IONIZATION AND FRAGMENTATION OF DNA, RNA COMPONENS INDUCED BY PROTON IMPACT
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IONIZATION AND FRAGMENTATION OF IONIZATION AND FRAGMENTATION OF DNA, RNA COMPONENS INDUCED BY PROTON IMPACT DNA, RNA COMPONENS INDUCED BY PROTON IMPACT P.Moretto-Capelle, A.Le Padellec, M.Richard-Viard, J.P.Champeaux and P.Cafarelli Laboratoire Collisions, Agregats, Reactivité (UMR5589 CNRS-Univ.Paul Sabatier Toulouse 3) IRSAMC 31062 Toulouse cedex 9, France Damages induced by ionizing radiation can directly be linked to alteration of the DNA molecule. In this work, we investigate interactions between protons and phase gas DNA/RNA bases and nucleoside Energy loss by a proton in matter? Example of transport of 100 MeV proton in liquid water Important dose deposition in a well defined spatial zone Bragg Peack (BP): PROTONTHERAPY Maximum dose: proton decellerated around 100keV: maximum LET Corresponding DNA damages: evoluated Monte-Carlo codes (Nikjoo,O’Neill, Terrisol, Goodheart Rad.Env.Biophys (1999)38), we used more simpler MCDS program whose coefficients are fitted on MC codes. (Semennenko, Steward Rad.Res. (2004) 161) 10 100 10 -21 10 -20 10 -19 10 -18 D D C S (c m 2 eV -1 sr -1 ) E lectronic energy (eV ) 100 keV 50 keV 25 keV Thy FROM BASES DAMAGES EMISSION OF SECONDARY ELECTRONS Damages induced by secondary electron depend on kinetic energy: Need to know energy spectrum of the emitted electrons BUT also the absolute yield (cross section) Low energy (<20eV): dissociative attachment High energy(>20eV): ionization,fragme ntation -40 -30 -20 -10 0 10 20 30 40 0 10 20 30 40 50 60 70 80 X mm D e p th (m m) 1 10 100 1000 10000 100000 0 10 20 30 40 50 60 70 80 D epth (m m) P ro to n E n erg y (keV ) 1 10 100 1000 10000 100000 0 20 40 60 80 P ro to n E n erg y (keV ) LET (keV/ m) O u r accelerato r en erg y ran g e 100 1000 10000 100000 0.1 1 10 100 % DNA dam ages P ro to n E n erg y (keV ) BD SSB SSBp 2SSD DSB DSBp DSBpp Range around 100keV is interesting=> ultra thin target=> biomolecule in gaz phase 120 130 140 150 160 170 180 190 200 210 220 230 240 250 0 100 200 300 400 500 600 700 800 900 1000 TOWARDS ELEMENTARY STRAND BREAK: Irradiation of URIDINE 0 10 20 30 40 50 60 70 80 90 100 110 120 0 10000 20000 30000 40000 C ounts Additi vi ty? Destruction of the sugar=> Strand Break RADIOSENSITIZER? PHYSICAL MECHANISMS? 1-PHYSICAL Studies at molecular scale (… gaz phase) fragmentation patterns, electronic emission, corresponding cross sections Difference with ‘standart’ molecules? 2-IRRADIATION of DNA (plasmid) deposited SURFACE without and with molecule Carboplat ine Cisplatine Halo-Uracil (F,Br,I) ANALYSIS OF STRAND BREAKS: LINKS? Measurment of electron spectra: majority of low energy electrons Caracterization by CTMC modeling: -Total cross sections -Yield in angle and energy 10 100 0 2 4 6 8 S15 S35 S55 S75 S 95 S 135 S 155 S 175 D D C S (arb.u nit) E C C peack Many small molecules are formed PHYSICAL STAGE OF THE INTERACTION (fs): PRODUCTION OF DATA Formation of numerous small fragments: - Identification and branching ratio Can interact with neighbouring structures Number of molecule / base pair ? SRIM 2006 Moretto-Capelle, Le Padellec, Phys.Rev.A (2006)
