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Yves LEMOIGNE, ESI, Archamps, France
Medical Physics (a Peacefull activity!)
Thanks to Nuclear Physics ….
Yves Lemoigne, ESI-Archamps (near Geneva)
European School of Medical Physics (ESMP)
Note for this presentation: - Slides with green background concern mainly ESMP organisation-Slides with yellow background concern mainly Medical Physics taught during the School (within other topics taught in Archamps…)
Yves LEMOIGNE, ESI, Archamps, France
Yves LEMOIGNE, ESI, Archamps, FranceESMP=6 weeks: 3 Imaging, 3 RT
Yves LEMOIGNE, ESI, Archamps, France
• - Help to diagnosis (anatomical imaging and functional imaging) : MRI, Echography, X-ray Radiology, SPECT & PET…
• - Radiotherapy: tele- and Brachy-therapy (with X-rays, inserted radioactive products, protons & Ions beams..)
Since More than 50 years Physics is a great help to Medicine and Biomedical research :
Now: (X-rays)
Future: Protons / Ions
Chic
ago
Univ
ers
ity
Yves LEMOIGNE, ESI, Archamps, France
Medical Physics & Nuclear Physics
They have clear links :
-Because techniques used in MP are directly coming from Nuclear Physics :
Ex : Particle accelerators for Radiotherapy (electrons, protons, ions…) or radiotracer production
EX : sealed sources used in Brachytherapy
EX : Radiotracers with PET (SPECT) cameras The case of PET will be developped here
Yves LEMOIGNE, ESI, Archamps, France
• X-ray imaging is “trans-
mission imaging” and is used mainly for “anatomy”
imaging”
• Nuclear medicine is
“emission imaging”
and is used for “functional
Imaging” (i.e. how this is
Working as function of time) More powerful for oncology
Basic principles for Medical IMAGING
CT-Scan
PET-Scan
Yves LEMOIGNE, ESI, Archamps, France
• Precise Medical Imaging is now compulsory for Radiotherapy BEFORE and AFTER Radiotherapy
• BEFORE: - Diagnosis- Input for Treatment plannings (accuracy…)
Needed
If available
Future….
• AFTER: - Treatment results
TPS
Yves LEMOIGNE, ESI, Archamps, France
Estimated absolute yearly
rate (%) of 2nd cancer
Tumor site X-rays IMXT Protons
Oesoph. & stomach 0.15 0.110.00
Colon 0.15 0.070.00
Breast 0.00 0.000.00
Lung 0.07 0.070.01
Thyroid 0.18 0.060.00
Bone & soft tissue 0.03 0.020.01
Leukemia 0.07 0.050.03
All 0.75 0.43 0.05
Compared to X-rays 1 0.60.07
BEFOREAFTER
• AFTER: - Treatment results
3D whole-body PET imaging
Yves LEMOIGNE, ESI, Archamps, France
• Radio tracers can be used to label the chemical molecule we would like to follow inside the patient body. Positrons emitters more used in PET are : F18
(110mn), C11 (20 mn), (in research :N13 (10 mn), O15
(2mn)….). • They allow to see metabolism, while X-ray scan or
MRI are better to see the anatomy • Nuclear medicine (imaging of metabolism using
molecules labeled with an appropriate radioisotope) is therefore not in competition, but in complement of imaging techniques such as X-ray, X-ray scan or MRI (Magnetic Resonance Imaging).
Yves LEMOIGNE, ESI, Archamps, France
MRI CT PET
Specification of the GTVComplementarity of imaging devices
Nuclear Magnetic Resonance
X-rays
Positron-electron annihilation
Excellent accuracy but specific only in some cases (could give functional imaging) : detects resonance of atom nucleus
Good accuracy for anatomical imaging
(Only density is measured)
Modest accuracy but good for functionnal imaging (very good sensitivity) : because their abnormal metabolism tumor are avid of glucose which emits photon from e+e-annihilation if radiotracer have been injected previously
Example of brain tumor :
Complementarity :- CT-PET devices are available (Bodygraph-Siemens…)- MRI-PET could be available soon for Small-Animal-PET camera only (Biomedical research only)
Yves LEMOIGNE, ESI, Archamps, France
Positron Emission Tomography (PET) is one form of radio-pharmaceutical diagnosis. It is a powerful technique whose development owes Nuclear Research. Due to its good sensitivity, PET allows disease-related changes in tissues and organs could be detected long before serious symptoms set in.
