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
Roentgen (unit) the roentgen. From 1977 to 1998, the US NIST's translations of the SI brochure stated that the CIPM temporarily accepted the use of the roentgen (and other radiology units) with SI units since 1969. However, the only related CIPM decision shown in the appendix are with regards to the curie in 1964. The NIST brochures defined the roentgen as 2.58 × 10 C/kg, to be employed with exposures of x or γ radiation, but did not state the medium to be ionized. The CIPM's current SI brochure excludes the roentgen from the tables of non-SI units accepted for use with