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INFN-LNS. DOSIMETRY COMMISSIONING OF THE LNS-INFN. PROTON THERAPY FACILITY THE DOSIMETRIC CHARACTERISTICS OF NARROW PROTON BEAMS USED IN EYE THERAPY HAVE BEEN DEFINED BY USING DIFFERENT RADIATION DETECTORS IONIZATION CHAMBERS ( parallel-plate, mini thimble chambers ) SILICON DIODES - PowerPoint PPT Presentation
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DOSIMETRY COMMISSIONING OF THE LNS-INFN
PROTON THERAPY FACILITY
THE DOSIMETRIC CHARACTERISTICS OF NARROW PROTON BEAMS USED IN EYE
THERAPY HAVE BEEN DEFINED BY USING DIFFERENT RADIATION DETECTORS
IONIZATION CHAMBERS (parallel-plate,minithimble chambers)
SILICON DIODES
RADIOCHROMIC AND RADIOGHRAPHIC FILMS
THERMOLUMINESCENCE DETECTORS
1) CENTRAL AXIS DEPTH-DOSE DISTRIBUTIONS
2) LATERAL (TRANSVERSE) PROFILES
3) OUTPUT FACTORS (FSDF)
TO PROVIDE INPUT TO THE TPS AND FOR M.U. CALCULATIONS.
QUALITY CONTROL PROCEDURES
DOSIMETRIC COMMISSIONING OF 60 MeV PROTON BEAMS
PRODUCED AT LNS FOR EYE THERAPY
SHAPED WITH 5 - 30 mm CIRCULAR BRASS COLLIMATORS.
INFN-LNS
PROTON DEPTH-DOSE DISTRIBUTIONS
THE PTW MARKUS PLANE-PARALLEL ION CHAMBER WAS USED IN THE
COMMISSIONING AS THE REFERENCE DETECTOR FOR DEPTH-DOSE
MEASUREMENT IN PROTON BEAMS (ICRU 59, IAEA 398)
THE DESIGN OF THE MARKUS CHAMBER
1) Active volume=0.05 cm3, 2) Electrode separation=2 mm, 3) Collector diameter=5.4
mm
4) tentrance window=2.3 mg/cm2 5) Exact Location of peff.
PROVIDES DEPTH-DOSE DISTRIBUTIONS
WITH HIGH SPATIAL RESOLUTION AND HIGH PRECISION
) PMMA CUP IS PROVIDED TO SEAL THE CHAMBER FOR USE IN WATER
) A SPACER IS PROVIDED FOR USE IN A SOLID PHANTOM, WHICH ALSO
SERVES AS A HOLDER FOR A RADIOACTIVE SOURCE FOR STABILITY CHECKS.
INFN-LNS
PTW MARKUS PLANE-PARALLER ION CHAMBER IN WATER PHANTOM
INFN-LNS
INFN-LNS
^ taken from BJR Supplement 25 (1996)
CENTRE
MAXIMUM RANGE
(mm)
EQUIVALENT ENERGY
(MeV)
PEAK PLATEAU
RATIO
F.W.H.M.(mm)
Distal-dose falloff d90%-10%
(mm)
CATANA
30.60
60.2
4.68
3.29
0.81
CCO^
31.0
60.4
4.85
3.65
0.80
PSI^
30.0
60.0
4.47
1.10
0
10
20
30
40
50
60
70
80
90
100
110
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35
Depth in water (mm)
Re
lati
ve
do
se
(%
)
PTW- MARKUS ION CHAMBER
PLATEAU REGION
BRAGG PEAK
INFN - LNS
THE NEW SCANDITRONIX Si-DIODE IN PROTON BEAMS (Proton Field waterproof Detector-narrow beam no.DZA192 1001)
INFN-LNS
THE NEW SCANDITRONIX Si-DIODE IN PROTON BEAMS (Proton Field waterproof Detector-narrow beam no.DZA192 1001)
CYLINDRICAL MINIDIODE SPECIFICATIONS
Detector Material: Hi-pSi, high doped p-type silicon (preirradiated for use in proton beams).
