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PRospective Multicenter Study On RadiaTion Dose Estimates Of Cardiac CT AngIOgraphy IN Daily Practice – PROTECTION I – J. Hausleiter, T. Meyer, F. Hermann, M. Hadamitzky, C. McCollough, T. Gerber, S. Martinoff, A. Kastrati, A. Schömig, S. Achenbach Deutsches Herzzentrum München Mayo Clinic Rochester and Jacksonville Friedrich Alexander Universität Erlangen–Nürnberg No disclosures related to this presentation.
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PR ospective Multicenter Study O n Radia T ion Dose E stimates Of Cardiac CT Ang IO graphy I N Daily Practice – PROTECTION I – - PowerPoint PPT Presentation
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PRospective Multicenter Study On RadiaTion Dose Estimates
Of Cardiac CT AngIOgraphy IN Daily Practice
– PROTECTION I –
J. Hausleiter, T. Meyer, F. Hermann, M. Hadamitzky, C. McCollough, T. Gerber, S. Martinoff, A. Kastrati,
A. Schömig, S. Achenbach
Deutsches Herzzentrum MünchenMayo Clinic Rochester and Jacksonville
Friedrich Alexander Universität Erlangen–Nürnberg
No disclosures related to this presentation.
Cardiac CT angiography (CCTA) has evolved as a useful non-invasiveimaging modality.
With its rapid increase in use, the exposure to ionizing radiation associated with cardiac CT angiography has raised serious concerns.
Background
to determine in a prospective study:
the radiation dose of cardiac
CT angiographies in daily practice
the efficacy of dose saving algorithms
independent predictors associated with
radiation dose
Rationale
Study design: prospective, observationalmulti-centermulti-vendorindustry-independent
Enrollment period: Feb. – Dec. 2007
50 participating study sites1965 CCTAs
Image data, patient and scan information of all consecutive ECG-gated or -triggered CCTAs performed during one month
Methods I
Calculation of estimated radiation dose:European Working Group for Guidelines on Quality Criteria in CT
Dose-length-product (DLP) * 0.017 (conversion factor chest)
Image quality:Diagnostic image quality assessed on a per-vessel basis (diagnostic vs. non-diagnostic)
Linear regression analysis:Identification of independent factors influencing dose
Methods II
50 participating study sites
50 participating study sites
Argentina Vicente Lopez, P. Carrascosa, A. DeviggianoAustralia Frankston, G. Szto, A. WatsonAustria Innsbruck, G. Feuchtner, G. FriedrichBelgium Aalst, P. Vanhoenacker, I. Decramer
Brussels, E. Coche, B. GerberAntwerp, B. Shivalkar, R. Salgado
Brazil Sao Paolo, R. Sasdelli Neto, I. PintoRio de Janeiro, A. Oliveira, D. M. Moreira
Canada Montreal, C. Chartrand-Lefebvre, J. PrenovaultVancouver, B. Forster, D. Malpas
Denmark Aarhus, O. Gøtzsche, E. Morre PedersenGermany Bad Krotzingen, J. Allgeier, F.-J. Neumann
Bad Nauheim, T. Dill, J. RixeBad Oeynhausen, C. Langer, D. HorstkotteErlangen, S. Achenbach, T. PfledererEssen, O. Bruder, T. SchlosserFrankfurt, A. Schmermund, A. MagedanzKiel, T. Jahnke, T. HuemmeLandshut, E. Sauer, J. DietlMunich, C. Becker, A. LeberMunich, R. Haberl, G.-E. BöhmeMunich, J. Hausleiter, S. MartinoffRosenheim, M. Block, C. BaierlSaarbrücken, G. Goerge, J. SchmittTraunstein, W. Moshage, A. OpitzUlm, M. Hoffmann, O. Klass
Great Britain London, C. di Mario, N. ArcuriMiddlesex, T. Mittal, T. Patel
Greece Athen, I. Mastorakou, T. SyrigouIsrael Haifa, O.-R. Brook, S. AbadiItaly Rome, E. Martuscelli, E. CascianiJapan Hiroshima, T. Kitagawa, J. Horiguchi
Tokyo, S. Kuribayashi, M. YamadaTokyo, N. Yokoyama, S. Suzuki
Korea Seoul, J.-W. Kang, J.B. SeoMalaysia Sarawak, T. Ong, K.-H. SimMexico Mexico City, E. Alexanderson, A. Meave
