Our (US) legal system doesn&#x27;t work that way.  If something isn&#x27;t explicitly prohibited, it&#x27;s permitted.  This is a feature, not a bug.<p>While it&#x27;s not illegal to purchase and use an x-ray machine itself, it would be illegal to use one on human subjects without the proper training and licensing.  (Unless, of course, you work for the TSA.)