Can Phototherapy Treat White Patches On Feet And Hands?

i am now 50 years, i have vitiligo since i was 10 years and i was taking medicines for about 12-15 years (ayurvedic). there was some good improvement as well. but there were still some patches on my feet and hands. the reason to stop the medicine was difficulty to get the medicine. later i attempted to try allopaphy but i was sensitive and unable to withstand nausia. there is no spreading of the patches yet recently, since three months i have started phototherapy. i want to know can phototherapy cure the patches which are as old as 25-30 years.