Comparison of MDCT radiation dose: a phantom study

Abstract

Objective: Recently there has been a significant increase in the use of CT imaging resulting in a significant increase in radiation exposure to the population. Few studies have compared the degree of radiation exposure among the currently available MDCT units. Our objective is to make such a comparison.

Materials and methods: Using a Rando anthropomorphic phantom, we placed thermoluminescent dosimeters into the center, anterior, and lateral aspect of the lower chest of the phantom. Standard CT of the chest was performed with the current protocols used at our institution on 4-, 8-, and 16-MDCT GE Healthcare systems. Next, near-identical CT scans of the entire chest were performed on the same CT systems.

Results: The 4-detector array showed statistically significantly higher radiation dose compared with the 16-detector array with near-identical technique (p < 0.01). There is a trend toward decreasing radiation dose with the increasing number of detectors using both standard and near-identical technique. An inverse relationship exists between measured radiation dose and the number of detectors.

Conclusion: We theorize that as the number of detectors increases, there is a decrease in the amount of nonutilized radiation exposure, thus resulting in a lower total radiation dose.