Detector diameter: 0.6 mm (t = 60 m)
DETECTOR
PEAKDEPTH (mm)
PEAK-PLATEAU
RATIO
F.W.H.M(mm)
Distal-dose
falloff (1)
d90%-10%
(mm)
Distal-dose
falloff (2)
d80%-20%
(mm
PRACTICAL RANGE
(d10%, ICRU 59)
MARKUS PTW
30.14
4.68
3.19
0.71
0.50
31.15
DIODE
SCANDITRONIX
30.07
4.89
3.07
0.80
0.60
31.06
0
10
20
30
40
50
60
70
80
90
100
0 5 10 15 20 25 30 35
Depth in water (mm)
Re
lati
ve
Do
se
(%
)
Markus LNS
Scanditronix LNS Diode
INFN-LNS
MODULATED PROTON DEPTH DOSES FOR EYE THERAPY
0
10
20
30
40
50
60
70
80
90
100
110
0 5 10 15 20 25 30 35
Depth in water (mm)
Rel
ativ
e D
ose
(%
)
20 mm SOBPRS 1.8 mm
11 mm SOBPRS 10 mm
14.5 mm SOBPRS 14 mm
MODULATOR
RANGE SHIFTER
MODULATION (SOBP)
(mm eye tissue)
DISTAL-DOSE FALLOFF (1)
d90%-10%
(mm eye-tissue)
DISTAL-DOSE FALLOFF (2)
d80%-20%
(mm eye tissue)
MAXIMUM DOSE
IN SOBP %
BEAM RANGE(90% DISTAL)
(mm eye-tissue)
MOD: 000/00RS: 14 mm
14.5
0.91
0.65
101.6
14.38
MOD: 010/02RS: 10 mm
10.5
0.90
0.60
104
18.27
MOD: 009/02RS: 1.8 mm
20.30
0.80
0.55
103.9
27.04
CCO 17 0.90 0.75 < 102
INFN-LNS
INFN-LNS
15 MM SOBP vs RANGE SHIFTER
MODULATED PROTON DEPTH DOSES FOR EYE THERAPY
0
10
20
30
40
50
60
70
80
90
100
110
0 5 10 15 20 25 30 35
Depth in water (mm)
Rel
ativ
e D
ose
(%)
RS = 14 mm
RS = 2 mmRS = 10 mm
BEFORE EACH TREATMENT PERIOD TREATMENT DEPTH DOSE PROFILES HAVE TO BE VERIFIED.
TO VERIFY RANGE MODULATION AND MAXIMUM RANGE OF THE BEAM
DEPTH-DOSE MEASUREMENT WHEEL (CCO DIODE SCANNER)
WHEEL IS COMPUTER CONTROLLED, AND RELATIVE DOSE MEASURED AS RATIO BETWEEN WHEEL’S DETECTOR AND REFERENCE DETECTOR
TOLERANCES
1) [(MEASURED RANGE) / (REQUIRED RANGE)]: 0.2 mm
2) [(MEASURED MODULATION) / (REQUIRED MODULATION)]: [ -0.1 mm // +0.9 mm ]
INFN-LNS
INFN-LNS
LATERAL OFF-AXIS BEAM PROFILES
1) LATERAL PENUMBRA: d80%-20%
2) Field ratio: 3) L95%
4) SIMMETRY (AREA RATIO): 5) FLATNESS:
MD-55-2 RADIOCHROMIC FILMS WERE USED IN COMMISSIONING
tissue equivalence – dose rate indipendenceLinear dose response – high spatial resolution
ONLY ONE CALIBRATION FILE IS NEEDED TO EVALUATE FILMS EXPOSED AT DIFFERENT DEPTHS
Energy indipendence
fieldsize
fieldsizeH
%50
%90
ba
baABSSr
%200).(
%100%minmax
minmax
PP
PPRT
0
10
20
30
40
50
60
70
80
90
100
110
-20 -10 0 10 20
X (mm)
N.O
.D.%
1.3 mm
P M M A F a n t o m
I s o c e n t e r
N o z z l e
F i n a l c o l l i m a t o r
B e a m a x i s
y = - 4 E - 0 5 x 2 + 0 , 0 2 0 7 x - 0 , 0 0 9 5R 2 = 0 , 9 9 8 9
0
0 . 2
0 . 4
0 . 6
0 . 8
1
1 . 2
1 . 4
1 . 6
1 . 8
2
0 2 0 4 0 6 0 8 0 1 0 0 1 2 0
D o s e ( G y )
N.O
.D.
y = 0 , 0 1 9 3 x - 0 , 0 0 4 7R 2 = 0 , 9 9 8
0
0 . 2
0 . 4
0 . 6
0 . 8
1
1 . 2
0 1 0 2 0 3 0 4 0 5 0 6 0
D o s e ( G y )
N.O
.D.
