In 2003, according to National Center for Health statistics, US national expenditures for health exceeded $1.5 trillion, representing almost 15% of the gross domestic product. Costs have been increasing at an annual rate greater than 7.5%. In 2002, per-capita expendituresforhealthintheUnitedStates surpassed $5,440. These expenditures greatly exceed those of any other country in the world, and the question of whether they could be reduced without affecting quality is rightly asked. Although the expenditure figures for total medical imaging procedures are not available, on the basis of an extrapolation from known Medicare imaging expenditures, they should amount to $65 billion to $75 billion peryear.Thisisbasedonaroughrule of thumb multiplying Medicare imaging expenditures by a factor of 3.5 [1]. This amount for medical imaging is also considered to be higher than it should be. The value of modern, cross-sectional medical imaging is undisputed, and much of the increase in itsutilizationisapparentlyjustified.