funding - irpa thu boisdale behrens ts7e.3.pdf · funding. monitoring the eye lens dr. rolf behrens...

Physikalisch-Technische Bundesanstalt

TS7e.3

Monitoring the eye lens

Rolf Behrens

Funding


Dr. Rolf Behrens Physikalisch-Technische Bundesanstalt

IRPA13

Glasgow

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• Main question:

Which quantity / kind of dosemeter is suitable?

Hp(0.07), Hp(3) or Hp(10)?

• Method:

Compare indication of ideal dosemeters and Hlens,

i.e. compare conversion coefficients for Hp(d) and Hlens

Introduction

• April 2011:

Limit of Hlens: 150 mSv 20 mSv per year

Protecting and monitoring may be necessary!

Hp(3) should work well, BUT:

not used in the past,

only few dosemeters available.



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Glasgow

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Data base

Radiation Quantity Data source

Electrons

Hp(0.07)slab

Hp(3)slab

Hp(10)slab

Hp(3)cyl

ICRP74 + ICRU57

Ferarri and Gualdrini

Photons

Hp(0.07)slab

Hp(10)slab

Hp(0.07)rod

Hp(3)slab

Hp(3)cyl

ICRP74 + ICRU57

Grosswendt

Till et al.

Vanhavere et al.

)(lens Eh

Quantity Data source

Hlens

ICRP116 (Rev. ICRP74);

Behrens

Hlens

ICRP116 (Rev. ICRP74);

Behrens and Dietze

}

}

?> Organ dose to the lens

(Equivalent dose)

Operational quantity

(Dose equivalent)

?=

ORAMEDICRU / ISO

);(p Edh



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Glasgow

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Data base

Biology Simulation

Organ dose to the lens

Complete lens: ICRP state of art



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Glasgow

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Data base

Biology Simulation

R. Behrens et al. in Phys. Med. Biol. (PMB):

PMB 54 (2009) 4069 + PMB 55 (2010) 3937,

PMB 56 (2011) 415 and PMB 57 (2012) submitted


Sensitive cells: In ICRP discussion



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10 100 10000.6

0.8

1.0

1.2

1.4

10

60

Hp(3)

cyl/H

lens

Hp(0.07)

rod/H

lens

Hp(0.07)

slab/H

lens

Hp(3)

slab/H

lens

Hp(10)

slab/H

lens

keV

= 0°

Eph

Hp(d

) / H

len

s

Photon radiation: Hp(d) / Hlens (based on complete lens)

Conservative

------------------------

Not conservative

ICRP state of art

rod slab cyl

ORAMEDICRU / ISO



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10 100 10000.6

0.8

1.0

1.2

1.4

10

60

Hp(d

) / H

len

s

Hp(3)

cyl/H

lens

Hp(0.07)

rod/H

lens

Hp(0.07)

slab/H

lens

Hp(3)

slab/H

lens

Hp(10)

slab/H

lens

keV

= 75°

Eph


Conservative

------------------------

Not conservative

ICRP state of art

rod slab cyl

ORAMEDICRU / ISO



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10 100 10000.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

10

60

Hp(d

) / H

len

s

Hp(0.07)

rod/H

lens

Hp(10)

slab/H

lens

Hp(3)

cyl/H

lens

Hp(0.07)

slab/H

lens

Hp(3)

slab/H

lens

keV

= 90°

Eph


Conservative

------------------------

Not conservative

ICRP state of art

rod slab cyl

ORAMEDICRU / ISO



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Glasgow

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0.6 1 100.0

0.4

0.8

1.2

1.6

2.0

10

100

Hp(d

) / H

len

s

Hp(3)

cyl/H

lens

Hp(0.07)

slab/H

lens

Hp(3)

slab/H

lens

Hp(10)

slab/H

lens

MeV

= 0°

Eel

Electron radiation: Hp(d) / Hlens (based on complete lens)

Conservative

------------------------

Not conservative

ICRP state of art



IRPA13

Glasgow

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Conservative

------------------------

Not conservative

ICRP state of art

0.6 1 100.0

0.4

0.8

1.2

1.6

2.0

10

100

Hp(d

) / H

len

s

Hp(3)

cyl/H

lens

Hp(0.07)

slab/H

lens

Hp(3)

slab/H

lens

Hp(10)

slab/H

lens

MeV

= 60°

Eel



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Glasgow

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0.6 1 100.0

0.4

0.8

1.2

1.6

2.0

10

100

Hp(d

) / H

len

s

Hp(3)

cyl/H

lens

Hp(0.07)

slab/H

lens

Hp(3)

slab/H

lens

Hp(10)

slab/H

lens

MeV

= 75°

Eel

ICRP state of art


Conservative

------------------------

Not conservative



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0.6 1 100.0

0.4

0.8

1.2

1.6

2.0

10

100

Hp(d

) / H

len

s,s

Hp(3)

cyl/H

lens,s

Hp(0.07)

slab/H

lens,s

Hp(3)

slab/H

lens,s

Hp(10)

slab/H

lens,s

MeV

= 0°

Eel

In ICRP discussion

Electron radiation: Hp(d) / Hlens,s (based on sensitive cells)