0
2 0
4 0
6 0
8 0
1 0 0
1 2 0
0 5 1 0 1 5 2 0 2 5 3 0 3 5
D e p t h i n w a t e r ( m m )
Rel
ativ
e Io
niz
atio
n %
E x p o s i t i o n p o i n t
6 c m2 . 5 c m
1 c m
I N F N - L N SG a f c h r o m i c f i l m M D 5 5 - 2
P M M A F a n t o m
I s o c e n t e r
N o z z l e
F i n a l c o l l i m a t o r
B e a m a x i sP M M A F a n t o m
I s o c e n t e r
N o z z l e
F i n a l c o l l i m a t o r
B e a m a x i s
y = - 4 E - 0 5 x 2 + 0 , 0 2 0 7 x - 0 , 0 0 9 5R 2 = 0 , 9 9 8 9
0
0 . 2
0 . 4
0 . 6
0 . 8
1
1 . 2
1 . 4
1 . 6
1 . 8
2
0 2 0 4 0 6 0 8 0 1 0 0 1 2 0
D o s e ( G y )
N.O
.D.
y = 0 , 0 1 9 3 x - 0 , 0 0 4 7R 2 = 0 , 9 9 8
0
0 . 2
0 . 4
0 . 6
0 . 8
1
1 . 2
0 1 0 2 0 3 0 4 0 5 0 6 0
D o s e ( G y )
N.O
.D.
y = - 4 E - 0 5 x 2 + 0 , 0 2 0 7 x - 0 , 0 0 9 5R 2 = 0 , 9 9 8 9
0
0 . 2
0 . 4
0 . 6
0 . 8
1
1 . 2
1 . 4
1 . 6
1 . 8
2
0 2 0 4 0 6 0 8 0 1 0 0 1 2 0
D o s e ( G y )
N.O
.D.
y = 0 , 0 1 9 3 x - 0 , 0 0 4 7R 2 = 0 , 9 9 8
0
0 . 2
0 . 4
0 . 6
0 . 8
1
1 . 2
0 1 0 2 0 3 0 4 0 5 0 6 0
D o s e ( G y )
N.O
.D.
0
2 0
4 0
6 0
8 0
1 0 0
1 2 0
0 5 1 0 1 5 2 0 2 5 3 0 3 5
D e p t h i n w a t e r ( m m )
Rel
ativ
e Io
niz
atio
n %
E x p o s i t i o n p o i n t
0
2 0
4 0
6 0
8 0
1 0 0
1 2 0
0 5 1 0 1 5 2 0 2 5 3 0 3 5
D e p t h i n w a t e r ( m m )
Rel
ativ
e Io
niz
atio
n %
E x p o s i t i o n p o i n t
6 c m2 . 5 c m
1 c m
6 c m2 . 5 c m
1 c m
6 c m2 . 5 c m
1 c m
I N F N - L N SG a f c h r o m i c f i l m M D 5 5 - 2
PMMA Phantom
He-Ne Scanning Laser Densitomiter
INFN - LNS
PROFILE MEASUREMENTS MD - 55 RADIOCHROMIC FILM
0
20
40
60
80
100
120
-20 -15 -10 -5 0 5 10 15 20
Distance from central axis (mm)
= 25mm
Rel
ativ
e d
ose
EXPERIMENTAL
SET-UP
(=25 mm)
SOBP
(WIDTH) H L95%
(mm)
Sr%
(simmetry)
Rt%
(flatness)
Lateral penumbra (mm)
d80%-20%
MOD: 000/00
RS: 14 mm
14 mmzirr.=7 mm
0.92 23 3% 3% 1.40
MOD: 010/02
RS: 10 mm
10 mm
zirr.= 12 mm
0.92 23 2% 3% 1.30
MOD: 009/02
RS:1.8 mm
20 mm
zirr.= 14 mm
0.93 23 3% 3% 1.15
CCO
18
zirr.= ½ SOBP
3% 1.10
CAL
18
zirr.= ½ SOBP
1.50
KODAK XV FILMS AND SCANDITRONIX DIODE WERE USED IN COMMISSIONING
IF CALIBRATION FILES PRODUCED FOR KODAK XV FILMS
AT DEPTH OF SOBP ARE USED FOR TRANSVERSE BEAM MEASUREMENTS
GAF MD55-2 = KODAK XV FILM
MOD 010/02
RS:10 MM
zirr.=12 mm
Lateral penumbra (mm)
