My wife has done DMRD (2014-2016),has done SR ship in DDU(Delhi), then pvt practice for about 1 Yr and is secondary DNB (Radio Diagnosis) resident now. So I can give you a fair idea about its scope.
There are two types of options after M. D. /DNB Radiology
1.Join any govt hospital. Get fixed salary. Few states allow pvt practice also, so if you give few hours to it then its good. But this is less preferred option for maximum candidates.
2. Do pvt practice. This thing is booming. With the advent of evidence based medicine, maximum doctors want radiological investigations done before treatment. The starting salary of radiologist is 1.5–2 lakh if he does USG and Xray only daily for 4–5 hr. There can be fixed salary or you can agree on share based system. In share based system radiologist gets 25-33% of total cost of investigation. So if a USG costs 1000 rs than radiologist will get 250–350 rs. Similarly in higher investigation like MRI, CT scan.