The title is confusing without context and it doesn't clarify its meaning for a quite a while. I made the same wrong assumption as you at first. Then, before I made it to the end, I made the same wrong new assumption you made in your update to your comment! (it being about negative second-order effects - it's not)

No, what they are saying is that getting an MRI is as good as smoking for a year is bad, using some very fuzzy units of measurement. So getting an MRI "earns" you the reward of being allowed to smoke for a year (the author is being humorous).