The Broad-band UV Light give 290-320 nano-meter having a peak wavelength of 306 nano-meter.
Narrow-band UV Light give a 311-313 nano-meter, having a peak wavelength of 312 nano-meter.
The Broadband UVB Lights have a stronger medical effect on the skin than the Narrowband UVB Lights, and they are more cost effective.
Both Lights are FDA approved for skin diseases medical use.
A small UVB Light can treat small area of the skin, while in clinics and hospitals there are full body cabins that treat the whole body.
There are thousands of dermatology clinics in the world that treat with UVB Lights.
Many people that suffer from Psoriasis or other skin disease hold a UVB Light and use it at home.
The main diseases that are treated with UVB Lights are psoriasis, vitiligo (when the skin loses the color), lichen planus and atopic dermatitis (eczema).
2.When the skin is exposed to UVB light, the Cholesterol in the skin is transferred into Vitamin D3.
In general the skin does not need much of the UVB energy to generate vitamin D3, and 15 minutes of strong sunshine every day are enough.
In Northern European countries pregnant women receive UVB light in clinics so that their babies will have more vitamin D3 when born.
