X-ray surface irradiation

Treatment of the skin surface with X-rays. In some dermatological centers the therapy with so-called soft X-ray devices is still common for certain indications. In this radiation therapy, the penetration depth of the X-rays into the tissue is relatively low, so that the deeper tissue is spared. The still operated soft beam devices (mostly Dermopan/Fa. Siemens) allow operating voltages of the X-ray tube between 10 and 50 kV (at 25 mA). The range up to and including 10 kV is called boundary radiation therapy (Bucky rays). The dose of X-rays is measured in Gray (Gy) (previously: rad = radiation absorbed dose).

The indication for X-ray therapy is increasingly rarely given in dermatology, mostly due to sufficient or better alternative methods without the known late damage of X-ray therapy or in the absence of functioning X-ray equipment (the devices are no longer manufactured).

• Basal cell carcinoma: Most frequent indication, especially in elderly people. For a solid basal cell carcinoma a total dosage (GD) of 50-70 Gy (43-50 kV/25 mA) is necessary. Single doses (ED) of 4-5 Gy 5 times/week.
• M. Bowen: Common indication. The total dosage (GD) is 25-30 Gy (29 kV/25 mA). The total dose is fractionated into single doses (ED) of 5 Gy at intervals of 2 days.
• Lentigo maligna: Frequent indication; especially in elderly people who can hardly be expected to undergo major surgery (note the special localization of lentigo maligna!). According to Miescher, a total dosage (GD) of 100 Gy (10 kV/25 mA = soft jet technique) is necessary for a lentigo maligna. The total dose is fractionated in ED of 20 Gy in intervals of 3-4 days
• Diffuse melanoma metastases of the skin: palliative measure if other therapeutic measures are exhausted; in this indication other radiation sources (electron accelerators) are to be preferred. GD 90-10 Gy; ED 5 Gy.
• Skin lymphomas: Common indication for isolated cutaneous B- and T-cell lymphomas of the skin. A total dosage (GD) of 25-30 Gy (50 kV/25 mA) is required for nodular lymphoma. The GD is fractionated in ED of 2-5 Gy at intervals of 2 days. The results are initially very convincing. With repeated x-ray irradiation an increasing radiation resistance is observed. In the case of erythrodermic T-cell lymphomas, remote x-ray irradiation of the whole body should be considered if there is any other resistance to treatment. The focal skin distance (FHA) is 2 m; the GD is 10-15 Gy (50 kV/25 mA, without aluminium filter), the ED is 0.5-1.5 Gy daily. Irradiation alternately from the front and the back.

X-ray applications for infant hemangiomas, naevi flammei and chronic inflammatory dermatoses.