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THE ISEULT WHOLE BODY
11.7 T MRI MAGNET
Prepared by Lionel QUETTIER, project manager
Presented by Antoine DAËL, CEA/DRF/Irfu
CERN KT Forum on Medical Applications
24th of September 2019
THE ISEULT WHOLE BODY 11.7 T MRI MAGNET
CERN KT Forum on Medical Applications ISEULT Magnet Page 224th September 2019
Thank you gor giving us the opportunity to tell you the story of this exceptional magnet
B0=11.72T
Proton resonance
Frequency is 500MHz
In recent decades neuroscience made extraordinary progress
Neuroimaging
CognitiveNeurosciences
Pathological brain singularityHuman brain singularity
PhysiquePhysics,
ElectronicsPhysiqueMedicine& Biology
PhysiqueMathematics& Statistics
PhysiqueImage Processing PhysiquePsychology & Sociology
ClinicalNeurosciences
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NEUROSPIN : A UNIQUE CONCEPT IN NEUROSCIENCE RESEARCH
Observer
CEA together with its partners funded at Saclay
Neurospin
a large Neuroscience Research Center
gathering all these specialists.
SACLAY
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3 teslas 7 teslas 11,7 teslas
Siemens Siemens
THE ISEULT PROJET - A FRENCH GERMAN INITIATIVE
24th September 2019 CERN KT Forum on Medical Applications ISEULT Magnet
Franco-German industrial collaboration developing :
Molecular Imaging at Ultra High Magnetic Fields.
Agreement signed between Président Jacques Chirac and
Chancellor Gerhard Schröder in 2004.
Funding agreement for the French Consortium validated by the
French Industrial Innovation Agency in 2006.
Leader of French Consortium : Pharmaceutical Company Guerbet
The Project Program has 3
Work Packages including
major industry partners
Ultra-hight field
MRI system
operating at 11.7T
Translational
research to
clinical magnets
(7T)
New contrast media
for Alzheimer’s
Disease, stroke
and Brain tumors)
CEA, SiemensSiemens,
Freiburg, Bruker
WP1 WP2 WP3
Guerbet, CEA
Observer
Alstom-GE
Oséo / BPI
Page 5
THE ISEULT PROJET - SCIENTIFIC GOALS
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Exploration of the brain at the
mesoscopic scale :
Non-invasive imaging
Whole human brain
In vivo
Ultra High Field MRI :
- Signal increase
- New contrasts
New discoveries
Identify new biomarkers for the diagnosis or monitoring of neurological
and psychiatric disorders
Post-mortem inference of the human
hippocampal connectivity at 11.7T.
J. Beaujoin, C. Poupon et al.
Brain Structure and Function, 2018.
Effects of anesthetic agents on brain blood
oxygenation level at 17.2T.
L. Ciobanu, D. Le Bihan et al.
PLoSOne, 2012.
Explore brain function and metabolism using new contrast mechanisms
Study the brain anatomy and connectivity at unprecedented spatial resolution
SNRB01.65
Pohmann et al. Magn Reson Med 2016;75:801–809
SNR GAIN B0 : CLINICAL RESEARCH APPLICATIONS
7T3T
1 to 2 mm resolution 0.1 to 0.2 mm
resolution
11.7T (post-mortem)
Example of a human hippocampus imageCourtesy Neurospin/CEA
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0.5 to 0.3 mm
resolutionAt the ultra-high spatial resolution provided by 7T and soon 11.7T MRI :
High accuracy segmentation of the hippocampus becomes possible!
