p. scampoli - 24th icnts bologna, september 4, 2008 1
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P. Scampoli - 24th ICNTS Bologna, September 4, 2008P. Scampoli - 24th ICNTS Bologna, September 4, 2008 11
P. Scampoli - 24th ICNTS Bologna, September 4, 2008P. Scampoli - 24th ICNTS Bologna, September 4, 2008 22
What is common in RT and Space explorationWhat is common in RT and Space exploration
Mixed fields of charged particles are present in Mixed fields of charged particles are present in astronauts environment and patients treated with astronauts environment and patients treated with carbon ionscarbon ions
Dose calculation and radiological risk Dose calculation and radiological risk assessment assessment
Nuclear measurements are needed Nuclear measurements are needed Radiobiological measurements are neededRadiobiological measurements are needed
P. Scampoli - 24th ICNTS Bologna, September 4, 2008P. Scampoli - 24th ICNTS Bologna, September 4, 2008 33
Heavy ion fragmentationHeavy ion fragmentation
The HZE particles of CGR The HZE particles of CGR produce secondary particles produce secondary particles both in human body, and in both in human body, and in needed shielding materials needed shielding materials
Change in the beam qualityCarbon ions in radiation Carbon ions in radiation therapy undergo therapy undergo fragmentations inside the fragmentations inside the patient bodypatient body
P. Scampoli - 24th ICNTS Bologna, September 4, 2008P. Scampoli - 24th ICNTS Bologna, September 4, 2008 44
Radiation field in SpaceRadiation field in Space Trapped radiationTrapped radiation: Van Allen belts (electrons, protons up to : Van Allen belts (electrons, protons up to
600 MeV)600 MeV)
Solar radiationSolar radiation: about 90% protons, E<1 GeV, seldom but : about 90% protons, E<1 GeV, seldom but potentially dangerous (high dose) eventspotentially dangerous (high dose) events
Galactic Cosmic Radiation (GCR)Galactic Cosmic Radiation (GCR):: 2% electrons and positrons 2% electrons and positrons 98% particles : 98% particles :
87% protons 87% protons 12% 12% particles particles 1% heavier ions (1% heavier ions (HZE particlesHZE particles))
P. Scampoli - 24th ICNTS Bologna, September 4, 2008P. Scampoli - 24th ICNTS Bologna, September 4, 2008 55
GCR charge contributionGCR charge contribution
Dose eq. on EarthEarth: 10 Sv/d
Dose eq. on MarsMars: 100-200 mSv/d
Dose eq. on MoonMoon: 300-400 mSv/d
Dose eq. from GCRGCR: 1 mSv/d
P. Scampoli - 24th ICNTS Bologna, September 4, 2008P. Scampoli - 24th ICNTS Bologna, September 4, 2008 66
DNA dsb visualized by immuno-fluorescence of -H2AX histone in human skin fibroblasts exposed to 2 Gy of ionizing radiation
-rays
silicon
ironCucinotta and Durante, Lancet Oncol. 2006
P. Scampoli - 24th ICNTS Bologna, September 4, 2008P. Scampoli - 24th ICNTS Bologna, September 4, 2008 77
Risk associated to a manned Space Risk associated to a manned Space explorationexploration
CarcinogenesisCarcinogenesis
Acute Radiation SicknessAcute Radiation Sickness
Degenerative Tissue Damage (heart, lens, Degenerative Tissue Damage (heart, lens,
digestive, …)digestive, …)
Central Nervous System damageCentral Nervous System damage
P. Scampoli - 24th ICNTS Bologna, September 4, 2008P. Scampoli - 24th ICNTS Bologna, September 4, 2008 88
Uncertainties for risk estimationUncertainties for risk estimation
)()( LLQLdLFHT
T
TT HsexageRdosesexageRisk ),(),,( ,0
Overall uncertainty:
400-1500%
P. Scampoli - 24th ICNTS Bologna, September 4, 2008P. Scampoli - 24th ICNTS Bologna, September 4, 2008 99
Carbon-ion therapyCarbon-ion therapy
An extensive database on nuclear fragmentation cross sections and fluences are needed at therapeutic energy region
