Whole Body Scanning Whole Body Scanning
U.S. Food and Drug Administration
Currently some medical imaging facilities are promoting a new use of computed tomography (CT), also called computerized axial tomography (CAT) scanning. This use is referred to as whole-body CT scanning or whole-body CT screening, and it is marketed as a preventive or proactive healthcare measure to healthy individuals who have no symptoms or suspicion of disease. At this time the FDA knows of no data demonstrating that whole-body CT screening is effective in detecting any particular disease early enough for the disease to be managed, treated, or cured and advantageously spare a person at least some of the detriment associated with serious illness or premature death. Any such presumed benefit of whole-body CT screening is currently uncertain, and such benefit may not be great enough to offset the potential harms such screening could cause.
Public health agencies and national medical and professional societies-the American College of Radiology, the American College of Cardiology / American Heart Association, the American Association of Physicists in Medicine, the Health Physics Society, the Agency for Healthcare Research and Quality’s U.S. Preventive Services Task Force, and the American Medical Association – do not recommend CT screening.
FDA has published a brochure titled:
” Full-Body CT Scans – What You Need to Know”
CT is a diagnostic imaging procedure that uses x rays to obtain cross-sectional images of the body. Since its introduction and rapid adoption into medicine in the mid-1970s, CT has become recognized as a valuable medical tool for the diagnosis of disease, trauma, or abnormality and for planning, guiding, and monitoring therapy.
Important information regarding whole-body CT screening:
Such screening provides uncertain benefit with potential for some risk – The most likely outcomes of CT screening of a healthy person with no symptoms of illness are:
Normal findings or
Suspicious findings requiring follow-up tests
Normal findings carry the possibility of inaccuracy and false reassurance. For suspicious findings, follow-up may involve simple, non-invasive testing. It may also involve invasive procedures associated with surgical risks of anesthesia, bleeding, infection, scarring, or it may entail additional radiological exams, associated with radiation risk and the potential risk of allergic reaction to injected contrast material. In any case, it is unlikely that CT screening will benefit an individual lacking signs or symptoms of disease by detecting a serious disease early enough to treat it and alter the outcome significantly.
Radiation Dose – CT screening subjects the individual screened to radiation exposure from x rays. The dose a patient receives during a typical CT procedure is generally much larger than the radiation doses associated with most conventional x-ray imaging procedures. The principal risk associated with the radiation dose resulting to a person from a CT procedure is the small possibility of developing a radiation-induced cancer some time later in that person’s life. For a patient with a medical need, the benefit of a diagnostic or therapeutic CT procedure recommended by a physician normally far exceeds the small cancer risk associated with a CT procedure. For a person without symptoms, CT screening is unlikely to discover serious disease, and the potential harm to the individual may be greater than the presumed benefit.
Scientific Studies – There are no data demonstrating that whole-body CT screening of individuals without symptoms provides a greater probability of benefit than harm. Nor is there any scientific study known to be underway to develop such data. Although there are several ongoing investigational studies of the effectiveness of using CT to screen people, the studies are focused on high-risk groups for specific diseases (e.g., cigarette smokers for lung cancer). In such studies only a limited portion of the body is irradiated, not the whole body, and only screening for a specific type of disease is being evaluated, rather than screening for just anything that might be found anywhere in the body.
No Food and Drug Administration (FDA) Approval of CT for Screening – Statements by CT imaging facilities that imply FDA “approval,” “clearance,” or “certification” of CT for screening procedures misrepresent the actual situation. FDA has never approved or cleared or certified any CT system specifically for use in screening (i.e., of individuals without symptoms), because no manufacturer has ever demonstrated to the FDA that their CT scanner is effective for screening for any disease or condition.
Pediatric Use – Radiation exposure is a concern in both adults and children. However, children are more sensitive to radiation than adults and have a longer life expectancy. Using the same exposure parameters on a child as used on an adult may result in larger doses to the child. There is no need for these larger doses to children, and CT settings can be adjusted to reduce dose significantly while maintaining diagnostic image quality. The National Cancer Institute and The Society for Pediatric Radiology developed a brochure, Radiation Risks and Pediatric Computed Tomography: A Guide for Health Care Providers, and the FDA issued a Public Health Notification, Reducing Radiation Risk from Computed Tomography for Pediatric and Small Adult Patients, that discuss the value of CT and the importance of minimizing the radiation dose, especially in children.