Monterrey, E. de la Pena-Almaguer, R. Zamarripa-Morales
Monaco Monaco, F. Civaia, P. Rossithe Netherlands Groningen, M. Greuter, M. OudkerkSpain Oviedo, C. Paz, J.F. VillameytidePakistan Karachi, R. Ahmed, S. KureshiPortugal Vila Nova de Gaia, N. Bettencourt de Sousa, V. G. RibeiroSingapore Singapore, K.-T. Ho, G. KawSpain Malaga, E. Gonzalez Cocina, A. RuizSwitzerland Zurich, H. Alkadhi, P. StolzmannTurkey Erzurum, M. Kantarci, F. FilUSA Iowa City, E.J.R. van Beek, J.M. Wilson
Fairfax, J.P. Earls, E. BermanWashington, A. Taylor, P.J. Devine
Study site characteristics
50 study sites
Experience in cardiac CT, months 35 [18; 57]
CT system manufacturer- GE, n (%)- Philips, n (%)- Siemens, n (%)- Toshiba, n (%)
11 (22)5 (10)
26 (52)8 (16)
CT system configuration- 16-slice, n (%)- single-source 64-slice, n (%)- dual-source 64-slice, n (%)
3 (6) *36 (72)11 (22)
Cardiac CTAs / month 31 [19; 48]* Excluded in analysis of dose saving algorithms and linear regression model
Patient & scan characteristics
1965 patients
Patient height, m 1.69 ±0.10
Patient weight, kg 77.3 ±15.9
Indication for CCTA - coronary, n (%)- non-coronary, n (%)
1611 (82)354 (18)
Betablocker for CCTA, n (%) 904 (46)
Stable sinus rhythm, n (%) 1874 (95)
Heart rate, bpm 63.2 ±12.0
Scan length, mm 144 ±37
Estimated radiation dose
0
10
20
30
40
50
15.4 [9.8; 22.0]
Dose (mSv)
0
10
20
30
40
50
Study sites
Dose (mSv)
Range of medians: 5.7 to 36.5 mSv
Estimated radiation dose
Automatic exposure controladaption of tube current to pat.‘s anatomy
ECG pulsingmodulation of tube current to pat.‘s ECG
100 kV tube voltageinstead of conventional ≥ 120 kV tube voltage
Sequential scanning (step and shoot)instead of conventional spiral scan technique
Dose saving algorithms
Automatic exposure control– 64-slice systems –
62.1 37.90
50
100(%)
Frequency of use
15.4 15.80
10
20
30(mSv)
Estimated dose
automatic exposure controlwithwithout
ECG pulsing– 64-slice systems –
(%)
Frequency of use
21.3 78.70
50
100
ECG pulsingwithwithout
(mSv)
Estimated dose
20.9 16.70
10
20
30
20%
100 kV tube voltage– 64-slice systems –
(%)
Frequency of use
kV tube voltage100≥ 120
0
50
100
94.25.8
0
50
100
Image quality
(%)
97.3 97.3
(mSv)
Estimated dose
0
10
20
30
17.4 8.7
50%
Spiral vs. sequential scanning– 64-slice systems –
(%)
Frequency of use
scanningsequentialspiral
0
50
100
93.86.2
Image quality
(%)
0
50
100
97.2 98.3
(mSv)
Estimated dose
0
10
20
30
17.6 5.6
68%
Predictors of radiation dose– in 64-slice systems –
-25 -20 -15 -10 -5 0 5 10 15
Effect in linear regression analysis [mSv]
Indication (coronary vs. non-coronary)
Heart rate ( 10bpm)
Heart rhythm (sinus vs. non-sinus)
Weight ( 10kg)
0.98
0.58
0.0002
<.0001
Site experience ( 1 year) 0.005
CT system (highest vs. lowest) <.0001
Sequential scanning
100 vs. ≥120kV tube voltage
<.0001
<.0001
Scan length ( 1cm) <.0001
ECG pulsing <.0001
Predictors of radiation dose- Impact of CT system -
0 2 4 6 8 10 12 14
Siemens single-source 64
Philips 64
Siemens dual-source 64
Toshiba 64
GE 64
Effect in linear regression analysis [mSv]
Conclusion I
Radiation dose from cardiac CT angiography varies significantly between study sites and CT systems.
Although very effective measures to reduce the radiation dose are available (100 kV and sequential scanning),these are rarely used in daily practice.
Conclusion II
Worldwide educational efforts (by medical societies & CT vendors) are mandatory to ensure the uniform and consistent use of dose saving algorithms where applicable.
Further developments and critical evaluations of additional strategies for radiation dose savings are needed.
