Using the Slicer for preoperative planning measurements in CT based 3D models of Bones

Operating system: MacOS

Can I sue the Slicer for preoperative planning purposes - specifically angle measurements in CT based 3D models of Bones?

Yes, sure, you can do it. As always, it is your responsibility to make sure that all tools, including Slicer, works appropriately for your task. Make sure to thoroughly test your complete workflow on phantoms or animal models.