Carbon ions fragmentation:
Fall of dose in the tumour target region
Unwanted dose in normal tissue behind the target volume
P. Scampoli - 24th ICNTS Bologna, September 4, 2008P. Scampoli - 24th ICNTS Bologna, September 4, 2008 1010
Radiation-biophysics needsRadiation-biophysics needs
Biology
Assessment of the biological effects of HZE particles
Physics
•Assessment of the radiation environment
•Shielding optimization
P. Scampoli - 24th ICNTS Bologna, September 4, 2008P. Scampoli - 24th ICNTS Bologna, September 4, 2008 1111
Biological effects in mixed radiation fieldBiological effects in mixed radiation field
Biophysical model of radiation actionBiophysical model of radiation action
Model for determining the ion track Model for determining the ion track structure and energy deposition at local structure and energy deposition at local levellevel
Experimental measurements are essential for benchmarking physics models and transport code to give fluence, energy, and dose distribution with the required accuracy
P. Scampoli - 24th ICNTS Bologna, September 4, 2008P. Scampoli - 24th ICNTS Bologna, September 4, 2008 1212
Ground-based experimentsGround-based experiments
P. Scampoli - 24th ICNTS Bologna, September 4, 2008P. Scampoli - 24th ICNTS Bologna, September 4, 2008 1313
Experimental configuration for mixed radiation Experimental configuration for mixed radiation field studies and shielding optimizationfield studies and shielding optimization
Physics Beam
detector detector
Target
Radiobiology
Target IC
P. Scampoli - 24th ICNTS Bologna, September 4, 2008P. Scampoli - 24th ICNTS Bologna, September 4, 2008 1414
Thick and thin targets Thick and thin targets
Physics
Beam
detector detector
Target
i
iiLD 6.1
iii
i LLQdLLDLQD
DQDH 1
Thick target=
fluence measurements
Thin target=
cross section measurements
P. Scampoli - 24th ICNTS Bologna, September 4, 2008P. Scampoli - 24th ICNTS Bologna, September 4, 2008 1515
CR39 SSNTD in ground-based experiments CR39 SSNTD in ground-based experiments
p2
2
LET
LET
Z
Z
p
2Z
LET
pp LET
LETZZ
LET spectrum measurement through appropriate calibration
Geometrical track parameters measurement
Fe 114 MeV/nLET 414 keV/m
D = 62 m
Fe 1000 MeV/n LET 147 keV/m
Si 600 MeV/n LET 50 keVm
D = 46 mD = 35 m
Etching condition:6 N NaOH water solutiont=24hT=70°C
P. Scampoli - 24th ICNTS Bologna, September 4, 2008P. Scampoli - 24th ICNTS Bologna, September 4, 2008 1616
CR39 SSNTD in ground-based experimentsCR39 SSNTD in ground-based experiments
Very good charge Very good charge resolution resolution
Easy to useEasy to use
LET threshold LET threshold ((~keV/~keV/m)m)
Low fluence irradiation Low fluence irradiation (10(1033 p/cm p/cm22))
Track analysis cannot Track analysis cannot be done manuallybe done manually
ADVANTAGES LIMITATIONS
P. Scampoli - 24th ICNTS Bologna, September 4, 2008P. Scampoli - 24th ICNTS Bologna, September 4, 2008 1717
Automatic track analysis systems Automatic track analysis systems
Microscope development for image digitization
Yasuda et al., Radiat. Meas., 2005
Tawara et al., NIM A., 2008
P. Scampoli - 24th ICNTS Bologna, September 4, 2008P. Scampoli - 24th ICNTS Bologna, September 4, 2008 1818
Cross section measurements (“thin” target)Cross section measurements (“thin” target)
Fe, 1 GeV/n Fe, 1 GeV/n+1 cm PMMA
Cecchini S. et al., Nucl. Phys., 2008
INTERCAST CR39Etching condition:6 N NaOH water solutiont=30 hT=70°C
targ
et
P. Scampoli - 24th ICNTS Bologna, September 4, 2008P. Scampoli - 24th ICNTS Bologna, September 4, 2008 1919
5 10 15 20 25 30 35 40
500
1000
1500
2000
2500
3000
Zeitling et al. Scampoli et al.
