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

24th September 2019 CERN KT Forum on Medical Applications ISEULT Magnet Page 3

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

24th September 2019 CERN KT Forum on Medical Applications ISEULT Magnet Page 14

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

24th September 2019 CERN KT Forum on Medical Applications ISEULT Magnet Page 21

• 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

24th September 2019 CERN KT Forum on Medical Applications ISEULT Magnet Page 23

• 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 !!!

24th September 2019 CERN KT Forum on Medical Applications ISEULT Magnet Page 26

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

28

Annex : more scientific publications to go further…