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Title: Automatic exposure control in pediatric and adult multidetector CT examinations: A phantom study on dose reduction and image quality

Abstract

The aim of this study was to assess the potential of a modern x,y,z modulation-based automatic exposure control system (AEC) for dose reduction in pediatric and adult multidetector CT (MDCT) imaging and evaluate the quality of the images obtained. Five physical anthropomorphic phantoms that simulate the average individual as neonate, 1-, 5-, 10-year old child, and adult were scanned with a MDCT scanner, equipped with a modern AEC system. Dose reduction (%DR) was calculated as the percentage difference of the mean modulated and the preset tube current-time product that is prescribed for standard head and body scan protocols. The effect of the tube potential and the orientation of the topogram acquisition on dose reduction were assessed. Image quality was evaluated on the basis of image noise and signal to noise ratio (SNR). The dose reduction values achieved in pediatric phantoms were remarkably lower than those achieved for the adult. The efficiency of the AEC is decreased at 80 kVp compared to higher tube potentials and for helical scans following an anterior posterior (AP-AEC) compared to a lateral (LAT-AEC) topogram acquisition. In AP-AEC scans, the dose reduction ranged between 4.7 and 34.7% for neonate, 15.4 and 30.9% for 1 year old,more » 3.1 and 26.7% for 5 years old, 1.2 and 58.7% for 10 years old, and 15.5 and 57.4% for adult. In LAT-AEC scans, the corresponding dose reduction ranged between 11.0 and 36.5%, 27.2 and 35.7%, 11.3 and 35.6%, 0.3 and 67.0%, and 15.0 and 61.7%, respectively. AP-AEC scans resulted in a 17.1% and 19.7% dose increase in the thorax of neonate and the pelvis of the 10-year old phantom, respectively. The variation in the measured noise among images obtained along the scanning z axis was lower in AEC activated compared to fixed milliamperes scans. However, image noise was significantly increased (P<.001) and SNR significantly decreased (P<.001) in most AEC activated compared to fixed milliamperes scans. In conclusion, AEC resulted in a (i) substantial dose reduction, which is less pronounced in children compared to adult, (ii) higher dose reduction in scans following a lateral compared to scans following an anterior-posterior topogram acquisition, (iii) increase of image noise and degradation of SNR in the obtained images compared to the fixed milliamperes technique.« less

Authors:
; ;  [1]
  1. Department of Medical Physics, Faculty of Medicine, University of Crete, P.O. Box 1352, Iraklion 71110, Crete (Greece)
Publication Date:
OSTI Identifier:
22095221
Resource Type:
Journal Article
Journal Name:
Medical Physics
Additional Journal Information:
Journal Volume: 35; Journal Issue: 10; Other Information: (c) 2008 American Association of Physicists in Medicine; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0094-2405
Country of Publication:
United States
Language:
English
Subject:
62 RADIOLOGY AND NUCLEAR MEDICINE; ADULTS; CHILDREN; COMPUTERIZED TOMOGRAPHY; CONTROL; DOSIMETRY; IMAGE PROCESSING; PHANTOMS; RADIATION DOSES; SIGNAL-TO-NOISE RATIO

Citation Formats

Papadakis, Antonios E., Perisinakis, Kostas, and Damilakis, John. Automatic exposure control in pediatric and adult multidetector CT examinations: A phantom study on dose reduction and image quality. United States: N. p., 2008. Web. doi:10.1118/1.2977535.
Papadakis, Antonios E., Perisinakis, Kostas, & Damilakis, John. Automatic exposure control in pediatric and adult multidetector CT examinations: A phantom study on dose reduction and image quality. United States. https://doi.org/10.1118/1.2977535
Papadakis, Antonios E., Perisinakis, Kostas, and Damilakis, John. 2008. "Automatic exposure control in pediatric and adult multidetector CT examinations: A phantom study on dose reduction and image quality". United States. https://doi.org/10.1118/1.2977535.
@article{osti_22095221,
title = {Automatic exposure control in pediatric and adult multidetector CT examinations: A phantom study on dose reduction and image quality},
author = {Papadakis, Antonios E. and Perisinakis, Kostas and Damilakis, John},
abstractNote = {The aim of this study was to assess the potential of a modern x,y,z modulation-based automatic exposure control system (AEC) for dose reduction in pediatric and adult multidetector CT (MDCT) imaging and evaluate the quality of the images obtained. Five physical anthropomorphic phantoms that simulate the average individual as neonate, 1-, 5-, 10-year old child, and adult were scanned with a MDCT scanner, equipped with a modern AEC system. Dose reduction (%DR) was calculated as the percentage difference of the mean modulated and the preset tube current-time product that is prescribed for standard head and body scan protocols. The effect of the tube potential and the orientation of the topogram acquisition on dose reduction were assessed. Image quality was evaluated on the basis of image noise and signal to noise ratio (SNR). The dose reduction values achieved in pediatric phantoms were remarkably lower than those achieved for the adult. The efficiency of the AEC is decreased at 80 kVp compared to higher tube potentials and for helical scans following an anterior posterior (AP-AEC) compared to a lateral (LAT-AEC) topogram acquisition. In AP-AEC scans, the dose reduction ranged between 4.7 and 34.7% for neonate, 15.4 and 30.9% for 1 year old, 3.1 and 26.7% for 5 years old, 1.2 and 58.7% for 10 years old, and 15.5 and 57.4% for adult. In LAT-AEC scans, the corresponding dose reduction ranged between 11.0 and 36.5%, 27.2 and 35.7%, 11.3 and 35.6%, 0.3 and 67.0%, and 15.0 and 61.7%, respectively. AP-AEC scans resulted in a 17.1% and 19.7% dose increase in the thorax of neonate and the pelvis of the 10-year old phantom, respectively. The variation in the measured noise among images obtained along the scanning z axis was lower in AEC activated compared to fixed milliamperes scans. However, image noise was significantly increased (P<.001) and SNR significantly decreased (P<.001) in most AEC activated compared to fixed milliamperes scans. In conclusion, AEC resulted in a (i) substantial dose reduction, which is less pronounced in children compared to adult, (ii) higher dose reduction in scans following a lateral compared to scans following an anterior-posterior topogram acquisition, (iii) increase of image noise and degradation of SNR in the obtained images compared to the fixed milliamperes technique.},
doi = {10.1118/1.2977535},
url = {https://www.osti.gov/biblio/22095221}, journal = {Medical Physics},
issn = {0094-2405},
number = 10,
volume = 35,
place = {United States},
year = {Wed Oct 15 00:00:00 EDT 2008},
month = {Wed Oct 15 00:00:00 EDT 2008}
}