there is a debate as to what is more important - step I or step II; the selection by a program varies greatly. A few will factor all things near-equally (i.e.: bsgpa, step scores, clinical evals, LORs etc.), and then base their decision on your interview; but for the most part, I believe most programs use a cutoff system leading up to the interview - and the vast majority of these programs use step 1 as their first cutoff measure.
both radiology and radio-oncology are fairly competitive, though I believe radio-onc is more competitive (could be wrong?).
My cousin got into a good radiology program about three years ago, and he scored 240+; to be honest I think >230 will be borderline competitive...but like I said, some programs will factor all things considering.