Article 660 in the 2017 National Electrical Code (NEC) provides the requirements for X-ray equipment. Exposure concerns have greatly diminished with the widespread adoption of digital X-ray machines, which produce much less radiation than their older film counterparts. So, the beam is less of a problem than it used to be. But Art. 660 is not about the beam [Sec. 660.1]. Generating X-rays still requires high voltage, and the Art. 660 requirements mostly address that hazard.
NEC Rules for X-Ray Equipment
Generating X-rays requires high voltage, and Art. 660 requirements mostly address that hazard.