Sir after 12th what should i have to do for Radiology i mean their is any entrance exam i have to clear for getting this course..?
You can check the complete details about Radiology here:
Radiology- All about!
This link above includes all details.
Good Luck.

and another one thing in which i confused tht i have recently filled the form of AIIMS (B.sc MTR) but i dnt knw how the exam will conducetd i.e offline or online ..?
medicine.careers360.com/articles/aiims-mbbs-exam-pattern