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 the probability tissue-density function in the PTV for Patients 1 and 2 comparing CT scanning methods: (a) Helical 3DCT scan with patient under free-breathing and (b) 4DCT scanning with the SE0% (inhale phase) represented in the figure. This illustrates density variations due to patient breathing.
