I think you posted in another section so I've copied my same reply here:
I assume these fractures were in the thoracic spine? I'd say given the proximity of the CT and the manipulations, there's a good chance of the maneuver causing the fractures.
It would help to know which manipulation was done. For example, a prone technique would make it more likely.
Did your mom notice any unusual pain with twisting or bending after the treatment?