from the ionization chamber to the on-line microstrip devices · from the ionization chamber to the...

From the ionization chamber to the on-line microstrip devices:

the status of the art of detectors in proton therapy under the experience gained at the CATANA facility

G.A.P. Cirrone, Ph.D.Laboratori Nazionali del Sud – INFN Catania (I)

10th Topical Seminar on Innovative Particle and Radiation Detectors (IPRD06) 1 - 5 October 2006 Siena, Italy

On behalf of

G. Cuttone, F. Di Rosa, P. Lojacono, V. Mongelli, S. Pittera, L. Raffaele, G. Russo, M.G. Sabini, L.M. Valastro

R. Cirio, F . Marchetto C. De Angelis, P. Fattibene, S. Onori

Laboratori Nazionali del Sud – INFN, Catania (I)

INFN Sezione di Torino, Torino (I)

Istituto Superiore di Sanità, Roma (I)

TALK OUTLINE

1. CATANA: the Italian proton therapy facility

4. What future for clinical proton beam detectors?

2. Absolute and relative dosimetry in proton therapy:starting point for the dosimetric commissioning

3. Ten years of detector characterisation

THE ITALIAN PROTON THERAPY CENTERTHE ITALIAN PROTON THERAPY CENTERTHE ITALIAN PROTON THERAPY CENTER

City of Catania

Nuclear physics Laboratory of INFN (National Institute for Nuclear Physics)

Superconductor cyclotron developed for research and now used also for the clynic

[email protected]

CyclotronLocation

Treatment Room

Location

Laboratori Nazionali del Sud –INFN Catania, Italy

ProtonBeam

THE TREATMENT BEAM LINETHE TREATMENT BEAM LINETHE TREATMENT BEAM LINE

First patient: March 12, 2001

Work started in 1996

Patient Distribution by Origin RegionPatient Distribution by Origin RegionPatient Distribution by Origin Region

42

9

5

13

11

6

2

7

2

1

1

Total number of patients :

110

Patient Distribution by PathologiesPatient Distribution by PathologiesPatient Distribution by Pathologies

Uveal Melanoma 99 patients (89.89 %)

Conjunctival MALT-NHL 1 patient (1.01 %)

Conjunctival Melanoma 5 patients (4.04 %)

Conjunctivalrhabdomyosarcoma

1 patient (1.01 %)

Eyelid Carcinomaand metastases

2 patient (2.02 %)

Conjunctival Papilloma 2 patient (2.02 %)

SURVAIVAL RESULTSPatientsTotal Number

(April 2006)102

Dead patients 4

Metastatis 3

Other 1

Eye retention rate 92,68 %

TOTAL SURVIVAL 95 %

LOCAL CONTROL 97 %

TALK OUTLINE





DETECTOR DEVELOPMENT AND CHARACTERIZATIONDETECTOR DEVELOPMENT AND CHARACTERIZATIONDETECTOR DEVELOPMENT AND CHARACTERIZATION

STILL A NEED IN RADIATION THERAPY AND, IN PARTICULAR, IN A YET PIONEERING TECHNIQUE LIKE PROTON THERAPY

CONTINOUS R&D WORK

ABSOLUTE AND RELATIVE DOSIMETRY

(Dosimetric commissioning)

Absolute Dosimetry: Energy Released in Water (Gray)

Relative Dosimetry: Three dimensional dose distributionmeasurements

⇓Considering the high gradient dose, conformation and small fields often used the detectors have to be kindlycharacterized in terms of spatial resolution, energy or

fluence dependence to be use in hadrontherapy.

Dosimetric commissioning: absolute & relative dosimetryDosimetricDosimetric commissioningcommissioning: : absoluteabsolute & relative & relative dosimetrydosimetry

Relative and Relative and AbsoluteAbsolute DosimetryDosimetry are are fundamentalfundamental forfor::

CustomizingCustomizing of TPS of TPS Monitor Monitor UnitUnit CalculationCalculation

QualityQuality ControlControl

Activity started in 1996 with the first test on 62 MeV protons

Gas detector (ionisation chambers)

Film detectors

Solid state detectors

Farmer

Exradin

Pin Point

Markus

Advanced Markus

Radiographic films

GAF Chromic films

(MD52, EBT, …

•Plastic scintillators

•Diamond detector

•TLD

•MOSfet

•Silicon diode

•Silicon microstrip

10 year of work

43 papers in review journals

61 conference proceeding

DETECTOR OVERVIEWDETECTOR OVERVIEWDETECTOR OVERVIEW

FULL ENERGY BEAM

0

20

40

60

80

100

-20 -15 -10 -5 0 5 10 15 20

Distance from axis [ mm ]

