TY - JOUR
T1 - The reliability of CT numbers as absolute values for diagnostic scanning, dental imaging, and radiation therapy simulation
T2 - A narrative review
AU - Al-Hayek, Yazan
AU - Spuur, Kelly
AU - Zheng, Xiaoming
AU - Hayre, Christopher
AU - Davidson, Rob
N1 - Funding Information:
The authors owe deep gratitude to Dr. Andrew Kilgour for his valuable discussions and consultations. I would like to give my special thanks to The Hashemite University for their generosity with my PhD scholarship. Funding: This study did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors (OR Disclose any funding here). Competing interests: The author(s) have no financial disclosures or conflicts of interest to declare.
Publisher Copyright:
© 2021
PY - 2022/3/1
Y1 - 2022/3/1
N2 - Background and purpose: The purpose of this review was to examine the reported factors that affect the reliability of Computed Tomography (CT) numbers and their impact on clinical applications in diagnostic scanning, dental imaging, and radiation therapy dose calculation. Methods: A comprehensive search of the literature was conducted using Medline (PubMed), Google Scholar, and Ovid databases which were searched using the keywords CT number variability, CT number accuracy and uniformity, tube voltage, patient positioning, patient off-centring, and size dependence. A narrative summary was used to compile the findings under the overarching theme. Discussion: A total of 47 articles were identified to address the aim of this review. There is clear evidence that CT numbers are highly dependent on the energy level applied based on the effective atomic number of the scanned tissue. Furthermore, body size and anatomical location have also indicated an influence on measured CT numbers, especially for high-density materials such as bone tissue and dental implants. Patient off-centring was reported during CT imaging, affecting dose and CT number reliability, which was demonstrated to be dependent on the shaping filter size. Conclusion: CT number accuracy for all energy levels, body sizes, anatomical locations, and degrees of patient off-centring is observed to be a variable under certain common conditions. This has significant implications for several clinical applications. It is crucial for those involved in CT imaging to understand the limitations of their CT system to ensure radiologists and operators avoid potential pitfalls associated with using CT numbers as absolute values for diagnostic scanning, dental imaging, and radiation therapy dose calculation.
AB - Background and purpose: The purpose of this review was to examine the reported factors that affect the reliability of Computed Tomography (CT) numbers and their impact on clinical applications in diagnostic scanning, dental imaging, and radiation therapy dose calculation. Methods: A comprehensive search of the literature was conducted using Medline (PubMed), Google Scholar, and Ovid databases which were searched using the keywords CT number variability, CT number accuracy and uniformity, tube voltage, patient positioning, patient off-centring, and size dependence. A narrative summary was used to compile the findings under the overarching theme. Discussion: A total of 47 articles were identified to address the aim of this review. There is clear evidence that CT numbers are highly dependent on the energy level applied based on the effective atomic number of the scanned tissue. Furthermore, body size and anatomical location have also indicated an influence on measured CT numbers, especially for high-density materials such as bone tissue and dental implants. Patient off-centring was reported during CT imaging, affecting dose and CT number reliability, which was demonstrated to be dependent on the shaping filter size. Conclusion: CT number accuracy for all energy levels, body sizes, anatomical locations, and degrees of patient off-centring is observed to be a variable under certain common conditions. This has significant implications for several clinical applications. It is crucial for those involved in CT imaging to understand the limitations of their CT system to ensure radiologists and operators avoid potential pitfalls associated with using CT numbers as absolute values for diagnostic scanning, dental imaging, and radiation therapy dose calculation.
KW - CT number accuracy and uniformity
KW - CT number variability
KW - Patient off-centring
KW - Patient positioning
KW - Size dependence
KW - Tube voltage
KW - Reproducibility of Results
KW - Patient Positioning
KW - Computer Simulation
KW - Humans
KW - Tomography, X-Ray Computed
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U2 - 10.1016/j.jmir.2021.11.007
DO - 10.1016/j.jmir.2021.11.007
M3 - Review article
C2 - 34911666
AN - SCOPUS:85121113818
SN - 1939-8654
VL - 53
SP - 138
EP - 146
JO - Journal of Medical Imaging and Radiation Sciences
JF - Journal of Medical Imaging and Radiation Sciences
IS - 1
ER -