1 3rd oPAC Topical Workshop on Beam Diagnostics, CIVIDEC, Vienna, 8th-9th May 2014

 Motivation  The RADIA project  Detector characteristics  Characterization of the system (setup and data analysis)  Algorithm for 2D dose map reconstruction (setup, theory and tests)  Conclusions and perspectives  Bibliography 2 3rd oPAC Topical Workshop on Beam Diagnostics, CIVIDEC, Vienna, 8th-9th May 2014

3 Radiotherapy plays an important role in the treatment of a wide range of cancers Very important: monitoring the dose delivered to the patient A novel dosimetric system based on silicon detector for radiotherapy treatment verification. Advantages: silicon detectors have good radiation hardness; on line treatment verification -> for example, no need of film development; acceptable spatial resolution; reproducibility; dose maps in the axial plane.

4 3rd oPAC Topical Workshop on Beam Diagnostics, CIVIDEC, Vienna, 8th-9th May 2014 TWO DETECTORS A feasibility study:W1 SS 500 A commercial Single Sided Silicon Strip Detector (SSSSD) New detector based on BB7 technology Dual chip SSSSD, designed by our group, following clinical constraints Patent at OEMP (Oficinal Española de Patentes y Marcas), Ministry of Industry & Commerce: Number P (13/09/2011)

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

6 Mechanical system BOX SLAB PHANTOM Siemens Linac in 6 MV photon mode Irradiation tests performed at the Virgen Macarena Hospital in Seville Detector placed perpendicularly to the beam

3rd oPAC Topical Workshop on Beam Diagnostics, CIVIDEC, Vienna, 8th-9th May Complete characterization of the system in terms of: (a)linearity: The response of each strip is linear as function of irradiation time

3rd oPAC Topical Workshop on Beam Diagnostics, CIVIDEC, Vienna, 8th-9th May Complete characterization of the system in terms of: (b) uniformity: a fundamental step to establish a common ground behavior for the strips of each detector

3rd oPAC Topical Workshop on Beam Diagnostics, CIVIDEC, Vienna, 8th-9th May Complete characterization of the system in terms of: (c) Percentage Depth Dose (PDD): study of the dose at different depth in solid water, compared to the ionization chamber data

3rd oPAC Topical Workshop on Beam Diagnostics, CIVIDEC, Vienna, 8th-9th May Complete characterization of the system in terms of: (d) Penumbra: penumbra is defined as the region located between 20% and 80 % of the maximum dose level along X and Y directions Detector irradiated by asymmetric fields

3rd oPAC Topical Workshop on Beam Diagnostics, CIVIDEC, Vienna, 8th-9th May Cylindrical phantom: new project Housing the detector Versatile and rotating phantom; homogeneus: water equivalent material; Able to house different detectors (films, ionization chambers, strip detectors,..) Detector parallel to the beam field Dose maps in the axial plane Old system setup

3rd oPAC Topical Workshop on Beam Diagnostics, CIVIDEC, Vienna, 8th-9th May Mathematical algorithm for dose map reconstruction based on: Radon Transform To solve the equation: back projection theorem

3rd oPAC Topical Workshop on Beam Diagnostics, CIVIDEC, Vienna, 8th-9th May Real case with the detectorDiscretization is needed The dose in each pixel is reconstructed by the formula: Where: a is the strip lenght, n is the number of strips, q is the number of measurements, Δθ is the angular step between consecutive measurements. Filter

3rd oPAC Topical Workshop on Beam Diagnostics, CIVIDEC, Vienna, 8th-9th May Dual chip SSSSD: 32 strips for both detectors SSSSD: 16 strips (developed by M.A. Cortés Giraldo, University of Seville) Simulated dose map image of a circle (R=9 mm) for both the systems Reconstructed area48x48 mm 2 64x64 mm 2 Image resolution3 mm2 mm Angular range0º-180º0º-90º Angular step5º3º

3rd oPAC Topical Workshop on Beam Diagnostics, CIVIDEC, Vienna, 8th-9th May The new detection system shows good performances in radiotherapy conditions; A preliminary, complete characterization of the system as a dosimeter has been done; New set of measurements, with the new cylindrical phantom; Calibration of the system in such configuration; Implementation of new algorithm for dose map reconstruction Work to be done :

3rd oPAC Topical Workshop on Beam Diagnostics, CIVIDEC, Vienna, 8th-9th May Appreciated contributions to make this project a success have been received from the silicon detector manufacturer, Micron Semiconductor Ltd., web: (Dr Susanne Walsh Design /Colin D.Wilburn Director), ATI Sistemas S. L., (Mrs. Marta Trueba) and Instalaciones Inabensa. Radia Collaboration Department of Atomic, Molecular and Nuclear Physics, University of Seville: GETERUS group (M. A. Cortés Giraldo, M. I. Gallardo, J. M. Quesada), J. M. Espino (also CNA), M. C. Ovejero and A. Selva. University Hospital “Virgen Macarena”, Seville (SAS): R. Arráns, H. Miras. National Accelerator Centre (CNA): Z. Abou-Haïdar, M. Alvarez, M. C. Battaglia, A. Bocci. Department of Electronic Engineering, University of Seville: A. Pérez Vega-Leal

3rd oPAC Topical Workshop on Beam Diagnostics, CIVIDEC, Vienna, 8th-9th May (1)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, “Silicon strip detector for a novel 2D dosimetric method for radiotherapy treatment verification”, Nucl. Instrum. Methods Phys. 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 determination for dose measurements in axial and perpendicular planes using a silicon strip detector”, Phys. Rev. ST Accel. Beams 15, (2012). (3) M.A.Cortés-Giraldo, M.I. Gallardo, R. Arráns, J.M. Quesada, A. Bocci, J.M. Espino, Z. Abou-Haïdar and M. A. G. Alvarez, "Geant4 simulation to study the sensitivity of a Micron silicon strip detector irradiated by a Siemens PRIMUS linac", Progress in Nuclear Science and Technology, Vol. 2, pp (2011). (4) Patent at the OEMP - Oficina Española de Patentes y Marcas – Ministry of Industry & Commerce: Number P (13/09/2011).

3rd oPAC Topical Workshop on Beam Diagnostics, CIVIDEC, Vienna, 8th-9th May Thank you Any questions?