Sig

nal [

% ]

Radiochromic Film

62 MeV experimental proton beam62 62 MeVMeV experimentalexperimental protonproton beambeam

0102030405060708090

100

0 5 10 15 20 25 30 35Depth in water (mm)

Dos

e

Markus Chamber

62 MeV experimental proton beam62 62 MeVMeV experimentalexperimental protonproton beambeam

0

10

20

30

40

50

60

70

80

90

100

110

0 5 10 15 20 25 30 35

Depth in Eye Tissue (mm)

CCO Diode BPW34l

TALK OUTLINE





WHAT WE NEED FROM A DOSEMETER?WHAT WE NEED FROM A DOSEMETER?WHAT WE NEED FROM A DOSEMETER?

• Tissue equivalence (<Z> = 6, <Z/A> = 0.5 )

• Linearity vs absorbed dose

• Independence from dose rate

• Independence from energy

• Radiation hardness

• Spatial resolution (< 1 mm)

• Small size: no perturbation of the proton fluency (Bragg-Gray theory)

MEASUREMENT CONFIGURATIONMEASUREMENT CONFIGURATIONMEASUREMENT CONFIGURATION

0102030405060708090

100

0 5 10 15 20 25 30 35Depth in water (mm)

Dos

e

Markus Chamber

0

10

20

30

40

50

60

70

80

90

100

110

0 5 10 15 20 25 30 35

Depth in Eye Tissue (mm)

CCO Diode BPW34l

Detector placed at isocenter on a special table mounted on the treatment chair

ABSOLUTE DOSIMETRYABSOLUTE DOSIMETRYABSOLUTE DOSIMETRY

ICRU 59 AND TRS 398 IAEA ICRU 59 AND TRS 398 IAEA RECOMMENDATIONRECOMMENDATION

⇓⇓

““ FOR MEASUREMENTS OF DEPTHFOR MEASUREMENTS OF DEPTH--DOSE DOSE DISTRIBUTION IN PROTON BEAMSDISTRIBUTION IN PROTON BEAMS

THE USE OF PLANETHE USE OF PLANE--PARALLEL CHAMBERS IS PARALLEL CHAMBERS IS RECOMMENDEDRECOMMENDED””

⇓⇓

ParallelParallel plateplate MARKUS PTWMARKUS PTW isis the golden the golden standard standard forfor depthdepth dose dose measurementsmeasurements

Dosimetric commissioning: absolute & relative dosimetryDosimetricDosimetric commissioningcommissioning: : absoluteabsolute & relative & relative dosimetrydosimetry

ADVANCED MARKUS CHAMBERADVANCED MARKUS CHAMBER

Response: 670 pC/GyDirectional dependence: smaller than 0.1% for tilting of the chamber by up to 10ºElectrode Acrylic (PMMA), graphite coated 5 mm ØLeakage current ± 4 fA

VP = 400 V V×cm-1 = 4000 kS = 1.00 (1÷100 Gy/min.).

Pressure equilibrium ≤ 10 sec

Temperature equilibrium = 2-3 min./K

Proton beam

Ionisation, free air monitor chamber calibrated against the Markus:

Sensibility: 5 pC

Reprucibility: 0.5 %

DETECTOR FOR RELATIVE DOSIMETRYDETECTOR FOR RELATIVE DOSIMETRYDETECTOR FOR RELATIVE DOSIMETRY

1 2 3

5 64

1) Film Kodak: XV and EDR2 2) TLD 3) Radiochromic Film

4) Scanditronix Diode 5) PTW Natural Diamond 6) Mosfet

• In collaboration with ISS (S. Onori..) and DFC Florence (M. Bucciolini…)

RELATIVE DOSIMETRY: FILM DETECTORSRELATIVE DOSIMETRY: FILM DETECTORSRELATIVE DOSIMETRY: FILM DETECTORS

GAFCHROMICGAFCHROMIC®® EBT ConfigurationEBT Configuration

CLEAR POLYESTER - 97 microns

CLEAR POLYESTER - 97 microns

ACTIVE LAYER - 17 microns

ACTIVE LAYER - 17 micronsSURFACE LAYER - 6 microns

1) Transmission densitometer2) Colour scanner

SPECTRA OF NEW AND OLD RADIOCHROMIC FILMSSPECTRA OF NEW AND OLD RADIOCHROMIC FILMSSPECTRA OF NEW AND OLD RADIOCHROMIC FILMS

