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Novel system for 2D dose map s in complex radiotherapy treatment verification. Maria Cristina Battaglia. Outline. Motivation The RADIA project Detector characteristics Characterization of the system ( setup and data analysis )
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Novel systemfor 2D dosemaps in complexradiotherapytreatmentverification Maria Cristina Battaglia 3rd oPAC Topical Workshop on Beam Diagnostics, CIVIDEC, Vienna, 8th-9th May 2014
Outline • Motivation • The RADIA project • Detector characteristics • Characterization of thesystem(setup and data analysis) • Algorithm for 2D dose map reconstruction (setup, theory and tests) • Conclusions and perspectives • Bibliography 3rd oPAC Topical Workshop on Beam Diagnostics, CIVIDEC, Vienna, 8th-9th May 2014
Motivation Radiotherapyplaysanimportant role in thetreatment of a widerange of cancers Veryimportant: monitoringthedosedeliveredto thepatient A novel dosimetricsystembasedonsilicon detector forradiotherapy treatmentverification. Advantages: silicondetectorshavegoodradiationhardness; on line treatmentverification -> forexample, no need of film development; acceptablespatialresolution; reproducibility; dosemaps in the axial plane. 3rd oPAC Topical Workshop on Beam Diagnostics, CIVIDEC, Vienna, 8th-9th May 2014
The RADIA project: 2D dosimetricmethodforradiotherapytreatmentverificationusingsilicondetectors TWO DETECTORS A feasibility study:W1 SS 500 New detector basedon BB7 technology A commercial Single SidedSiliconStrip Detector (SSSSD) Dual chip SSSSD, designedbyourgroup, followingclinicalconstraints Patent at OEMP (Oficinal Española de Patentes y Marcas), Ministry of Industry & Commerce: Number P201101009 (13/09/2011) 3rd oPAC Topical Workshop on Beam Diagnostics, CIVIDEC, Vienna, 8th-9th May 2014
Detectorscharacteristics 3rd oPAC Topical Workshop on Beam Diagnostics, CIVIDEC, Vienna, 8th-9th May 2014
Characterization of thesystem: experimental set up (1) Siemens Linac in 6 MV photonmode Mechanicalsystem BOX SLAB PHANTOM Irradiationtestsperformed at the Virgen Macarena Hospital in Seville Detector placed perpendicularly to thebeam 3rd oPAC Topical Workshop on Beam Diagnostics, CIVIDEC, Vienna, 8th-9th May 2014
Characterization of the detector(2) Complete characterization of thesystem in terms of: linearity: The response of eachstripis linear as function of irradiation time 3rd oPAC Topical Workshop on Beam Diagnostics, CIVIDEC, Vienna, 8th-9th May 2014
Characterization of the detector(2) Complete characterization of thesystem in terms of: (b) uniformity: a fundamental step to establish a commongroundbehaviorforthestrips of each detector 3rd oPAC Topical Workshop on Beam Diagnostics, CIVIDEC, Vienna, 8th-9th May 2014
Characterization of the detector(2) Complete characterization of thesystem in terms of: (c) PercentageDepthDose (PDD): study of thedose at differentdepth in solidwater, compared to theionizationchamber data 3rd oPAC Topical Workshop on Beam Diagnostics, CIVIDEC, Vienna, 8th-9th May 2014
Characterization of the detector(2) Complete characterization of thesystem in terms of: (d) Penumbra: penumbra isdefined as theregionlocatedbetween 20% and 80 % of themaximumdoselevelalong X and Y directions Detector irradiatedbyasymmetricfields 3rd oPAC Topical Workshop on Beam Diagnostics, CIVIDEC, Vienna, 8th-9th May 2014
Algorithmfordosemapreconstruction (setup) Old systemsetup Dosemaps in the axial plane Detector parallelto thebeamfield Cylindricalphantom: new project • Versatile and rotatingphantom; • homogeneus: waterequivalent material; • Able to housedifferentdetectors (films, ionizationchambers, stripdetectors,..) Housingthe detector 3rd oPAC Topical Workshop on Beam Diagnostics, CIVIDEC, Vienna, 8th-9th May 2014
