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.
Representation of the seven AEC sensor positions labeled 1 through 7 and marked with red squares on the images of PMMA (a) and IAEA (b) phantoms. C, N1, N2, CW1 and CW2 indicate the positions of the five regions of interest used for signal-to-noise measurements.