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

450 500 550 600 650 700 750

Wavelength, nm

Abs

orba

nce

GAFCHROMIC EBT

GAFCHROMIC HS

EPSON flatbedcolor scanner

OLD: HS ISPOLD: HS ISPNEW: EBT ISPNEW: EBT ISP

RESPONSE ENHANCED RESPONSE ENHANCED BY MEASUREMENT BY MEASUREMENT

WITH RED LIGHTWITH RED LIGHT

EBT

ENERGY INDEPENDENCE HS GAF ENERGY INDEPENDENCE HS GAF ENERGY INDEPENDENCE HS GAF

0,0

0,5

1,0

1,5

2,0

2,5

3,0

0 5 10 15 20 25 30 35

DOSE (Gy)

N.O

.D

Full energy (62MeV), Rres.=28.9 mm

Modulated Beam (Rres.= 12 mm)

y = 0.0801x R2 = 0.9966

y = 0.0791x R2 = 0.9976

0,0

0,5

1,0

1,5

2,0

2,5

3,0

0 5 10 15 20 25 30 35

DOSE (Gy)

N.O

.D

Full energy (62MeV), Rres.=28.9 mm

Modulated Beam (Rres.= 12 mm)

y = 0.0801x R2 = 0.9966

y = 0.0791x R2 = 0.9976

EBT GAFEBT GAF

Calibrazione Protoni 62 MeV

00,10,20,30,40,50,60,70,80,9

0 200 400 600 800 1000

Dose (cGy)

N.O

.DCalibrazione Protoni 62 MeV

00,10,20,30,40,50,60,70,80,9

0 200 400 600 800 1000

Dose (cGy)

N.O

.D

EPSON flatbedcolor scannerRED CHANNELRED CHANNEL

DOSE CALIBRATION DOSE CALIBRATION DOSE CALIBRATION

RELATIVE DOSIMETRY: plastic scintilatorsRELATIVE DOSIMETRY: plastic RELATIVE DOSIMETRY: plastic scintilatorsscintilators

Plastic scintillatorBC 400

Alumina (Al2O3) Caesium Iodide (CsI)

• Alumina: poor in light efficiency;

• Caesium Iodide: excellent light efficiency, but scarce homogeneity;

• BC 400: good brightness and homogeneity;

BC 400 has been chosen for our experimental purposes.

DETECTOR ARRANGEMENTDETECTOR ARRANGEMENTDETECTOR ARRANGEMENT

Mirror forming45° with the beam direction.

Camera forming90° with the beam axis, framing the image reflected by the mirror.

Scintillating screen lodged on a support,

perpendicularly to the beam axis.

LabView EnvironmentLabViewLabView EnvironmentEnvironment

CHARACTERIZATIONCHARACTERIZATIONCHARACTERIZATION

LINEARITY SIGNAL TO NOISE RATIO

0 2 4 6 80

50

100

150

200

250

300

Experimental data linear FIT

Equazion: y = A*x + B

A = 30.03107 ± 0.63571B = 10.58847 ± 2.77585

R2 = 0.99421

SNR

sqrt (frames)

SNR vs sqrt(frames)

Castleman says: SNR (N)= N^0.5*SNR(1)Linearity in the treatment range(10 ÷ 20 Gy/min) Experimental results

are in good agreementwith theoretical considerations

RELATIVE DOSIMETRY: diamond detectors(synthetic and natural)RELATIVE DOSIMETRY: RELATIVE DOSIMETRY: diamonddiamond detectorsdetectors((syntheticsynthetic and and naturalnatural))

PROPRIETA’ DIAMANTE SILICIO Gap [eV] 5.5 1.12

Campo di rottura [V/cm] 107 3·105

Hole mobility [cm2/Vs] 1200 450 Velocità di saturazione [cm/s] 2.2·107 0.8·107

Mobilità elettronica [cm2/Vs] 1800 1450 Vita media dei portatori minoritari [s] 10-9 2.5·10-3

Costante dielettrica εr 5.7 11.9

Numero atomico effettivo Zeff 6 14 Energia per creare un coppia elettrone-lacuna [eV] 13 3.6

Energia di Wigner [eV] 43 13-20

Low dark current

Fast responce

time

Tissueequivalence

Radiationhardness

ON-LINE CONFIGURATION (CVD diamond)ONON--LINE CONFIGURATION (CVD LINE CONFIGURATION (CVD diamonddiamond))

De Beer’s diamond sample with two bonding solution

ON LINE CONFIGURATION: CVD vs NATURALON LINE CONFIGURATION: CVD ON LINE CONFIGURATION: CVD vsvs NATURALNATURAL

-200.0

-150.0

-100.0

-50.0

0.0

50.0

100.0

150.0

200.0

-500 -400 -300 -200 -100 0 100 200 300 400 500

Bias [V]

