AJR:194, April 2010
Keith J. Strauss1 Marilyn J. Goske2 Sue C. Kaste3 Dorothy Bulas4 Donald P. Frush5 Priscilla Butler6 Gregory Morrison7 Michael J. Callahan1 Kimberly E. Applegate8
The number of CT examinations performed in the United States has doubled in the past 5 years, with reports of more than 60 million performed yearly [1]. As many as 4-7 million of these examinations are performed in children [2]. Because of the dramatic rise in CT use, it is imperative that scanning techniques be optimized. Optimization is defined as "finding the best compromise among several often conflicting requirements" [3]. Optimization in the context of the performance of CT requires that the scan be of diagnostic quality for the clinical task at hand, yet be performed at a radiation dose that addresses radiation risk to the patient and to the public. Will the critical clinical finding be found in the soft tissue, vasculature, or bone? Optimization for various tissue types requires different adjustments to the scanning parameters. The adjustment of these parameters determines the radiation dose to the patient. Radiation dose is of particular concern in the pediatric patient. Children's rapidly dividing cells are more radiosensitive than those of adults [4]. Children have a longer lifetime to manifest potential radiation injuries, some of which have long latency periods before they are expressed [4]. The potential for expression of radiation-induced cancer later in life is the primary concern in pediatric patients [4].Optimization of CT protocols and the management of scanned patients remains a work in progress. Advances in technology continually change the design and capabilities of CT scanners, even from the same manufacturer and certainly from different manufacturers. Each CT scanner requires unique protocol development to optimize dose savings. That is why working with the medical physicist at your institution is important. Although these steps are focused on pediatric imaging, many of the principles also apply to adult imaging.
This article suggests 10 steps that radiologists and radiologic technologists, with the assistance of their medical physicist, can take to obtain good quality CT images while properly managing radiation dose for children undergoing CT. The first six steps ideally should be completed before performing any CT on a pediatric patient. The final four steps address the unique consideration that should be given for each scanned patient.