I've solved this myself! In my class spritefont. I've been edit it flowing:
<characterregions>
<characterregion>
<start>& #32;</start>
<end>& #126;</end>
</characterregion>
<characterregion>
<start>& #913;</start>
<end>& #969;</end>
</characterregion>
</characterregions>
& #913 -> & # 969 are Greek charaters like "π,Ω,θ,ξ". It begin "A" and the end "ω"