Roentgen (unit) absorbed dose in a wide range of matter. When measuring absorbed dose in a human due to external exposure, the SI unit the gray, or the related non-SI rad are used. From these can be developed the dose equivalents to consider biological effects from differing radiation types and target materials. These are equivalent dose, and effective dose for which the SI unit sievert or the non-SI rem are used. The following table shows radiation quantities in SI and non-SI units: Roentgen (unit) The roentgen or röntgen () (symbol R) is a legacy unit of measurement for the exposure of X-rays
The Amazing Race en Discovery Channel 2 January 2010 and filming took place between May and June 2010. The show was to be broadcast in high-definition television. Filming for the second season of "The Amazing Race en Discovery Channel" lasted for 25 days and covered nearly . The second season spanned eight countries in two continents. Among them, 4 were unvisited countries, including Bolivia, Guatemala, Ecuador and Venezuela. Previously visited countries were Mexico, Brazil and Argentina. Colombia was also a previously visited country never visited in the original American version at the time of air, it will later be visited in the twenty-eighth season in 2016. The