Highlights
- •The GATE MC toolkit was used to model and validate the multislice helical GE BrightSpeed Elite CT model.
- •An organ dose database for individuals (2.1–14 years age range), undergoing CT examinations was created.
- •Dependency of absorbed dose and the anatomical characteristics was researched for several organs.
- •Effective doses-normalized-to-DLP were estimated and correlated with the total body weight.
Abstract
Purpose
The purpose of this study is to create an organ dose database for pediatric individuals
undergoing chest, abdomen/pelvis, and head computed tomography (CT) examinations,
and to report the differences in absorbed organ doses, when anatomical differences
exist for pediatric patients.
Methods
The GATE Monte Carlo (MC) toolkit was used to model the GE BrightSpeed Elite CT model.
The simulated scanner model was validated with the standard Computed Tomography Dose
Index (CTDI) head phantom. Twelve computational models (2.1–14 years old) were used.
First, contributions to effective dose and absorbed doses per CTDIvol and per 100 mAs were estimated for all organs. Then, doses per CTDIvol were correlated with patient model weight for the organs inside the scan range for
chest and abdomen/pelvis protocols. Finally, effective doses per dose-length product
(DLP) were estimated and compared with the conventional conversion k-factors.
Results
The system was validated against experimental CTDIw measurements. The doses per CTDIvol and per 100 mAs for selected organs were estimated. The magnitude of the dependency
between the dose and the anatomical characteristics was calculated with the coefficient
of determination at 0.5–0.7 for the internal scan organs for chest and abdomen/pelvis
protocols. Finally, effective doses per DLP were compared with already published data,
showing discrepancies between 13 and 29% and were correlated strongly with the total
weight (R2 > 0.8) for the chest and abdomen protocols.
Conclusions
Big differences in absorbed doses are reported even for patients of similar age or
same gender, when anatomical differences exist on internal organs of the body.
Keywords
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Article info
Publication history
Published online: September 05, 2019
Accepted:
August 29,
2019
Received in revised form:
July 24,
2019
Received:
May 16,
2019
Identification
Copyright
© 2019 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.
