All this week, we're finding you the fast money in the future in medicine, including how diagnostics can mean big money and big danger.

From MRIs to CT scans, nearly 100 million such tests are performed each year. The tests are used to find hard-to-detect dangers, but now some are worried about the possible radiation these machines may emit. Others fear overexposure. In turn, doctors are asking how they can make the best of modern technology while still obeying their promise to 'first do no harm'?