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.
Characteristic curve of a screen-film mammography image receptor. There is an approximately linear relationship between optical density of the processed film and the logarithm of relative X-ray exposure, but only over a limited region of exposure.
