Se Byeong Lee, Ph.D Chief Medical Physicist Proton Therapy Center in NCC, Korea

Proton Treatment Planning : Accurate dose calculation ? Radiation Shielding : Patient & worker safety ? Patient simulation (Respiratory gating) : 4D Dose distribution ? Beam Nozzle simulation : Design study, QA ?  Monte Carlo Simulation

Target Ex.) 5mm beam off on Target (1 portal) - Proton : 100%  0% dose - Photon : 100%  > 95% dose

MGH study

Proton beam facility in NCC Proton beam facility in NCC Proteus 235 Specification Weight : 220 ton Height : 210 cm Diameter : 434 cm Energy : 230MeV Max. extracted beam current : 300nA RF frequency :106 MHz

1. Modeling  Modeling Nozzle  Modeling Treatment scheme 2. User interface for M.C set-up  Convalgo (“Conversion Algorithm” by IBA) interface 3. Validation  Geant4 physics test on CSDA range and non-elastic interaction probability  Bragg peaks comparison  Conversion function (Range2MCEnergy) 4. Applications  SOBP reproduction for Proton therapy

Scanning Magnet 1 st Ion Chamber 1 st Scatterer 2 nd Scatterer Range Modulator Variable Collimator SnoutSnout 2 nd & 3 rd Ion Chamber Aperture & Compensator Compensator

Passive mode Dynamic mode

Geant4 version: 8.2.p01 - EM model : G4hIonization with ICRU49 parameterized table - Hadronic : LHEP_PRECO_HP ( precompound model ) NCC Proton Beam Delivery MC Simulation MC Simulation validation Test

15 X 15 Voxelized Water Phantom

Milling machineRTPG EANT 4

 Patient geometry ◦ Patient scanned data from CT in DICOM format ◦ Each CT is assigned to a voxel ◦ 3D Reformation / 2D Clustering of voxels ◦ HU – Material Table

CT Scanner CT Data Set G EANT 4 Geometry GDD Data

 In order to display the G EANT 4 output ◦ Volume data (including overlay of more than one set) ◦ Trajectories ◦ Geometry  Runs on: ◦ Windows, Linux and Mac ◦ Based on a commercial package but offered freely to all G EANT 4 users  Download ◦

 Developed based on DICOM-pyler  Written in python language  Function ◦ Visualize CT data set and simulated geometry ◦ Dose distribution ◦ Analysis and comparison of dose distribution

TPS MC Doss diff. Gamma Index  Plan Evaluation  Dose Difference  Gamma Index  Dose Volume Histogram  Plan Evaluation  Dose Difference  Gamma Index  Dose Volume Histogram TPS MC  Plan Evaluation  Dose Difference  Dose Volume Histogram  Gamma Index  Plan Evaluation  Dose Difference  Dose Volume Histogram  Gamma Index  Plan Evaluation  Dose Differencce  Dose Volume Histogram  Gamma Index  Plan Evaluation  Dose Differencce  Dose Volume Histogram  Gamma Index

 Proton Beam Dosimetry ◦ Scintillator-CCD system development ◦ Glass dosimetry ◦ Gold Maker for Patient Setup  Radiation Safety ◦ Secondary Neutron dose evaluation  Patient Treatment Planning ◦ Dose Calculation Accuracy of Commercial PTS ◦ Geant4-DNA

4  Beam mode modeling  DICOM data handling  Dose calculation using Geant4 MC simulation  Radiobiology Modeling Example of NCC study Example of NCC study

24  The capability of Geant4-DNA physics component can be complemented by advanced geometry modelling  DNA model inspired by M. A. Bernal and J. A. Liendo, Med. Phys., vol. 36, pp , 2009  Geant4 DNA model by S. Incerti 500 keV He +  Geant4 can predict number of SSBs and DSBs generated by direct effects of ionising radiation

 Able to model 5 physical interaction processes ◦ Single ionisation (p, H) ◦ Single capture (p) ◦ Double ionisation (p) ◦ Ionisation transfer (p) ◦ Stripping (H)  Applicable to protons and neutral hydrogen  Covering the energy range 10 keV – 1 MeV  Materials include ◦ Liquid water ◦ DNA nucleobases: Adenine, Thymine, Cytosine and Guanine  Their implementation started at CENBG during Spring and the venue of Jae Ik Shin ◦ Computation of total cross sections ◦ Computation of final state

 These cross section models will be combined with a geometrical model of a cellular nucleus including DNA structures, containing ◦ Either pure liquid water ◦ or liquid water and DNA material (A-T-G-C)  These models have been developed by Mr J. I. Shin in NCC ◦ Nucleotides ◦ Nucleosomes ◦ Chromatin fiber

Liquid waterAdenine One order of magnitude difference for dominant processes (SI, SC) Two orders of magnitude for DI preliminary

by J.I.Shin(NCC) Nucleotides Nucleosomes Make simple geometry having ratio of ATGC materials preliminary

- Joint workshop with Korean Society of Medical Physics(KSMP) Program and KISTI Geant4 supporting Program - Apr. 14, 2012 / Tong Young, Korea ~ 100 participants.

Thank you! Current & Past Geant4 Researchers in NCC - Dr. Jungwook Shin UCSF (TOPAS Collaboration) - Mr. Dae Hyun Kim Catholic University of Korea - Mr. Sey-Joon Park NCC Korea - Mr. Jae Ik Shin NCC Korea - Etc.. Proton Therapy Center