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PENCIL BEAM STEPS
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Beforehand
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Calculate pencil beam kernels from Monte Carlo
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Kernel for each energy
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Fit energy spectrum to measured depth dose curves using Monte
Carlo
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Generate polyenergetic pencil beam kernel
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At time of calculation
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Ray trace through accelerator head components and patient
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Take into account energy spectrum and off-axis spectral changes
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Convolve with source distribution
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Convolve with polyenergetic pencil beams at 8-10 depths
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Calculate dose by interpolation between convolutions
Slide from Dr. James Bedford
ESTRO physics course,
June 2017