Radiation Dose Associated with CT Scans
The following is a summary of articles on Radiology Dose Associated with CT Scans.
CT (computed tomography) examinations -- commonly called "cat scans" -- in children were the focus of three articles featured in the February 2001 issue of the American Journal of Roentgenology (AJR). The articles deal with different aspects of the dose of radiation associated with performing CT scans in children. Two of the three articles are by authors from Cincinnati Children's Hospital Medical Center.
The articles have received a large amount of attention in the press and have caused great concern for many parents. Since the information reported in the press may not have touched on the full scope of each study, we are providing the summaries below to clarify what was stated in the actual AJR articles and how CT's are performed here at Cincinnati Children's.
What Parents Should Know
For many pediatric medical problems, CT scan is an invaluable test. Often, it is the only test that can provide the information needed to optimally treat a child. The benefits from the information obtained from CT are far superior to the minimal risk associated with the low dose radiation associated with the CT. Although the risk of radiation from a CT scan is low, it is not zero.
The physicians at Cincinnati Children's who work with CT have been on the leading edge for making adjustments in our CT protocols so that the radiation dose for a CT scan can be reduced by up to five times less than that obtained from a routine adult CT study. We have decreased the CT dose as low as possible without compromising the quality of the test. Therefore, the risk associated with radiation from a CT at Cincinnati Children's is even less than from a typical CT obtained elsewhere.
Article Summaries
- Brenner D.J., et al. Estimated Risks of Radiation-Induced Fatal Cancer from Pediatric CT, AJR, 2001;176:289-296.
This article by authors at Columbia University has caused much of the alarm in the press. The article discusses speculative possibilities for cancer risks for low dose radiation associated with a CT. Much of this information is extrapolated from high radiation dose exposure studied in the atomic bomb experience. This is very controversial and there are many who do not believe that this is an accurate way of predicting cancer risks from the low dose radiation associated with CT.
- Paterson A., Frush D.P., Donnelly L.F. Helical CT of the Body: Are Settings Adjusted for Pediatric Patients?, AJR, 2001;176:297-302.
This article by authors at Cincinnati Children's and Duke University surveyed CT scans that were performed throughout the community and referred for second readings. The authors evaluated whether the CT parameters that affect radiation dose were being adjusted for children. The conclusion was that no adjustments were routinely being made. Children were routinely being scanned with parameters for adults and therefore receiving more radiation than necessary.
- Donnelly L.F., Emery K.H., Brody A.S., Laor T., Gylys-Morin V.M., Anton C.G., Thomas S.R., Frush D.P. Minimizing Radiation Dose for Pediatric Body Applications of Single-Detector Helical CT: Strategies at a Large Children's Hospital, AJR, 2001;176:303-306.
This article by authors at Cincinnati Children's describes the changes that we have made here at Cincinnati Children's so that the radiation doses from a CT can be reduced by up to five times what is received when using an adult protocol. A weight-based table for tube current (a parameter directly proportional to dose) that uses less radiation for less weight was introduced. Phantom and clinical data was presented which showed that high-quality images can be obtained despite the reduced dose. It is our hope that such practices will be employed in CT scanners elsewhere.
The three articles are in the February 2001 edition of AJR and can be viewed at http://www.ajronline.org/.