Highly interesting information for clinical research : Alzheimer’s Disease,
epilepsy, schizophrenia …
THE ISEULT MAGNET : MORE THAN CHALLENGING
ObserverObserver
Observer
11.7 T magnet section : in orange the windings,
in blue the mechanical structure at 1.8 K and
in violet the cryostat
A more than challenging specification:
• B0 / Aperture 11.75T / 900mm
• Field stability 0.05 ppm/h
• Homogeneity < 0.5 ppm on 22 cm DSV
• Stray field 5 G13.5 m axial, 10.5 m radial
Innovative solutions for a MRI magnet
• 170 NbTi double pancakes for the main coil
• 2 NbTi shielding coils to reduce the fringe field
• Cryostat for superfluid helium at 1.8 K, 1.25 bars
• Dedicated cryorefrigerator (80 l/h + 40 W @ 4.2 K)
• Driven mode operation two 1500 A power supplies
Stored Energy 338 MJ
Inductance 308 H
Current 1483 A
Length 5.2 m
Diameter 5 m
Weight 132 t
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CERN KT Forum on Medical Applications
ISEULT Magnet 9
MAGNETIC DESIGN : WINDING PACK WITH 170 DOUBLE PANCAKES
ORIGINAL DOUBLE PANCAKE DESIGN
THE OBJECTIVE IS TO DESIGN A MAGNET INTRINSICALLY HOMOGENEOUS
DESIGN CROSS-CHECK SEVERAL TIME
1 1
0 )(cos
sin
cos
)(cos),,(n
n
m
m
n
m
n
m
n
m
n
nn
n
z PW
mY
mX
PZrBrB
x
yz
O O’
2s
O’’
2s
DOUBLE PANCAKE WINDING
170 Double pancakes wound and controlled (external diameter of 2 m)
- 330kg each
- Tolerance at inner bore +/-0,05mm
- Control of each +/-0,2mm
- Planarity 0,1mm
- Parallelism à 0,2mm
24th September 2019 CERN KT Forum on Medical Applications ISEULT
Magnet 10 / 153
conductor:9.2mm*4.9mm
NbTi Cable in Channel
cooled at 1.8 K
CERN KT Forum on Medical Applications
ISEULT Magnet 11
Assembly of the double pancakes
STRONG R&D AND PROTOTYPING ACTIVITIES 2006-2009
winding techniques, mechanics, cryogenics,
thermo-hydraulic studies…
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MAGNET MANUFACTURING IN BELFORT (2010 – 2017)
Main coil - DP stacking
MLI wrapping Vacuum vessel welding
Main coil / Shielding coils integrationShielding coil fabrication
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2 WEEKS OF TRANSPORT FROM BELFORT TO SACLAY
Belfort
Corbeil EssonnesSaclay
Strasbourg
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Power
supplies
Magnet
control
room
ELECTRICAL & CRYOGENIC INFRASTRUCTURE
48 V
batteries
Vacuum
Circuit MSS/MCS
racks
Dump
Resistor
Cryogenic
plant
Cryogenic satellite24th September 2019 CERN KT Forum on Medical Applications ISEULT Magnet Page 15
Two main power supplies
48V batteries in case of power failure
Building equipped with a diesel generator
MAGNET SAFETY SYSTEM TO ENSURE 24 HOUR OPERATION
High availability
Redundancy of all
key equipment
Fast discharge to be
avoided for minor
causes
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CALODUC ASSEMBLY – OCT 2017- OCT 2018
Caloduc : « umbilical cord » connecting the magnet with the cryogenic/electrical facilities
• « Helium tight » connection of cryogenic circuits, electrical connection of superconductors and of the inner
magnet instrumentation : voltage taps (20), cryoshims (96), quench heaters (8), temperature sensors (96), strain
gauges (24)
• Complex mechanical structure made of more than 200 parts (900kg mass)
• Cold mass (1.8K)
• Thermal Shield
• Vacuum Vessel
• Cooling circuits (TS and VV)
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CALODUC COMPLETION - OCTOBER 2018
In blue the cryogenic “satellite” hosting the superfluid helium cooling exchanger, the current
leads and the instrumentation
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COOLDOWN – 19 NOV 2018 – 7 MARCH 2019
• Huge mass to be cooled: cold mass (105 tons @ 1.8K) + thermal shield (3.4 tons @ 55K)
• Cooling rate limited by the thermal gradients across the coils (50K max)
Température masse froide
250 000 L liquid nitrogen
18 500 L helium (filling and cooling down)
150 kW of electrical power to operate the cryoplant
Cooldown with nitrogen
(thermal shield and cold mass)
7 weeks
Turbo-expenders activation
Cooldown with helium (thermal shield and cold mass)
5 weeks
Cold mass filling with helium
Cooldown from 4.2K to 1.8K
4 weeks
Cold mass temperature
Pumping units activation
Power outage
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STEP BY STEP ENERGIZATION
Current
1350A
1200A
1050A
900A
600A
450A
300A
150A
0A
750A
1500A
1.5T
3T
7T
5.9T
8.3T
3/27 4/25 5/2 5/16 5/22
11.72T
10.55T
9.51T
7/1824th September 2019 CERN KT Forum on Medical Applications ISEULT Magnet Page 20
ERDB Test
Emergency
Ramp Down
Button
THE GREAT DAY: 11.72T – JULY 18TH 2019
Test duration of 2 days• Ramp-up in 30 hours• Switching test between the two power supplies• Plateau of 18 hours @ 11.72T• First magnetic measurements (homogeneity and drift)• Slow discharge in 3 hours to unload the magnet
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• Magnetic field drift adjusted using a fault current limiter
• 0.04 ppm/h obtained after only 4 hours of tests @ 11.72T ( vs. spec 0.05ppm/hour)
FIELD HOMOGENEITY MEASUREMENTS
• Magnetic measurements @ 1.5T, 3T, 7T and 11.72T
Mechanical system designed to allow
translations/rotations of the probe array
New field camera 499MHz developed
by Metrolab
• 40 NMR probes
• 50 cm diameter
• It is more than the brain volume !