Cur

rent

[nA

]

CVD

-0.5

0.0

0.5

1.0

1.5

2.0

2.5

3.0

-150 -100 -50 0 50 100 1

Bias [V]

Cur

rent

[nA

]

Diamante Naturale

RESPONCE vs ABSORBED DOSE (CVD diamond)RESPONCE RESPONCE vsvs ABSORBED DOSE (CVD ABSORBED DOSE (CVD diamonddiamond))

0

5

10

15

20

25

30

0 5 10 15 20 25Absorbed Dose [Gy]

Cha

rge(µC

)

Protons 62 MeVPhotons 6 MVElectrons 15 MeV

PTW NATURAL DIAMONDPTW NATURAL DIAMONDPTW NATURAL DIAMOND

TWO PTW DIFFERENT DETECTORS HAVE BEEN STUDIEDTWO PTW DIFFERENT DETECTORS HAVE BEEN STUDIED

20 mm20 mm

7.3mm7.3mm

•Sensitive area: 4.3/4.5 mm2

•Sensitive volume: 1.3/1.4 mm3

•Thickness of sensitive volume: 0.30/0.31 mm

•Operating bias: 100 V

In photon and electron beams the relative differences have been studied and already published (see De Angelis C et al. Med. Phys. 2002; 29(2): 248-254.)

In proton beams the measured repeatibility is 0.1%


PTW Diamond Linearity (protons, photons, electrons)

0

200

400

600

800

1000

1200

1400

0 200 400 600 800 1000 1200 1400 1600Dose (Gy)

Cha

rge[

nC

ProtoniFotoni 6MVElettroni, 25 MeV


0

0,5

1

1,5

2

2,5

3

3,5

4

4,5

5

0,0 5,0 10,0 15,0 20,0 25,0 30,0 35,0 40,0

Depth in water (mm)

Ioni

zatio

n [a

.

Markus chamber

PTW Diamond

Bragg Peak Measurements

RELATIVE DOSIMETRY: surface TLD detectorRELATIVE DOSIMETRY: RELATIVE DOSIMETRY: surfacesurface TLD detectorTLD detector

PHANTOM & DETECTORS• 0.27mm mean thickness,

• 7 detectors in each set,

• 10 detector sets.

6 setsirradiated!

in dose range4.5 – 18Gy

READOUTS

READOUTS

(visible photo and heated)

NOISE SUBTRACTION

HOT PIXELS & ZERO BACKGROUND SETTINGS

THICKNESS CORRECTIONING FACTORS (RELATIVE TO

CALIBRATION DETECTORS)

CALIBRATION

(Co60 SOURCE UP TO 20Gy)

RELATIVE DOSIMETRY: silicon diode and MOSFET RELATIVE DOSIMETRY: RELATIVE DOSIMETRY: siliconsilicon diodediode and MOSFET and MOSFET

MOSFET e MicroMOSFET

SILICON DIODE SILICON DIODE SILICON DIODE SCANDITRONIX Silicon Diode

Two different p-type Scanditronix detectors having the followingfeatures have been studied:

•Thickness: 0.06 mm•Sensitive Area: 0.28 mm2

•Sensitive Volume: 0.017 mm3

•Materials tickness in front of the detectors: 0.42/0.54 mm•Center Distance from Detector Surface: 0.546/0.684

Both samples were preirradiated in proton beams, beforeshipping.

Measured repeatibility (10 meas. at 4 Gy): 0.2%Sensitivity change after 300 Gy irradiation 0.7%

SILICON DIODE SILICON DIODE SILICON DIODE

Silicon Diode Linearity with 62 MeV Proton Beam

0

2

4

6

8

10

12

14

16

18

0 200 400 600 800 1000 1200 1400 1600 1800

Dose (cGy)

Car

ica

(nC

0

20

40

60

80

100

120

0 10 20 30 40

Depth in w ater (mm)

Rela

tive

resp

onse

(%)

diodo LNS

Markus

0

100

200

300

400

500

600

0 10 20 30 40Depth in water (mm)

Rel

ativ

e re

spon

se (%

) Markus

Diodo ISS

The two detectors givedifferent positions of the peak.

An overestimation of the peak has beennoted (up to 6%).

SILICON DIODE: full energy Bragg peak SILICON DIODE: full SILICON DIODE: full energyenergy BraggBragg peak peak

SILICON DIODE: Spread Out Bragg PeakSILICON DIODE: SILICON DIODE: SpreadSpread Out Out BraggBragg PeakPeak

0,0

0,2

0,4

0,6

0,8

1,0

1,2

1,4

1,6

0,0 5,0 10,0 15,0 20,0 25,0 30,0 35,0

Depth in water [mm]

Ioni

zatio

n [a

.u.]

