Gregory Michalak1, Joshua Grimes1, Joel Fletcher1, Ahmed Halaweish2, Lifeng Yu1, Shuai Leng1, Cynthia McCollough3. 1. Department of Radiology, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA. 2. Siemens Healthcare, 40 Liberty Blvd, Malvern, PA, 19355, USA. 3. Department of Radiology, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA. mccollough.cynthia@mayo.edu.
Abstract
PURPOSE: To determine the appropriate tube potential settings for dual-source, dual-energy data acquisition across a range of phantom sizes, and to determine the optimal photon energies for virtual mono-energetic imaging. METHODS: Water phantoms (15-50-cm wide) containing an iodine test object were scanned on a third-generation dual-source CT scanner using all available tube potential pairs. Virtual mono-energetic images at 40, 50, 60, and 70 keV were produced using Mono-energetic Plus. To determine the practical operating parameters for the evaluated CT system, data exclusions were made based on water CT number accuracy, artifacts, and using a noise constraint. Image quality metrics were measured and compared. RESULTS: Excluded tube potential pairs were identified; these were generally at low tube potentials for the low-energy beam and low photon energies. For non-excluded conditions, the highest CNR was obtained using the 70/150Sn setting in phantoms ≤35 cm at 40 keV. CONCLUSIONS: 70/150Sn provided optimal iodine CNR below 40 cm lateral phantom width at 40 keV, while 90/150Sn allowed acceptable image quality in phantoms >40-cm wide at or above 60 keV.
PURPOSE: To determine the appropriate tube potential settings for dual-source, dual-energy data acquisition across a range of phantom sizes, and to determine the optimal photon energies for virtual mono-energetic imaging. METHODS:Water phantoms (15-50-cm wide) containing an iodine test object were scanned on a third-generation dual-source CT scanner using all available tube potential pairs. Virtual mono-energetic images at 40, 50, 60, and 70 keV were produced using Mono-energetic Plus. To determine the practical operating parameters for the evaluated CT system, data exclusions were made based on water CT number accuracy, artifacts, and using a noise constraint. Image quality metrics were measured and compared. RESULTS: Excluded tube potential pairs were identified; these were generally at low tube potentials for the low-energy beam and low photon energies. For non-excluded conditions, the highest CNR was obtained using the 70/150Sn setting in phantoms ≤35 cm at 40 keV. CONCLUSIONS: 70/150Sn provided optimal iodine CNR below 40 cm lateral phantom width at 40 keV, while 90/150Sn allowed acceptable image quality in phantoms >40-cm wide at or above 60 keV.
Authors: Wei Zhou; Dilbar Abdurakhimova; Michael Bruesewitz; Ahmed Halaweish; Cynthia H McCollough; Shuai Leng Journal: Proc SPIE Int Soc Opt Eng Date: 2018-03