1. Technological Transfer from HEP to Medical Physics How precise Brachytherapy MonteCarlo simulations can be applied in Clinics Reality Problem: How to achieve accuracy and quickness? Problem: How to achieve accuracy and quickness? Tests Intermediate system between applications and GRID  precision in calculation of dose distribution  reproduction of the real geometry and tissues (CT )  calculation speed  simple to use ( for hospitals !) Solution from HEP World : Geant4 + GRID + WEB Functionalities (User Requirements) Design Software Process (USDP) A rigorous software process permits the development of reliable software: necessary feature for tools addressed to medical physics Test from a microscopic point of view S.Agostinelli 1, F.Foppiano 1, S.Garelli 1, G.Ghiso 2, S.Guatelli 3, J.Moscicki 4, M.G.Pia 3,M.Tropeano 5 1.Cancer Institute (IST), Genova,Italy 2.Servizio Sanitario Savona,Italy 3.INFN Genova,Italy, 4.CERN, Geneve,Switzerland, 5.University of Genova,Italy DIANE R&D project: Application oriented gateway to GRID DIANE permits the parallelisation on the application and the access to GRID The application developer is shielded from complexity of underlying technology Geant4 is an Object Oriented Toolkit for the simulation of the passage of particles through matter.Its application areas include high energy and nuclear physics experiments, astrophysics, medical physics, radiation background studies, radioprotection and space science. Geant4 exploits advanced Software Engineering techniques and Object Oriented technology to achieve the transparency of the physics implementation and hence provide the possibility of validating the physics results. Geant4 has been developed and maintained by a world-wide collaboration of more than 100 scientists. The source code and libraries are freely distributed from the Geant4 web site www.cern.ch/geant4. GRID is a project funded by European Union. The objective is to build the next generation computing infrastructure providing distributed computering resources across the world cancer treatment Brachytherapy is a medical therapy used for cancer treatment Radioactive sources deliver therapeutic dose to tumors, preserving the surrounding healthy tissues  Interstitial brachytherapy ( prostate)  Endocavitary brachytherapy (lungs,vagina,uterus)  Superficial brachytherapy (skin) Three devices: Brachytherapy Calculation of dose delivered to tissues (as for example Prowes, Variseed V7) used in clinical practice  Analytical calculation methods  All the tissues are approximated to water Advantages High calculation speed Disadvantages  Approximated dose calculation  density insensitivity  The source is approximated to a point Software characteristics for brachytherapy Commercial software available Such a software does not exist for superficial brachytherapy! Speed is a fundamental requirement for software used in the clinical practice The medical physicist sometimes has got to take decisions about the position of the sources in few seconds MC simulation were never been used in the clinical practice for the long calculations MonteCarlo simulations are more accurate in the dose calculation but to slow for a realistic clinical use Analysis AIDA/Anaphe Precision Real geometry reproduction Simple to use, Use in hospitals Calculation speed Other user requirements  MonteCarlo method  Accurate physical processes simulation  Test to guarantee the quality of the software  Accurate description of the geometry  Possibility to interface the software to CT  Graphic visualisation + user interface  Dose distribution analysis ( i.e. isodose curves)  Parallel system  Calculation shared resource access  Estensivity to new functionalities  Public access Project : Project : development of a software for dose calculation which is accurate in the dose calculation and fast by a clinical use point of view 3D dose distribution calculation Isodose curves Calculation speed DIANE, GRID Simulation Geant4  Tests on Geant4 e- and gamma electromagnetic processes : CSDA range for e- and Gamma attenuation coefficient in different absorber materials  Comparison of different Geant4 physics models (Standard/LowEnergy/Penelope)  Comparison with protocol data ( ICRU 37 and ICRU 49) Macroscopic Test  Test about the dose distribution of brachytherapic sources ( I-125, Ir –131) along the perpendicular to the major axes on the source. G4LowE EPDL G4Standard NIST reference data Penelope gamma processes Reference data NIST  Geant4 results have been compared with experimental measurements and protocol reference data (TG43 and Italian Association of Medical Physics (AIFB) protocol)  The experimental dosimetric measurements of the seed Microselectron HDR (Ir-131) have been performed with ionisation chambers at the Italian National Institute of Cancer (IST), Genova (Italy)  The experimental measurements of the seed Bebig Isoseed I-125 have been performed with films at the Medical Physics Institute of Savona (Italy) G. Ghiso and S.Guatelli At Medical Physics Institute in Savona(Italy) Brachytherapy application Dose distribution calculation Isodose curves Development of the project Sofware planning and development For all the brachytherapic devices Generalisation of the software  Each treatment planning software is specific to one brachytherapic technique.  Treatment planning software is expensive (~ hundreds k Euro)  The software we developed is transparent to the particular brachytherapic source; this is possible because Geant4 simulates the involved physics without any approximation.  3D dose distribution  Isodose curves  Choice of the materials of the phantom  Graphical visualization  Possibility to interface the system to CT  source composition geometry, materials, spectrum Use of abstract classes Radioactive source definition thanks to the design pattern: Abstract Factory Simulation result: energy deposit Analysis: dose distribution and isodose curves Parametrization of the volumes in the geometry Parametrization function: volume -> material Generalization+ Specific aspects of the source Interface to CT Dosimetry Functionalities Some Results  The radioactive source is positioned in the center of a phantom filled with water.  The results can be generalised to more seed and in a human anatomy Isodose curves Dose distribution of a MicroSelectron- HDR source (Ir-131) Isodose Curves The plots describe the dose distribution in plans parallel to the one containing the source (y = 0. mm) Dose distribution for Bebig Isoseed I-125 The Leipzig applicator is positioned on the phantom Problem: The simulations are very long (compared to clinical use scale of time) in order to obtain results with high statistics. Leipzig applicator Performance Endocavitary brachytherapy Interstitial brachytherapy Superficial brachytherapy 1M events 61 minutes 1M events 67 minutes 1M events 65 minutes On a average PIII machine, As an “average hospital” may have The simulations are two slow The time required to obtain results with high statistics do not permit the use of MC in clinical practice Parallel cluster processing Make fine tuning and customisation easy Transparently using the GRID Application independent The application developer is shielded from complexity and underlying technology Not affecting the original code application Good separation of the subsystem the application does not need to know that it runs in distributed environment Performance in parallel mode Endocavitary brachytherapy Interstitial brachytherapy Superficial brachytherapy 1M events 4 minutes, 34 sec 1M events 4 minutes, 36 sec 1M events 4 minutes, 25 sec On up to 50 workers, LSF at CERN, PIII machine, 500/1000 MHz It is not realistic to expect such CPU resources in the “ average hospital”  Via DIANE  A hospital is not required to own and maintain extensive Computing resources to exploit the scientific advantages of MonteCarlo simulation of radiotherapy  Any hospital –even small ones- or in less wealthy countries, that can not afford expensive commercial software systems – may have access to advanced software technologies and tools for radiotherapy  Work in progress: submission to the GRID and retrieval of results from a web portal(to facilitate the usage by end-users) Parallelisation and access to the GRID Running on the GRID Migration to distributed environment