The GOOD NEWS for anyone with a traditional X-ray machine (one that uses a high voltage generator feeding an X-ray tube) is that there are no radioisotopes involved. Radiation is only emitted when its powered up and running. OTOH, before portable high-voltage systems became common, radioisotope-based radiography was used (e.g. radium in WWI) and often called "X-rays". And even today, some modern industrial radiography systems use Cobalt-60 for simplicity's sake. However, medical imaging today (since the 1920s) is either near-100% or actually 100% high-voltage X-ray tubes that only get jiggy when they get the high voltage.