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)
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From the ionization chamber to the on-line microstrip devices · From the ionization chamber to the on-line microstrip devices: the status of the art of detectors in proton therapy
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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
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
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
1. CATANA: the Italian proton therapy facility
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
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
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
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%