Algorithmfordosemapreconstruction: radontransform Mathematicalalgorithmfordosemapreconstructionbasedon: RadonTransform : our set of data foreachangleθ f(x,y): thefunctionrepresentingthedosemapwewant to reconstruct To solvetheequation: back projectiontheorem 3rd oPAC Topical Workshop on Beam Diagnostics, CIVIDEC, Vienna, 8th-9th May 2014
Algorithmfordosemapreconstruction: back projection Filter Real case withthe detector Discretizationisneeded Thedose in each pixel isreconstructedbythe formula: ,(, • Where: • a isthestriplenght, • n isthenumber of strips, • q isthenumber of measurements, • Δθisthe angular stepbetweenconsecutivemeasurements. 3rd oPAC Topical Workshop on Beam Diagnostics, CIVIDEC, Vienna, 8th-9th May 2014
Algorithmfordosemapreconstruction: tests Dual chip SSSSD: 32 stripsforbothdetectors SSSSD: 16 strips (developedby M.A. Cortés Giraldo, University of Seville) Simulateddosemapimage of a circle (R=9 mm) forboththesystems 3rd oPAC Topical Workshop on Beam Diagnostics, CIVIDEC, Vienna, 8th-9th May 2014
Conclusions and perspectives • The new detectionsystem shows good performances in radiotherapyconditions; • A preliminary, complete characterization of thesystem as a dosimeter has been done; • New set of measurements, withthenew cylindricalphantom; • Calibration of thesystem in suchconfiguration; • Implementation of new algorithmfordosemapreconstruction Work to be done : 3rd oPAC Topical Workshop on Beam Diagnostics, CIVIDEC, Vienna, 8th-9th May 2014
Acknowledgment Appreciatedcontributions to makethisproject a successhavebeenreceived fromthesilicon detector manufacturer, Micron Semiconductor Ltd., web: www.micronsemiconductor.co.uk (DrSusanne Walsh Design /ColinD.Wilburn Director), ATI Sistemas S. L., www.atisistemas.com (Mrs. Marta Trueba) and Instalaciones Inabensa. Radia Collaboration Department of Atomic, Molecular and Nuclear Physics, Universityof Seville: GETERUS group (M. A. Cortés Giraldo, M. I. Gallardo, J. M. Quesada), J. M. Espino (also CNA), M. C. Ovejero and A. Selva. UniversityHospital “Virgen Macarena”, Seville (SAS): R. Arráns, H. Miras. NationalAccelerator Centre (CNA): Z. Abou-Haïdar, M. Alvarez, M. C. Battaglia, A. Bocci. Department of ElectronicEngineering, University of Seville: A. Pérez Vega-Leal 3rd oPAC Topical Workshop on Beam Diagnostics, CIVIDEC, Vienna, 8th-9th May 2014
Bibliography A. Bocci, M. A. Cortés-Giraldo, M. I. Gallardo, J. M. Espino, R. Arráns, M. A. G. Alvarez, Z. Abou-Haïdar, J. M. Quesada, A. Pérez Vega-Leal, and F. J. Pérez Nieto, “Siliconstrip detector for a novel 2D dosimetricmethodfor radiotherapytreatmentverification”, Nucl. Instrum. MethodsPhys. Res., Sect. A. 673, 98 (2012). (2) Z. Abou-Haïdar, A.Bocci, M. A. G. Alvarez, J.M. Espino, M.I. Gallardo, M.A. Cortés-Giraldo, M.C. Ovejero, J.M. Quesada, R. Arráns, M. Ruiz Prieto, A. Pérez Vega-Leal y F.J. Pérez Nieto. “Output factor determinationfor dosemeasurements in axial and perpendicular planes using a siliconstrip detector”, Phys. Rev. ST Accel. Beams15,042802 (2012). (3) M.A.Cortés-Giraldo, M.I. Gallardo, R. Arráns, J.M. Quesada, A. Bocci, J.M. Espino, Z. Abou-Haïdarand M. A. G. Alvarez, "Geant4 simulation to studythesensitivity of a Micronsiliconstrip detector irradiatedby a Siemens PRIMUS linac", Progress in Nuclear Science and Technology, Vol. 2, pp. 191-196 (2011). (4) Patent at the OEMP - Oficina Española de Patentes y Marcas – Ministry of Industry & Commerce: Number P201101009 (13/09/2011). 3rd oPAC Topical Workshop on Beam Diagnostics, CIVIDEC, Vienna, 8th-9th May 2014
Thankyou Anyquestions? 3rd oPAC Topical Workshop on Beam Diagnostics, CIVIDEC, Vienna, 8th-9th May 2014