Dr. Mirvis is the Editor-in-Chief of this journal and Professor of Radiology, Diagnostic Imaging Department, University of Maryland Medical Center, Baltiimore, MD.

In this issue of Applied Radiology Drs. Gotway and Webb do a wonderful job describing the confusing and controversial topic of CT screening for patients at high risk for lung cancer. In reviewing the article, I was struck by how many criteria must be considered in the scientific process to ascertain what value, if any, CT screening has in this specific application. It appears that, despite previous screening studies, the efficacy of CT in this application for a selected at-risk population remains debatable. The matters of CT screening for coronary artery calcification and colon pathology (virtual colonoscopy) still have a long way to go toward establishing scientific credibility as a tool that may influence either quality of life or longevity and thus serve as a useful screening test. ^1-3

Despite the equivocal roles of screening with multidetector row CT for the above specific conditions in high-risk persons, its more general application for "total body screening" seems to have taken on a life of its own, separated from any scientific or risk-benefit considerations. The ready availability of on-demand screening CT, for those with the cash to pay the bill, is worrisome.

The situation is loosely analogous to another application of radiation used from the late 1920s to the early 1950s involving fluoroscopy of children's feet to "assure" that new shoes fit properly. One could simply look into a box and watch the child's toes moving within the confines of the shoes. In some manner this experience both amazed and dazzled the prospective buyer (the high technology aspect) and assured that the shoe selection was proper (the business aspect). The fact that a properly trained shoe salesman could do an equal or better job at fitting shoes was not considered as reassuring. Apparently (no pun intended), children left on their own could activate the system for as long as they cared. ⁴ Eventually, as the scientific communities' understanding of the risks of ionizing radiation became more evolved, particularly the risks of X-ray radiation to osseous growth plates and skin burns, these devices were gradually abandoned with progressively restrictive legislation. ^5,6

Now there are many radiologists who would defend the utility of CT screening in the whole-body manner and in a nonselective general adult population. Undoubtedly, many of these defenders would also have a financial interest in such services. They would point out the "great save" of this patient or that by detecting an otherwise occult pancreatic tail cancer, or a 10-mm colonic adenomatous polyp. They might emphasize the reassurance many patients gain after a normal study since nothing is seriously wrong, whether or not such reassurance is valid. Some unfortunate folks will be told about the "nodule" or funny shadow that's probably nothing, but will spend a lot of time and money (insurance or out-of-pocket) anxiously having this finding evaluated further.

Having said this, I am confident that most CT screening centers try very hard to give their customers, not patients, a realistic overview of the technique and its strengths and limitations, and to counsel them and follow up on any findings that are made. Though, I do not know how such communication would be assured.

What are we doing by offering screening CT to the well-to-do public in our outpatient centers and shopping malls? Are we being responsible physicians using this advanced technology for some well-established benefit? Or is the whole-body CT venue a new sort of carnival attraction, a pacifier for the chronically anxious, a business tool to "clear" executives before purchasing or renewing big insurance policies, or a profitable business venture in the free-enterprise market? Is there any solid science available at all in the current literature to justify its current use as a general screening study? Should not the application of multidetector row CT for any screening purpose be based on the best current scientific understanding of natural disease progression, statistical methodology, and treatment potential with a focus on achieving a real benefit for high-risk populations? The answers should be obvious.