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
Anton Wilhelm Plaz Anton Wilhelm Plaz Anton Wilhelm Plaz (1 January 1708, Leipzig – 26 February 1784, Leipzig) was a German physician and botanist. From 1723 he studied medicine at the universities of Leipzig and Halle, receiving his doctorate at the latter institution in 1728. In 1733 he became an associate professor of botany at Leipzig, where afterwards, he successively served as a full professor of botany (1749–54), physiology (1754–58), anatomy and surgery (1758), pathology (1758–73) and therapy (1773–84). From 1773 to 1784 he was dean to the medical faculty at the university. He was a member of the Römisch Kaiserlichen Akademie der