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Distribuzione di radicali liberi in dosimetri EPR irradiati con radiazioni di diverso LET
aDipartimento di Fisica, Università di PalermobSezione INFN di Catania Catania
cDipartimento di Scienze Chimiche, Università di Padova e INFN Sezione di PadovadLaboratori Nazionali del Sud-INFN Catania
eMuseo Storico della Fisica e Centro Studi e Ricerche "E. Fermi" RomafAzienda Sanitaria Provinciale N° 2, Pres. Osped. "M. Raimondi" S. Cataldo (CL)
M. Marralea,b, A. Longoa,b, M. Braia,b, A. Barbonc, M. Brustolonc, G.A.P. Cirroned, F. Romanod,e, F. Di Rosaf, G.Cuttoned
E-mail: [email protected]
XCVIII Congresso Nazionale SIF Napoli 17-21 Settembre 2012
M. Marrale et al.– Distribuzione di radicali liberi in dosimetri EPR
Hadrontherapy Hadrontherapy vsvs photon radiotherapy photon radiotherapy
XCVIII Congresso Nazionale SIF Napoli 17-21 Settembre 2012
M. Marrale et al.– Distribuzione di radicali liberi in dosimetri EPR
Hadrontherapy Hadrontherapy vsvs photon radiotherapy photon radiotherapy
XCVIII Congresso Nazionale SIF Napoli 17-21 Settembre 2012
M. Marrale et al.– Distribuzione di radicali liberi in dosimetri EPR
Hadrontherapy Hadrontherapy vsvs photon radiotherapy photon radiotherapy
XCVIII Congresso Nazionale SIF Napoli 17-21 Settembre 2012
M. Marrale et al.– Distribuzione di radicali liberi in dosimetri EPR
Differences in Relative Biological EffectivenessDifferences in Relative Biological Effectiveness
Hall E. J. (2000). Radiation Biology for the Radiologist. Lippincott Williams & Wilkins: Philadelphia.
The surviving cell fraction decreases with LET
Cell response depends on Linear Energy Transfer (LET)
XCVIII Congresso Nazionale SIF Napoli 17-21 Settembre 2012
M. Marrale et al.– Distribuzione di radicali liberi in dosimetri EPR
Differences in Relative Biological EffectivenessDifferences in Relative Biological Effectiveness
Hall E. J. (2000). Radiation Biology for the Radiologist. Lippincott Williams & Wilkins: Philadelphia.
Cucinotta, F. A. & Durante, M. Lancet Oncol. (2006) 7 431-435.
The surviving cell fraction decreases with LET
Cell response depends on Linear Energy Transfer (LET)
XCVIII Congresso Nazionale SIF Napoli 17-21 Settembre 2012
M. Marrale et al.– Distribuzione di radicali liberi in dosimetri EPR
Radiation interaction in nanometer dimensions
In order to optimize the therapy it is necessary to grasp the mechanisms on the basis of the biological damages induced by ionizing radiations.
XCVIII Congresso Nazionale SIF Napoli 17-21 Settembre 2012
M. Marrale et al.– Distribuzione di radicali liberi in dosimetri EPR
Radiation interaction in nanometer dimensions
In order to optimize the therapy it is necessary to grasp the mechanisms on the basis of the biological damages induced by ionizing radiations.
Analysis of the Analysis of the Track StructureTrack Structure
Figures from Hans Rabus, PTB (Germany)
XCVIII Congresso Nazionale SIF Napoli 17-21 Settembre 2012
M. Marrale et al.– Distribuzione di radicali liberi in dosimetri EPR
Target of this workTarget of this work
XCVIII Congresso Nazionale SIF Napoli 17-21 Settembre 2012
M. Marrale et al.– Distribuzione di radicali liberi in dosimetri EPR
Target of this workTarget of this work This work is aimed at the analysis of the distribution of free radicals produced by various LET radiations through Electron Spin Resonance (ESR or EPR) technique. This spectroscopic tool allows dose measurements via the detection of the free radicals produced by ionizing radiations.
