Carbon beam dosimetry using VIP polymer gel and MRI

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Carbon beam dosimetry using VIP polymer gel and
MRI

• I Kantemiris, L Petrokokkinos, A Angelopoulos, N
  Bassler, I Seimenis, P Karaiskos

DOSGEL 2008
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?ax Beam Energy (MeV)
Beam
Country
?ax Beam Energy (MeV)
Beam
Country
160
p
Harvard (U.S.A.)
200
p
ITEP(Russia)
1000
p
St.Petersbur(Russia)
70
p
Chiba (Japan)
70
p
PMRC (Japan)
72
p
PSI (Swededn)
200
p
Dubna (Russia)
200
p
Uppsala (Sweden)
Clatterbridge (U.K.)
62
p
250
p
Loma Linda (U.S.?.)
65
p
?ice (France)
200
p
?rsay (France)
200
p
iThemba Labs(S. Africa)
200
p
?PRI(2) (U.S.?.)
60
p
UCSF (U.S.?.)
800/u
ion
HIMAC (Japan)
72
p
TRIUMF (Canada)
230
p
PSI (Sweden)
430/u
ion
GSI (Germany)
250
p
RPTC,Koeln (Germany)
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The polymer gels have been tested in photon and
electron beams and they seems to work very well.
What would be the outcome of gels irradiation by
carbon ions???
We prepared two vials of VIP polymer
gel (normoxic formulation)
After the gels were prepared in Athens they were
shipped to GSI, Germany and after the irradiation
they were shipped to Cyprus in order to be
scanned.
The whole procedure lasted 6 days
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1st bottle A monoenergetic beam of 150MeV/n was
used to deliver 10Gy dose to water in plateau. A
square field of 2x2cm2 was used and the direction
of the beam was from the cap to the bottom of the
bottle (in order to avoid interactions with glass)
2nd bottle An energy spectrum was used to
deliver 5Gy dose in water to a spread out Bragg
peak (SOBP) residing between 3 and 6cm depth in
water. A square field of 1x1cm2 was used with the
same direction as in the 1st bottle.
The gels data were compared with MC
calculations. FLUKA2006.3b was implemented for
this purpose.
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1st vial
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After correcting caps thickness
8mm
6mm due to composition
2mm due to density
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12C 200MeV/n
12mm
2.5mm due to density and 9.5mm due to composition
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12C 250MeV/n
17mm
3mm due to density and 14mm due to composition
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The typical dose response characteristics of VIP
with photon beams Linear response 2.5 - 35Gy
Linear response function
(1)
(1)
10.38 Gy
Planned plateau dose 10Gy
(FLUKA)
10.83Gy VIP
? Efficiency in plateau100
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In the 2nd vial 5Gy water equivalent dose was
delivered to the SOBP.
This dose is slightly over the detection limit
(signal1.87 s-1, R2(0)1.76 s-1).
In peak 5.88Gy were measured in SOPB.
Efficiency in peak region 100 !!!
One possible conclusion
Low efficiency of VIP dosimeter in high LET-high
dose regions may be also related to the specific
dose characteristics of the gel dosimeter (dose
range, dose response and in general the specific
monomers used which determine these
characteristics).
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Thank you
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