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Comparison of electronic portal imaging device (EPID) sag measurement results for the tested Elekta linear accelerators (linacs) (Elekta AB, Stockholm, Sweden) in (a) cross-plane and (b) in-plane directions. The solid lines show the fitted curves through the average of data points at each angle.
