absolute and relative dosimetry of proton beams - … workshop, teddington uk, 12-13 mar 2014...

Vorlage / template. ZA000_10700_1310013, Vers4.0 PPRIG workshop, Teddington UK, 12-13 Mar 2014

1

Absolute and Relative Dosimetry of Proton Beams

Hugo Palmans

MedAustron, Wiener Neustadt, Austria

and National Physical Laboratory, Teddington, UK


2

Overview

Absolute dosimetry

Primary standards: calorimetry, Faraday cup,…

Reference dosimetry: ionisation chambers

Relative dosimetry

Depth dose measurements; quenching

Lateral measurements, position sensitive detection

Examples from literature and NPL

Specific issues scanned beams


3

Absolute dosimetry – Fluence based methods

N protons A

𝐷𝑚𝑒𝑑 = ࢶ𝑆

ρ𝑚𝑒𝑑

≈𝑁

𝐴

𝑆

ρ𝑚𝑒𝑑


4

Faraday cup – collimator scatter

4

guard

collecting electrode housing entrance window

winding

N protons

B


5

Faraday cup – collimator scatter

5

guard

collecting electrode housing entrance window

winding

N protons

B

Kacperek (2009) Appl. Rad. Isot. 67:378-86


6

Absolute dosimetry – Activation measurement

12C(p,pn)11C reaction

4p bg-coincidence counting

(Nichoporov 2003, Med Phys 30:972-8)


7

Faraday cup – scanned beams

Large area ion chamber: pdd(z)

Faraday cup: N/MU

S/ρ: DAP(zref)

Integrate lateral dose profiles over all spots 7


8

Calorimetry

Absorbed dose = energy imparted per unit of mass

Calorimetry directly determines energy imparted by either

Comparing with electrical energy dissipation

Measuring temperature rise

Assumes medium doesn’t change its physical or chemical state

Accounts with contributions/absorptions from nuclear reactions

± no particle type dependence

8


9

Calorimetry - principle

c

(J·kg-1·K-1)

ΔT/D

(mK·Gy-1)

water 4180 0.24

graphite 710 1.41

a

(m2·s-1)

1.44×10-7

0.80×10-4

D=c·ΔT


10

Calorimetry for proton beams

At least 15 papers in the past 20 years so it’s a proven technique

No primary standards

Lack of interest/demand

No beams in NMI

Not much in scanned beams

Relatively new modality

Calibration methods not established/standardised

10


11

Water calorimetry - chemical heat defect

Experiment Simulations

H20/Ar

H20/H2

H20+NaCOOH/O2

0,0

1,0

2,0

3,0

LET (keV.mm-1)

G (

100 e

V-1

)

10-1 100 101 102

H+ OH•

e¯aq

H•

OH¯

H2

HO2

H2O2

60Co (100 MeV) (1MeV) protons

0,00

1,00

2,00

3,00

4,00

0,0 0,2 0,4 0,6 0,8 1,0 t (s)

G (

100eV

-1) (-) H2O

H2 H• H2O2

H+ OH• e-

aq

OH-


12

Water calorimetry - chemical heat defect

12

0.98

1.00

1.02

1.04

1.06

1.08

0 200 400 600

D acc / Gy

D ca

l / D ca

l , ss

0 200 400

H 2 O/H 2

H 2 O/ Ar

NaCOOH /O 2

85 MeV protons

60 Co

H 2 O/H 2

H 2 O/ Ar

0.98

1.00

1.02

1.04

1.06

1.08

0 200 400 600

D acc / Gy

D ca

l / D ca

l , ss

0 200 400

H 2 O/H 2

H 2 O/ Ar

NaCOOH /O 2

85 MeV protons

60 Co

H 2 O/H 2

H 2 O/ Ar

Palmans et al (1996) Med. Phys. 23:643-50

Steady state dose points


13

Water calorimetry - heat conduction

13 Sarfehnia et al (2010) Med. Phys. 37:3541-50


14

Graphite calorimetry

14

Core

Inner jacket

Outer

jacket Annular PCB

Graphite vacuum

body

Palmans et al (2004) Phys Med Biol 49:3737


15

Graphite calorimetry

15

Core

Inner jacket

Outer

jacket Annular PCB

Graphite vacuum

body

Palmans et al (2004) Phys Med Biol 49:3737

Seuntjens and Duane (2009) Metrologia 46:S39-58


16

Graphite – heat defect?

