To become a radiologist you wil need to have a mbbs degree which denotes you will have to get yourself admitted in a medical college ,in india there are 3 Medical entrance examination first one is neet which will help you to get yourself admitted in any government / private Medical college in india .
Next one is aiims which will help to get admission in aiims
And the last one is jipmer pondicherry
You can crack either one of them and fulfill your dream as a radiologist..
Hope it helps..