Prompt GammaRay Imaging Using the GEANT4 Code

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Prompt Gamma-Ray Imaging Using the GEANT4 Code

• Libai Xu and Robin Gardner
• Center of Engineering Applications of
  Radioisotopes
• Department of Nuclear Engineering
• North Carolina State University
• For Presentation at CEAR Annual Meeting 2007
• Oct 2, 2007

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OUTLINE

• Introduction
• Prompt Gamma-ray Modeling
• Prompt Gamma-ray Imaging
• Conclusions
• Future work

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Introduction

• Prompt Gamma Neutron Activation Analysis
• Identify elements and their abundance
• Prompt Gamma-ray Imaging
• Identify elements, abundances, and positions

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System Design
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Potential Application 1

• NCT (Neutron Capture Therapy) for Cancer
  treatment
• Selectively deliver 10B or Gd to the tumor
• Irradiate the tumor region with low energy
  neutrons
• The short range of the 10B(n,a)7Li reaction
  products restricts most of the dose to the tumor
  cells

?
Coderre, J. A. and Morris, G. M. 1999. The
radiation biology of boron neutron capture
therapy Radiat. Res. 151 1-18
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Potential Application 2

• Small animal imaging

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Prompt Gamma-ray Modeling

• Currently Available Codes
• MCNP5
• CEARCPG
• GEANT4
• Requirements for PGI
• Must be capable of simulating coincident gamma
  rays
• Must be capable of simulating repeated
  structures
• 3-D Visualization

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Neutron Capture Reaction
Prompt Gamma-ray Modeling
12C
13C
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Prompt Gamma-ray Modeling Geant4 Modification
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Hg prompt gamma-ray spectrum
Prompt Gamma-ray Modeling
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Neutron Capture Reaction by Geant4
Prompt Gamma-ray Modeling

• Prompt gamma rays are produced in coincidence.
• 2) Prompt gamma-ray intensity information agrees
  with ENSDF

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Prompt Gamma-Ray Yields
Prompt Gamma-ray Modeling
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Prompt Gamma-Ray Yields
Prompt Gamma-ray Modeling
Capture reactions for each component in soft
tissue (per 1.E6 thermal neutrons)
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Neutron Capture Therapy106 thermal neutronsFor
neutron fluence of 1012 yields are 1.4 X 1010 (B)
and 5.9 X 1010 (Gd) compared to 2.2 X 1010 for
SPECT
Prompt Gamma-ray Modeling
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Prompt Gamma-ray Imaging

• Physical collimations

sample
Detector plane
Pinhole
Coincident detector
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Prompt Gamma-ray Imaging
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Prompt Gamma-ray Imaging
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Raw Projection Images
Prompt Gamma-ray Imaging
370kev prompt gamma rays
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Coded Aperture
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Conclusions

• PGI is good for H, B, Gd, or Hg
• Either pinhole or coded aperture may be used for
  imaging coded aperture appears to be the best

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Future Work

• Coded Aperture
• Simulation Code Development
• Develop and Test a Prototype

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THANKS