Project

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Dose en CT cardiaque chez l'enfants et les jeunes adultes: un optimum entre qualité d'image et dose de radiations

English title Dose in cardiac CT for children and young adults: an optimal image quality and patient radiation dose
Applicant Verdun Francis
Number 120382
Funding scheme Project funding (Div. I-III)
Research institution Institut de Radiophysique Département de Radiologie Université de Lausanne/CHUV
Institution of higher education University of Lausanne - LA
Main discipline Paediatrics
Start/End 01.12.2008 - 30.11.2011
Approved amount 168'419.00
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All Disciplines (2)

Discipline
Paediatrics
Paediatrics

Keywords (9)

paediatric; cardiac; image quality; radiation exposure optimization; Computed tomography; paediatric radiology; cardiac CT; signal detection; observe performance

Lay Summary (English)

Lead
Lay summary
Computed Tomography, CT, is certainly a fantastic tool that runs the risk of becoming a victim of its own success due to the public health concerns it may elicit. Already on Jan 23rd 2001, USA Today published a particularly alarming paper (titled: “Radiologists agree CT scans harm kids”) where it was mentioned that 1,500 patients from the 1.6 million children (under the age of fifteen) scanned might eventually die from cancer caused by excess radiation; this, without any emphasis on the fact that CT actually saves lives. More recently, the June 19th, 2007 edition of The New York Times highlighted once again the impact of CT on the population’s exposure level. It mentioned in particular that the 62 million CT scans performed in the US in 2006 were responsible for more than half of the population’s total exposure from radiological investigations. Since one or two years, cardiac CT acquisition is becoming more and more popular. This might pose an additional problem concerning population’s exposure since relatively high doses (from 12 to 40 mSv per examination) are typically delivered to patients over 45 - 50 years old. If this situation is already problematic for an adult population, it is even more so for young children investigated for cardiac malformations which are then followed-up by many CTs over their entire life. Knowing that such a population is particularly sensitive to ionising radiation, it becomes an ethical imperative to make every effort to reduce its exposure as much as possible. At the moment, data acquisition protocols have not been optimized along the lines of a sound methodology. The aim of this project is to address this problem by answering the following questions:1) What is the situation concerning data acquisition of cardiac CT (for children and the follow-up of a young population surgically treated for heart malformations)? 2) How to objectively balance patient dose and image quality of static and moving structures? 3) Are the optimal set of parameters using the methodology presented just above (point 2 of the project) adequate in clinical applications? - When dealing with very young children (up to 10 years old)? - When dealing with follow-up studies for young adults? This study will assure that cardiac CT examinations performed on children and young adults in Switzerland are optimized using a state-of-the-art methodology. This study will also provide the scientific community with a methodology allowing an objective way to reconcile image quality and patient dose by means of the very latest concepts from a dose and image quality point of view (introduction of new dosimetric concepts such as equilibrium dose, dose line integral … and use of objective image quality descriptors such as NEQ and DQE, parameters that are being adapted for the particular case of CT). Finally, the development of scientific competences in this field in Switzerland will help future international collaborations.
Direct link to Lay Summary Last update: 21.02.2013

Responsible applicant and co-applicants

Employees

Publications

Publication
Potential benefit of the CT adaptive statistical iterative reconstruction method for pediatric cardiac diagnosis
Miéville F. A et al. (2010), Potential benefit of the CT adaptive statistical iterative reconstruction method for pediatric cardiac diagnosis, Proc. SPIE 7622, 76222D-1–76222D-11 , USA.
Comparison of organ doses and image quality between CT and flat panel XperCT scans in wrist and inner ear examinations
Damet J, Sans-Merce M, Mieville F, Becker M, Poletti PA, Verdun FR, Baechler S (2010), Comparison of organ doses and image quality between CT and flat panel XperCT scans in wrist and inner ear examinations, in RADIATION PROTECTION DOSIMETRY, 139(1-3), 164-168.
Computed tomography commissioning programmes: how to obtain a reliable MTF with an automatic approach?
Mieville F, Beaumont S, Torfeh T, Gudinchet F, Verdun FR (2010), Computed tomography commissioning programmes: how to obtain a reliable MTF with an automatic approach?, in RADIATION PROTECTION DOSIMETRY, 139(1-3), 443-448.
3D noise power spectrum applied on clinical MDCT scanners: effects of reconstruction algorithms and reconstruction filters
Mievielle F.A., 3D noise power spectrum applied on clinical MDCT scanners: effects of reconstruction algorithms and reconstruction filters, Proc. SPIE 7961-13 (2011), USA.
Paediatric cardiac CT examinations: impact of the iterative reconstruction method ASIR on image quality--preliminary findings
Mieville F.A., Paediatric cardiac CT examinations: impact of the iterative reconstruction method ASIR on image quality--preliminary findings, in Pediatr Radiol., 41(9), 1154-1164.

