Grenz rays are absorbed predominantly through the photoelectric effect.
Since their energy is small at the outset, the path of the photoelectron is short, so that its entire quantum of energy is absorbed within one cell. However, thousands of collisions occur along that short path.
This produces ions and excited atoms and molecules that are able to enter into chemical combinations with free radicals or other molecules to form new molecules of unpredictable effect on the tissue.
(2) Recent research has shown that grenz-ray therapy decreases the number of Langerhans' cells in the epidermis. After a single dose of 400 cGy of 10 kV grenz rays on human epidermis, it was found that the number of Langerhans' cells (OKT-6 positive) was slightly reduced after 30 minutes and markedly reduced 1 and 3 weeks after irradiation.
(3) By counting the Langerhans' cells at electron microscopic resolution in human epidermis before and after grenz-ray therapy, it was confirmed that the Langerhans' cells disappeared from the epidermis after treatment. No consistent differences in kerat inocyte morphology was observed.
(4) By pretreating nickel-sensitive patients with grenz rays and then applying nickel patch tests on the treated area and on untreated control skin, it has been shown that grenz-ray therapy can almost totally suppress allergic contact dermatitis.
(5) This suppression lasts for about 3 weeks after treatment and is paralleled by a suppression of the number of Langerhans' cells in the epidermis.
(6) The mechanism of action of grenz rays on psoriasis is not known, but an antimitotic effect or an influence on the dermal infiltrate in psoriasis may be an explanation.