This is a test of commonsense. Complete the next sentence:

How to treat psoriasis with phototherapy 
Try uvb phototherapy. 
There are two different types of ultraviolet b (uvb) phototherapy, home and clinical. Uvb phototherapy is undergone when the light penetrates the skin, which slows down the growth of the skin cells.
Whether it is done at home or in a clinic, uvb phototherapy is given for specified periods of time and on a regular schedule. The specific time periods and your schedule for this treatment depend on how extensive your psoriasis is and the specific areas of your body that are affected.