Diode

Markus

MOSFET (Metal Oxide Semiconductor Field Effect Transistor)MOSFET (Metal MOSFET (Metal OxideOxide Semiconductor Semiconductor FieldField EffectEffect Transistor)Transistor)

Why a MOSFET:stable, reproduciblelinear vs absorbed dosedose-rate independenceon-line readingtemperature indipendenceno fluence perturbationsmall size

It is OK for in-vivo dosimetry

INSTRMENTATIONINSTRMENTATIONINSTRMENTATION

•Autosense™ reader• “Dual Sensitivity Bias Supply” (up to 5 MOSFETs)

2 sensibility modality: High e Standard• MOSFET TN-502RD

AutoSense™ PCSoftware V. 1.1

Linearità MOSFETs vs MicroMOSFETs

y = 2,0309x + 12,708R2 = 0,9999

y = 2,1485x + 7,9625R2 = 1

y = 0,743x + 3,8749R2 = 0,9998

0

500

1000

1500

2000

2500

3000

3500

0 200 400 600 800 1000 1200 1400 1600

Dose assorbita in acqua [cGy]

Lettu

ra M

OSF

ET

[m

V]

MOSFET 3301 - High Sensitivity

MicroMOSFET 0132 - High Sensitivity

MOSFET 3051 - Standard Sensitivity

RESPONCE vs ABSORBED DOSERESPONCE RESPONCE vsvs ABSORBED DOSEABSORBED DOSE

A STUDY OF THE OUTPUT FACTORSA STUDY OF THE OUTPUT FACTORSA STUDY OF THE OUTPUT FACTORS

Output Factor All dosimeters

80

85

90

95

100

105

110

0 5 10 15 20 25 30

Collimator diameter [mm]

Out

put F

acto

r

MOSFETTLDDiode ScanditronixGAFchromic FilmMicroMOSFET

TALK OUTLINE





WHY proton Computed Tomography (pCT) ? WHY WHY protonproton ComputedComputed TomographyTomography ((pCTpCT) ? ) ?

TOMOGRAPHIC IMAGE RECONSTRUCTION USING HIGH ENERGY PROTON BEAMS

MAIN IUSSUES IN PROTON THERAPY QUALITY

Patient positioning

Actually TPS are based on the xCTimages as input and this bring a sensible

amount of imprecisionDose planning

EXPERIMENTAL SOLUTION FOR SINGLE TRAKINGEXPERIMENTAL SOLUTION FOR SINGLE TRAKINGEXPERIMENTAL SOLUTION FOR SINGLE TRAKING

All the studies and prototypes developed in the last years are based on the

principle of follow each single proton traversing the medium to investigate

( ) ( )∫∫ =in

out

E

ELe ES

dEKrdrηThe “single tracking” approach should permit toimprove the spatial risolution up to 1 mm or less

THE PRIMA (PRoton IMAging DETECTORTHE PRIMA (THE PRIMA (PRotonPRoton IMAgingIMAging DETECTORDETECTOR

CALORIMETRO

DATA OUT USB

USB

TRIGGER

DAQ CALORIMETRO

MODULO STRIP

Single tracking

Acquisition rate up to 1 MHz

Detector: 2 orthogonal microstrip; 200 um picth x 256 strips; about 5x5 cm of active area

Trigger from the calorimeter

THE ROLE OF MONTE CARLOTHE ROLE OF MONTE CARLOTHE ROLE OF MONTE CARLO

•Study of the proton paths inside objects

•Study of the algorithms for image reconstructions

GEANT4 tomographic image

3.3 l/cm

200 MeV, 179 projections at 1°, 5M Histories, 20 cm circular phantom

THE ROLE OF MONTE CARLOTHE ROLE OF MONTE CARLOTHE ROLE OF MONTE CARLO

Experiment: 250 MeVproton beams (LLUMC)

Our Geant4 application and results on detector

study

THE MOPI ONLINE MONITOR:TEST SET-UPTHE MOPI ONLINE MONITOR:TEST SETTHE MOPI ONLINE MONITOR:TEST SET--UPUP

p beam

x-y ion. strip chambersMOPI

ionization chambers

THE MOPI ONLINE MONITORTHE MOPI ONLINE MONITORTHE MOPI ONLINE MONITOR

Three different currents of the beam steering magnetThree different currents of the beam steering magnet

a .u .

Thank you

for your attention

from the ionization chamber to the on-line microstrip devices · from the ionization chamber to the...

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