the magic cube and the pixel ionization chamber: detectors for monitor and dosimetry of radiotherapy...
TRANSCRIPT
The Magic Cube and the Pixel Ionization
Chamber: detectors for monitor and
dosimetry of radiotherapy beams S. Amerio1, A. Boriano2 , F. Bourhaleb2,3 , R. Cirio2 , M. Donetti2,3,
E. Garelli2,4 , S. Giordanengo2#, E. Madon5 , F. Marchetto2 , U. Nastasi1 ,
C. Peroni2 , C. J. Sanz Freire2, A. Sardo5, E. Trevisiol5
1 Ospedale S. Giovanni A. S., Torino 2 Universiy and INFN, Torino3 Fondazione TERA, Novara
4 A.S.P. , Torino5 O.I.R.M. S. Anna, Torino Partially financed by IBA, Ion Beam Application, Louvain-la-
Neuve(Belgium)
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Highly conformal radiotherapy
GOAL
use radiation to kill cancer cells and spare healthy
tissue
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Hadron radiotherapy
Uses (mainly, nowadays) protons and carbon ionsGood for specific diseases1% of totalIt is becoming hospital based
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Photon radiotherapy (IMRT)
Intensity Modulated RadioTherapyState-of-the-artUses photons obtained with e- linear acceleratorsSpecific diseasesHas become very popularStill not very widespread due to verification problems
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The Magic Cube
A tool for verification of hadrontherapy treatment plan in reasonably short time (1-2 minutes)Sampling calorimeter with strip ionization chambersVLSI electronics readout
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In the beginning
At GSI Darmstadt
Strip ionization chambers
(6 for X-view
6 for Y-view)
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One of the chambers
64 strips4 mm wide24 cm long24x24 cm2 active area
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The VLSI chip
64 channelsAMS 0.8 m CMOS16 bit outputRecycling integrator
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VLSI block diagram
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A simple beam (X-view)
At CPO Orsay
beamdirection
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A Carbon Bragg peak
270 MeV/u 12C at GSI Darmstadt
beamdirection
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The Cube on tour
GSI Darmstadt
C synchrotron
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PSI Villigen
p synchrotron
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CPO Orsay
p cyclotron
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Commercial version sold to
Loma Linda University Medical Center
and
Ion Beam Application
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The Pixel Chamber
The aim: let’s go real 3D
1024 pixels7.5 mm wide24x24 cm2 active area
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Precision in the reconstruction of the center of gravity of a C
beam
Precision in the reconstruction of the center of gravity of a C
beam
<0.13 mm <0.08 mm
Vertical axis Horizontal axis
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Dedicated to photons
No inhomogeneitiesCareful shielding
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A calibration with 24x24 cm2
6 MV photon beam
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Dynamic MultiLeaf Collimator
Treatment verification
Breast cancer treatment Breast cancer treatment
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Treatment plan (=simulation) vs. measurement with pixel
chamber
Treatment plan (=simulation) vs. measurement with pixel
chamber1.01
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c amera pixe l
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piano xy E R G O
Pixel chamber
Treatment plan
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1.10
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150.0-150.0 -100.0 -50.0 0.0 50.0 100.0
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1.02
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Pixel chamber Treatment plan
ii
j j
A closer look…
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Nowadays things are moving
Intensity Modulated RadioTherapy (IMRT)
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Time: 0 secTime: 1 secTime: 2 secTime: 3 secTime: 4 secTime: 5 secTime: 6 secTime: 7 secTime: 8 secTime: 9 secTime: 10 secTime: 11 secTime: 12 secTime: 13 secTime: 14 sec
Deposited dose as function of time
Measuring DURING treatment
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Research Industry
The VLSI chip produced and used by IBA and Wellhofer/Scanditronix
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Research Industry
Pixel and strip chambers during a test at IBA
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Research Industry
Dose deposition with the new IBA raster scan as measured with the pixel chamber
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Conclusions
HEP techniques may be extremely interesting for medical applicationsMagic Cube, TERA VLSI and Pixel Chamber have fulfilled the design requirementsIndustry has taken advantage of these University/INFN driven projects
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The VLSI and radiation damage
30 kV photons
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The VLSI and radiation damage
Legnaro fast neutrons
@5x1012still OK
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Fast data acquisition
Real time OS1024 channels readout in 100 s
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Slow data acquisition
National Instruments I/O boardLabview on PC1024 channels readout in 500 s
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Chamber layout
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Target contourEnergy deposit
Voxel
Using a raster scan (GSI test)
Using a raster scan (GSI test)
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Caratterstiche del fascio
Irraggiamento di tipo raster-scan
C+6, dimensioni del fascio = 8.8 mm (FWHM)
Obiettivi
Risoluzione spaziale
Omogeneità della risposta
Acquisizione dati sincronizzata con il raster-scan
Test sistema monitor di fascio
Test al GSI (Darmstadt) ioni carbonio
Test al GSI (Darmstadt) ioni carbonio
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0.07
-0.05
-0.03
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D ifferenza tre E rgo e P ixe l
Arc #7
0.0093
mean
0.00 -0.00 -0.01 -0.02 -0.01 -0.02
0.00 0.00 -0.00 -0.01 0.00 0.01 -0.03
0.00 -0.01 0.00 -0.01 0.01 -0.02 -0.02
-0.00 0.00 0.01 -0.01 -0.01 0.01 -0.02
-0.01 0.00 0.00 -0.00 -0.01 -0.01 -0.00
0.02 -0.01 -0.01 -0.00 -0.01 0.00 -0.02
-0.00 -0.00 -0.00 -0.00 -0.00 0.07 -0.02
0.00 0.02 0.00 -0.00 0.01 -0.01 -0.02
-0.01 0.00 0.00 -0.00 -0.01 0.01 -0.02
0.01 0.00 0.00 0.02 -0.01 -0.00 -0.02
0.00 0.00 -0.00 0.00 -0.01 -0.00 -0.02
-0.00 0.00 -0.00 -0.01 -0.01 -0.01 -0.03
0.01 -0.00 0.00 -0.01 -0.00 -0.01 0.09
-0.01
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