CT x-ray tube voltage optimisation and image reconstruction evaluation using visual grading analysis

Xiaoming Zheng, Ted M. Kim, Rob Davidson, Seongju Lee, Cheongil Shin, Sook Yang

Research output: A Conference proceeding or a Chapter in BookConference contribution

5 Citations (Scopus)


The purposes of this work were to find an optimal x-ray voltage for CT imaging and to determine the diagnostic effectiveness of image reconstruction techniques by using the visual grading analysis (VGA). Images of the PH-5 CT abdomen phantom (Kagaku Co, Kyoto) were acquired by the Toshiba Aquillion One 320 slices CT system with various exposures (from 10 to 580 mAs) under different tube peak voltages (80, 100 and 120 kVp). The images were reconstructed by employing the FBP and the AIDR 3D iterative reconstructions with Mild, Standard and Strong FBP blending. Image quality was assessed by measuring noise, contrast to noise ratio and human observer’s VGA scores. The CT dose index CTDIv was obtained from the values displayed on the images. The best fit for the curves of the image quality VGA vs dose CTDIv is a logistic function from the SPSS estimation. A threshold dose Dt is defined as the CTDIv at the just acceptable for diagnostic image quality and a figure of merit (FOM) is defined as the slope of the standardised logistic function. The Dt and FOM were found to be 5.4, 8.1 and 9.1 mGy and 0.47, 0.51 and 0.38 under the tube voltages of 80, 100 and 120 kVp, respectively, from images reconstructed by the FBP technique. The Dt and FOM values were lower from the images reconstructed by the AIDR 3D in comparison with the FBP technique. The optimal xray peak voltage for the imaging of the PH-5 abdomen phantom by the Aquillion One CT system was found to be at 100 kVp. The images reconstructed by the FBP are more diagnostically effective than that by the AIDR 3D but with a higher dose Dt to the patients.

Original languageEnglish
Title of host publicationMedical Imaging 2014
Subtitle of host publicationPhysics of Medical Imaging
EditorsB R Whiting, C Hoeschen, D Kontos
Place of PublicationBellingham, WA, USA
Number of pages10
ISBN (Print)9780819498267
Publication statusPublished - 2014
Externally publishedYes
EventMedical Imaging 2014: Physics of Medical Imaging - San Diego, CA, United States
Duration: 17 Feb 201420 Feb 2014

Publication series

NameProgress in Biomedical Optics and Imaging
ISSN (Print)1605-7422


ConferenceMedical Imaging 2014: Physics of Medical Imaging
Country/TerritoryUnited States
CitySan Diego, CA


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