d80%-20%
H L95%
(mm)
Sr%
(simmetry)
KODAK XV 1.30 0.92 22.8 0.50
MD-55-2 1.27 0.92 22.7 0.90
0
20
40
60
80
100
120
-25 -20 -15 -10 -5 0 5 10 15 20 25
X Axis (Water m m )
N.O
.D. %
Diodo
MD55
X-OMAT V
INFN-LNS
BEFORE EACH TREATMENT
PROTON BEAM PROFILES AT ISOCENTRE ARE TO BE CHECKED
IN AIR X-Y DIODE SCANNING COMPUTER CONTROLLED DEVICE
PLANNED TOLERANCES
1) LATERAL PENUMBRA (d80%-20%) 1.50 mm 2) BEAM SIMMETRY (Sr ) 3%
3) BEAM FLATNESS: Rt%3% 4) FIELD RATIO: H0.90
-30 -20 -10 0 10 20 300
20
40
60
80
100
120
140
160EXPERIMENTAL AND INTERPOLATED TRASVERSAL DOSE DISTRIBUTIONS (X Axis)
Distance from axes [mm]
Dos
e [a
.u.]
Collimator diameter [mm]: 25
Interpolation step [mm]: 0.1
R90/50: 0.89922
Simmetria [%]: 0.54297
Penombra sinistra [mm]: 1.2
Penombra destra [mm]: 1.3
Omogeneità 95% [mm]: 21.7
Rt [%]: 2.7259
Path: Z:\Misure\Trattamenti Marzo2002\20mar2002\preliminari\profilo11.prf
Experimental dataInterpolated data
INFN-LNS
DOSE MONITORING SYSTEM (IN-BEAM DOSE MONITORS)
THE PROTON DOSE IS MONITORED BY TWO INDEPENDENT TRANSMISSION
UNSEALED ION CHAMBERS, PLACED IMMEDIATELY UPSTREAM OF THE PROTON
NOZZLE.
TRANSMISSION CHAMBERS HAVE SEPARATE CABLING, BIAS SUPPLIES (800 V) AND
CURRENT INTEGRATORS AND ARE ARRANGED AS A REDUNDANT COMBINATION TO
TERMINATE THE BEAM.
TRANSMISSION ION CHAMBERS ARE CALIBRATED DAILY AGAINST A REFERENCE
PARALLEL-PLATE MARKUS ION CHAMBER, LOCATED AT THE ISOCENTRE.
COMMISSIONING TESTS
1) PRECISION
1a) SHORT TERM PRECISION: (CV) OF THE RATIO R OF DOSE MONITOR UNITS TO
DOSIMETER SCALE READING FOR n=5 CONSECUTIVE IRRADIATIONS OF 15 Gy.
MEASURED CV = 0.1%
1b) LONG TERM PRECISION (WEEKLY STABILITY):
MEASURED [(cGy/U.M.)WEEK] : 1.5%.
2) LINEARITY
THE RATIO V BETWEEN THE MEASURED PROTON DOSE AND DOSE MONITOR UNITS
SHALL BE WITHIN 1% AT ALL MONITOR SCALE READINGS, i.e. IN THE CLINICAL
RANGE UP TO 15–20 Gy.
MEASURED RATIO 005.1min
max V
V
INFN-LNS
MONITOR CHAMBER LINEARITY
R2 = 1
0200400600800
10001200140016001800200022002400
0 50000 100000 150000 200000 250000
U.M. SENT
ME
AS
UR
ED
DO
SE
, cG
y (
Mar
kus
cham
ber
)
(Dose rate = 51.10 Gy/min.)
DOSE MONITORING SISTEMTRANSMISSION ION CHAMBER
STABILITY OF CALIBRATION (long term )
97
98
99
100
101
102
103
0 1 2 3 4 5 6
tim e (days)
cG
y/U
.M.
