Dr. Mir Md. Akramuzzaman 1 , G.A. Zakaria 2 , G.H. Hartmann 3 1 Department of Physics, Jahangirnagar University, Savar, Dh...
<ul><li>To calculate the Air  kerma strength  for BEBIG  60 Co source with Monte Carlo codes </li></ul><ul><li>To calculat...
<ul><li>BEBIG  60 Co HDR brachytherapy source model </li></ul><ul><li>Using EGSnrc Monte Carlo codes developed by National...
Monte Carlo Procedure Filtering Apply physical/ statistical law/ theory Group of Random Events Analysis Apply Physical Law...
Applications of Monte Carlo <ul><li>Computational Physics </li></ul><ul><li>Physical Chemistry </li></ul><ul><li>Quantum C...
Monte Carlo code for Radiation Transport <ul><li>The following codes are available for the simulation of radiation transpo...
Cont. <ul><li>PEREGRINE: code for radiation therapy dose calculations  </li></ul><ul><li>PENELOPE: code for coupled transp...
EGSnrc Monte Carlo codes <ul><li>The EGSnrc Monte Carlo codes are used in this work. This code is very powerful research t...
BEBIG  60 Co HDR source models Real geometry of the source Model geometry of the source
Monte Carlo input of source model Sagittal Section   Fig:  Equal sagittal section for Monte Carlo source input
TG-43 Formalism  General 2D formalism The general, two-dimensional ~2D dose-rate equation from the TG-43 protocol is retai...
Fig: Coordinate system used for brachytherapy  dosimetry calculations TG-43 Formalism
Using Formula for fluence calculation And finally,  S k /A = 2 × K΄ air (d) × d 2 Where, is the total air-kerma at the dis...
Dose calculation formula <ul><li>Calculation grid: Slab and radial thickness = 1-2 mm </li></ul><ul><li>Photon cutoff ener...
Dose calculation formula The user-code DOSRZnrc is used to calculate,  D photons where  D photons   is the total dose by p...
Phantom Model
Geometric Preview Window  Calculated point
Tissue basis absorbed dose calculation Some body equivalent tissues (shows in table below) are simulated to investigate th...
Results Energy fluence vs. Spectrum
Calculated  60 Co fluence data   (MeV-1 cm-2)
Calculated  60 Co fluence data   (MeV-1 cm-2)
Calculated  60 Co fluence data   (MeV-1 cm-2)
Air-kerma strength Article Air-kerma strength Per unit source activity (c Gy.cm 2 .h -1 .Bq -1   ) This work 3.035×10 -7  ...
Dose Rate Constant Article Dose rate constant,  Λ (cGy h -1  U -1 ) This work  1.097  ± 0.12%   T. Palani Selvam et al.(20...
Tissue basis relative absorbed dose
Relative absorbed dose with distance Lung Comp. bone
Conclusion <ul><li>In the calculation of air-kerma strength and dose rate constant, uncertainty were 0.15% and 0.12% which...
 
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Calculation of air-kerma strength and dose rate constant for new BEBIG 60Co HDR brachytherapy source: an EGSnrc Monte Carlo study

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Calculation of air-kerma strength and dose rate constant for new BEBIG 60Co HDR brachytherapy source: an EGSnrc Monte Carlo study
M. Anwarul Islam, Medical Physicist
SQUARE Hospitals Ltd, Bangladesh
anwar.amch@yahoo.com

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Calculation of air-kerma strength and dose rate constant for new BEBIG 60Co HDR brachytherapy source: an EGSnrc Monte Carlo study

