Superficial X-rays are low-energy X-rays that do not penetrate very far before they are absorbed. They are produced by X-ray tubes operating at voltages in the 10–100 kV range, and therefore have peak energies in the 10–100 keV range.[1] The Maximar-100 was a widely-adopted superficial radiation therapy unit.
Precise naming and definitions of energy ranges may vary, and X-rays at the lower end of this range may also be known as Grenz rays.[2] They are useful in radiation therapy for the treatment of various benign or malignant skin problems, including skin cancer and severe eczema.[3][4] They have a useful depth of up to 5 mm.[2][5] In some locations, orthovoltage treatment is being replaced by electron therapy or brachytherapy.[6]
^Alikhan, Ali; Maibach, Howard; Lachapelle, Jean-Marie (2013). "Radiotherapy in the Treatment of Hand Eczema". Textbook of Hand Eczema. Berlin: Springer Berlin. doi:10.1007/978-3-642-39546-8_33. ISBN978-3-642-39545-1.