Results of a Study into the Use of Low-Tube-Voltage for CT Colonography Published

Researchers from the Department of Diagnostic Radiology, at the Kumamoto University (Kumamoto, Japan) investigating the effect of a low-tube voltage technique and iterative reconstruction on the image quality and radiation dose of Computed Tomography Colonography (CTC), have been published in the April 11, 2015, online issue of the Journal Academic Radiology.

The researchers studied 14 women and 16 men, 39–90 years old, who had been referred for surgical treatment for colorectal cancer. The patients all underwent CTC with fecal tagging using standard 120-kVp, and 100-kVp protocols. Both sets of images were processed using Filtered Back Projection (FBP). The 100-kVp images were also processed with 3-D adaptive iterative dose reduction. The researchers then compared the image noise, Contrast-to-Noise Ratio (CNR), and the Effective Radiation Dose (ED) among the three protocols, and gave a score for the visual image quality.

The results showed that using low-tube-voltage, 100-kVp protocol CTC resulted in a 27% reduction in radiation dose, a reduction of image noise by 48%, a mean attenuation increase of tagged fluid from 452 to 558 HU compared to the 120-kVp protocol, while image quality remained the same. The average ED was significantly lower under the 100 kVp protocol, and the CNR was significantly higher. The researchers did not find any significant differences in the visual scores for diagnostic utility.

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