Scientific events

Active participation

Title Type of contribution Title of article or contribution Date Place Persons involved
Journées scientifiques de la Société Suisse de Radiologie 09.06.2011 Interlaken
SPIE 2011 Medical Imaging 12.02.2011 Orlando
96th Radiological Society of North America, Chicago-USA 28.11.2010 Chicago
Journées scientifiques de la Société Suisse de Radiobiologie et de Physique Médicale 11.11.2010 Wabern
Journées scientifiques de la Société Suisse de Radiologie, 97ème congrès annuel,Lugano 03.06.2010 Lugano
SPIE – Medical Imaging 2010 13.02.2010 San Diego
Journées scientifiques de la Société Suisse de Radiobiologie et de Physique Médicale 19.11.2009 Bâle
3rd Conference on Medical X-Ray Imaging – Optimisation in Medical X-ray and molcular imaging 25.06.2009 Malmö
Journées scientifiques de la Société Suisse de Radiologie, 96ème congrès annuel 04.06.2009 Gevève


Awards

Title Year
prix Andres Giedion de la SSRP 2011

Associated projects

Number Title Start Funding scheme
105951 Développement d'une stratégie pour optimiser les doses délivrées en CT pédiatrique 01.01.2005 Project funding (Div. I-III)
140995 Iterative reconstruction in CT: by how much can we divide the doses delivered to children and young adults? 01.01.2013 Project funding (Div. I-III)
136785 Le suivi de jeunes patients d'oncologie par des examens de radiodiagnostic: une évaluation du risque radiologique en vue d'une optimisation des partiques 01.06.2012 DORE project funding
105951 Développement d'une stratégie pour optimiser les doses délivrées en CT pédiatrique 01.01.2005 Project funding (Div. I-III)

Abstract

Computed Tomography, CT, is certainly a fantastic tool that runs the risk of becoming a victim of its own success due to the public health concerns it may elicit. Already on Jan 23rd 2001, USA Today published a particularly alarming paper (titled: “Radiologists agree CT scans harm kids”) where it was mentioned that 1,500 patients from the 1.6 million children (under the age of fifteen) scanned might eventually die from cancer caused by excess radiation; this, without any emphasis on the fact that CT actually saves lives. More recently, the June 19th, 2007 edition of The New York Times highlighted once again the impact of CT on the population’s exposure level. It mentioned in particular that the 62 million CT scans performed in the US in 2006 were responsible for more than half of the population’s total exposure from radiological investigations. Since one or two years, cardiac CT acquisition is becoming more and more popular. This might pose an additional problem concerning population’s exposure since relatively high doses (from 12 to 40 mSv per examination) are typically delivered to patients over 45 - 50 years old. If this situation is already problematic for an adult population, it is even more so for young children investigated for cardiac malformations which are then followed-up by many CTs over their entire life. Knowing that such a population is particularly sensitive to ionising radiation, it becomes an ethical imperative to make every effort to reduce its exposure as much as possible. At the moment, data acquisition protocols have not been optimized along the lines of a sound methodology. The aim of this project is to address this problem by answering the following questions:1) What is the situation concerning data acquisition of cardiac CT (for children and the follow-up of a young population surgically treated for heart malformations)? 2) How to objectively balance patient dose and image quality of static and moving structures? - How valid is the CTDIvol (volume Computed Tomography Dose Index) concept in assessing patient dose? - What are the benefits and limits of the NEQ (Noise Equivalent Quanta) and DQE (Detective Quantum Efficiency) metrics when applied to CT? - In the patient dose-image quality space (expressed in terms of CTDIvol or a more appropriate quantity and NEQ) how fast image quality is reduced when changing acquisition parameters such as kV, mAs, pitch values, X-ray tube rotation time…?- Where is located the present state of the practice (obtained from point 1 of this project) situated and which parameters could be proposed to improve the situation? - What gain in dose can be expected from iterative image reconstruction algorithms recently introduced for CT? 3) Are the optimal set of parameters using the methodology presented just above (point 2 of the project) adequate in clinical applications? - When dealing with very young children (up to 10 years old)? - When dealing with follow-up studies for young adults? This study will assure that cardiac CT examinations performed on children and young adults in Switzerland are optimized using a state-of-the-art methodology. This study will also provide the scientific community with a methodology allowing an objective way to reconcile image quality and patient dose by means of the very latest concepts from a dose and image quality point of view (introduction of new dosimetric concepts such as equilibrium dose, dose line integral … and use of objective image quality descriptors such as NEQ and DQE, parameters that are being adapted for the particular case of CT). Finally, the development of scientific competences in this field in Switzerland will help future international collaborations.
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