Toyota injector clean/service

[jogal]

I just had a 110k service and was asked if I wanted the injector service and decided to go ahead with it even though I have know concerns with the injectors regarding noise or anything else.
Unless it's my imagination I reckon it drives smoother,accelerates better and holds gears longer.
Would like to know from someone that works at Toyota to explain what is actually involved with the Toyota injector service