NMR probe
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FIELD HOMOGENEITY MEASUREMENTS
1,5 T
∆𝐵 = 142 PPM
7 T
∆𝐵 = 128 PPM
• Very good agreement between the measurements
• Improvement of the field quality due to the shielding
coils re-centering (behaviour anticipated during the
design phase to specify the coil geometry at 300K)
• Effect of thermal contraction at low temperature
• Effect of magnetic forces that tend to push the two
shielding coils toward the magnetic centre
• Field homogeneity specification is achievable using the available shimming power
(cryoshims & iron shims),
• Additional passive shimming system for Y11 is being designed
Ø 22 cm
300K1.8K1.5T
1.8K3T
1.8K7T
Cryoshimpower
Z1 [PPM] -132 -16 -7 -5 +/- 300
Z2 [PPM] -105 -22 -16 -15 +/- 70
Z3 [PPM] 20 2 2 2 +/- 10
X11 [PPM] -1 22 21 22 +/- 32
Y11 [PPM] 59 63 59 60 +/- 32
X21 [PPM] - 2 2 2 +/- 14
Y21 [PPM] - -6 -6 -6 +/- 14
X22 [PPM] - -1 -1 0 +/- 10
Y22 [PPM] - 0 -1 -1 +/- 10
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• Installation of the MRI equipment (Gradient Coils, RF antenna), of Faraday cages and of patient bed
• Final energization step by step
• Commissioning of the high-availability control and protection systems
• Adjustment of the field homogeneity (iron shims – cryoshims)
• Adjustment of the field stability
• Tests of the Gradient Coils vs. main magnet interaction : the most critical object
FINAL COMMISSIONING STEPS TOWARDS AN IMAGING SYSTEM
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AFTER 15 YEARS, THE FIRST IMAGE !!!
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In the human brain, neural codes specific to Homo Sapiens are certainly waiting to be discovered, for the representation of words, sentences, mathematical formulas, musical conventions ...
The NeuroSpin teams are particularly at the forefront of the research on the emergence of the language.Thanks to the functional MRI at 7T, they begin to visualize how the syntax tree of a sentence is coded….
Their goal is now to understand the "human singularity", the specific codes that exist only in the human brain, and not in the other primates.Brain image at 7T (courtesy of Neurospin)….11.72T ?
Warm thanks to all the people involved
in this fascinating scientific adventure !!!
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KT Seminars: https://indico.cern.ch/event/574545/ dec 2016
Neurospin Seminar: From the Proton to the Human Brain
By Pr Denis Le Bihan (funding Director of Neurospin)
SEMINAR@CERN : THE ISEULT WHOLE BODY 11.7 T MRI MAGNET
Dr Lionel QUETTIER CEA/DRF/Irfu
Date : Wednesday 30th October @11.00 am
Room: Kjell Johnsen Auditorium (30/7-018).
T Schild and D. Le Bihan, “Human brain MRI at 500 MHz, scientific perspectives and technological challenges”, Superconductor Science and Technology, vol. 30, Number 3, 2017.
T. Schild, et al., “The Iseult/INUMAC Whole Body 11.7 T MRI Magnet R&D Program,”,IEEE Trans. Appl. Supercond. vol. 20, issue 3, pp. 702-705, 2010.
L. Quettier, et al. , “Manufacturing Completion of the Iseult Whole Body 11.7 T MRI System”, IEEE Transactions on Applied Superconductivity, Vol. 28, 2018
MORE KNOWLEDGE TRANSFER
CERN KT Forum on Medical Applications ISEULT Magnet Page 2724th September 2019
IMPORTANCE OF LOCALIZATION OF LESIONS IN MULTIPLE SCLEROSIS:
HTTPS://PUBS.RSNA.ORG/DOI/PDF/10.1148/RADIOL.2019190398
HTTPS://WWW.NCBI.NLM.NIH.GOV/PUBMED/30715195
INTEREST OF ULTRA-HIGH MAGNETIC FIELDS FOR THE DETECTION OF SMALL CORTICAL DYSPLASIAS (INCREASES THE
THERAPEUTIC POTENTIAL IN CERTAIN EPILEPSIES):
HTTPS://WWW.NCBI.NLM.NIH.GOV/PUBMED/26778405
HTTPS://WWW.NCBI.NLM.NIH.GOV/PUBMED/25258368
INTEREST OF ULTRA-HIGH MAGNETIC FIELDS FOR CLINICAL RESEARCH ON NEURODEGENERATIVE DISEASES:
HTTPS://WWW.NCBI.NLM.NIH.GOV/PUBMED/28259856
HTTPS://WWW.NCBI.NLM.NIH.GOV/PUBMED/25171715
CONTRIBUTION OF ULTRAFAST MAGNETIC FIELD SPECTROSCOPY TO CLINICAL RESEARCH ON PSYCHIATRIC DISEASES:
HTTPS://WWW.NCBI.NLM.NIH.GOV/PUBMED/28744229
INTEREST OF HIGH MAGNETIC FIELD SODIUM IMAGING FOR MULTIPLE SCLEROSIS CLINICAL RESEARCH:
HTTPS://WWW.FRONTIERSIN.ORG/ARTICLES/10.3389/FNEUR.2019.00084/FULL
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Annex : more scientific publications to go further…