PET cameras for IMAGING
Image fusion (CT + PET)
“Standard “is now CT+PET devices
Yves LEMOIGNE, ESI, Archamps, France
Because its principle :
P
P
N
PP P
PP
P
P
N
NN
N
NN
N
N
P
P
N
PP P
PP
N
P
N
NN
N
NN
N
NF18
O18
e+
e+ e-
y
y
180°±0.25
PET CAMERA : a child of Nuclear PhysicsMatter – Antimatter annihilation e+ e- =>
e+ e- =>
Yves LEMOIGNE, ESI, Archamps, France
PET camera Nuclear Physics (detector @ CERN)
e+ e- => at 1024 KeV
e+ e- => + … because higher energy (100000000 KeV !)
In principle :
Realisation:
Size and cost are different !
Particlebeam
Particlebeam
Positron Radio-Tracer Emitter inside the body
detectors in circle around Colliding
point of the two beams
Take care of Scale : 1 meter 15 meters !
In Hospitals … In Research centers (CERN, Geneva)
Versus
Yves LEMOIGNE, ESI, Archamps, France
Inside a PET camera(here CPET from Philips) in 90’s
Medical imaging / Nuclear Physics : Similar techniques
Scintillators + PM’sNuclear Physiscs research (ex: CMS exp @ CERN) have
replaced photomultipliers (PM) by Avalanche Photodiode (APD). Medical imaging begins to do the same (ex: Lab-PET)
Yves LEMOIGNE, ESI, Archamps, France
Coincidence detection in a PET scanner
Why PET camera are powerful …
From Y. Yongen (IBA)
Great selectivity due to the 3 conditions we are demanding: -1- detect with Energy selection ≈ 511 KeV-2- detect two in sharp timecoincidence (≈ 10 nanosecond)-3- detect two in opposite directions (within a few degres)
Yves LEMOIGNE, ESI, Archamps, France
Medical Physics &Nuclear Physics
PET Photon detectors are done like several Nuclear Physics detectors.
Typically : Crystals, PM, gantry, electronic chains and controllers, computer interfaces, hard discs or tapes for mass storage, displays devices…
Yves LEMOIGNE, ESI, Archamps, France
• A PET needs a complex environment… Chemistry, Bio-Chemistry, Physics,
mathema-tics, computing and… medicine.
• A cyclotron to produce radioactive tracers (F18, C11..) is needed not too
far…
• Previously only availablein big centres (USA, UE…).
• With modern transport facilities, a regional centrecould supply hospitals in a 1500 km radius (about)…
• PET camera for biomedical research can use
“generator” Ge68 - Ga68 => e+
(not for human use)
Yves LEMOIGNE, ESI, Archamps, France
• All these techniques are studied during the three first weeks of ESMP (111 hours) with some of the best experts from Belgium, France, Germany, Italy, Nether-lands, Switzerland, USA….
+ One week of Medical computingSimulation / modelling of Physics and/or Live systems, Networks,Tools for computer simulation (GEANT4, EGS5…), Image reconstruc- tion algoritms, Data compression and processing…
ESMP organisation
Yves LEMOIGNE, ESI, Archamps, France
Then ESMP students study the sophisticated techniques of tumors killing by use of radiations (External sources for Radiotherapy, internal sources for brachytherapy) = 74 h
Modern Radiotherapy is more and more obliged to use accurate medical imaging of previous ESMP weeks (Role of Treatment Planning Systems)
or teletherapy or curiethérapie
Yves LEMOIGNE, ESI, Archamps, France
• External radiation therapy refers to radiation applied externally to the body using a beam of high-energy x-rays (or proton / light ion beams) to kill tumor cells (also called Tele-Therapy).