  1. 1. Dr. Mir Md. Akramuzzaman 1 , G.A. Zakaria 2 , G.H. Hartmann 3 1 Department of Physics, Jahangirnagar University, Savar, Dhaka, Bangladesh. 2 Gummersbach Academic Teaching Hospital, University of Cologne, Germany. 3 Department of Medical Physics in Radiotherapy, German Cancer Research Center, Heidelberg, Germany. M. Anwarul Islam Department of Physics Jahangirnagar University Calculation of air-kerma strength and dose rate constant for new BEBIG 60 Co HDR brachytherapy source: an EGSnrc Monte Carlo study
  2. 2. <ul><li>To calculate the Air kerma strength for BEBIG 60 Co source with Monte Carlo codes </li></ul><ul><li>To calculate the dose rate constant for BEBIG 60 Co source with the protocol of TG-43 (AAPM) </li></ul><ul><li>To compare the calculated Air kerma strength with published or measured value </li></ul>Objectives
  3. 3. <ul><li>BEBIG 60 Co HDR brachytherapy source model </li></ul><ul><li>Using EGSnrc Monte Carlo codes developed by National Research Council (NRC) of Canada </li></ul><ul><li>Calculating the photon fluence rate in air with the source </li></ul><ul><li>Using the AAPM TG-43 protocol </li></ul>Materials and Method
  4. 4. Monte Carlo Procedure Filtering Apply physical/ statistical law/ theory Group of Random Events Analysis Apply Physical Law/theory Apply Boundary Condition Apply Statistical Law Apply Probability theory
  5. 5. Applications of Monte Carlo <ul><li>Computational Physics </li></ul><ul><li>Physical Chemistry </li></ul><ul><li>Quantum Cromodynamics </li></ul><ul><li>Heat Shielding </li></ul><ul><li>Aerodynamics </li></ul><ul><li>Statistical Physics </li></ul><ul><li>Molecular modeling </li></ul><ul><li>Particle Physics </li></ul><ul><li>Radiation Physics </li></ul><ul><li>Energy Transport </li></ul><ul><li>Stochastic Financial Modeling </li></ul><ul><li>Telecommunication </li></ul><ul><li>Mathematical Solution </li></ul><ul><li>Weather Forecast </li></ul><ul><li>Light transport in biological tissue </li></ul><ul><li>Reliability Engineering etc </li></ul>
  6. 6. Monte Carlo code for Radiation Transport <ul><li>The following codes are available for the simulation of radiation transport : </li></ul><ul><li>GEANT: simulation of high energy particles interacting with a detector. </li></ul><ul><li>CompHEP, PYTHIA: Monte-Carlo generators of particle collisions </li></ul><ul><li>MCNP(X): radiation transport codes </li></ul><ul><li>MCU: particles (electrons, photons, neutrons) transport code </li></ul>
  7. 7. Cont. <ul><li>PEREGRINE: code for radiation therapy dose calculations </li></ul><ul><li>PENELOPE: code for coupled transport of photons and electrons </li></ul><ul><li>BEAMnrc: code system for modeling radiotherapy sources (Linac) </li></ul><ul><li>EGSnrc: code for coupled transport of electrons and photons </li></ul>
  8. 8. EGSnrc Monte Carlo codes <ul><li>The EGSnrc Monte Carlo codes are used in this work. This code is very powerful research tool for radiotherapy field in brachytherapy. </li></ul><ul><li>The EGS (Electron-Gamma Shower) system of computer codes is a general purpose package for Monte Carlo simulation of the coupled transport of electrons and photons. </li></ul><ul><li>The EGSnrc codes developed by National Research Council of Canada </li></ul><ul><li>The EGSnrc is capable to calculate fluence, dose, stopping power ratio, kerma etc. </li></ul>
  9. 9. BEBIG 60 Co HDR source models Real geometry of the source Model geometry of the source
  10. 10. Monte Carlo input of source model Sagittal Section Fig: Equal sagittal section for Monte Carlo source input
  11. 11. TG-43 Formalism General 2D formalism The general, two-dimensional ~2D dose-rate equation from the TG-43 protocol is retained , Where, = dose rate at the point (r, θ )
  12. 12. Fig: Coordinate system used for brachytherapy dosimetry calculations TG-43 Formalism
  13. 13. Using Formula for fluence calculation And finally, S k /A = 2 × K΄ air (d) × d 2 Where, is the total air-kerma at the distance, d and the unit is Gy/Photon is the photon fluence per unit energy and it’s unit MeV -1 cm -2 is the mass energy absorption coefficient and it’s unit cm 2 gm -1 E i is the energy spectrum and Δ E is the energy bin size The factor 1.602×10 -10 is required to convert K air (d) from MeV gm -1 into Gy S k /A is the air-kerma strength per unit source activity. The unit is μ Gym2h-1.Bq-1 or UBq-1 D = 100 cm according to the TG-43 formalism
  14. 14. Dose calculation formula <ul><li>Calculation grid: Slab and radial thickness = 1-2 mm </li></ul><ul><li>Photon cutoff energy = 0.001 MeV </li></ul><ul><li>Electron cutoff energy = 0.521 MeV </li></ul><ul><li>No. of history simulated for every point = 10 9 </li></ul><ul><li>Dose for photon contribution simulated </li></ul><ul><li>Considered one decay will result in the emission of 2 photons </li></ul><ul><li>Average time per simulation is 5 hours for photon </li></ul>
  15. 15. Dose calculation formula The user-code DOSRZnrc is used to calculate, D photons where D photons is the total dose by photons S k /A is air-kerma strength per source activity into [U Bq-1] is the true dose rate per unit air-kerma strength for 60 Co source in [cGy h-1 U-1]
  16. 16. Phantom Model
  17. 17. Geometric Preview Window Calculated point
  18. 18. Tissue basis absorbed dose calculation Some body equivalent tissues (shows in table below) are simulated to investigate the relative absorbed dose with different distances in respective tissue phantom and also in vacuum phantom with 5 cm distance. Tissue basis density table 1.04 1.0 1.12 0.92 0.26 1.06 1.02 1.85 1.00 Density g/cm 3 Testese Soft tissue Muscle Adipose tissue Lung Blood Breast Com bone Water Tissue
  19. 19. Results Energy fluence vs. Spectrum
  20. 20. Calculated 60 Co fluence data (MeV-1 cm-2)
  21. 21. Calculated 60 Co fluence data (MeV-1 cm-2)
  22. 22. Calculated 60 Co fluence data (MeV-1 cm-2)
  23. 23. Air-kerma strength Article Air-kerma strength Per unit source activity (c Gy.cm 2 .h -1 .Bq -1 ) This work 3.035×10 -7 ±0.15% T. Palani Selvam et al.(2010), India 3.04×10 -7 ±0.05%
  24. 24. Dose Rate Constant Article Dose rate constant, Λ (cGy h -1 U -1 ) This work 1.097 ± 0.12% T. Palani Selvam et al.(2010), India 1.086 ± 0.06%
  25. 25. Tissue basis relative absorbed dose
  26. 26. Relative absorbed dose with distance Lung Comp. bone
  27. 27. Conclusion <ul><li>In the calculation of air-kerma strength and dose rate constant, uncertainty were 0.15% and 0.12% which is acceptable limit. </li></ul><ul><li>Published data of Palani Selvam, the uncertainty were 0.05% and 0.06% which are lower than our values. </li></ul><ul><li>In this study, EGSnrc Monte Carlo code was used but Palani Selvam used MCNP code </li></ul><ul><li>Relative absorbed dose in different tissues in 5 cm distance are approximately same accept lung tissue. 22% less dose in lung tissue with water </li></ul><ul><li>The relative absorbed dose with different distances in respective tissue phantom, the lung doses are higher than the compact bone </li></ul>

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