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)

Siena, October 22 2002 R.Cirio 2/28

Highly conformal radiotherapy

GOAL

use radiation to kill cancer cells and spare healthy

tissue

Siena, October 22 2002 R.Cirio 3/28

Hadron radiotherapy

Uses (mainly, nowadays) protons and carbon ionsGood for specific diseases1% of totalIt is becoming hospital based

Siena, October 22 2002 R.Cirio 4/28

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

Siena, October 22 2002 R.Cirio 5/28

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

Siena, October 22 2002 R.Cirio 6/28

In the beginning

At GSI Darmstadt

Strip ionization chambers

(6 for X-view

6 for Y-view)

Siena, October 22 2002 R.Cirio 7/28

One of the chambers

64 strips4 mm wide24 cm long24x24 cm2 active area

Siena, October 22 2002 R.Cirio 8/28

The VLSI chip

64 channelsAMS 0.8 m CMOS16 bit outputRecycling integrator

Siena, October 22 2002 R.Cirio 9/28

VLSI block diagram

Siena, October 22 2002 R.Cirio 10/28

A simple beam (X-view)

At CPO Orsay

beamdirection

Siena, October 22 2002 R.Cirio 11/28

A Carbon Bragg peak

270 MeV/u 12C at GSI Darmstadt

beamdirection

Siena, October 22 2002 R.Cirio 12/28

The Cube on tour

GSI Darmstadt

C synchrotron

Siena, October 22 2002 R.Cirio 13/28

PSI Villigen

p synchrotron

Siena, October 22 2002 R.Cirio 14/28

CPO Orsay

p cyclotron

Siena, October 22 2002 R.Cirio 15/28

Commercial version sold to

Loma Linda University Medical Center

and

Ion Beam Application

Siena, October 22 2002 R.Cirio 16/28

The Pixel Chamber

The aim: let’s go real 3D

1024 pixels7.5 mm wide24x24 cm2 active area

Siena, October 22 2002 R.Cirio 17/28

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

Siena, October 22 2002 R.Cirio 18/28

Dedicated to photons

No inhomogeneitiesCareful shielding

Siena, October 22 2002 R.Cirio 19/28

A calibration with 24x24 cm2

6 MV photon beam

Siena, October 22 2002 R.Cirio 20/28

Dynamic MultiLeaf Collimator

Treatment verification

Breast cancer treatment Breast cancer treatment

Siena, October 22 2002 R.Cirio 21/28

Treatment plan (=simulation) vs. measurement with pixel

chamber

Treatment plan (=simulation) vs. measurement with pixel

chamber1.01

0.00

0.50

32

0

5

10

15

20

25

320 5 10 15 20 25 30

c amera pixe l

1.00

0.00

0.50

32

0

5

10

15

20

25

320 5 10 15 20 25 30

piano xy E R G O

Pixel chamber

Treatment plan

Siena, October 22 2002 R.Cirio 22/28

1.10

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

0.80

0.90

1.00

150.0-150.0 -100.0 -50.0 0.0 50.0 100.0

1.00

0.00

0.50

28

0

5

10

15

20

25

280 5 10 15 20 25

1.02

0.00

0.51

28

0

5

10

15

20

25

280 5 10 15 20 25

Pixel chamber Treatment plan

ii

j j

A closer look…

Siena, October 22 2002 R.Cirio 23/28

Nowadays things are moving

Intensity Modulated RadioTherapy (IMRT)

Siena, October 22 2002 R.Cirio 24/28

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

Siena, October 22 2002 R.Cirio 25/28

Research Industry

The VLSI chip produced and used by IBA and Wellhofer/Scanditronix

Siena, October 22 2002 R.Cirio 26/28

Research Industry

Pixel and strip chambers during a test at IBA

Siena, October 22 2002 R.Cirio 27/28

Research Industry

Dose deposition with the new IBA raster scan as measured with the pixel chamber

Siena, October 22 2002 R.Cirio 28/28

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

Siena, October 22 2002 R.Cirio 29/28

The VLSI and radiation damage

30 kV photons

Siena, October 22 2002 R.Cirio 30/28

The VLSI and radiation damage

Legnaro fast neutrons

@5x1012still OK

Siena, October 22 2002 R.Cirio 31/28

Fast data acquisition

Real time OS1024 channels readout in 100 s

Siena, October 22 2002 R.Cirio 32/28

Slow data acquisition

National Instruments I/O boardLabview on PC1024 channels readout in 500 s

Siena, October 22 2002 R.Cirio 33/28

Chamber layout

Siena, October 22 2002 R.Cirio 34/28

Target contourEnergy deposit

Voxel

Using a raster scan (GSI test)

Using a raster scan (GSI test)

Siena, October 22 2002 R.Cirio 35/28

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

Siena, October 22 2002 R.Cirio 36/28

0.07

-0.05

-0.03

-0.01

0.02

0.03

28

0

5

10

15

20

25

280 5 10 15 20 25

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

9

12

13x7