Cross section measurementsCross section measurements
Cecchini S. et al., Nucl. Phys., 2008
Database:Database:
Ion Energy range Target
4He; 6C; 14N, 16C; 20Ne; 28Si; 40Ar; 48Ti 0.2 – 10 A GeV CH2; PMMA; C; Al; Cu; Pb
P. Scampoli - 24th ICNTS Bologna, September 4, 2008P. Scampoli - 24th ICNTS Bologna, September 4, 2008 2020
Measurements with “thick” targetMeasurements with “thick” target
Same condition as biological experimentsSame condition as biological experiments
Fe, E=1 A GeV
Measurements of primary beam contribution to the total dose after different shielding materials
P. Scampoli - 24th ICNTS Bologna, September 4, 2008P. Scampoli - 24th ICNTS Bologna, September 4, 2008 2121
Shielding properties of different materialsShielding properties of different materials
Scampoli P. et al., Radiat. Res., 2005
Surviving fraction of incoming particles after different shielding materials is measured with CR39 Intercast detectors
1 A GeV 5 A GeV
P. Scampoli - 24th ICNTS Bologna, September 4, 2008P. Scampoli - 24th ICNTS Bologna, September 4, 2008 2222
Biological effectiveness of shieldingBiological effectiveness of shielding
20
25
30
35
40
45
0 2 4 6 8 10 12
PMMAAlPb
Thickness (g/cm2)
Ab
err
atio
ns
pe
r p
art
icle
(µ
m2)
0
0,1
0,2
0,3
0,4
0,5
0,6
0,7
0 5 10 15 20 25 30
PMMAAlPbLDPEC
Do
se p
er
pa
rtic
le (
µG
y x
cm2)
Thickness (g/cm2)
500 MeV/n
1 GeV/n
5
10
15
20
25
30
35
0 5 10 15 20 25 30
PMMAAlPbLDPEC
Abe
rrat
ions
per
par
ticle
(µ
m2)
Thickness (g/cm2)
Durante et al., Radiat. Res, 2005
500 A MeV 1 A GeV
Fe beam
P. Scampoli - 24th ICNTS Bologna, September 4, 2008P. Scampoli - 24th ICNTS Bologna, September 4, 2008 2323
Measurements with carbon ions for RTMeasurements with carbon ions for RT
Energies up to 500 A MeV
Track etched detector are used with suitable etching condition
Emulsion detector
Low fluence
Z ≤ 6e
Target: tissue equivalent material
Analysis
P. Scampoli - 24th ICNTS Bologna, September 4, 2008P. Scampoli - 24th ICNTS Bologna, September 4, 2008 2424
Emulsion Cloud ChamberEmulsion Cloud Chamber
Toshito. et al., Phys. Rev. C., 2008
High spatial resolution (~m)
Multiparticle separation
Density grain is proportional to energy loss
Refreshing method for extending the dynamic range of response
High angular resolution (~mrad)
P. Scampoli - 24th ICNTS Bologna, September 4, 2008P. Scampoli - 24th ICNTS Bologna, September 4, 2008 2525
Cross section measurementsCross section measurements
Toshito. et al., Phys. Rev. C., 2008
Shall et al., Nim B, 1996Golovchenko et al., Nim B, 1996 and Phys. Rev. C 2002
Golovchenko et al., Nim B, 1996 and Phys. Rev. C 2002
Golovchenko et al., Nim B, 1996 and Phys. Rev. C 2002
Good agreement with previous experimental data
Discrepancy of about 10% and 20% with model
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ConclusionsConclusions
Ground based experiments are still necessary for code bench marking, both in Space radiation-protection and radio-therapy with carbon ions
Shielding properties of new material (e.g. Kevlar and Nextel) have to be investigated
Development of technology make more suitable track-etch detectors for these purposes
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