Increasingly, doctors are using mobile apps to access patient information. Hard data is scarce. For instance, the annual market for mobile monitoring devices is estimated to be a $7.7 billion to $43 billion industry, as cited by a PricewaterhouseCoopers report, "Healthcare Unwired," released in September 2010. But the trend is clear. "This level of adoption is unprecedented. Things are changing very quickly," said healthcare innovation analyst Chris Wasden of PricewaterhouseCoopers. According to a Manhattan Research study released this month, 75% of U.S. physicians own some form of Apple mobile device, whether it's an iPad, iPhone or iPod. The iPhone is the top smartphone choice for doctors, according to the study. About 30% have an iPad, and another 28% say they plan to buy one within six months. Apple's popularity, says the study, is largely driven by the increasing number of apps providing access to electronic medical records.