Final answer:
The protective housing around x-ray tubes contains shielding which acts as both an insulator against electrical shock and a thermal sink for heat dissipation.
Step-by-step explanation:
The protective housing around some x-ray tubes contains shielding that serves as both an insulator against electric shock, and as a thermal sink to dissipate heat. This shielding can range from steel shells 3-20-centimeters thick to main shields of 1-3 meters of high-density concrete, as well as lighter materials for personnel protection from x-rays and gamma rays. Protective measures in medical diagnostics have evolved to include faster films which require less exposure time, reducing radiation doses significantly.