The US has specific rules in HIPAA that allow for research, especially when using deidentified datasets. The company I'm working at (based in Berkeley, CA) has almost 400tb of radiology studies- and that's not even counting the data we've found in India. At Google Next just a few weeks ago there were representatives from NIH who were talking about the datasets they are building and making public as well.

Point being, I don't see us running behind on this.