Unable to penetrate the Earth's atmosphere, the X-rays from the flare can only be detected from space.
There's no visible problem when X-rays or endoscopes are used, so it is usually diagnosed by taking a history from the patient and using a process of elimination to learn that it is not some other health problem.
The electromagnetic spectrum includes (from longest wavelength to shortest) radio waves, microwaves, infrared, red, orange, yellow, green, blue, indigo, violet, ultraviolet, x-rays, and gamma rays.
This type of policy normally covers emergency room visits and hospital stays, diagnostic tests and x-rays, surgery, and medications while traveling, but coverage would end when the trip ends.
The percentage of cost covered by a dental insurance plan varies from policy to policy, but the standard rate is 70-80 percent of preventative dental care (exams, cleanings, X-rays etc).