"Oh, I've seen the world change immensely. Some for the good, obviously, but some for the worse. The sheer advance in fighting disease has been incredible to behold. When I first started studying to be a physician, we had no way to truly visualize the body without opening it up. Now we have CT, MRI, PET...it's boundless."

Helen was enthusiastic about this because it was what she'd loved about being able to live so long. "I want to help as many people as I can."