Hey , THX1138, thanks for your help! It's seems there was something strange in my SSS settings. I deleted the previous SSS shader and made a new one. My key light has a intensity of 5 and linear as decay. I', m using two background lights, no dacay, 0.5 each one. And a fill light, linear, intensity 2.
This render was made using Production setting, with Final Gather enabled. I think the volumes are more defined now.

https://www.amauriilustra.com.br/CGTalk/Bjork_30.jpg