• Internal radiation therapy refers to the use of small radioactive seeds implanted in the tumor tissue. The seeds emit radiation over a period of time to kill tumor cells (Brachytherapy or Curiethérapie).
Yves LEMOIGNE, ESI, Archamps, France
21
In TeletherapyIn Teletherapy linear linear accelerators dominateaccelerators dominate
To irradiate only the tumour oncologists To irradiate only the tumour oncologists use :use :
• collimator homothetic to tumor shape collimator homothetic to tumor shape ((BlocksBlocks))
• MMulti-ulti-LLeaf eaf CCollimator (static) : Conformal ollimator (static) : Conformal RTRT
• Dynamic MLC (position varyingDynamic MLC (position varying during during the irradiation). Driven by computer, it’s the irradiation). Driven by computer, it’s IMRT IMRT ((IIntensity ntensity MModulated odulated RRadiation adiation TTherapy)herapy)
IMRT is an advanced RT technique to treat tumor and to spare surrounding tissue from doses above tolerances.
In the world radiation oncologists use 10 In the world radiation oncologists use 10 000 electron linacs delivering X-ray 000 electron linacs delivering X-ray beams.beams.The planning of RadioTherapy treatment has been revolutionized by the ability to delineate tumors.
Hight-tailored computing applications are needed to perform optimisation and treatment simulation (treatment planning)
Often limitations due to availibility of experienced medical personnel (time consuming technique)…
High-level education needed…. (ESMP provides it)
Screen Blocks
or
Yves LEMOIGNE, ESI, Archamps, France
SIMULATORand/or
ELECTRONIC PORTAL IMAGING
ACCELERATOR
BLOCK CUTTING DEVICE
or MLC
MRI or / and PETCT-SCAN
VERIFIY AND RECORD SYSTEM
OPTIMISATION
•Dose distribution •Dose-Volume
Histograms •Biological indices
BEAM DEFINITION
•Treatment parameters•Treatment
time(monitor units)
•Field shapeor
•Position of leaves
•Reconstructed radiographs
(DRR)
•beam data library
REGISTRATION
•anatomical structures
•external contours •densities•anatomical
structures
TREATMENT PLANNING SYSTEM
CENTRAL ROLE OF TPS
Yves LEMOIGNE, ESI, Archamps, France
MRI CT PET
Specification of the GTV
Impact of the imaging method on the Tumor Volume definitionKneschaurek, 2002
Recall Summary Volumes and Margins[ICRU-50 Supplement of rules definitions]
GTV
CTV
ITV
PTV
Specification of the GTV
Nuclear Magnetic Resonance
X-rays
Positron-electron annihilation
Yves LEMOIGNE, ESI, Archamps, France
Target Volume
In case of deep tumor, it is better to use “several” beams, all converging to the tumor, to avoid excessive doseirradiation of heathly tissues around
Beam 1
Beam 2Beam 3
“Simplest” way : Rotate the accelerator or the patient
X-ray BeamProton beam@PSI
Yves LEMOIGNE, ESI, Archamps, France
Inverse Planning
TreatedVolume
OAR
Target Volume
TreatedVolume
OAR
Target Volume
Inverse Planning"Conventional" Planning
OAR = Organ At Risk (for instance Spinal Cord) which is compulsory to protect from high dose.