XCVIII Congresso Nazionale SIF Napoli 17-21 Settembre 2012
M. Marrale et al.– Distribuzione di radicali liberi in dosimetri EPR
Target of this workTarget of this work
In this work we analyzed and simulated the experimental results obtained by Pulse ESR techniques with the aim of obtaining information about the microscopic local concentration and the spin-spin distance distribution of free radicals.
This spectroscopic tool allows dose measurements via the detection of the free radicals produced by ionizing radiations.
This work is aimed at the analysis of the distribution of free radicals produced by various LET radiations through Electron Spin Resonance (ESR or EPR) technique.
XCVIII Congresso Nazionale SIF Napoli 17-21 Settembre 2012
M. Marrale et al.– Distribuzione di radicali liberi in dosimetri EPR
ORGANIC COMPOUND USED – AMMONIUM TARTRATE (AT)
ESR spectrumSTRUCTURE
.
M. Brustolon, A. L. Maniero, S. Jovine, and U. Segre, Res. Chem. Intermed. 22(4), 359 (1996).
Powder samples
XCVIII Congresso Nazionale SIF Napoli 17-21 Settembre 2012
M. Marrale et al.– Distribuzione di radicali liberi in dosimetri EPR
Free radicals distributions for radiations with Free radicals distributions for radiations with various LETvarious LET
XCVIII Congresso Nazionale SIF Napoli 17-21 Settembre 2012
M. Marrale et al.– Distribuzione di radicali liberi in dosimetri EPR
Free radicals distributions for radiations with Free radicals distributions for radiations with various LETvarious LET
Low LET radiations Small local concentrationof free radicals
XCVIII Congresso Nazionale SIF Napoli 17-21 Settembre 2012
M. Marrale et al.– Distribuzione di radicali liberi in dosimetri EPR
Free radicals distributions for radiations with Free radicals distributions for radiations with various LETvarious LET
Low LET radiations
High LET radiations High local concentrationof free radicals
Small local concentrationof free radicals
XCVIII Congresso Nazionale SIF Napoli 17-21 Settembre 2012
M. Marrale et al.– Distribuzione di radicali liberi in dosimetri EPR
LET in Ammonium tartrateLET in Ammonium tartrate
— 60Co γ-photons
— 19.3 MeV protons— 0.62 MeV protons (thermal neutrons)
AVERAGE AVERAGE
EFFECTIVE LETEFFECTIVE LET
~ 0.35 keV/~ 0.35 keV/µµmm
~ 4.5 keV/~ 4.5 keV/µµmm
~ 70 keV/~ 70 keV/µµmm
We have used for protons simulations the TRIM software for photon simulations the MCNP software.
XCVIII Congresso Nazionale SIF Napoli 17-21 Settembre 2012
M. Marrale et al.– Distribuzione di radicali liberi in dosimetri EPR
Pulsed EPR techniques employed
Two pulses EPR echo decay with varying microwave power intensity in order to obtain information about the microscopic local concentration of free radicals for pellets exposed to various radiation beams.
Double Electron-Electron Resonance (DEER) in order to obtain information about the spin-spin distance distributions for pellets exposed to various radiation beams.
XCVIII Congresso Nazionale SIF Napoli 17-21 Settembre 2012
M. Marrale et al.– Distribuzione di radicali liberi in dosimetri EPR
Two pulses EPR echo decay analysisTwo pulses EPR echo decay analysis
XCVIII Congresso Nazionale SIF Napoli 17-21 Settembre 2012
M. Marrale et al.– Distribuzione di radicali liberi in dosimetri EPR
AT exposed to 5kGy ofgamma photons.
