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بسم الله الرحمن الرحيم. Simulation of Photon Beam Interaction with the ZUBAL Head Phantom. Presented by: Mostafa Hossni El-Soubki. Plan-UNC-Image plotter. Outline. Preparing the phantom and Converting to MCNP using the MATLAB software Commissioning the geometry
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Simulation of Photon Beam Interaction with the ZUBAL Head Phantom Presented by: Mostafa Hossni El-Soubki Plan-UNC-Image plotter
Outline • Preparing the phantom and Converting to MCNP using the MATLAB software • Commissioning the geometry • Dealing with MATLAB GI to view the output data. • Transfer the phantom to plan-UNC, and compare the same plan with MCNP • Conclusion • References.
Preparing the Phantom • Maximum number of cells allowed is 99999 • (#cells x-axis * #cells y-axis* #cells z-axis)<99999
Fig-4 (By image-j) Preparing the Phantom • The voxels outside the head have been excluded
Slice 23 after resizing from 59*40 to 50*37 Preparing the Phantom • The slice matrix has to be resized
Fig-5 Preparing the Phantom • Material indexing has to be adjusted for MCNP.
Converting From material excel sheets to MCNP. Preparing the Phantom • Converting all slices to MCNP
Validating the Geometry Applied Beam: • SSD =100cm • Field size = 5x5 cm2. • Photon Beam energy = 6 MV
Primary collimator Ion chambers Light mirror X-y jaws Light field reticle (MYLER) Fig-11 Blue is air. Blue sky is water Validation in a Water Phantom Voxel volume = 0.5*0.5*0.5 cm3 Phantom volume= 30* 30 * 30 cm3
Fig-21 Percent Depth Dose Comparison
Fig-24 Percent Depth Dose Comparison
Measured and Simulated Profile at 1.5cm Depth (Field Size 5x5 cm2)
Measured and Simulated Profile at 5 cm Depth (Field Size 5x5 cm2)
Measured and Simulated Profile at 10 cm Depth (Field Size 5x5 cm2)
6 MV Beam Interaction with Head Phantom Applied Beam: SSD =100 cm Field size =5x5 cm2 Photon Beam energy = 6 Mev
Fig-25 slice-8 (MCNP-MATLAB GUI) Transverse Cross Section
Fig-29 Coronal Cross Section
MCNP Plan-UNC Transfer the Phantom to Plan-UNC converting to excel sheets converting to dicom
Beam Setup of Head Phantom in Plan-UNC SSD = 100 cm at slice number 8. Field size = 5 x 5 cm2. Photon Beam energy = 6 Mev
Fig-27 Central PDD of slice-8 Skull bones at 2cm depth Fig-28 the inhomogeneous region in slice 8 Central PDD
Isodose Lines ISO-Dose levels: [ 0.98 0.95 0.9 0.7 0.5 ] MCNP Plan-UNC Plan-UNC-Image plotter
Fig-30 MCNP surface dose distribution
Conclusions • Validation of geometry • Good agreement in PDD in decay region • Need better agreement in dose profiles in penumbra region • There is disagreement between MCNP and Plan UNC in the inhomogeneous regions (transition from bone to soft tissue • Need for better quantitative methods to compare dose distribution in the phantom
References • Visual Basic 6 MSDN library. • Matlab7 Help. • http://noodle.med.yale.edu/phantom/getdata.htm (ZUBAL phantom).