Schulz et al (1990) Phys. Med. Biol. 35:1563-74

graphite:

kHD = 1.004 ± 0.003

A150:

kHD = 1.042 ± 0.004


17

Dose conversion graphite calorimetry

0.60

0.70

0.80

0.90

1.00

1.10

1.20

0 50 100 150 200 250

proton energy / MeV

(L/

)w,g

or

(<E

>

/A)w

,g

Stopping power ratio

Total non-elastic absorption

Emitted protons

Emitted deuterons Emitted alpha particles

?

w

g

ggww

SzDzD

)()(


18

Dose conversion graphite calorimetry

0.60

0.70

0.80

0.90

1.00

1.10

1.20

0 50 100 150 200 250

proton energy / MeV

(L/

)w,g

or

(<E

>

/A)w

,g

Stopping power ratio

Total non-elastic absorption

Emitted protons

Emitted deuterons Emitted alpha particles

?

w

g

ggww

SzDzD

)()(

0.960

0.980

1.000

1.020

1.040

1.060

0.0 5.0 10.0 15.0 20.0 25.0

z w-eq / g cm-2

kfl o

r k

'fl

p

all charged

thick lines = k f l from fluence

symbols = k 'f l from fluence

thin lines = k f l from dose calculation


19

Graphite calorimetry – heat transfer within core

19

0.0

0.5

1.0

1.5

2.0

2.5

3.0

100 110 120 130 140

tem

peratu

re r

ise /

mK

time / s

thermistor

1

0.0

0.5

1.0

1.5

2.0

2.5

3.0

100 110 120 130 140

tem

peratu

re r

ise /

mK

time / s

thermistor

1


20

Graphite calorimetry – heat transfer within core

20

0.0

0.5

1.0

1.5

2.0

2.5

3.0

100 110 120 130 140

tem

peratu

re r

ise /

mK

time / s

thermistor

1

0.0

0.5

1.0

1.5

2.0

2.5

3.0

100 110 120 130 140

tem

peratu

re r

ise /

mK

time / s

thermistor

1

1.0

1.2

1.4

1.6

1.8

2.0

104 105 106 107 108

tem

peratu

re r

ise /

mK

time / s

thermistor

1thermistor

2

1.0

1.2

1.4

1.6

1.8

2.0

104 105 106 107 108

tem

peratu

re r

ise /

mK

time / s

thermistor 1

thermistor 2


21

Graphite calorimetry – dose-area-product

Large area ion chamber: pdd(z)

Faraday cup: N/MU

S/ρ: DAP(z0 or zref)

Integrate lateral dose profiles over all spots

21

Calorimeter: DAP(zref)


22

Reference dosimetry with ion chambers

TRS-398

ICRU report 78

Dw,Q = Mcorr,Q ND,w kQ

calibr

replcelwall

w

air

air

p

replcelwall

w

air

air

Q

PPPL

W

PPPL

k

w

p

w

air

L

(wair)p = 34.2 J/C based mainly on calorimetry data

from Medin and Andreo 1997, Phys Med Biol 42:89

[PwallPcelPrepl]p = 1


23

Residual range – beam quality for protons

0

20

40

60

80

100

0 5 10 15 20 25 30 35 40

depth in water / cm

rela

tive

do

se

235 MeVSOBP

z ref

R res

R p


24

Wair / protons

TRS-398


25

Wair / protons

TRS-398 Jones 2006 RPC 75:541


r o,p = 1mm r o,e = 1mm

Stopping powers – protons versus electrons

100

101

102

103

10-6 10-4 10-2 100 102

t = E k /E rest

S co

ll / (

MeV

cm

2

g -1

)

proton water

protons air

electrons water

electrons air

0.90

1.00

1.10

1.20

1.30

s w

,air

sw,air protons

sw,air electrons

ICRU 49 ICRU 37


27

Electron slowing down spectrum

(Medin and Andreo 1997, Phys Med Biol 42:89-105)

