Novel system for 2d dose map s in complex radiotherapy treatment verification
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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 system for 2D dose map s in complex radiotherapy treatment verification

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Novel system for 2d dose map s in complex radiotherapy treatment verification

Novel systemfor 2D dosemaps in complexradiotherapytreatmentverification

Maria Cristina Battaglia

3rd oPAC Topical Workshop on Beam Diagnostics, CIVIDEC, Vienna, 8th-9th May 2014


Outline

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

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


Novel system for 2d dose map s in complex radiotherapy treatment verification

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


Detectors characteristics

Detectorscharacteristics

3rd oPAC Topical Workshop on Beam Diagnostics, CIVIDEC, Vienna, 8th-9th May 2014


Characterization of the system experimental set up 1

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

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 21

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 22

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 23

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


Algorithm for dose map reconstruction setup

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


Algorithm for dose map reconstruction radon transform

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


Algorithm for dose map reconstruction back projection

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


Algorithm for dose map reconstruction tests

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

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

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

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


Novel system for 2d dose map s in complex radiotherapy treatment verification

Thankyou

Anyquestions?

3rd oPAC Topical Workshop on Beam Diagnostics, CIVIDEC, Vienna, 8th-9th May 2014


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