Andreas Laupacis and William Evans have deftly accomplished the difficult task of synthesizing the major issues at hand. Their comments are timely, reflecting society's increasing preoccupation with rapid access to diagnostic imaging. Paradoxically, the recent CIHI report on medical imaging records a steady increase in scanners, without the expected reduction in wait times. The role of private facilities is unclear, and the value of screening asymptomatic patients is unproven. There are few clear guidelines for ordering images. New intraoperative, functional and molecular imaging technologies will further strain the system. This array of challenges should be urgently tackled by a decisive panel of national experts, who would in turn supervise consultants working full-time on guideline development.