Methods of designing an x-ray tube shielded for operation in static and dynamic externally applied magnetic fields are described. The methods include passive shielding of the insert frame, housing, design of an external shield envelope, tube port, tube collimator, and combinations thereof. The resulting x-ray tube devices are appropriate for use in a variety of applications ranging from magnetic navigation with x-ray monitoring and guidance for interventional procedures to multi-modality imaging and interventional procedures using an x-ray system in the vicinity of an MRI system.