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 1.Preparing the phantom and Converting to MCNP using the MATLAB software 2.Commissioning the geometry 3.Dealing with MATLAB GI to view the output data. 4.Transfer the phantom to plan-UNC, and compare the same plan with MCNP 5.Conclusion 6.References.

Preparing the Phantom Maximum number of cells allowed is (#cells x-axis * #cells y-axis* #cells z-axis)<99999

Preparing the Phantom The voxels outside the head have been excluded Fig-4 (By image-j)

Preparing the Phantom The slice matrix has to be resized Slice 23 after resizing from 59*40 to 50*37

Preparing the Phantom Material indexing has to be adjusted for MCNP. Fig-5

Preparing the Phantom Material #OrganMaterial #Organ 1outside phantom86medulla oblongata 2skin23fat 3brain24blood pool 4spinal cord27bone marrow 5skull92pons 6spine30trachea 71dens of axis31cartilage 72jaw bone100uncus (ear bones) 10skeletal muscle105sinuses/mouth cavity 75lachrymal glands107optic nerve 76spinal canal114cerebral falx 77hard palate120eye 78cerebellum122lens 79tongue123cerebral aqueduct 16pharynx126teeth 17esophagus

Preparing the Phantom Converting all slices to MCNP Converting From material excel sheets to MCNP.

Validating the Geometry Applied Beam: SSD =100cm Field size = 5x5 cm2. Photon Beam energy = 6 MV

Validation in a Water Phantom Fig-11 Blue is air. Blue sky is water Primary collimator Ion chambers Light mirror X-y jaws Light field reticle (MYLER) Voxel volume = 0.5*0.5*0.5 cm3 Phantom volume= 30* 30 * 30 cm3

Percent Depth Dose Comparison Fig-21

Percent Depth Dose Comparison Fig-24

PDD Comparison beam energy6MV dmax=1.5 cm field size cm2depth cmPDD%±ΔPDD 5* * * * * *

Beam Profile Comparison

Measured and Simulated Profile at 1.5cm Depth (Field Size 5x5 cm 2 )

Measured and Simulated Profile at 5 cm Depth (Field Size 5x5 cm 2 )

Measured and Simulated Profile at 10 cm Depth (Field Size 5x5 cm 2 )

6 MV Beam Interaction with Head Phantom Applied Beam: SSD =100 cm Field size =5x5 cm 2 Photon Beam energy = 6 Mev

Transverse Cross Section Fig-25 slice-8 (MCNP- MATLAB GUI)

Coronal Cross Section Fig-29

Transfer the Phantom to Plan-UNC MCNP Plan-UNC converting to dicom converting to excel sheets

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

Central PDD Fig-27 Central PDD of slice-8 Fig-28 the inhomogeneous region in slice 8 Skull bones at 2cm depth

Isodose Lines Plan-UNC-Image plotter MCNP Plan-UNC ISO-Dose levels: [ ]

MCNP surface dose distribution Fig-30

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. data.htm (ZUBAL phantom). data.htm

Thank you