A couple of things to consider here:
- You will have to take whatever you get. Many hospitals are too cheap to sponsor H1b, so unless you want to take a pass on a rads residency spot, you will have to take whatever they give you.
- H1b is the better option if you have long-term plans to immigrate into the US. You can change directly from a H1b to a green-card with limited buerocratic hassles. If you go the J1 route, you have the requirement to take a 'waiver job' first.
- radiology residency is 5 years (6 years with a fellowship). This can put you into a time crunch when you are forced to get the process for a green-card started before your training is finished. This is less of an issue in medicine for example where you still have 3 years of 'H time' once you are done with residency. In rads or surgery this tends to be an issue on H1b.
- At this time, the job market for radiologists is exeptionally good. The few people coming out on J1 these days have no difficulty securing private practice 'J1 waiver' positions in underserved areas (or as a fall-back VA positions). 8 years ago, the situation was the opposite. There were plenty of J1s coming out of residencies, but only few VA or PP positions to take them (those where the days when J1s did several fellowships or had to hang out on O1 visas at academic hospitals until a VA job at the affilated VA opened up).
So, if I could promise you that the job market for radiologists will remain the way it is right now (conflicting data out there on this issue), going for a J1 would be an entirely reasonable option. Otherwise: H1b or not to be
