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Dose and microdosimetry in sub-cellular volumes associated with the uptake of
high-Z materials
Richard P. Hugtenburg1,2
1. School of Physics and Astronomy, University of Birmingham, U.K2. Queen Elizabeth Medical Centre, University Hospital Birmingham, U.K.
Synchrotron binary therapy at ESRF with cisplatin (Pt) better than BNCT for F98 Glioma cells in Fischer rats
Biston et al., 2004, Cancer Research 64 2317–2323
Cisplatin + radiotherapy
Controls
Biston et al., 2004, show that irradiation with monoenergetic synchrotron X-rays less than 500 eV above and below K-edge
of Pt are indistinguishable
Dosimeter intercomparisons on Station 16.5 – SRS
Measurement of variation of dose-rate on Wiggler 16 at the SRS (Daresbury, UK)
2.0E-05
2.2E-05
2.4E-05
2.6E-05
2.8E-05
3.0E-05
24.0 24.5 25.0 25.5 26.0 26.5 27.0
Energy (keV)
Res
pons
eG
y/m
A/S
ec0.0E+00
5.0E-05
1.0E-04
1.5E-04
2.0E-04
2.5E-04
3.0E-04
5 10 15 20 25Energy (keV)
Rela
tive
Resp
onse
Gy/
mA
/Sec
Models of the response agree with expt to within 5% over a wide range of energies (5 keV – 5 MeV)
0.0
0.2
0.4
0.6
0.8
1.0
0 5 10 15 20 25Energy (keV)
Rat
io o
f Dos
e D
iam
ond:
Ion
cham
ber
0.0
0.2
0.4
0.6
0.8
1.0
5 55 105 155 205
Enrgy (kev )
Rat
io o
f Dos
e di
amon
d/ch
ambe
r
ratio C/Wratio diam/WExp. ratioYin No. !7
Experimental set-up and Monte Carlo models
DETECTOR(DIAMOND)
PHANTOM(rw-1)
2 cmPOLYTHENE
0.03 cmDIAMOND
0.15 cmPOLYTHENE
DIAMONDDETECTOR
DETECTOR(WATER)
PHANTOM(WATER)
IONISATIONCHAMBER
1×10 mm
Synchrotron beam
Parallel Plate Chamber
1×10 mm
Synchrotron beam
Diamond Detector Impeded in RW-1
1×10 mm
Synchrotron beam
Diamond Detector Impeded in RW-1
Silver FLUORESCENT
0
20
40
60
80
100
120
140
160
-400 -200 0 200 400 600 800 1000
Gold FLUORESCENT
0
20
40
60
80
100
120
-400 -200 0 200 400 600
More detailed Monte Carlo models incorporating data obtained from µXRF
EGS4/LSCAT v. absorption models for Ag
Hainfeld et al., 2004Au nanoparticles for enhanced 250 kVp RT,PMB, 49: N309, 2004
Adam et al, 2003, Synchrotron RT of I and Gd loaded glioma, IntJ RadiatOncBiolPhys 57: 1413
Dose enhancement through high-Z targeted RT
Maximum enhancement occurs beyond K-edge
Energy used by Adam et al.
Biston et al., 2004, Irradiation above or below K-edge radiobiologically indistinguishable, Cancer Res., 64: 2317
EGS4/LSCAT versus absorption models for Pt
Dose enhancement for localised 10 mg/ml concentrations of Pt relative to that of a water-filled volume
Region size @ 10 mg/ml 78.0 keV 78.8 keV 90 keV
0.2 micron 1.02 1.20 1.16
2 micron 1.10 1.33 1.38
20 micron 1.26 1.53 1.51
Determination of energy deposition within small volumes – Going beyond dose and LET
• Tissue equivalent proportional counter (TEPC)• Lineal energy calculations via PENELOPE
Schematic and photograph of a single wire TEPC microdosimeter
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
0.10 1.00 10.00 100.00 1000.00
Lineal energy (keV/µm)
y.d(y
) (a
rb.u
nits)
Photons
ProtonsHeavy ions
f
Microdosimetry measurements of mixed photon neutron field using TEPC
Variation in mean lineal energy with photons energy
f
0
2
4
6
8
10
12
1 10 100 1000
Photon energy (keV)
Mea
n lin
eal e
nerg
y
y_D 1000nmy_T 1000nmy_D 200nmy_T 200 nm
Transformation rate of CGL-1 for a 29 kVp Mo X-ray mammography set relative to Sr-90 beta electrons and A-bomb like linear accelerator irradiations
Heyes and Mill, 2004, Radiat. Res. 162: 120-7
29 kVp Mo X-rays
Sr 90
A-bomb
Lineal energy spectra for 29 kVp Mo X-rays relative to Sr-90 beta-electrons
-0.10
0.00
0.10
0.20
0.30
0.40
0.50
0.01 0.1 1 10 100
y, lineal energy (keV / µm)
y. d
(y),
dose
wie
ghte
d fr
eq.
29 kVp Mo X-raysSr-90 beta-rays
Lineal energy spectra for 15 keV photons in a 2 micron site
f
0.00
0.20
0.40
0.60
0.80
1.00
1.20
1.40
1.60
1.80
0.1 1.0 10.0 100.0y, lineal energy (keV / µm)
y. d
(y),
dose
wie
ghte
d fr
eq.
15 keV, water15 keV, TEP15 keV TEPC meas.
Lineal energy spectra for 33 keV for a 2 micron cell
f
0.00
0.20
0.40
0.60
0.80
1.00
1.20
0.1 1.0 10.0 100.0y, lineal energy (keV / µm)
y. d
(y),
dose
wie
ghte
d fr
eq.
33 keV, water33 keV, plastic33 keV TEPC meas.
Lineal energy in water and aq. Gd inside a 1 micron cell
Lineal energy spectra from Gd particle outside a 1 micron site
f
f
Lineal energy spectra for Pt enhanced medical radiation (1 micron site)
0.00
0.10
0.20
0.30
0.40
0.50
0.60
0.1 1.0 10.0 100.0
y, lineal energy (keV / µm)
y. d
(y),
dose
wie
ghte
d fr
eq.
78.0 keV in aq Pt78.8 keV in aq. Pt78.8 keV in water90 keV in aq. Pt
Lineal energy spectra from U particle enhancing natural background radiation (1 micron site)
f
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
0.40
0.01 0.1 1 10 100y, lineal energy (keV / µm)
y. d
(y),
dose
wie
ghte
d fr
eq.
NBG in H2ONBG near U
Acknowledgements and Participants:
University of Birmingham:Fathy Saeedi, Adam Baker, Mohammed Ariff
Queen Elizabeth Medical Centre:Stuart Green, Alun Beddoe, Bleddyn Jones
University of South Australia:John Pattison
University of Setif, Algeria:Zine-El-Abidine Chaoui
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