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28.07.2015
1
New trends in ion beam therapy
Katia Parodi, Ph.D.
Ludwig-Maximilians University (LMU) Munich, Germany
(also affiliated to Heidelberg Ion Beam Therapy Center)
MPP Colloqium
München, July 21, 2015
Munich-Centre for Advanced Photonics
Surgery Radiotherapy
Survival Quality of life
Chemotherapy and others
The three columns in the fight against cancer
Localised tumour Metastatic tumour
Local tumour control, Palliative treatment
28.07.2015
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Munich-Centre for Advanced Photonics
Surgery Radiotherapy Chemotherapy and others
The three columns in the fight against cancer
Survival Quality of life
Localised tumour Metastatic tumour
Local tumour control, Palliative treatment
08.06.2013 K.Frey, LMU – PTCOG 2013
Advantages of ion beams: depth conformality
Sparing of normal tissue in entrance channel
No / low dose in exit channel distal to the tumour
Water
Deph in water (cm)
Bio
logi
cal e
ffec
tive
do
se (
%)
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Treatment delivery uncertainties
But is what we see in TPS what we really deliver?
We want to exploit clinically the dosimetric advantages of ion beams
In-vivo verification
Tang et. al. Med.Phys. 2012
Organ at risk Tumor volume
Daily practice of compromising dose conformality for safe delivery
Range uncertainties result in conservative margin expansion and choice of beam angles avoiding Bragg peak before OARs
In-vivo verification could enable full exploitation of ion therapy potential
28.07.2015
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X-ray
source
X-ray
imager
Current efforts for in-room imaging in ion beam therapy
- Anatomical confirmation via X-rays or transmitted ions
Imaging for confirmation of - Treatment geometry
Imaging for treatment verification
X-ray
source
X-ray
imager
PET
Current efforts for in-room imaging in ion beam therapy
- Anatomical confirmation via X-rays or transmitted ions
Prompt
gamma
Charged
secondary
particles
- Range monitoring via emerging secondary radiation or transmitted ions
Imaging for confirmation of - Treatment geometry - Treatment delivery
Imaging for treatment verification
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As in photon therapy, use integrated on-board X-ray imager for
volumetric so called cone beam imaging (CBCT)
In-room imaging for patient positioning
CBCT vs CT
10 Courtesy G. Landry
28.07.2015
6
+
Landry...Parodi Med. Phys. 2015
=
In-room imaging for dosimetric assessment
CBCT (and DIR)-based image guidance for dose recalculation on daily anatomy
However relying on CT-range calibration and dose calculation engine
• Nuclear reactions induce measurable emerging radiation
p or 12C
Target (e.g., 16O)
Projectile fragment (Z>1)
(vf ~ vp )
Target fragment (vt ~ 0 )
„Prompt“ p, d, t, n, g, …
„Delayed“ radioactive decay
• Primary ions are stopped somewhere within the patient, with dose
and range mainly dependent on Coulomb interaction
Only Positron-Emission-Tomography clinically investigated so far
In-vivo treatment visualization
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p in PMMA
12C ions in PMMA
K. Parodi et al, IEEE TNS 2005
In-vivo PET-based verification
g-emission
b+-emitter yield (15O, 11C,..., with T1/2 ~ 2,
20,... min) as by-product of irradiation
A(r) D(r)
Tradeoff between better spatial
correlation (12C) and stronger signal (p)
Dose-guidance from comparison of
measured vs expected b+-activity
p or 12C
15O, 11C, ...
15O, 11C, ...