200 MeV proton beam, z = 20 cm

1.E-04

1.E-03

1.E-02

1.E-01

1.E+00

1.E+01

1.E-02 1.E-01 1.E+00 1.E+01 1.E+02 1.E+03

energy / MeV

parti

cle

flu

en

ce p

er i

ncid

en

t p

ro

ton

/ M

eV

-1

cm

-2

proton

electrons


28

Secondary electron perturbations

1.000

1.002

1.004

1.006

0 50 100 150 200 250

proton energy / MeV

pw

all

0.998

0.999

1.000

A150

graphite

1.000

1.002

1.004

1.006

1.008

0 50 100 150 200 250

proton energy / MeV

pw

all,

A15

0 /

pw

all,

C

A150

Palmans et al. 2001 - ND,w based

Palmans et al. 2001 - NK based

average

0.997

0.998

0.999

1.000

1.001

0 50 100 150 200 250

proton energy / MeV

pce

l

aluminium central electrode graphite central electrode

0.994

0.996

0.998

1.000

1.002

0 50 100 150 200 250

proton energy / MeV

pce

l,A

l / p

cel,

C

Monte Carlo

Medin et al. 1995

Palmans et al. 2001 - ND,w-based

Palmans et al. 2001 - NK-based

Palmans et al. (2011) Proc IDOS, IAEA-CN182-230


29

Ion chamber dosimetry of scanned beams

0.960

0.980

1.000

1.020

1.040

1.060

1.080

k Q

Vatn

itsky 1

996

PTW

30001 2

50 M

eV

Vatn

itsky 1

996

PTW

30001 1

55 M

eV

Vatn

itsky 1

996

Capin

tec P

R06 2

50 M

eV

Vatn

itsky 1

996

Capin

tec P

R06 2

50 M

eV

Medin

2006

NE2571 1

80 M

eV

Medin

2010

NE2571 1

80 M

eV

Sarf

ehnia

2010

Exra

din

T1 2

35 M

eV

Sarf

ehnia

2010

Exra

din

T1 2

35 M

eV

Gagnebin

2010

Exra

din

T2 1

70 M

eV

Scattered beams Scanned beams


30

Ion recombination I

Analogy IMRT beams: Palmans et al. 2010 Med. Phys. 37 2876-2889

dxdti

dxdti

V

B

V

AP

sat

sat

ion

2

21

offset

1.024 1.009 250 MeV

1.015 1.006 60 MeV

Gauss Rectangle

Scan direction

0.95

1.00

1.05

1.10

0 1 2 3 4 5 6 7

position #re

lati

ve

vo

lum

e r

ec

om

bin

ati

on 60 MeV

250 MeV


31

Ion recombination II Continuous Pulsed PBS


32

Reference dosimetry scanned beams

Jaekel 2004

ΔX

ΔY

𝐷𝑤,𝑄𝑐𝑦𝑙

=𝑀𝑄𝑐𝑦𝑙

𝑁𝐷,𝑤,𝑄0

𝑐𝑦𝑙𝑘𝑄,𝑄0𝑐𝑦𝑙

𝑁=𝐷𝑤,𝑄𝑐𝑦𝑙ΔXΔY

(𝑆 ρ )𝑤


33

Reference dosimetry scanned beams

Gillin 2010

𝐷𝐴𝑃𝑤,𝑄𝐵𝑃 =𝑀𝑄

𝐵𝑃𝑁𝐷𝐴𝑃,𝑤,𝑄0𝐵𝑃 κ𝑄,𝑄0

𝐵𝑃

𝑁=𝐷𝐴𝑃𝑤,𝑄

𝐵𝑃 (𝑆 ρ )𝑤


34

Relative dosimetry

Lateral profiles in general not problematic (except for volume averaging in small fields) Depth dose profiles: LET dependence! Resulting in an under response in the Bragg peak

Single hit theory (saturation of the sensitive site with one ionisation), e.g. alanine, film

Inter-radical recombination, e.g gel dosimeters More complex models including charge transport, e.g. TLD


