Design and Performance Of A Thermal Neutron Beam for Boron Neutron Capture Therapy At The University Of Missouri Research Reactor

Transcription

1 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

2 In situ activation reaction, 10 B(n, a) 7 Li; releases ionizing energy within volume of single cancer cell: Targets of traditional and current interest: High-grade Glioma Primary and Metastatic Melanoma Neutron 5 mm 10 mm 7Li(+3) (0.85 MeV) 10 B Gamma (0.48 MeV) Current FDA approved boron delivery agents: BSH: Sodium Borocaptate BPA: Boronophenylalanine GB-10: Na 2 B 10 H 10 Head and Neck Tumors Metastatic Liver Tumors a (+2) (1.49 MeV)

3 Thermal neutron beam Au cadmium ratio >100 Th flux ~1X10 9 n/cm 2 /s Minimize gamma dose Irradiation facility accessible during reactor operation Irradiate small animals up to large dogs

4 Key Design Feature: Single Crystal Silicon and Single Crystal Bismuth Neutron Filters Silicon Bismuth

5 Silicon and Bismuth Total Cross Sections (Amorphous) Si (Natural) 209Bi 1 ev 1 ev Source: OECD-NEA (Janis)

6 Thermal Cross Sections for Silicon and Bismuth Source: Kim et al. Phys. Med. Bio (2007) Lee, Byung-Chul, 2007 KAERI, Private communication. Freund (1983)

7 KAERI Data for S.C. Si and Bi ENDF/B Nuclear Data ENDF/B Nuclear Data MCNP5 Monte Carlo Angular Neutron Flux at Silicon Filter Entrance Neutron Flux at Irradiation location COMBINE 7.1 (W.Yoon, INL) 59-Group ENDF/B VII Custom Library DORT 2D S n S. R. Slattery, D. W. Nigg, J. D. Brockman, M. F. Hawthrone, PHYSOR, May , Pittsburg, Pa

8 59 group Source from DORT calculation

9 1e+10 1e+9 1e+8 Flux/lethargy 1e+7 1e+6 1e+5 Empty Beam Tube 50 cm Silicon Crystal 50 cm Si + 8 cm Bi 1e+4 1e-9 1e-8 1e-7 1e-6 1e-5 1e-4 1e-3 1e-2 1e-1 1e+0 1e+1 1e+2 Energy, MeV

10 1. Voided Beam cm Silicon crystal 3. 8 cm Bismuth Crystal cm Silicon + 8 cm Bismuth Crystal

11 Measured Thermal Flux (n/cm 2 -s) Calculated Thermal Flux DORT + MCNP5 (n/cm 2 -s) Cadmium Ratio Wire saturation activity ratio (Au/Cu) Voided Beamline 9.8 x 10 9 (11%) 9.4 x 10 9 (10%) 3.18 (7%) 8 cm Bi Crystal 3.4 x 10 9 (8%) 3.8 x 10 9 (10%) 5.10 (7%) 50 cm Si Crystal 2.6 x 10 9 (8%) 2.2 x 10 9 (10%) 65.3 (7%) 50 cm Si + 8 cm Bi 9.4 x 10 8 (8%) 9.6 x 10 8 (10%) (7%)

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13 Neutron Interaction 197 Au (n, γ) Bare Foil 55 Mn (n, γ) Bare Foil Thermal Thermal Energy Range of Primary Response Activation Gamma Energy (kev) 115 In (n, γ) Cd Cover 1 ev Resonance Group spectrum Au (n, γ) Cd Cover 5 ev Resonance W (n, γ) Cd Cover 18 ev Resonance Mn (n, γ) Cd Cover 340 ev Resonance Cu (n, γ) Cd Cover 1 kev Resonance 511 (Positron) In (n,n') Boron Sphere 300 kev Threshold 336 6

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15 Flux/Lethargy 1.E+09 6 Group spectrum E+08 Bare Au, Mn 1.E+07 Cd W group 1 group 2 group 3 group 4 1.E+06 Cd In Cd Au Cd Cu, Mn B In group 5 group 6 A-Priori 1.E+05 1.E-04 1.E-02 1.E+00 1.E+02 1.E+04 1.E+06 1.E+08 Energy, ev Nigg, et al, Med Phys

16 Measured Φ th 2012 = 7.65 x 10 8 n/cm2-s (±8.6%) Measured Φ th 2009 = 8.85 x 10 8 n/cm2-s (±8.3%) Measured Φ th 2008 = 8.18 x 10 8 n/cm2-s (±6.0%) Calculated Φ = 9.6 x 10 8 n/cm2-s (±5%) Cadmium Ratio (Au) = 108 Calculated D γ = 2.12 cgy/min Measured D γ = 3.4 cgy/min (paired ion chamber technique)

17 1e+8 1e+9 n/cm 2 /s 1e+7 1e+6 Group 6 n/cm 2 /s 1e Energy Group 1e+8

18 Cu/Au wires Mean Au activity: 9.73X10 14 dps/n ± 4% Mean Au/Cu ratio: 22.1 ± 1.7%

19 Profile flux wire Profile flux wire Phantom A Phantom B Start of Shielding Center, index wire Phantom D Phantom C

20 Au Activity Relative to center wire 180 Start of Li Carbonate neutron shielding Edge of animal holder Inside Shielding Phantom inside beam Center of Beam Phantom A Phantom B Distance in cm from top edge of black cap

21 Cu activity, relative to center wire Phantom D Front Back Li Shielding Start Cap Start Length, cm

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23 Tumor Flank downstream thorax in beam thorax down stream Thermal Flux, n/cm^2/s 1.3X X X EX10 7 Thermal Flux Relative to tumor 100% 14% 10% 5% Thorax upstream 6 Li shield Tumor Thorax Down Stream Flank Downstream

24 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

25 [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 [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 [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 [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, [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, [8] W. A. Rhoades et al., :Tort-Dort: Two and Three-Dimensional Discrete-Ordinates Transport, Radiation Shielding Information Center, Oak Ridge National Laboratory, USA [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 , 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