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Design and Performance Of A Thermal Neutron
Beam for Boron Neutron Capture Therapy At The
University Of Missouri Research Reactor
J.D. Brockman
J.C. McKibben
Neutron 5 mm
10 mm
Gamma (0.48 MeV)
a (+2) (1.49 MeV)
10 B
7Li(+3)
(0.85 MeV)
In situ activation reaction, 10B(n, a) 7Li; releases ionizing
energy within volume of single cancer cell:
Targets of traditional
and current interest:
•High-grade Glioma
•Primary and Metastatic
Melanoma
•Head and Neck Tumors
•Metastatic Liver Tumors
Current FDA
approved boron
delivery agents:
•BSH: Sodium
Borocaptate
•BPA: Borono-
phenylalanine
•GB-10:
Na2B10H10
• Thermal neutron beam – Au cadmium ratio >100
– Th flux ~1X109 n/cm2/s
• Minimize gamma dose
• Irradiation facility accessible during reactor operation
• Irradiate small animals up to large dogs
Silicon Bismuth
Key Design Feature: Single Crystal Silicon and Single
Crystal Bismuth Neutron Filters
Si (Natural) 209Bi
Silicon and Bismuth Total Cross Sections
(Amorphous)
Source: OECD-NEA (Janis)
1 eV
1 eV
Thermal Cross Sections for Silicon and Bismuth
Source: Kim et al. Phys. Med. Bio (2007)
Lee, Byung-Chul, 2007 KAERI, Private communication.
Freund (1983)
ENDF/B
Nuclear
Data
COMBINE 7.1 (W.Yoon,
INL)
DORT 2D Sn
Angular Neutron Flux at
Silicon Filter Entrance
MCNP5 Monte Carlo
KAERI
Data for
S.C. Si
and Bi
59-Group ENDF/B–VII
Custom Library
Neutron Flux
at Irradiation
location
S. R. Slattery, D. W. Nigg, J. D. Brockman, M. F. Hawthrone, PHYSOR, May 9 2010, Pittsburg, Pa
ENDF/B
Nuclear Data
Energy, MeV
1e-9 1e-8 1e-7 1e-6 1e-5 1e-4 1e-3 1e-2 1e-1 1e+0 1e+1 1e+2
Flu
x/leth
arg
y
1e+4
1e+5
1e+6
1e+7
1e+8
1e+9
1e+10
Empty Beam Tube
50 cm Silicon Crystal
50 cm Si + 8 cm Bi
1. Voided Beam
2. 50 cm Silicon crystal
3. 8 cm Bismuth Crystal
4. 50 cm Silicon + 8 cm Bismuth Crystal
Voided
Beamline
8 cm Bi
Crystal
50 cm Si
Crystal
50 cm Si +
8 cm Bi
Measured
Thermal Flux
(n/cm2-s)
9.8 x 109
(11%)
3.4 x 109
(8%)
2.6 x 109
(8%)
9.4 x 108
(8%)
Calculated
Thermal Flux
DORT +
MCNP5
(n/cm2-s)
9.4 x 109
(10%)
3.8 x 109
(10%)
2.2 x 109
(10%)
9.6 x 108
(10%)
Cadmium
Ratio
3.18
(7%)
5.10
(7%)
65.3
(7%)
105.5
(7%)
Wire
saturation
activity ratio
(Au/Cu)
36.4 28.4 22.4 22.4
Neutron
Interaction
Energy Range
of Primary
Response
Activation
Gamma
Energy
(keV)
6 –Group
spectrum
197Au (n, γ) Bare Foil 55Mn (n, γ) Bare Foil
Thermal
Thermal
411
847
1
115In (n, γ) Cd Cover 1 eV Resonance 1293 2
197Au (n, γ) Cd Cover 5 eV Resonance 411 3
186W (n, γ) Cd Cover 18 eV Resonance 686 4
55Mn (n, γ) Cd Cover 340 eV Resonance 847 5
63Cu (n, γ) Cd Cover 1 keV Resonance 511 (Positron) 5
115In (n,n') Boron
Sphere
300 keV Threshold 336 6
1.E+05
1.E+06
1.E+07
1.E+08
1.E+09
1.E-04 1.E-02 1.E+00 1.E+02 1.E+04 1.E+06 1.E+08
Flu
x/L
eth
arg
y
Energy, eV
6 Group spectrum 2012
group 1
group 2
group 3
group 4
group 5
group 6
A-Priori
Bare Au, Mn
Cd In
Cd Au
Cd W
Cd Cu, Mn
B In
Nigg, et al, Med Phys. 27 359-367
• Measured Φth 2012 = 7.65 x 108 n/cm2-s (±8.6%)
• Measured Φth 2009 = 8.85 x 108 n/cm2-s (±8.3%)
• Measured Φth 2008 = 8.18 x 108 n/cm2-s (±6.0%)
• Calculated Φ = 9.6 x 108 n/cm2-s (±5%)
