Document Detail

Assessment of radiation exposure on a dual-source computed tomography-scanner performing coronary computed tomography-angiography.
MedLine Citation:
PMID:  19608362     Owner:  NLM     Status:  MEDLINE    
OBJECTIVE: The radiation exposure of a dual-source-64-channel multi-detector-computed-tomography-scanner (Somatom-Defintion, Siemens, Germany) was assessed in a phantom-study performing coronary-CT-angiography (CTCA) in comparison to patients' data randomly selected from routine scanning.
METHODS: 240 CT-acquisitions of a computed tomography dose index (CTDI)-phantom (PTW, Freiburg, Germany) were performed using a synthetically generated Electrocardiography (ECG)-signal with variable heart rates (30-180 beats per minute (bpm)). 120 measurements were acquired using continuous tube-output; 120 measurements were performed using ECG-synchronized tube-modulation. The pulsing window was set at minimum duration at 65% of the cardiac cycle between 30 and 75 bpm. From 90-180 bpm the pulsing window was set at 30-70% of the cardiac cycle. Automated pitch adaptation was always used. A comparison between phantom CTDI and two patient groups' CTDI corresponding to the two pulsing groups was performed.
RESULTS: Without ECG-tube-modulation CDTI-values were affected by heart-rate-changes resulting in 85.7 mGray (mGy) at 30 and 45 bpm, 65.5 mGy/60 bpm, 54.7 mGy/75 bpm, 46.5 mGy/90 bpm, 34.2 mGy/120 bpm, 27.0 mGy/150 bpm and 22.1 mGy/180 bpm equal to effective doses between 14.5 mSievert (mSv) at 30/45 bpm and 3.6 mSv at 180 bpm. Using ECG-tube-modulation these CTDI-values resulted: 32.6 mGy/30 bpm, 36.6 mGy/45 bpm, 31.4 mGy/60 bpm, 26.8 mGy/75 bpm, 23.7 mGy/90 bpm, 19.4 mGy/120 bpm, 17.2 mGy/150 bpm and 15.6 mGy/180 bpm equal to effective doses between 5.5 mSv at 30 bpm and 2.6 mSv at 180 bpm. Significant CTDI-differences were found between patients with lower/moderate and higher heart rates in comparison to the phantom CTDI-results.
CONCLUSIONS: Dual source CTCA is particularly dose efficient at high heart rates when automated pitch adaptation, especially in combination with ECG-based tube-modulation is used. However in clinical routine scanning for patients with higher heart rates and corresponding enlarged pulsing window a significant different dose resulted.
S Kirchhoff; P Herzog; T Johnson; H Böhm; K Nikolaou; M F Reiser; C H Becker
Publication Detail:
Type:  Journal Article     Date:  2009-07-16
Journal Detail:
Title:  European journal of radiology     Volume:  74     ISSN:  1872-7727     ISO Abbreviation:  Eur J Radiol     Publication Date:  2010 Jun 
Date Detail:
Created Date:  2010-08-05     Completed Date:  2011-01-11     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  8106411     Medline TA:  Eur J Radiol     Country:  Ireland    
Other Details:
Languages:  eng     Pagination:  e181-5     Citation Subset:  IM    
Copyright Information:
Copyright (c) 2009 Elsevier Ireland Ltd. All rights reserved.
Institute of Clinical Radiology, University Hospital Munich - Grosshadern, Ludwig Maximilians-Universität München, Klinikum Grosshadern, Marchioninistrasse 15, 81377 Munich, Germany.
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MeSH Terms
Body Burden*
Coronary Angiography / instrumentation*
Equipment Design
Equipment Failure Analysis
Phantoms, Imaging
Radiation Dosage*
Radiography, Dual-Energy Scanned Projection / instrumentation*
Radiometry / methods*
Tomography, X-Ray Computed / instrumentation*

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