You need to wait until next year I think. The AAMC mcat exams are considerably easier than taking the real thing and with pressure. Your pressure will be even higher since you will not have withdrawn. Release the pressure valve, bring up your grades for a year, and take the MCAT. Then, apply when you are really ready. YOur GPA right now is even low for DO, so I don't think you are i a position to want anything more than to get into medical school. Worry about radiology later, if you eventually get in, and you still even care about that field.