When working with multi-thread systems, care must be taken to prevent 2 threads from working on the same frame at the same time. In sliceOmatic this is done by using the "Lock_Get" and "Lock_Set" methods.
The SliceO_Class also has "Mutex_Open" and "Mutex_Close" methods, but these are for internal use by TomoVision (they are used among other things to implement the "Lock_Set"/"Lock_Get" methods) and should not be used in user modules.