Use-Case on treatment planning at HIMAC

1. Use-Case on treatment planning at HIMAC Koichi Murakami KEK 1st Workshop on the Italy-Japan Collaboration on Geant4 Medical Application 8/Mar./04, INFN Genova 1st Workshopon the Italy-Japan Collaboration on Geant4 Medical Application

2. Introduction • Our project was just started and we are not yet familiar with practical use-cases in medical application. • It is important to collect practical use-cases and requirements for medical users. • We had hearing for treatment planning system at HIMAC (NIRS) on last Dec. • with a brief demonstration of the system. • collecting use-cases and documentation • picking up requirements from use-cases 1st Workshopon the Italy-Japan Collaboration on Geant4 Medical Application

3. Basic Flow of Radiation Treatment • Diagnosis • Prescription according to the treatment protocol. • Treatment planning (our scope) • Discussion based on the results of treatment planning • Treatment 1st Workshopon the Italy-Japan Collaboration on Geant4 Medical Application

4. Input/Output of the system • At first, we list up items taking part in the system. • Diagnosis (input) • “Treatment protocol” to be applied • Image data (CT) of a patient • DICOM format • Specification of ROI (Region Of Interest) • Identification of organs • Specification of target (cancer) volume • Parameters of treatment system • beam energy, parameters of beam line (input) • parameters of collimators (range shifter, MLC, Bolus) (i/o) • Discussion based on the results of treatment planning (output) • Dose distribution • DVH (Dose Volume Histogram) 1st Workshopon the Italy-Japan Collaboration on Geant4 Medical Application

5. Image Data (CT) • DICOM format • “Dr. View” is used as visualization tools. • Resolution • 512x512 pixels of 0.7mm2 in xy-plane • 21cm x 15cm (at MLC in HIMAC) • dz=3/5 mm along z-direction, 30cm in total • Correction • position • smoothing • density (removal of artifact) • Conversion from CT-value to density • material is defined as “water”. 1st Workshopon the Italy-Japan Collaboration on Geant4 Medical Application

6. Specification of ROI • ROI (Region Of Interest) • region for scoring DVH • OAR (Organs At Risk) • Tumor (Target) Volume • GTV < CTV < PTV • GTV (Gloss Tumor Volume) • CTV (Clinical Target Volume) • PTV (Planning Target Volume) • TV = PTV + 6mm (HIMAC) • Operation is carried out by doctors. • Marking ROI for each sliced CT image by hand • Automatic identification of organs is possible with commercial tools. 1st Workshopon the Italy-Japan Collaboration on Geant4 Medical Application

7. Parameters of Treatment System • Beam energy • depending on the depth to tumor • Parameters of magnets • making laterally uniform beam area • Wobbler magnet and scatterer thickness • Ridge filter • forming SOBP (Spread Out Bragg Peak) • Range Shifter • adjusting range • Collimators • Ring collimators • MLC (multi leaf collimator) • Bolus • being sculpted for tumor depth • Control protocols of hardware • GPIB • Original format 1st Workshopon the Italy-Japan Collaboration on Geant4 Medical Application

8. Discussion for Treatment • Treatment team has discussion based on the results of treatment planning. • Dose Distribution • Spatial resolution • 2 times larger size of cells than CT image (1.4mmx1.4mm) • same size along z-direction • more fine resolution in other facilities • DVH (Dose Volume Histogram) • Integrated volume having dose more than given over ROI. • DVH in TV vs. DVH in OAR (Organ At Risk) 1st Workshopon the Italy-Japan Collaboration on Geant4 Medical Application

9. Documentation 1st Workshopon the Italy-Japan Collaboration on Geant4 Medical Application

10. Documentation • Making formatted documentation was just started for our situation. • Digging out actors (list of actors) • Breaking down to sub-systems (tentative) • Glossary of terminology • Description of use-cases 1st Workshopon the Italy-Japan Collaboration on Geant4 Medical Application

11. Digging out Actors • List of Actors • Doctors • MRT (Medical Radiation Technologists) as Operators/Planners • This is our (japanese) situation. Situation can be different between countries. • Other concerned participants • Patients • QA of system (design/study/evaluation) 1st Workshopon the Italy-Japan Collaboration on Geant4 Medical Application

12. System Component • Breaking down to sub-systems • This is currently tentative. • Modeling / Visualization • Management of Geometry and Parameters • Dose Calculation • Analysis 1st Workshopon the Italy-Japan Collaboration on Geant4 Medical Application

13. Scope of System Component (1)Modeling / Visualization • I/O of image data • Interface with CT-system and image servers • Visualization of image data • Image processing in medical use • automatic detection of organs • editing CT-values • modeling of human body • production of DRR (Digitally Reconstructed Radiograph) • (Graphical) user interface 1st Workshopon the Italy-Japan Collaboration on Geant4 Medical Application

14. Scope of System Component (2)Management of Geometry and Parameters • I/O and management of geometry and parameters • beam line parameters and (Geant4) geometry • information of patients • converted from CT images to a suitable for planning (e.g. Geant4 geometry) • Calculation and management of parameters of instruments forming exposure area • collimators/filters • interface with CAD/CAM system • (Graphical) user interface 1st Workshopon the Italy-Japan Collaboration on Geant4 Medical Application

15. Scope of System Component (3)Dose Calculation / Analysis • Dose Calculation • Dose calculation engine • non-MC base code • MC code (e.g. Geant4) • Scoring (Tally) package • Analysis • Analysis (histogramming) package • Interface with visualization of result • (Graphical) user interface 1st Workshopon the Italy-Japan Collaboration on Geant4 Medical Application

16. Description of Use-cases • Items in each use-case • Identifier • Goals in Context • Scope • System / Sub-system / Component • as Black Box / White Box • Level • Summary / User-goal / Function (according to abstraction level) • Actors • Pre-condition • Guarantees • Scenario • Extensions • branches for main scinario • alternatives in cases of failure • variations of what to do for main scenario • Technology and Data Variation • variations of how to do for main scenario • Notes 1st Workshopon the Italy-Japan Collaboration on Geant4 Medical Application

17. Documentation of Use-Case • We’ve made documentation for higher level of use-cases. • 1 summary level of use-case and 4 user-goal level of use-cases for sub-systems • Use-Case: Planning radiation treatment • Making treatment plan with treatment planning system. • summary (top) level • scope : radiation treatment planning system • sub-systems are used as black boxes. 1st Workshopon the Italy-Japan Collaboration on Geant4 Medical Application

18. User-goal level of Use-Cases (1) • Input of treatment information • Scope : Visualization / Modeling (White Box) • Processing CT image of a patient and setting information of treatment • Input of exposure condition • Scope: Management of geometry and parameters (WB) • Setting exposure condition of the system • beam line parameters • exposed dose 1st Workshopon the Italy-Japan Collaboration on Geant4 Medical Application

19. User-goal level Use-Cases (2) • Calculation of parameters of instruments • Scope: Management of geometry and parameters (WB) • Calculating parameters of instruments forming exposed area • ridge filter • range shifter • bolus • MLF (Multi Leaf Collimator) • Calculation of Dose Distribution • Scope : Dose Calculation (WB) • Calculating dose distribution in ROI under the given condition 1st Workshopon the Italy-Japan Collaboration on Geant4 Medical Application

20. Future Direction • Collecting Use-Cases for as many facility / system of treatment planning system as possible • Documentation of Use-Cases • Breaking down to well-defined sub-systems • Finding components which can be shared between different system. • Picking up requirements 1st Workshopon the Italy-Japan Collaboration on Geant4 Medical Application