All honesty, your chances would most likely be worse than in the scramble. Radiology is on pace to have another year with a relatively large number of scramble spots (was >30 last year with fewer applications this year).
There will be far fewer positions opening up for PGY2 during your PGY1 year and many will likely fill before you are even aware of them.
If you fail to match/scramble and are really dead set on radiology, probably the best path is to complete another residency and then apply again. If you are particularly interested in IR, there are slots available specifically for people who have already completed a medicine/surgery/etc residency. Nuclear medicine is also an option, but frankly that's riskier because there are few job prospects without a second residency.