Grenz ray machine used for superficial therapy, by Siemens Reiniger, 1930-1940, Germany

The Grenz ray machine was used for radiation therapy on the skin. It was invented by German radiologist Dr Gustav Bucky (1880-1963), who had discovered Grenz waves (low energy radiation waves) in 1925. Radiation therapy treatment was used extensively during the early 1900s. It involved passing ionising radiation through the body to treat certain skin disorders and conditions such as rheumatism.

The Grenz ray machine was made by German company Siemens Reiniger during the 1930s. It was used for superficial skin therapy. This means the rays did not pass deep into the body, but worked on a surface level. Manufacturing details in German, French and English show the machine was intended for European-wide export.