Companion Studies Focus on Need to Minimize Exposure

A study published in the February 2001 issue of the American Journal of Roentgenology that dealt with helical (spiral) computed tomography (CT) scanning in children gained wide attention when media reports appeared implying routine overexposure and a substantial risk that cancer will develop in later life. Some of the coverage, notably that in USA Today (1/22/01), can fairly be characterized as distorted and sensationalistic. Claiming that radiation doses as much as six times greater than needed are "typically" administered to children, the report compares the situation unfavorably to Three Mile Island. The situation is further distorted by misreported information from the original study. While the study cites that out of 1.6 million children annually who receive CT scans to the head and abdomen, 500 "might" die of radiation-induced cancer later in life, the article gives the number as about 1,500 who "will" ultimately die from this cause. Consequent fear on the part of parents who may feel that they are exposing their child to a heightened risk of cancer has, in turn, fostered concern by radiologists that some of these parents may turn down a needed and recommended CT exam. This may well place their child at jeopardy that a serious but curable illness will go undetected.

CT Has Vital Diagnostic Role in Pediatric Practice

Today more than 1.5 million American children have CT scans of the head or abdomen each year. More efficient techniques such as helical CT have drastically lowered scan times and, therefore, the need for anesthesia and sedation, making this procedure an important diagnostic approach. The chief purposes of pediatric CT scans are to locate and monitor cancers, detect inflammatory disorders such as abscesses and appendicitis, and evaluate trauma. The benefits far outweigh any confirmed risks. For instance, an estimated half million children each year are spared exploratory surgery because CT is available. According to Dr. Lane Donnelly, a contributor to two of three recent papers on the subject, a CT exam frequently is the only way of laying the groundwork for optimal treatment. In the three decades since CT was introduced, deaths from childhood cancer have dropped by half, no doubt in large part because of earlier detection. At the same time, it is important to acknowledge that in no instance has radiation exposure from CT in childhood been proved to cause cancer during a person's lifetime. The Society for Pediatric Radiology (SPR) holds that, while there likely is some risk, it is very small; it has the status of an estimate, not an observation; and it is based on questionable information and controversial statistics.

Fortunately it is possible to obtain high-quality CT images at substantially reduced exposure levels. Unlike film-screen radiography, CT permits considerable freedom in selecting exposure parameters that will ensure high-quality images for diagnosis.

What Needs to be Done?

When a CT exam is recommended for a child, parents should:

• know that radiologists are specifically trained to understand radiation dosimetry and to use the lowest possible dose to produce optimal image quality.
• be made aware that no substantial cancer risk has been convincingly associated with radiation exposure from CT scanning.
• be strongly encouraged to discuss any concerns with their primary care physician and, directly or indirectly, the radiologist before declining a needed CT study for their child.

The professional radiology community is taking a number of measures to ensure that this most valuable tool can maximize diagnostic accuracy while at the same time minimize radiation exposure.

• Members of the Society for Pediatric Radiology (SPR) are working with the American College of Radiology (ACR) to prepare clinical guidelines that will help referring physicians know when CT studies are appropriate for children.
• The Radiological Society of North America (RSNA) will be conducting a special focus session on CT radiation in children at its 2001 meeting in Chicago.
• The International Pediatric Radiology meeting to be held in Paris in May (co-sponsored by the SPR) will feature special focus sessions on radiation exposure from CT.
• The American College of Radiology (ACR) is in the final stages of evaluating its CT Facility Accreditation Program, which is to include pediatric units. The program's goal is to determine whether a given radiology practice is prepared to use the least radiation required to obtain diagnostically satisfactory CT scans.

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