Superficial X-rays

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.

Superficial X-rays
ICD-9	92.21

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]

As well as teletherapy, X-rays in this energy range (and the low orthovoltage range) are used for imaging patients, to analyse materials and objects in industrial radiography and for crystallography.