Er, what's going on? I replied to DPX yesterday, but now my reply is gone?
Yes, I know who the Hulk (Bruce Banner) and Spider-Man (Peter Parker) are. IIRC, Captain America was originally drawn during World War 2 as a 'super-soldier' who punched out Hitler.
And Iron Man was originally Tony Stark, a businessman who suffered traumatic chest injuries, which is why he built himself a protective suit of armour.
But if you suffer the sort of chest injuries that Tony Stark suffered, wouldn't you die within minutes? *shrug*
Obviously this is suspension of disbelief. First, there's the fact that (in the movies, anyway) they performed surgery on his open chest in a cave in the middle of a desert. No sterilised room here! Not to mention the size of the hole in his chest -- somehow Pepper Potts can put her hand in his chest?
No idea how they could have rearranged his organs to make room.
Second, the arc reactor is also capable of great magnitudes of energy to power the Iron Man suit. This is pure science fiction. The chest piece is also essential because it keeps the shrapnel (or fragments) from killing Tony by entering his heart. These fragments must be so small that even the cave desert surgery couldn't remove all of it.
So maybe we need to believe that the shrapnel truly can't be removed, or Tony dies. (Also, keep in mind that when the Iron Man comic first came out, a heart transplant wasn't possible, even experimentally).
So if we can believe that, why don't they have the technology to heal Tony Stark when he is back in the US? Maybe some kind of way to diffuse his blood, or some other fantastic surgery to remove the shrapnel. X-ray won't do it; MRI scans might. Maybe? But there's an answer to that:
The chest piece serves a purpose for the story and the character. It's part of the drama: if our hero doesn't have it in place, he dies. It gives him a weakness and makes him vulnerable, which keeps from becoming a munchkin!
And maybe Tony doesn't want someone operating on him, when he's unconscious and vulnerable, who could then simply steal his arc reactor technology? In the screenshot above, Tony is having Ms. Potts change out his chest piece in his own lab, not some doctor in a hospital.
Let's look at it this way: Tony's a genius, superhero, playboy billionaire with narcissistic tendencies. Maybe he doesn't
want to be cured.
It adds emphasis when he says, "I am Iron Man".