Yves LEMOIGNE, ESI, Archamps, France
Clinical Example
Modern RT technique : Intensity Modulated Radio-Therapy (Dose Intensity is driven by computer following the previously treatment planning calculating – only if precise imaging taken before)
Yves LEMOIGNE, ESI, Archamps, France
Accelerators for Hadrontherapy: developed first in physics labs
They are used routinely in hospitals
Courtesy of IBA
Hadron Therapy
Around 9000 of the 17000 accelerators operating in the World today are used for medicine. Very few ( less than 50) are hadron (P or light Ions) accelerators.(Future ? Next slide : why they are better despite higher cost: the Bragg peak)
Yves LEMOIGNE, ESI, Archamps, France
Archamps - 17.11.08 – U.Amaldi 2828
Protons and ions spare healthy Protons and ions spare healthy tissuestissues
charged hadron beam
that loses energy in matter
27 cm
tumour
target
200 MeV - 1 nA200 MeV - 1 nAprotonsprotons
4800 MeV – 0.1 nA4800 MeV – 0.1 nAcarbon ionscarbon ions
which can control which can control radioresistantradioresistant
tumourstumours
Photons ProtonsX raysprotons or
carbon ions
tail
cobalt 60
linac
httt://global.mitsubishielectric.com/bu/particlebeam/index_b.htmlhttt://global.mitsubishielectric.com/bu/particlebeam/index_b.html
light ion(carbon)
proton
Yves LEMOIGNE, ESI, Archamps, France
Photon IMRT Photon
Proton
Conventional Radiotherapy:Important dose outside the tumor
IMRT = Intensity Modulated
Radio Therapy:still non negligable dose
outside the tumor
Particle Therapy: Comparing Proton & photon Conventional RT
Scattering technique :Low dose outside
Y.Yongen (IBA)
Yves LEMOIGNE, ESI, Archamps, France
Proton Therapy is growing rapidly!
PT center under operation
Courtesy Janet Sisterson & PTCOG
0
10,000
20,000
30,000
40,000
50,000
60,000
70,000
1950 1960 1970 1980 1990 2000 2010
Pat
ien
ts t
reat
ed
0
5
10
15
20
25
30
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40
Op
erat
ing
fac
iliti
es
Yves LEMOIGNE, ESI, Archamps, FranceExample of IBA Proton Therapy System
• Hadron therapy owe very much to Nuclear Research Centres experience for accelerators, beam transport, detectors…
• A Proton therapy system is a complex system, filling a Hospital building.
• The treatment rooms are larger and complex (gantries),• The total investment is around 100 M€, about half for the
equipment,• A Proton facility can treat 1500 patients/year mainly for special
cases (Proximity organ-at-risk tumors, radioresistive tumor, children tumor…)
• Hadron facilities providing protons and carbon ions are more costly….
Yves LEMOIGNE, ESI, Archamps, France
3232
The accelerators used today The accelerators used today in hadrotherapy are in hadrotherapy are
“circular”“circular”
SYNCHROTRONS
18-25 metres
CYCLOTRONS (Normal or SC)
4-5 metres
OR
SYNCHROTRONS
6-9 metres
Teletherapy with protons (200-250 MeV)
Teletherapy with carbon ions (4800 MeV = 400 MeV/u)
Archamps - 17.11.08 - UA
Yves LEMOIGNE, ESI, Archamps, France
LET > 20 keV/μm = 200 MeV/cm =40 eV/(2 nm)LET > 20 keV/μm = 200 MeV/cm =40 eV/(2 nm)Production of many unreparable localized double strand
breaks and clustered damages DNA- double strand
Why light Ions (C12) are better than protons (photons):
Effect of Effect of ΔΔE/E/ΔΔx = x = LETLET
2 nmsize
Yves LEMOIGNE, ESI, Archamps, France
LOMA-LINDA :since 1992 : first Hospital-basedProton therapy centre
2005 : 160 sessions per day
Accelerators for Accelerators for protontherapyprotontherapy
Yves LEMOIGNE, ESI, Archamps, France
Concepts directly transferred from Nuclear Physics Reasearch centres (CERN, DESY, Fermilab…)
• In the world protontherapy has already treated 55'000 In the world protontherapy has already treated 55'000 patients.patients.
carbon ion therapy has already treated 4500 patients (Japan, carbon ion therapy has already treated 4500 patients (Japan, RFA)RFA)
• Close Future : CNAO in ItalyClose Future : CNAO in ItalyThe synchrotron (proton and CThe synchrotron (proton and C1212 ions ): beams ready in summer 2009 ions ): beams ready in summer 2009
25 m synchrotron and 3 treatment rooms
Other centres in progress:Germany (Heidelberg, Marburg)France (Lyon, Caen, Orsay),USA, China, India…
Yves LEMOIGNE, ESI, Archamps, France
A new concept: A new concept: CyclinacCyclinac=Cyclotron+ Linac for Image Guided =Cyclotron+ Linac for Image Guided HadronTherapyHadronTherapy
2 Modules tested at LNS, Catania, Italy
now in Microcosm at CERNnow in Microcosm at CERN
This project would allow radio-tracer production cyclotrons to be transformed at raisonable cost in hadrontherapy facility : A real breakthrough !