35

Relative dosimetry – ion chambers

1.135

1.140

1.145

1.150

1.155

0 50 100 150 200

depth / mm

(L/

)w,a

ir

33.8

34.0

34.2

34.4

34.6

34.8

0 50 100 150 200

wair (e

V)

0.99

1.00

1.01

1.02

1.03

1.04

1.05

1 10 100 1000

E / MeV

rela

tiv

e q

ua

nti

ty n

orm

alize

d a

t 1

00

Me

V

total A150-walled

total graphite-walled

W air/e

s w,air

p wall-A150

p wall-graphite

Palmans, Dosimetry, in : Proton Therapy Physics, Ed Paganetti


36

Relative dosimetry – Solid state detectors : diamond

(Fidanzio et al 2002, Med Phys 29:669-675)


37

Relative dosimetry – Solid state detectors : diamond

(Fidanzio et al 2002, Med Phys 29:669-675)


38

(Palmans 2003, Technol Cancer Res Treat. 2:579-86)

0.40

0.50

0.60

0.70

0.80

0.90

1.00

1.10

0.00 0.50 1.00 1.50 2.00

log(E eff )

ab

so

rb

ed

do

se s

en

sit

ivit

y

Bradshaw et al. (1962)

Ebert et al. (1965)

Hansen and Olsen (1985)

Onori et al. (1997)

Cuttone et al. (1999)

Bartolotta et al. (1999)

Fattibene et al. (2002)

Relative dosimetry – Solid state detectors : alanine/ESR


39

Alanine – stack in PMMA (Palmans 2003 Technol Cancer Res Treat. 2:579) experimental data from Onori et al 1997 Med. Phys. 24:447

0.0

2.0

4.0

6.0

8.0

10.0

0.5 1.0 1.5 2.0 2.5 3.0

depth (cm)

D (

MeV

g

-1 )

Experiment

McPTRAN.RZ


40

Alanine for protons and ions

Birmingham 15 MeV beam

CERN anti-proton beam

GSI 12C ion beam

Bassler et al. 2008

Herrmann et al. 2011


41

Relative dosimetry – Solid state detectors : mosfet

(Kohno et al 2006, Phys Med Biol 51:6077-86)


42

Relative dosimetry – Radiochromic film

(Piermattei et al 2000,Med Phys 27:1655-60)


43

Relative dosimetry – Gel dosimetry

(Gustavsson et al. 2004 Phys. Med. Biol. 49:3847-55)


44

Relative dosimetry – TLD

0.0

0.2

0.4

0.6

0.8

1.0

0.1 1 10 100 1000

energy / MeV

ab

so

rbe

d-d

ose

se

nsit

ivit

y

(Besserer et al 2001 Phys. Med. Biol. 46:473-85)


45

Relative dosimetry – Solid state detectors : diode

(Grusell and Medin 2000 Phys. Med. Biol. 45:2573-82)


46

Relative dosimetry – Plastic scintillator

(Safai et al. 2004 Phys. Med. Biol. 49:4637-55)


47




48




49

Reading

C. P. Karger, O. Jäkel, H. Palmans and T. Kanai, “Dosimetry for Ion Beam Radiotherapy,” Phys. Med. Biol. 55(21) R193-R234, 2010

H. Palmans, A. Kacperek and O. Jäkel, “Hadron dosimetry” In: Clinical Dosimetry Measurements in Radiotherapy (AAPM 2009 Summer School), Ed. D. W. O. Rogers and J. Cygler, (Madison WI, USA: Medical Physics Publishing), 2009, pp. 669-722

H. Palmans, “Dosimetry,” In: Proton Therapy Physics, Ed. H. Paganetti (London: Taylor & Francis), 2011, pp. 191-219

H. Palmans, “Monte Carlo for proton and ion beam dosimetry,” In: Monte Carlo Applications in Radiation Therapy, Ed. F. Verhaegen and J Seco, (London: Taylor & Francis), 2013, pp. 185-199

IAEA TRS-398

ICRU Reports 59 and 78

absolute and relative dosimetry of proton beams - … workshop, teddington uk, 12-13 mar 2014...

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