Here's the official White House transcript of Trump's remarks (emphasis added):

THE PRESIDENT: Thank you very much. So I asked Bill a question that probably some of you are thinking of, if you're totally into that world, which I find to be very interesting. So, supposing we hit the body with a tremendous — whether it's ultraviolet or just very powerful light — and I think you said that that hasn't been checked, but you're going to test it. And then I said, supposing you brought the light inside the body, which you can do either through the skin or in some other way, and I think you said you're going to test that too. It sounds interesting.

ACTING UNDER SECRETARY BRYAN: We'll get to the right folks who could.

THE PRESIDENT: Right. And then I see the disinfectant, where it knocks it out in a minute. One minute. And is there a way we can do something like that, by injection inside or almost a cleaning. Because you see it gets in the lungs and it does a tremendous number on the lungs. So it would be interesting to check that. So, that, you're going to have to use medical doctors with. But it sounds — it sounds interesting to me.

So we'll see. But the whole concept of the light, the way it kills it in one minute, that's — that's pretty powerful.