An official website of the United States government
Here's how you know
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.
The variable-aperture collimator in the microCT/RT system uses two disks with hexagonal shape that open and close like an iris camera. The disks are rotated 30° one with respect to the other to form a field of dodecagonal shape.