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Development of a tomographic system for online dose
measurements in BNCTMinsky D.M.1,2, Valda A.A. 1,2, Burlon A.A. 1,2,3, Kreiner A.J. 1,2,4 y Somacal H. 1,2
1. Departamento de Física (CAC, CNEA) 2. Escuela de Ciencia y Tecnología (UNSAM)
3. Fundación J.B. Sauberán4. CONICET
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VI Latin American Symp. on Nuc. Phys. and Applications Development of a tomographic system for online dose measurements in BNCT
Epithermalneutrons
Figure adapted from:http://web.mit.edu/nrl/www/bnct/info/description/description.html
[ ][ ] 1:4
ssueHealthy ti BTumor B
10
10≈
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VI Latin American Symp. on Nuc. Phys. and Applications Development of a tomographic system for online dose measurements in BNCT
10BThermalneutron
10B + n → 11B*→ 7Li* + 4He
7Li(0.84 MeV)
4He(1.47 MeV)
γ (478 keV)
5 µm
9 µm
↓ t ~ 10-14 s
Li + γ (478 keV)
VI Latin American Symp. on Nuc. Phys. and Applications Development of a tomographic system for online dose measurements in BNCT
γ-ray Telescope SystemNetherlands Energy Research Foundation, Petten, The NetherlandsEindhoven University of Technology, Eindhoven, The NetherlandsNuclear Research and Consultancy Group, Petten, The Netherlands
WFAR Verbakel, F Stecher-Rasmussen, Nucl. Instr. and Meth. in Phys. Res. A, 394, 163-172, 1997.WFAR Verbakel, W Sauerwein, K Hideghety, F Stecher-Rasmussen, Int. J. Radiation Oncology Biol. Phys. 55(3), 743–756, 2003.
Related works: γ-ray telescopeand PG-SPECT
PG-SPECT (Prompt Gamma-ray SPECT)Research Reactor Institute, Kyoto University, JapanResearch Institute for Radiation Biology and Medicine, Hiroshima Univ., Japan
T Kobayashi, Y Sakurai, M Ishikawa, Med. Phys. 27(9), 2124-2132, 2000.
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VI Latin American Symp. on Nuc. Phys. and Applications Development of a tomographic system for online dose measurements in BNCT
VI Latin American Symp. on Nuc. Phys. and Applications Development of a tomographic system for online dose measurements in BNCT
Collimator design
Requirements:• Trans-septal penetration
less than 6%• Spatial resolution 1cm
at 20 cm from detector
Results:• t=2 mm• ∅=4.4 mm• e=80 mm
e
t∅
Collimator thickness
Geo
met
rical
effic
ienc
y[%
]
Collimator Thickness (e) [mm]
Geo
met
rical
effic
ienc
y[%
]
Spatial Resolution [mm]
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VI Latin American Symp. on Nuc. Phys. and Applications Development of a tomographic system for online dose measurements in BNCT
VI Latin American Symp. on Nuc. Phys. and Applications Development of a tomographic system for online dose measurements in BNCT
System numerical simulation
• System matrix (influence of each pixel on each detector for every projection).
MonteCarlo simulation with MCNP-4C of:
Some data of the simulations:
• Image consisting in 21*21 pixels• Pixels of 1cm*1cm size• 37 detectors in each projection• 20 projections regularly spaced
by 9O
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VI Latin American Symp. on Nuc. Phys. and Applications Development of a tomographic system for online dose measurements in BNCT
P1 P2 P3 P4
P5 P6 P7 P8
P9 P10 P11 P12
P13 P14 P15 P16
B6
B7
B8
B9
B10
B1 B2 B3 B4 B5
System matrix calculation
VI Latin American Symp. on Nuc. Phys. and Applications Development of a tomographic system for online dose measurements in BNCT
…………
…m34m32m31
…m23m22m21
…m13m12m11
…
p3
p2
p1
…
b3
b2
b1
=.
System matrix calculation
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VI Latin American Symp. on Nuc. Phys. and Applications Development of a tomographic system for online dose measurements in BNCT
………
…m34m32
…m23m22
…m13m12
…
0
0
1
…
b3-1
b2-1
b1-1
=.
…
m31
m21
m11
…
b3-1
b2-1
b1-1
System matrix calculation
VI Latin American Symp. on Nuc. Phys. and Applications Development of a tomographic system for online dose measurements in BNCT
……...
…m34b1-2
…m23b1-2
…m13b1-1
…
0
1
0
=.
…
m33
m23
m12
…
b3-2
b2-2
b1-2
…
b3-2
b2-2
b1-2
System matrix calculation
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VI Latin American Symp. on Nuc. Phys. and Applications Development of a tomographic system for online dose measurements in BNCT
VI Latin American Symp. on Nuc. Phys. and Applications Development of a tomographic system for online dose measurements in BNCT
Phantoms numerical simulations
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VI Latin American Symp. on Nuc. Phys. and Applications Development of a tomographic system for online dose measurements in BNCT
WithoutBackground
→→→→
→→→→
↑↑↑↑Simulatedsource
↑↑↑↑Simulatedsinogram
↑↑↑↑Reconstructed
image
Numerical simulations of phantoms
WithBackground
VI Latin American Symp. on Nuc. Phys. and Applications Development of a tomographic system for online dose measurements in BNCT
Influence of statistical fluctuations
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VI Latin American Symp. on Nuc. Phys. and Applications Development of a tomographic system for online dose measurements in BNCT
Influence of tumor size
VI Latin American Symp. on Nuc. Phys. and Applications Development of a tomographic system for online dose measurements in BNCT
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VI Latin American Symp. on Nuc. Phys. and Applications Development of a tomographic system for online dose measurements in BNCT
TANDARLaboratory
VI Latin American Symp. on Nuc. Phys. and Applications Development of a tomographic system for online dose measurements in BNCT
Previous experimental measurements
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VI Latin American Symp. on Nuc. Phys. and Applications Development of a tomographic system for online dose measurements in BNCT
Experimental setup under characterization
VI Latin American Symp. on Nuc. Phys. and Applications Development of a tomographic system for online dose measurements in BNCT
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VI Latin American Symp. on Nuc. Phys. and Applications Development of a tomographic system for online dose measurements in BNCT
Conclusions and future work
• A tomographic SPECT system for online dose measurements in BNCT have been designed
• The whole system has been simulated by means of MonteCarlo calculations
• Sinograms from numerical phantoms have been simulated and used for image reconstruction
• Statistical fluctuations must be kept under 3-5%• The influence of the image reconstruction algorithm on
quantitative concentration measurements will be studied• The experimental setup is under characterization and
images will be acquired in the near future