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

59 group Source

from DORT

calculation

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

Mean Au activity: 9.73X1014 dps/n ± 4%

Mean Au/Cu ratio: 22.1 ± 1.7%

Cu/Au wires

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