Hello belal

To become a radiology doctor you first need to clear anyone of the neet ug, aiims, jipmer etc medical examination with good marks and pursue mbbs . Once your mbbs gets completed you need to give another examination for post graduation known as neet pg, aiims (pg), etc and try to secure top ranks. As the seats for pg are very few and radiology being on high demand have a very high cutoff. Securing a top rank would get you radiology as your main branch.

Goodluck

I hope it helps you