Yves LEMOIGNE, ESI, Archamps, France
Brachytherapy
A few words about Brachytherapy :Local Eradication of a Tumor by Radioactive Implants
Example of Prostate cancer
Real advantage in case of tumor on moving organs (ab-domen)… Note the spectacu-lar progress when seeds are implanted under Magnetic Resonance Imaging (Geneva)
Yves LEMOIGNE, ESI, Archamps, France
Last Part of ESMP : RADIOPROTECTION in Medical Physics
Public (and media) are very concerned by this topic !
Yves LEMOIGNE, ESI, Archamps, France
Origin of participants involved in EUROPEAN SCHOOL OF MEDICAL PHYSICS
.*
*
ESMP is known by all European countries (and farer…)
MORE THAN 1000 STUDENTS WENT IN ARCHAMPS-GENEVA SINCE THE SETTING UP OF THE SCHOOL
IN EUROPE….
… And IN The WORLD
EGYPT (as 6 other neighbouring countries) is eligible to a subsidy from
NATO Scientific Department in the frame of the “South Mediterranean Dialogue
group of countries”
Medical Physicists (or students in MP) can contact
the secretariat : filiz.zilif@yahoo.com
Yves LEMOIGNE, ESI, Archamps, France
Please, Visit our website :
www.cur-archamps.fr/esi
Or the EFOMP website :
www.efomp.org
For further information and application form for ESMP 2009 (deadline : June 2009)
School activities are on bothsides of the border : - French side : Archamps- Swiss side : Genevabut as Switzerland recently joined the “schengen System”, only one visa is needed !!
Yves LEMOIGNE, ESI, Archamps, France
Physics Medicine application in
Statics (mechanics) Orthopaedics
Dynamics (mechanics) Heart motion
Elasticity and strength of materials Orthopaedics
Fluid statics Blood pressure
Fluid dynamics Blood flow in vascular system
Sound and acoustics Stethoscope, ultrasound, acoustic microscope
Electricity All life processes, ion transfer at membranes
Magnetism Nuclear magnetic resonance imaging
Atomic physics and spectroscopy "Chemical shift" in NMR imaging, lasers in medicine
Molecular physics Genetics, antibodies, protein structure, electron microscope
Ultraviolet and infrared energy Skin treatment and imaging
X-rays Radiology, CT imaging
Quantum mechanics Electron diffraction microscope
Crystallography Structure of proteins
Solid-state physics & semiconductors Computers in medicine, scintigraphy, Fast electronics
Nuclear physics Radioisotope labelling, nuclear medicine, radiation therapy
Radioactivity Positron emission tomography (PET), Radiotracers
Elementary particle physics Proton & ion therapy, Huge & complex devices
Accelerators, cyclotrons, etc Tumour therapy,
etc…. etc…
Correlations between Physics & Medicine (from Nobel Prize Robert Hofstadter, Stanford University in 1983)still true As a Conclusion-1 :
Yves LEMOIGNE, ESI, Archamps, France
18.11.2006 ESMP 2006Key Areas for Biomedicine
In conclusion, there is no doubt that the contribution of Medical Physics (and thus Nuclear Physics) is not negligible in the better efficiency of Medicine during the past decades. This is why a high level education in Medical Physics, done by first class experts deeply involved in this science branch, is absolutely compulsory .
Fundamental breakthroughs in physics are continuing to yield new medical technologies for identifying and treating a range of diseases.
The 50-year tenure of Nuclear Physics in Medicine and Biology has coincided with some of the most important developments in oncology and radiological science, including the introduction of artificial radioactivity, computers and 3D imaging into medicine. These events have profoundly influenced the development of Medicine
CONCLUSION-2
Yves LEMOIGNE, ESI, Archamps, France
Further information : www.cur-archamps.fr/esior www.efomp.org
Yves LEMOIGNE, ESI, Archamps, France
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