Optimizing Radiation Dose in Computed Tomography of Articular Fractures

Objectives: To determine whether a substantially lowered radiation protocol would provide satisfactory information for the surgeon, using the distal tibia as a model. Methods: Eleven adult cadaveric distal tibia specimens were used to create Orthopaedic Trauma Association (OTA/AO) 43C distal tibia fractures with varying displacements in 2 planes. Each specimen was scanned at 3 modified protocols, which were then subsequently read by both qualified attending orthopaedists and midlevel residents. Observer reliability was evaluated, as well as confidence levels of identifying fracture pattern and treatment protocols. Results: On average, there was less than a millimeter of variability in the measured gap to true gap as a whole (mean = 0.74 mm, P < 0.0001). With regard to measurements in gap, pattern, and treatment plans, no significant difference was found between CT images acquired with standard (110 mAs) compared with medium (60 mAs; mean 0.0 mm, P = 1.0; k = 0.14, P = 0.56; k = 0.38, P = 0.13, respectively) and low protocols (45 mAs; mean 0.01 mm, P = 0.95; k = 0.24, P = 0.32; k = 0.31, P = 0.13, respectively). Furthermore, no significant difference was found in measuring step-off across standard, medium, and low radiation dose (0.21 mm, P = 0.46; 0.28 mm, P = 0.39; -0.16 mm, P = 0.48, respectively). Conclusion: The results of this study show no significant difference when evaluating current standard and low-dose CT scans using less than one-half the amount of exposure. This suggests that in complex extremity fractures, a new CT protocol may potentially be used. Our initial data show promise that we may retain satisfactory imaging to formulate a treatment plan while also reducing the collective radiation burden to the population.