DOSE MONITORING SISTEMTRANSMISSION ION CHAMBER
INFN - LNS
DOSE RATE MONITORING (BEAM INTENSITY MONITOR)
THE PROTON BEAM RATE IS MONITORED BY THE VOLTAGE SIGNAL (VSF) PROVIDED BY
THE FIRST SCATTERING FOIL, LOCATED IN VACUUM IMMEDIATELY UPSTREAM OF THE
EXIT WINDOW.
IBEAM (nA) = 0.0412 + 6.0835 VSF (R2=0.9999)
(VSF) IS USED BY THE C.S. TO STOP THE BEAM IF THE RATE XCEEDS A PRESET LIMIT.
NORMAL TREATMENT BEAM CURRENT 4 nA CLINICAL DOSE RATE =1220 Gy/min.
0.97
0.98
0.99
1
1.01
1.02
1.03
1.04
1.05
0 1 2 3 4 5 6 7 8 9 10
PROTON BEAM CURRENT (nA)
CO
LLE
CTE
D C
HA
RG
E (M
arku
s, n
C)
Normal current
Alarm current
Zmarkus = 1 mm Full energy
beam
U.M. =K
INFN-LNS
INFN-LNS
ABSOLUTE DOSIMETRY (BEAM CALIBRATION, cGy/U.M.)
FOR REFERENCE DOSIMETRY, AT LNS, A PLANE-PARALLEL MARKUS ION CHAMBER IS
USED IN A WATER PHANTOM, BY EXTENDING TO PROTON BEAMS THE FORMALISM OF THE
IAEA 381 CODE OF PRACTICE ON THE USE OF PLANE-PARALLEL ION CHAMBERS IN HIGH
ENERGY ELECTRON DOSIMETRY.
QQairwQairQairpp
QairDQeffQw pSWWNMPD ,0,, 0
)( cGy
spolP,TQ kkk)C(MM (nC) pp
refcel
refcav
refairD
refpp
QairD M
PPNMN
,
,, 0
cGy/nC
(sw,air)q
pQ = 1.00 (ICRU 59, IAEA TRS-398, MED.PHYS. 1995 :22)
( TAB. 7.1 ICRU 59) (Wair/e)cp = 1.031 (ICRU 59)
FOR DOSE CALIBRATIONS OF INDIVIDUAL PATIENTS, THE CALIBRATION IS MADE IN A
UNIFORM DOSE REGION AT THE MIDDLE OF SOBP, AT ISOCENTRE, WITH THE 25 mm
DIAMETER REFERENCE COLLIMATOR ON BEAM DELIVERY NOZZLE.
FOR DAILY DOSE CHECKS, A PMMA PHANTOM BLOCK IS USED: 87.0zz waterPMMA
A RADIOACTIVE CHECK DEVICE (90Sr) IS USED FOR OPERATIONAL AND CONSTANCY
CHECKS OF DOSIMETRY SYSTEM (1%, NCRP).
AN EXRADIN T1 THIMBLE ION CHAMBER [A-150 TE, 0.05 cm3, NK(60Co)]
CAN BE USED AT LNS IN THE WATER PHANTOM, ACCORDING TO ICRU 59
air,waterspolP,TQp,w /S031.19534.0nCGy6311.0kkknCMGyD
BECAUSE OF THE Cavity length AND Outer diameter of the chamber,
USE IS LIMITED TO ( ) 15 mm AND (SOBP WIDTH) 12 mm.
WORK IN PROGRESS
NOW AVAILABLE BY PTW ND,w,60
Co FOR T1 EXRADIN AND MARKUS LNS CHAMBERS
ADOPTION OF IAEA TRS-398 CODE OF PRACTICE
Dw,Q = MQ ND,w,Q0 kQ,Q0
ESTIMATED UNCERTAINTY OF Dw,Q UNDER REFERENCE CONDITIONS (1 S.D.)
