No, not healthy at all. There is a condition known as Gadolinium Deposition Disease (GDD) that some people are developing from the retention. The mechanics are not fully understood, and there is a multi-billion dollar industry preventing (or at least not encouraging) any serious inquiry into the matter, but my understanding is that if your body views gadolinium as a threat (similar to an allergy), it will mount an immune response against it. However immune responses are futile against heavy metals. So think of it as a permanent, never-ending allergic reaction to an element that refuses to leave your body.