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IONIZATION AND FRAGMENTATION OF DNA, RNA COMPONENS INDUCED BY PROTON IMPACT. P .Moretto-Capelle, A.Le Padellec, M.Richard-Viard, J.P.Champeaux and P.Cafarelli Laboratoire Collisions, Agregats, Reactivité (UMR5589 CNRS-Univ.Paul Sabatier Toulouse 3) IRSAMC 31062 Toulouse cedex 9, France. - PowerPoint PPT Presentation
Transcript of IONIZATION AND FRAGMENTATION OF DNA, RNA COMPONENS INDUCED BY PROTON IMPACT
IONIZATION AND FRAGMENTATION OFIONIZATION AND FRAGMENTATION OF DNA, RNA COMPONENS INDUCED BY PROTON IMPACTDNA, RNA COMPONENS INDUCED BY PROTON IMPACT
P.Moretto-Capelle, A.Le Padellec, M.Richard-Viard, J.P.Champeaux and P.Cafarelli
Laboratoire Collisions, Agregats, Reactivité (UMR5589 CNRS-Univ.Paul Sabatier Toulouse 3) IRSAMC 31062 Toulouse cedex 9, France
Damages induced by ionizing radiation can directly be linked to alteration of the DNA molecule. In this work, we investigate interactions between protons and phase gas DNA/RNA bases and nucleoside
Energy loss by a proton in matter? Example of transport of 100 MeV proton in liquid water
Important dose deposition in a well defined spatial zone Bragg Peack (BP):
PROTONTHERAPY
Maximum dose: proton decellerated around 100keV: maximum LET
Corresponding DNA damages: evoluated Monte-Carlo codes (Nikjoo,O’Neill, Terrisol, Goodheart
Rad.Env.Biophys (1999)38), we used more simpler MCDS program whose coefficients are fitted on MC codes. (Semennenko, Steward Rad.Res. (2004) 161)
10 10010-21
10-20
10-19
10-18
DD
CS
(cm
2 eV-1
sr-1
)
Electronic energy (eV)
100 keV 50 keV 25 keV
Thy
FROM BASES DAMAGES
EMISSION OF SECONDARY ELECTRONS
Damages induced by secondary electron depend on kinetic
energy:
Need to know energy spectrum of the emitted electrons
BUT also the absolute yield (cross section)
Low energy (<20eV): dissociative attachment
High energy(>20eV): ionization,fragmentation
-40 -30 -20 -10 0 10 20 30 400
10
20
30
40
50
60
70
80
X mm
Dep
th (
mm
)
1 10 100 1000 10000 1000000
10
20
30
40
50
60
70
80
Dep
th (m
m)
Proton Energy (keV)
1 10 100 1000 10000 1000000
20
40
60
80
Proton Energy (keV)
LET
(keV
/m
)
Our accelerator energy range
100 1000 10000 100000
0.1
1
10
100
% D
NA
dam
ages
Proton Energy (keV)
BD SSB SSBp 2SSD DSB DSBp DSBpp
Range around 100keV is interesting=> ultra thin target=> biomolecule in gaz phase
120 130 140 150 160 170 180 190 200 210 220 230 240 2500
100
200
300
400
500
600
700
800
900
1000
TOWARDS ELEMENTARY STRAND BREAK: Irradiation of URIDINE
0 10 20 30 40 50 60 70 80 90 100 110 1200
10000
20000
30000
40000
Counts
Additivity?
Destruction of the sugar=> Strand Break
RADIOSENSITIZER? PHYSICAL MECHANISMS?
1-PHYSICAL Studies at molecular scale (… gaz phase)
fragmentation patterns, electronic emission, corresponding cross sections
Difference with ‘standart’ molecules?
2-IRRADIATION of DNA (plasmid) deposited SURFACE
without and with molecule
Carboplatine Cisplatine Halo-Uracil (F,Br,I)ANALYSIS OF STRAND BREAKS:LINKS?
Measurment of electron spectra: majority of low energy electrons
Caracterization by CTMC modeling:-Total cross sections-Yield in angle and energy
10
100
0
2
4
6
8
S15S35
S55S75
S95S135
S155S175
DDCS (arb.unit)
ECC peack
Many small molecules are formed
PHYSICAL STAGE OF THE INTERACTION (fs): PRODUCTION OF DATA
Formation of numerous small fragments:- Identification and branching ratioCan interact with neighbouring structures
Number of molecule / base pair ?
SRIM 2006
Moretto-Capelle, Le Padellec, Phys.Rev.A (2006)