Tm
Two pulses EPR echo decay analysisTwo pulses EPR echo decay analysis
XCVIII Congresso Nazionale SIF Napoli 17-21 Settembre 2012
M. Marrale et al.– Distribuzione di radicali liberi in dosimetri EPR
Two pulses EPR echo decay analysisTwo pulses EPR echo decay analysis
XCVIII Congresso Nazionale SIF Napoli 17-21 Settembre 2012
M. Marrale et al.– Distribuzione di radicali liberi in dosimetri EPR
Local microscopic concentration of free radicals Local microscopic concentration of free radicals
AVERAGE EFFECTIVE LETAVERAGE EFFECTIVE LET
~ 0.35 keV/~ 0.35 keV/µµmm
~ 4.5 keV/~ 4.5 keV/µµmm
~ 70 keV/~ 70 keV/µµmm
High LET radiations (protons and thermal neutrons) are characterized by larger ratio Cmicroscopic/Cmacroscopic values than low LET radiations.
M. Marrale, M. Brai, A. Barbon, M. Brustolon Radiat. Res. (2009) 171,349–359
XCVIII Congresso Nazionale SIF Napoli 17-21 Settembre 2012
M. Marrale et al.– Distribuzione di radicali liberi in dosimetri EPR
Two pulses EPR echo decay analysis Two pulses EPR echo decay analysis ConclusionsConclusions
This technique is able to distinguish low LET This technique is able to distinguish low LET radiations (such as radiations (such as 6060Co Co γγ-photons) from -photons) from high high LET radiations (19.3 MeV protons LET radiations (19.3 MeV protons and thermal and thermal neutrons).neutrons).
The similarity of the microscopic concentrations The similarity of the microscopic concentrations of protons and thermal neutrons could be of protons and thermal neutrons could be ascribed to radicals recombination. ascribed to radicals recombination.
XCVIII Congresso Nazionale SIF Napoli 17-21 Settembre 2012
M. Marrale et al.– Distribuzione di radicali liberi in dosimetri EPR
Double Electron-Electron resonance (DEER)Double Electron-Electron resonance (DEER)
Measures dipolar coupling between Measures dipolar coupling between spatially separated unpaired electrons spatially separated unpaired electrons using pulsed EPRusing pulsed EPR
Dipolar coupling is related to radical Dipolar coupling is related to radical separationseparation
Hamiltonian:20
1 2 3 5
. ( . )( . )ˆ 34
1 2 1 2S S S r S rddH g g
r rβµ µπ
= − −
XCVIII Congresso Nazionale SIF Napoli 17-21 Settembre 2012
M. Marrale et al.– Distribuzione di radicali liberi in dosimetri EPR
Double electron-electron resonance (DEER)Double electron-electron resonance (DEER)
τ
Δν
Pump
Observe
Δν
Distance / nm2 4 6 8
Time / sμ20
-10 0 10Frequency / MHz
π/2π π
π
Janet BanhamTesting the Limits of the DEER Method for Distance Measurements in Proteins Oxford University
XCVIII Congresso Nazionale SIF Napoli 17-21 Settembre 2012
M. Marrale et al.– Distribuzione di radicali liberi in dosimetri EPR
Double electron-electron resonance (DEER)Double electron-electron resonance (DEER)
τ
Δν
Pump
Observe
Δν
Distance / nm2 4 6 8
Time / sμ20
-10 0 10Frequency / MHz
π/2π π
π
Janet BanhamTesting the Limits of the DEER Method for Distance Measurements in Proteins Oxford University
XCVIII Congresso Nazionale SIF Napoli 17-21 Settembre 2012
M. Marrale et al.– Distribuzione di radicali liberi in dosimetri EPR
Double electron-electron resonance (DEER)Double electron-electron resonance (DEER)
τ
Δν
Pump
Observe
Δν
Distance / nm2 4 6 8
Time / sμ20
-10 0 10Frequency / MHz
π/2π π
π
Janet BanhamTesting the Limits of the DEER Method for Distance Measurements in Proteins Oxford University
XCVIII Congresso Nazionale SIF Napoli 17-21 Settembre 2012
M. Marrale et al.– Distribuzione di radicali liberi in dosimetri EPR
Double Electron Electron Resonance (DEER)Double Electron Electron Resonance (DEER)
ν pump
ν detection
XCVIII Congresso Nazionale SIF Napoli 17-21 Settembre 2012
