Medical illustration is one well known human anatomy textbook that showcases a variety of anatomy depiction techniques. In 1895, Konrad Roentgen, a German physicist discovered the X-Ray. Internal imaging became a reality after the invention of the X-Ray. Since then internal imaging has progressed to include ultrasonic, CT, and MRI imaging. As a profession, medical illustration has a more recent history. In the late 1890s, Max Brödel, a talented artist from Leipzig, was brought to The Johns Hopkins School of Medicine in Baltimore to illustrate for Harvey Cushing, William Halsted, Howard Kelly, and other notable clinicians. In addition to being an extraordinary
Roentgen (unit) the accompanying text. In the meantime, the new concept of roentgen equivalent man (rem) had been developed. Starting in 1957, the ICRP began to publish their recommendations in terms of rem, and the roentgen fell into disuse. The medical imaging community still has a need for ionization measurements, but they gradually converted to using C/kg as legacy equipment was replaced. The ICRU recommended redefining the roentgen to be exactly 2.58 × 10 C/kg in 1971. In 1971 the European Economic Community, in Directive 71/354/EEC, catalogued the units of measure that could be used "for ... public health ... purposes". The