Can I use more than one Computational Graph in different threads?

When I run my program with one thread, it works fine and there is always one computation graph at a time. However, I want to run it with multi-threads then I get the "Attempt to create >1 CG" error. Could you please tell me the reason assuming one CG, and if there is any chance to use more CG in different threads. I think it is safe since the model is not changed in my predict program. Thank you very much.