Conservative

------------------------

Not conservative



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In ICRP discussion

Electron radiation: Hp(d) / Hlens,s (based on sensitive cells)

Conservative

------------------------

Not conservative

0.6 1 100.0

0.4

0.8

1.2

1.6

2.0

10

100

Hp(d

) / H

len

s,s

Hp(3)

cyl/H

lens,s

Hp(0.07)

slab/H

lens,s

Hp(3)

slab/H

lens,s

Hp(10)

slab/H

lens,s

MeV

= 60°

Eel



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Glasgow

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0.6 1 100.0

0.4

0.8

1.2

1.6

2.0

10

100

Hp(d

) / H

len

s,s

Hp(3)

cyl/H

lens,s

Hp(0.07)

slab/H

lens,s

Hp(3)

slab/H

lens,s

Hp(10)

slab/H

lens,s

MeV

= 75°

Eel

In ICRP discussion

Electron radiation: Hp(d) / Hlens,s (based on sensitive part)

Conservative

------------------------

Not conservative



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ORAMEDICRU / ISO

Conclusions

Radiation Quantity Good to estimate Hlens? Good to estimate Hlens,s?

Photons

Hp(0.07)rod

Hp(10)slab

Hp(0.07)slab

Hp(3)slab

Hp(3)cyl

Underestimating

Up to 75° appropriate


As for Hlens

Electrons

Hp(0.07)slab

Hp(3)slab

Hp(3)cyl

Hp(10)slab

Extrem. overestimating


Underestimating

Extremely overestimating

Underestimating,

Hp(d<3) necessary?

Underestimating

?>


(Equivalent dose)


(Dose equivalent)

}

?=

– equal for realistic radiation fields

ICRP state of art:Complete lens:

Hlens

In ICRP discussion:Sensitive cells :

Hlens,s

}}



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ORAMEDICRU / ISO

Conclusions

Radiation Quantity Good to estimate Hlens? Good to estimate Hlens,s?

Photons

Hp(0.07)rod

Hp(10)slab

Hp(0.07)slab

Hp(3)slab

Hp(3)cyl

Underestimating



As for Hlens

Electrons

Hp(0.07)slab

Hp(3)slab

Hp(3)cyl

Hp(10)slab

Extrem. overestimating


Underestimating

Extremely overestimating

Underestimating,

Hp(d<3) necessary?

Underestimating

?>


(Equivalent dose)


(Dose equivalent)

}

?=

– equal for realistic radiation fields

ICRP state of art:Complete lens:

Hlens

In ICRP discussion:Sensitive cells :

Hlens,s

P02.247 in hall 4, this afternoon

Electrons

}}P02.247 BSS 2



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Glasgow

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Radiation field Hp(0.07)rod /

Hlens

Hp(0.07)slab /

Hlens

Hp(3)slab /

Hlens

Hp(10)slab /

Hlens

Photons < 30 keV 0.9 – 5 1.1 – 5 0.6 – 1 0.01 – 0.9

Photons > 30 keV 0.8 – 0.9 ≈ 1.1 1 – 1.2 0.9 – 1.2

Electrons < 0.6 MeV

and photons

1 – 100 1 – 100 ≈ 1 see above

Electrons < 0.6 MeV

and photon

1 – 500 1 – 500 ≈ 1 2x10-4

– 1

Hp(10) is

NOT

adequate!

Hp(0.07)slab is ONLY

adequate for

photon radiation.

Hp(3) is

NECESSARY for

beta radiation.

Hp(0.07)rod, i.e. ring dosemeters worn near the eye, suitable for photons?

Same conclusions for realistic radiation fields

R. Behrens and G. Dietze:

Phys. Med. Biol. 55 (2010) 4047-4062 and

Phys. Med. Biol. 56 (2011) 511



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Extremity dosemeters suitable for the eye lens?

Are extremity dosemeters (for Hp(0.07)) appropriate?

Is a calibration on a rod phantom (as usual) appropriate?

Rod phantom Slab phantom

R. Behrens et al.:

Rad. Prot. Dosim. 148 (2012) 139-142



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Glasgow

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R. Behrens et al.:

Rad. Prot. Dosim. 148 (2012) 139-142



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Glasgow

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R. Behrens et al.:

Rad. Prot. Dosim. 148 (2012) 139-142

10 100 1000 20000.85

0.90

0.95

1.00

1.05

1.10

1.15

Rro

d /

Rsl

ab

Energy / keV

MPA-TKD-01 LPS-TLD-TK 03 LPS-TLD-TK 07

LPS-TLD-TK 08 GSF-TL-TD-60 GSF-TL-TD-70

BE-TLD-TD-PHOTONEN 01 BE-TLD-TD-Brille

Extremity dosemeters (for Hp(0.07)) estimate

the lens dose in pure photon radiation fields!




