Estimation of size-specific dose estimate (SSDE) of CT scans using an effective diameter electron density.

Autor: Almuqbil K; Radiological Sciences Department, College of Applied Medical Sciences, King Saud University, P.O. Box 145111, Riyadh 4545, Saudi Arabia., Abuhaimed A; King Abdulaziz City for Science and Technology (KACST), P.O Box 6086, Riyadh 11442 Saudi Arabia. Electronic address: aabuhaimed@kacst.edu.sa., Abanomy A; Radiological Sciences Department, College of Applied Medical Sciences, King Saud University, P.O. Box 145111, Riyadh 4545, Saudi Arabia., Alashban Y; Radiological Sciences Department, College of Applied Medical Sciences, King Saud University, P.O. Box 145111, Riyadh 4545, Saudi Arabia., Alhawas A; Radiology and Medical Imaging Department, College of Medicine, King Saud University, P.O. Box 145111, Riyadh 4545, Saudi Arabia., Martin CJ; Department of Clinical Physics and Bio-Engineering, Gartnavel Royal Hospital, University of Glasgow, Glasgow G12 8QQ, UK.
Jazyk: angličtina
Zdroj: European journal of radiology [Eur J Radiol] 2024 Mar; Vol. 172, pp. 111311. Date of Electronic Publication: 2024 Jan 12.
DOI: 10.1016/j.ejrad.2024.111311
Abstrakt: Objective: An assessment of the effective diameter of a patient's body using electron densities of tissues inside the scan area (D eff ρe ) was proposed to overcome challenges associated with the estimation of water-equivalent diameter (D w ), which is used for size-specific dose estimate (SSDE). The aims of this study were to (1) investigate the D eff ρe method in two different forms using a wide range of patient sizes and scanning protocols, and (2) compare between four methods used to estimate the patient size for SSDE.
Materials and Methods: Under IRB approval, a total of 350 patients of varying sizes have been collected retrospectively from the Hospital. The D w values were assessed over six different CT body protocols: (1) chest with contrast media, (2) chest High-Resolution Computed Tomography (HRCT) without contrast media, (3) abdomen-pelvis with contrast media, (4) abdomen-pelvis without contrast media, (5) chest-abdomen-pelvis with contrast media, and (6) pelvis without contrast media. A MATLAB-based code was developed in-house to assess the size of each patient using the conventional effective diameter method (D eff ), D eff ρe by correcting either both the lateral (LAT) and anterior-posterior (AP) dimensions (D eff,LAT+AP ρe ) or LAT only (D eff,LAT ρe ), and D w at the mid-CT slice of the patient images.
Results: The results of D eff,LAT+AP ρe and D eff,LAT ρe provided a better estimation for the chest protocols with the averages of absolute percentage difference (PD) values in the range of 3 - 7 % for all patient sizes as compared to the D w method, whereas the averages of PD values for the D eff method were 9 - 15 %. However, D eff gave a better estimation for D w values for the other body protocols, with differences of 2 - 4 %, which were lower than those obtained with the D eff,LAT+AP ρe and D eff,LAT ρe methods. For the chest protocols, statistically significant differences were found between D eff and the other methods, but there were no significant differences between all the methods for the other scanning protocols. The results show that the correction of both dimensions, LAT and AP, did not improve the accuracy of the D eff ρe method, and, for most protocols, D eff,LAT+AP ρe gave larger range differences compared to those based on correction of the LAT dimension only.
Conclusion: If the D w cannot be assessed, the D eff,LAT ρe method may only be considered for the chest protocols as an alternative approach. The D eff method may also be used for all regions taking into account the application of a correction factor for the chest protocols to avoid a significant under or overestimation of the patient dose.
Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
(Copyright © 2024 Elsevier B.V. All rights reserved.)
Databáze: MEDLINE
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