Speaker
Dr.
José M. Espino
(Department of Atomic, Molecular and Nuclear Physics (FAMN), University of Seville, Spain)
Description
In complex radiation therapy treatments with photons, such as Intensity Modulated Radiation Therapy (IMRT), dose distribution verification is highly advisable prior to real dose delivery to patient. In fact, the increasing sophistication and complexity of IMRT treatments is a major challenge for Treatment Planning Systems (TPS), which might miscalculate under some circumstances. We have developed a detection system for radiation therapy treatment verification based on a single sided silicon strip detector (SSSSD) housed inside a cylindrical phantom. This work started in the frame of the project Radia, a collaboration between the University of Seville, Instalaciones Inabensa S.A. (a company of Abengoa group), CNA and the Virgen Macarena University Hospital of Seville.
In our system, the detector is placed inside the cylindrical phantom with the detector plane perpendicular to the symmetry axis of the cylinder, and parallel to the radiation beam axis. This allows to obtain dose maps in axial planes, which are the most relevant in the process of treatment planning since they correspond, in general, to the orientation of the CT slices of the patient used during such process. This is the main innovation with respect to other recently developed systems, based on diode and ionization chamber arrays.
The cylindrical phantom is rotated so that data are taken for different relative orientations between the detector strips and the radiation fields. A software has been developed to operate the rotation of the phantom and to acquire the signals from the silicon strip detector. The dose maps are calculated from the set of data recorded for a certain sequence of relative orientations, using a reconstruction algorithm similar to that of computed tomography. A patent application of this procedure has been submitted to the Spanish Office of Patents (expedient nº P201101009).
Presently we are working on a new prototype, with these main improvements:
• A new detector, featuring a special configuration designed in collaboration with the Spanish company ATI Sistemas S.L., built by Micron Semiconductor Ltd. (UK). It consists of a dual chip 32x32 SSSSD, mounted back to back and using materials with densities as close as possible to water density.
• New electronics and software for phantom rotation control and for data acquisition and analysis, improving sensitivity, linearity and measurement bandwidth. Its performance is boosted with automated algorithms.
• A new phantom, more versatile than the previous one and with a better control of angular position.
• A new reconstruction algorithm to obtain the dose maps.
| Oral or poster presentation | Oral |
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Primary authors
Dr.
Alessio Bocci
(National Accelerator Centre (CNA), Seville)
Dr.
Alfredo Pérez Vega-Leal
(Department of Electronic Engineering, University of Seville)
Mr.
Francisco J. Pérez Nieto
(Instalaciones Inabensa S.A., Seville)
Dr.
José M. Espino
(Department of Atomic, Molecular and Nuclear Physics (FAMN), University of Seville, Spain)
Dr.
José M. Quesada
(Department of Atomic, Molecular and Nuclear Physics (FAMN), University of Seville)
Ms.
M. Carmen Ovejero
(Department of Atomic, Molecular and Nuclear Physics (FAMN), University of Seville)
Ms.
M. Cristina Battaglia
(National Accelerator Centre (CNA), Seville)
Dr.
M. Isabel Gallardo
(Department of Atomic, Molecular and Nuclear Physics (FAMN), University of Seville)
Dr.
Marcos A. G. Alvarez
(Department of Atomic, Molecular and Nuclear Physics (FAMN), University of Seville / National Accelerator Centre (CNA))
Dr.
Miguel A. Cortés-Giraldo
(Department of Atomic, Molecular and Nuclear Physics (FAMN), University of Seville)
Dr.
Rafael Arráns
(Virgen Macarena University Hospital, Seville)
Mr.
Raúl Núñez Martín
(Department of Electronic Engineering, University of Seville)
Dr.
Ziad Abou-Haïdar
(National Accelerator Centre (CNA), Seville)
