Estimates of the image quality and the radiation dose for head and abdomen phantom image acquisition by using dual-energy CT

Abstract

Using dual-energy computed tomography (CT) scans, we obtained images from a raw data set by using low- and high-energy scans (usually 80 and 140 kV, respectively). Generally, the head and the abdomen examinations were performed using single-energy (120 kV) scanning with a routine exposure protocol, and the images were used for diagnostic interpretation. The dual-energy CT scans can also be used for diagnosis by using the linearly-mixed method with low- and high-energy images. In the current study, we evaluated mixed images in dual-energy and single-energy scans for image quality and radiation dose. The CT scan protocol for single energy was adopted from IEC protocols, and the recommended dose from the EC. The dual-energy scan protocol was based on the Siemens dual-energy CT scan protocol. The CT scan protocols were extended further in the mA range for both scans to estimate the image quality corresponding to these dose alternations. The results demonstrate that the Contrast-to-noise ratio (CNR) value of a dual-energy mixed image is higher than that of a single-energy image in similar dose regions for both the head and the abdomen phantoms. We observed that the dual-energy images could reduce the dose compared to single-energy images. In the abdomen phantom study, the CNR of dual-energy images was even higher than that of single-energy images with half the radiation dose of the single-energy scan. Therefore, the dual-energy CT scan can accomplish a remarkable dose reduction while preserving image quality for head and abdomen imaging.