(projectile fragmentation only for Z>1)
11C, 10C
PET/CT-based verification at HIT
Ion sources
Synchrotron
Gantry
Treatment places
Commercial PET/CT next to treatment rooms Heidelberg Ion Beam Therapy Center
PET/CT
Biograph mCT
Pelvis/Head/Neck
Liver
28.07.2015
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Bauer, …, Parodi, Radiother Oncol 2013
Clinical examles of
offline PET/CT @HIT
PET Sim (on TP-CT) PET/CT Meas Dose
12C ions
Prompt gamma imaging
g-emission
p or 12C
In addition to b+- production, nuclear
reactions induce fast (sub-ns) prompt g
emission with broad energy spectrum
(up to several MeV)
Eliminate washout problematic
Lower cross section threshold than for
positron emitter production
Closer correlation to Bragg peak
H. Müller, FZD
Polf et al, PMB 2009
28.07.2015
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Proposed prompt gamma detection schemes
Mechanical collimation
Ray (IPN Lyon)
Electronic collimation
Ray (IPN Lyon)
Different generation detectors: From 1D detection of last few mm beam penetration to 3D imaging
18
Compton camera developments
Scatterer/Tracker DSSSD
Absorber LaBr3
z
x
y
e-
g
The MAP Compton camera
C. Lang, D. Habs, K. Parodi, P.G. Thirolf, JINST 2014
e , ee
Scatterer/ Tracker
Absorber
g ≥ 1 MeV
E‘g eg
Compton arc
Additional electron tracking of ee direction and energy Ee : origin of g can be restricted to an arc reconstruction of incompletely absorbed g events is possible
28.07.2015
10
• Nuclear reactions induce measurable emerging radiation
p or 12C
Target (e.g., 16O)
Projectile fragment (Z>1)
(vf ~ vp )
Target fragment (vt ~ 0 )
„Prompt“ p, d, t, n, g, …
„Delayed“ radioactive decay
What about electromagnetic interactions?
28.07.2015
11
21
Ionoacoustics
Particularly promising for highly pulsed delivery at laser-driven beams
W. Assmann, …, K. Parodi, Med Phys 2015
W. Assmann, S. Reinhardt, S. Lehrack, P.G. Thirolf, K. Parodi (LMU) M. Moser, G. Dollinger (UniBW) Kellnberger, M. Omar, V. Ntziachristos (IBMI/MHZ)
Transducer
The principle
Thermal expansion Acoustic wave
Localised energy deposition
Ionoacoustics at MLL
Experimental setup at the MLL Tandem accelerator:
• water phantom
• 3.5 – 10 MHz US detector, remotely controlled (scan)
• beam pulse width 8 ns – 4 ms
• 104 – 108 protons per pulse
W. Assmann et al Med Phys 2015
Systematic “ionoacoustic” investigations under ideal conditions
20 MeV protons, water
28.07.2015
12
Ion transmission imaging
Ion-based radiography / tomography could:
• Decrease range error via direct Relative Stopping Power determination
• Eliminate CT artifacts from metal / dental implants
• Replace X-ray imaging for daily, lower-dose image guidance
X-ray
source
X-ray
imager
Rinaldi, …, Parodi, PMB 58 2013
Rinaldi, …, Parodi, PMB 59 2014, 2014b
• 61 PPIC 30x30 cm2
• 3 mm PMMA absorber slabs
• 2 read-out modules of 32 channels
with real time controller
• Active scanning beam delivery system
Carbon ion radiography prototype using ionization
chambers @HIT
12C Ions X-rays
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08.06.2013 K.Frey, LMU – PTCOG 2013
A remaining challenge: compact and cost-effective instrumentation
… compared to modern photon LINAC
28.07.2015
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08.06.2013 K.Frey, LMU – PTCOG 2013
The Munich new laser-driven infrastructure
08.06.2013 K.Frey, LMU – PTCOG 2013
Laser-driven ion sources with new targets (AG Prof. Schreiber)
aperture
quadrupoles
D+ D-
aperture or
spectrometer plate
Target
ATLAS laser
(60 J, 20 fs,
3 PW, 1-5 Hz)
Detectors for online Diagnostics (Dr. Reinhardt et al)
Beam diagnostics/monitoring
Experimental Beamline LION at LEX/CALA
Monte Carlo Simulations (Dr. Dedes et al) In-vivo Verification through prompt gammas (PD Dr. Thirolf et al)
e-
g
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29
Dosimetry and beam monitoring
Main ion diagnostics in LEX: RadEye1 sensor
S. Reinhardt et al, JINST 6 (2011), S. Reinhardt et al, JINST 8 (2013)
Simultaneous detection of protons and 6+C-ions
Linear response to intense pulses
Saturation limit: 107 p/cm2 (@20 MeV) 50 x 100 mm2 sensitive area
Ongoing investigations on new solutions for higher fluxes/energies @CALA
30
Research lines
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Thank you
www.med.physik.uni-muenchen.de