First digital source

 In its "first" press release issued in November 2019,  Nanox says:

Nanox, founded by the serial entrepreneur Ran Poliakine, is an Israeli/Japanese cooperation that has created the world’s first commercial-grade digital X-ray source for real-world medical imaging applications

How do you define digital? Roentgen used a cold-cathode (gas discharge) tube when he discovered X-rays, and so did all commercial X-ray sources until 1913.  Carestream/Micro-X/XinRay got clearance for the mobile x-ray unit that uses CNT tubes in February 2018. 

Crookes tube, source:  https://www.emory.edu/X-RAYS/century_02.htm

 

Update March 31, 2021:  Vatech got clearance for its dental x-ray system that uses a CNT tube (V1-650304) in September 2016.