• Cadmium Ratio (Au) = 108
• Calculated Dγ = 2.12 cGy/min
• Measured Dγ = 3.4 cGy/min (paired ion chamber technique)
Energy Group
0 1 2 3 4 5 6
n/cm
2 /s
1e+5
1e+6
1e+7
1e+8
Gro
up 6
n/c
m2 /s
1e+8
1e+9
2008
2009
2012
Profile
flux wire
Center, index
wire
Phantom A Phantom B
Phantom C
Phantom D
Profile
flux wire
Start of
Shielding
0
20
40
60
80
100
120
140
160
180
-4.0 -3.0 -2.0 -1.0 0.0 1.0 2.0
Au A
ctiv
ity R
ela
tive to c
ente
r w
ire
Distance in cm from top edge of black cap
Phantom A
Phantom B
Inside Shielding
Phantom
inside beam
Start of Li Carbonate
neutron shielding Edge of animal holder
Center of
Beam
0
50
100
150
200
250
0 2 4 6 8
Cu a
ctiv
ity, re
lative to c
ente
r w
ire
Length, cm
Phantom D
Front
Back
Li Shielding Start
Cap Start
Tumor Flank
downstream thorax in
beam thorax down
stream
Thermal Flux,
n/cm^2/s 1.3X109 1.9X108 1.3X108 7.1EX107
Thermal Flux
Relative to
tumor 100% 14% 10% 5%
Tumor
Flank
Downstream
Thorax
upstream
Thorax
Down Stream
6Li shield
• Neutron spectrum has not changed since 2008
• Radial profile measurements
• Phantom measurements and animal experiments are
underway
Acknowledgements Dr. David Nigg INL
Dr. Frederick Hawthorne IINMM
MURR Staff
Operations
Health Physics
Machine Shop
Electrical Shop
[1] J. D. Brockman, D. W. Nigg, M. F. Hawthorne, M.W. Lee, J. C. McKibben, “Characterization of a Boron Neutron Capture Therapy
Beam Line at the University of Missouri Research Reactor” J. Radioanal. Nucl. Ch. 282 157-160
[2] E.C.C. Pozzi, S. Thorp, J. D. Brockman, M. Miller, D. W. Nigg, F. M. Hawthorne, Intercalibration of Physical Neutron Dosimetry for
the RA-3 and MURR Thermal Neutron Sources for BNCT Small-Animal Research” Appl. Radiat. Isotopes. 69 1921-1923
[3] M. S. Kim, B. C. Lee, S. Y. Hwang, B. J. Jun, “Development and characteristics of the HANARO neutron irradiation facility for
applications in the boron neutron capture therapy field” Phys. Med. Biol. 52 2553-2566
[4] R. F. Barth, et. Al., “Current status of boron neutron capture therapy of high grade gliomas and recurrent head and neck cancer”
Radiat. Oncol. 2012, 7 146-167
[5] J. D. Brockman, D. W. Nigg, M. F. Hawthorne, J. C. McKibben, ”Spectral performance of a composite single-crystal filtered thermal
neutron beam for BNCT research at the University of Missouri” Appl. Radiat. Isotopes. 67 S222-S225
[6] B. C. Lee, Korean Atomic Energy Research Institute, Private communication (2007)
[7] A. K. Freund, “Cross Sections of Materials used as Neutron Monochromators and Filters”, Nucl. Instrum. & Methods, 243 495-501.
[8] W. A. Rhoades et al., :Tort-Dort: Two and Three-Dimensional Discrete-Ordinates Transport”, Radiation Shielding Information
Center, Oak Ridge National Laboratory, USA 1980.
[9] S. R. Slattery, D. W. Nigg, J. D. Brockman, M. F. Hawthrone, “Improved computational characterization of the thermal neutron source
for neutron capture therapy at the University of Missouri” PHYSOR, May 9 2010, Pittsburg, Pa
[10] D. W. Nigg et al., “Modification of the University of Washington Neutron Radiotherapy Facility for Optimization of Neutron
Capture Enhanced Fast Neutron Therapy” Med. Phys. 27 359-367