We have examined the costs and benefits associated with the introduction of low-osmolality contrast agents into general radiology. The result is a cost of $2,000,000 to save a life and $100,000 to save a year-of-life if it is assumed that these agents are ten times safer than conventional contrast agents in terms of fatality rates. These values are comparable to the costs of saving a life, and a year-of-life, associated with radiation protection practice, but appear to be over an order of magnitude higher than the corresponding costs in contexts such as mammography screening programs. Cost-benefit analysis provides a useful insight into medical decision making when available resources are limited. It raises the important question of whether society at large is allocating sufficient resources to health care.