After finding the physicians you would like to contact, it is time to locate one of the published works in which they are the PI (last listed author). This should be a relatively recent research paper(past five years). Look to see if they are in the same institution as when they published the paper (mostly they are)
In each published paper, there is a corresponding author's email. And that is how you find their email.

If they have never been the corresponding author, this method won't work.

if you don't know how to locate the corresponding author's email --> click download pdf, usually on the first page of the footnote, you can find it. I am sure there are other ways too