An official website of the United States government
The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before
sharing sensitive information, make sure you’re on a federal
government site.
The site is secure.
The https:// ensures that you are connecting to the
official website and that any information you provide is encrypted
and transmitted securely.
Gaffke G, Nagel S, Hegemann O, Speck U, Grosse-Siestrup C, Jungnickel K, Stroszczynski C.Gaffke G, et al. Among authors: nagel s.Z Med Phys. 2009;19(1):21-8. doi: 10.1016/j.zemedi.2008.08.003.Z Med Phys. 2009.PMID: 19459582German.