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Whole body dosemeters measure Hp(10):

- must be worn on the trunk (far from the eyes);

- underestimate the lens dose (too thick cover)

- under the lead apron if in use;

danger for your eyes!

Extremity dosemeters measure Hp(0.07):

- must be worn “facing” the beam / source;

- can be worn near the eye, then it

- correctly estimate the lens dose in photon fields but

- overestimates the lens dose in beta fields (too thin cover)

your work may be changed although not necessary!

Eye dosemeters measure Hp(3):

- must be worn “facing” the beam / source;

- must be worn near the eye;

- is the only type of dosemeter that correctly esti-

mate Hlens (not Hlens,s) in beta and photon fields!

Practice: Choice of dosemeters

Physikalisch-Technische Bundesanstalt

Funding

TS7e.3


Rolf Behrens



IRPA13

Glasgow

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Irradiations and type tests in Hp(3)• Conversion coefficients for Ka Hp(3)slab:

Rad. Prot. Dosim. 147, 373 (2011)

• Conversion coefficients for Ka Hp(3)cyl: Rad. Prot. Dosim. doi:10.1093/rpd/ncs032 (2012)

Photon spectra:

Beta radiation: • Extension to the Beta Secondary Standard BSS 2:

Incl. conversion factors for Hp(0.07) Hp(3):J. Instrum. 6, P11007 (2011)

• Available for old instruments via SW update

Details: Poster P02.247 in hall 4, this afternoon

ICE 62387: • Passive dosimetry systems (Final draft FIDS 2012)

Hp(3) implemented for both photons and betas



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Glasgow

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Literature• Monitoring the eye lens: Which dose quantity is adequate?

Phys. Med. Biol. 55, 4047 (2010) and Phys. Med. Biol. 56, 511 (2011)

• Conversion coefficients for mono-energetic electrons: Heye:

Phys. Med. Biol. 54, 4069 (2009) and Phys. Med. Biol. 55, 3937 (2010)

• Conversion coefficients for mono-energetic photons: Heye:

Phys. Med. Biol. 56, 415 (2011)

• Conversion coefficients for photon spectra: Ka Hp(3)slab:

Rad. Prot. Dosim. 147, 373 (2011)

• Conversion coefficients for photon spectra: Ka Hp(3)cyl:

Rad. Prot. Dosim. doi:10.1093/rpd/ncs032 (2012)

• Hp(0.07) photon dosemeters: Calibration on a rod vs. a slab phantom:

Rad. Prot. Dosim. 148 (2012) 139-142

• Extensions to the Beta Secondary Standard BSS 2:

J. Instrum. 6, P11007 (2011) and Erratum and Addendum



IRPA13

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0.6 1 100

100

200

300

400

pSv cm²

600

MeV

{ Hlens

/ }head

{ Hlens

/ }ICRP116,eye

= 0°

Electron energy

H /

Electron radiation



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0.6 1 100.0

0.2

0.4

0.6

pSv cm²

1.0

MeV

{ Hlens

/ }head

{ Hlens

/ }ICRP116,voxel-phantom

= 180°

Electron energy

H /

Electron radiation



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Glasgow

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Total lens ↔ significant volume



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Data base Organ dose to the lens



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Data base

Biology Simulation




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Significant volume

Data base

Biology Simulation


PMB 54 (2009) 4069 + PMB 55 (2010) 3937,





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Data base

Biology Simulation


PMB 54 (2009) 4069 + PMB 55 (2010) 3937,






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Data base

Biology Simulation


PMB 54 (2009) 4069 + PMB 55 (2010) 3937,






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Data base

Biology Simulation


PMB 54 (2009) 4069 + PMB 55 (2010) 3937,






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Data base

Biology Simulation


PMB 54 (2009) 4069 + PMB 55 (2010) 3937,






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Data base

Biology Simulation


PMB 54 (2009) 4069 + PMB 55 (2010) 3937,






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Data baseImplementation in simulation program EGSnrc:


PMB 54 (2009) 4069 + PMB 55 (2010) 3937,

PMB 56 (2011) 415 and PMB 57 (2012) submitted Significant volume

• Mathematical model

• Small volumes possible

• No problems with finite

voxel sizes

• Correct calculation

of Hlens




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PMB 54 (2009) 4069 + PMB 55 (2010) 3937,





voxel sizes


of Hlens




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PMB 54 (2009) 4069 + PMB 55 (2010) 3937,





voxel sizes


of Hlens




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PMB 54 (2009) 4069 + PMB 55 (2010) 3937,





voxel sizes


of Hlens


funding - irpa thu boisdale behrens ts7e.3.pdf · funding. monitoring the eye lens dr. rolf behrens...

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