Reducing Radiation Dose Associated with Pediatric CT by Decreasing Unnecessary Examinations

Abstract

inimizing the radiation dose associated with pediatric imaging procedures has been seen as an important issue for decades. For the past several years, there has been an emphasis on reducing the radiation dose associated with pediatric CT within the radiology community. Attention was focused on this topic by a series of featured articles in the February 2001 issue of the AJR [1–3]. These articles discussed the potential risks associated with the dose of radiation being used for pediatric CT, a lack of attention to pediatric CT protocols within the radiology community, and suggestions for how CT technical parameters can be adjusted to minimize radiation dose [1–3]. Although the risk of carcinogenesis above the baseline cancer rate associated with a pediatric CT scan is low and this exact relationship is controversial [4], there is growing evidence that minimizing dose in children is important. Carcinogenesis above the baseline cancer rates is a risk associated with radiation doses lower than previously believed [1], and these doses can be achieved in children when nonadjusted adult protocols are used. We also know that the tissues of children are up to 10 times more radiosensitive than those of adults [1]. In this commentary, I review the progress that has been made in changing practices of the radiology community and attention given to dose reduction by CT manufacturers and emphasize the importance of decreasing unnecessary CT examinations in children. It can be argued that there has been marked progress in this area since the February 2001 AJR articles [1–3] appeared. Certainly, the attention given to the issue of radiation dose in imaging procedures has escalated dramatically during that time. Scientific articles, presentations at meetings, and review courses on the topic are now common. In fact, the monthly issues of the AJR often have a section dedicated to articles on dose reduction. All this attention in academic radiology most likely has had a positive effect on the practice of pediatric adjustments to CT protocols in the general radiology community. According to a recent publication [5], approximately 43% of imaging departments now report that they have programs to adjust CT parameters for children. Although this still leaves marked room for improvement, this change is a dramatic one compared with the near universal lack of such practices as recently as 2001 [3]. Likewise and just as important, the attention given to technology to reduce dose associated with CT by the manufacturers of CT equipment has dramatically increased. Before 2001, none of the CT manufacturers had programs of much priority in the area of dose reduction for CT. Currently, virtually all the CT manufacturers have such programs [6–9]. Now multiple initiatives are in place to develop technologies such as improving geometric efficiency of MDCT scanners, reducing technical errors, automated exposure control, improving image filtration, using cardiac gating of the CT X-ray source, and researching noise simulation [6–9]. Other dose-reducing programs such as the institution of in-plane shielding for radiosensitive areas such as the pediatric breast have been advocated and implemented at some institutions [10]. Although advances in the use of pediatric protocols in the general radiology community and technical advances by the CT manufacturers are all important, the most effective way to reduce the radiation dose associated with CT in pediatric patients is to reduce or eliminate unnecessary or inappropriate CT referrals. On the basis of 2003 data [5], CT examinations are estimated to account for approximately 15% of all imaging examinations that use ionizing radiation. Estimates also indicate that CT examinations account for approximately 70% of the dose to patients for medical imaging studies. On the basis of 2000 data [5, 11], it was estimated that approximately 2.7 million CT examinations per year are performed in children