Grenz rays
Grenz Rays are part of the electromagnetic spectrum comprising low energy (ultrasoft) X-rays. These were first developed by Gustav Bucky in 1923 using a cathode vacuum tube with a Lithium borate glass window which he labeled Grenz rays as he believed that the biological effects resembled UV light & traditional X-rays and hence was on the border between the two (Grenz = border in German). These rays are also known as Bucky rays.(Ref 1.)
Grenz rays are produced by specially calibrated X-ray machines generally operating in the 10-30 kV range to produce X-rays with HVL less than 0.035 mm Al (Ref2.) (HVL is half value layer & refers to a thickness of a given material that will cut the X-ray flux by 50%). Grenz rays are absorbed by air & therefore treatments must be given at fixed distances which the machine has been calibrated for. Grenz rays have a half value depth of 0.5mm & essentially absorbed within the first 2mm of skin (Ref3.). The exact mechanism of action is unknown but it does have effects on the Langerhans cells in the epidermis (Ref4,5)
Grenz rays are indicated for treatment of eczema, psoriasis, palmoplantar pustulosis, neurodermatitis and pruritus ani et vulvae. It has been reported to be helpful for lichen planus, Grover's disease, Darier's disease, & histiocytosis X.(Ref2.) Grenz ray has been used for treatment of actinic keratoses & Bowen's disease (Ref.1)
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[edit] References
1.Lewis H: Grenz ray therapy: Regimens & Results.Chapter 15 in Physical Modalities in Dermatologic Therapy. Goldschmidt H (ed.) 1978 Springer-Verlag
2.Hollander MB : Grenz rays. Journal of Investigative Dermatology 21,15–26 July 1953
3.Olivo MP :Grenz ray treatment of Benign Skin Diseases Chapter 5 Radiation treatment and Radiation Reactions in Dermatology Panizzon R & Cooper J (ed.) 2004 Springer-Verlag Berlin
4.Lindelof B,Linden S,Ros A-M Effect of Grenz rays on Langerhans cells in human epidermis.Acta Dermatol.Venereol (Stockh)64:436-8 1984
5.Beitner H,Nakatani T & Lindelof B An ultrastructural study of human epidermal Langerhans cells irradiated with Grenz rays and ultraviolet A Photodermatol Photoimmunol Photomed 1990 : 7 : 266-8