M. Marrale et al.– Distribuzione di radicali liberi in dosimetri EPR
Distance distributions of free radicalsDistance distributions of free radicals
M. Marrale, M. Brai, A. Barbon, M. Brustolon Radiat. Res. (2009) 171,349–359
XCVIII Congresso Nazionale SIF Napoli 17-21 Settembre 2012
M. Marrale et al.– Distribuzione di radicali liberi in dosimetri EPR
Distance distributions of free radicalsDistance distributions of free radicals
These curves are affected by two factors:
the lattice structure of the ammonium tartrate microcrystals in powders;
the spatial distribution of free radicals produced by ionizing radiations inside the volume
M. Marrale, M. Brai, A. Barbon, M. Brustolon Radiat. Res. (2009) 171,349–359
XCVIII Congresso Nazionale SIF Napoli 17-21 Settembre 2012
M. Marrale et al.– Distribuzione di radicali liberi in dosimetri EPR
Free radicals distributions assumed for simulationsFree radicals distributions assumed for simulations
XCVIII Congresso Nazionale SIF Napoli 17-21 Settembre 2012
M. Marrale et al.– Distribuzione di radicali liberi in dosimetri EPR
Free radicals distributions assumed for simulationsFree radicals distributions assumed for simulations
19.3 MeV Protons 19.3 MeV Protons
XCVIII Congresso Nazionale SIF Napoli 17-21 Settembre 2012
M. Marrale et al.– Distribuzione di radicali liberi in dosimetri EPR
Free radicals distributions assumed for simulationsFree radicals distributions assumed for simulations
6060Co Co γγ -photons-photons
19.3 MeV Protons 19.3 MeV Protons
XCVIII Congresso Nazionale SIF Napoli 17-21 Settembre 2012
M. Marrale et al.– Distribuzione di radicali liberi in dosimetri EPR
Distance distributions of free radicalsDistance distributions of free radicals
Good agreement Good agreement between experimental between experimental data and simulation data and simulation
results. results.
M. Marrale, M. Brai, A. Barbon, M. Brustolon Radiat. Res. (2009) 171,349–359
XCVIII Congresso Nazionale SIF Napoli 17-21 Settembre 2012
M. Marrale et al.– Distribuzione di radicali liberi in dosimetri EPR
This pulse EPR technique discriminates samples This pulse EPR technique discriminates samples exposed to exposed to γγ-photons from those exposed to protons.-photons from those exposed to protons.
The radical distributions assumed for protons The radical distributions assumed for protons (cylindrical distribution) and photons (spherical (cylindrical distribution) and photons (spherical distribution) exposure give rise to a good agreement distribution) exposure give rise to a good agreement between experimental data and simulations.between experimental data and simulations.
Double Electron Electron Resonance (DEER)Double Electron Electron Resonance (DEER)ConclusionsConclusions
Analyses on crystal samples exposed to various radiation Analyses on crystal samples exposed to various radiation beams (such as photons, thermal neutrons and ions)beams (such as photons, thermal neutrons and ions)are in progress.are in progress.
XCVIII Congresso Nazionale SIF Napoli 17-21 Settembre 2012
M. Marrale et al.– Distribuzione di radicali liberi in dosimetri EPR
AcknowledgementsAcknowledgements
We acknowledge funding from the Project NORMET of theIstituto Nazionale di Fisica Nucleare (INFN) Gruppo V.
National Project Leader: Dr. Maurizio Marrale
The research here described is related to the Project Biologically weighted quantities in radiotherapy (BIOQUART)
EMRP European Metrology Research Programme.Project Leader: Dr. Hans Rabus (PTB, Braunschweig, Germany)
XCVIII Congresso Nazionale SIF Napoli 17-21 Settembre 2012
M. Marrale et al.– Distribuzione di radicali liberi in dosimetri EPR
Thank you for your attention!Thank you for your attention!