ICRU 59 (Nk=1%) IAEA TRS-398 (ND,w,Q0 =1%)
EXRADIN T1 2.6% 2.1%
PTW MARKUS 3.1% 2.5%
INFN-LNS
PROTON DOSIMETRY INTERCOMPARISON (ECHED, ICRU 59)
BEFORE STARTING LNS PROTON THERAPY FACILITY
) INTERCOMPARISON (1) AT CCO (PHYSICA MEDICA, VOL.XV, N.3)
LNS (PTW MARKUS, T1-EXRADIN) CCO (A-150 FW-IC18, REFERENCE DOSE)
(Dw) [(PTW MARKUS) / (FW-IC18)]: 1%
(Dw) [(T1-exradin) / (FW-IC18)]: 1.4%
) INTERCOMPARISON (2) AT PSI (PHYSICA MEDICA VOL.XVII, S.3, PTCOG XXX 1999)
1) CCO (FW-IC18, MARKUS) 2) LNS (MARKUS, EXRADIN-T1, PTW PMMA FARMER)
3) PSI (PTW GRAPHITE FARMER, MARKUS) 4) TERA ( MARKUS, EXRADIN-T1)
% = 1.2% max (%) = 3.5%
INFN-LNS
DOSIMETRY INTERCOMPARISON AT PSI
(FULLY MODULATED BEAM)
-8
-6
-4
-2
0
2
4
6
MARKUSLNS
EXRADINT1 LNS
FARMERLNS
MARKUSCCO
FW T 683CCO
FW T 725CCO
MARKUSTERA
EXRADINT1 TERA
MARKUSPSI
FARMERPSI
Dev
iati
on fr
om th
e m
ean
(%)
Standard deviation of the mean = 1.13%Difference between maximum and minimum dose =
3.3%
INFN-LNS
OUTPUT FACTORS (FSDF)
) AT THE INITIAL CALIBRATION OF CYCLOTRON THE OUTPUT DOSE RATE HAS BEEN
MEASURED FOR ALL COLLIMATORS AREA ENCOUNTERD IN THE CLINICAL PRACTICE.
) TO EVALUATE IF THERE ARE SIGNIFICANT DROPS OF DOSE PER MONITOR UNIT
WHEN COLLIMATOR DIAMETER DECREASES TO A FEW MILLIMETERS.
) THE MOST RELIABLE RELATIVE OUTPUT VALUES ARE PROVIDED FROM
RADIOCHROMIC DETECTORS, ESPECIALLY FOR NARROWEST BEAMS
(VATNITSKY).
NO SIGNIFICANT DECREASE OF BEAM OUTPUT (cGy/U.M.)
FOR COLLIMATOR DIAMETER UP TO 5 mm
0
10
20
30
40
50
60
70
80
90
100
110
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28
Collimator diameter (mm)
Re
lati
ve
ou
tpu
t
GAF Markus Diode1
Diode2 TLD2 TLD1
MODULATED BEAM Z = 21 mm WED
PMMA PHANTOM
INFN-LNS
OUTPUT FACTORS (FSDF)
) FROM EXPERIMENTAL RESULTS WE CAN STATE THE LOWER BOUND OF COLLIMATOR
DIAMETER FOR WHICH FRELATIVE OUTPUT IS MEASURED ACCURATELY WITH EACH
DETECTOR
0
10
20
30
40
50
60
70
80
90
100
110
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28
Collimator diameter (mm)
Rel
ativ
e o
utp
ut
GAF Markus Diode1
Diode2 TLD2 TLD1
MODULATED BEAM Z = 21 mm WED
PMMA PHANTOM
1) MARKUS CHAMBER CAN BE USED IN PROTON BEAMS WITH 12 mm
2) TLDs AND SCANDITRONIX DIODE CAN BE USED UP TO =8 mm
IN CLINICAL PRACTICE AT LNS
GAF-DETECTOR IS USED FOR EVALUATION OF OUTPUT FACTOR
FOR SHAPED NARROWEST BEAMS
INFN-LNS
PATIENT DOSES (STRAY RADIATION)
(PERSONAL MONITORING, TWO PATIENTS TESTED)
A) TWO PERSONAL BADGE-DOSIMETERS WERE PLACED ON THE CHEST OF PATIENTS DURING THE WHOLE PROTON TREATMENT.
1) ENEA FILM BADGE PERSONAL DOSIMETER (, , x) 0.05 mSv 2) NRPB PADC NEUTRON PERSONAL DOSEMETER 0.20 mSv PATIENTS COMPLETING TREATMENT INDUCED DOSE RATE
15 Sv/h (10’) 1.5 Sv/h
INFN-LNS