Dose reduction in pediatric computed tomography with automated exposure control.

RATIONALE AND OBJECTIVES

Since the introduction of computed tomographic (CT) imaging in the 1970s, the number of examinations has increased steadily. CT imaging is an essential part of routine workup in diagnostic radiology. The great advantage of multidetector computed tomography is the acquisition of a large amount of data in a short time period, thus speeding up diagnostic procedures. To protect patients from unnecessary radiation exposure, different approaches have been developed. In this study, the efficacy of automated exposure control (AEC) software in multidetector CT imaging with a focus on dose reduction in pediatric examinations was assessed.

MATERIALS AND METHODS

Between August 2004 and September 2005, a total of 71 children (40 male, 31 female; age range, 2-13 years; mean age, 7.2 years) were examined using a multisource CT scanner. Three different regions (chest, upper abdomen, and pelvis) were examined. Overall image quality was assessed with a subjective scale (1 = excellent, 2 = diagnostic, 3 = nondiagnostic). For all examinations, AEC was used. From the scanner's patient protocol, dose-length product, volume CT dose index, and tube current-time product were calculated for each examination.

RESULTS

With AEC, a mean dose reduction of 30.6% was calculated. Images were rated as excellent (n = 39) or diagnostic (n = 32). Nondiagnostic image quality was not seen. Dose-length product and volume CT dose index were reduced by 30.4% and 29.5%, respectively. Overall, a mean dose reduction of 30.1% of the effective dose (5.8 ± 3.1 vs 8.4 ± 4.6 mSv) was achieved (P < .001).

CONCLUSIONS

With AEC software, a mean dose reduction of 30% without any loss in diagnostic image quality is possible.