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