NEUTOR: Neutrons Monitor for. Project financed by: Radiotherapy

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1 NEUTOR: Neutrons Monitor for Project financed by: Radiotherapy

2 PURPOSES OF THE PROJECT To develop a Neutrons monitor for its application in radiotherapy, to control, in real time, the dose of neutrons received by the patients exposed to treatment in high power linear accelerators (LINACS).

3 TECHNOLOGY TRASNFER Application to the radiotherapy field of the knowledge and experience cumulated by TECNOLOGICA (ALTER) in the area of space radiation testing. The final scope is to expand the technical capabilities of the company, through the development of their own products (electronic systems) applicable to a new commercial area for the company: electro-medicine.

4 TECHNOLOGY TRASNFER The project departs from a SEU monitor based on SRAM designed by TECNOLOGICA for the calibration of linear accelerators used for SEU testing of space electronics components sensitive to heavy ions. The calibration device has been modified and adapted for its application in radiotherapy and, more concretely, for the development of the neutrons detector.

5 ORIGIN OF THE IDEA The Universidad de Santiago de Compostela s and SIEMES invention related to the use, as detectors of neutrons, of SRAM memories that present state changes when irradited with low energy neutrons. During RADEX 2006, Dr. Faustino Gómez, from the Universidad de Santiago de Compostela, suggested that the SEUs detector developed by TECNOLOGICA could potentially be used to detect neutrons by replacing the SEUs sensitive SRAM memories by other memories sensitive to neutrons. TECNOLOGICA ACEPTED THE CHALENGE

6 PROJECT DESCRIPTION - Motivation Today, radiotherapy is one of the most efficient techniques for the treatment of certain types of cancer. Currently, the most common equipment used for gamma irradiation treatment are the linear accelerators (LINACS). LINACS can operate typically in a range from 6MV yo 20 MV. The external beams used are gamma photons (produced by Bremstrahlung on a metallic target) and electrons from the primary beam of the LINAC. Neutrons emission is produced when the accelerator is operated at energies higher that 10MV (the photonuclear cross-section threshold). The flux and the effects of the neutrons produced in such circumstances have not been determined yet. The exhaustive control on the neutrons dose affecting a patient will allow adjusting and optimising the photons and condition of a radiotherapy treatment. This will reduce the risk of secondary damage produced by the neutrons.

7 PARTICIPANTS IN THE PROJECT TECNOLOGICA and HIREX Engineering (ALTER Technology Group): Project management. Adaptation of the SEU s detector as a NEUTRONS detector. Detector design and selection and test of neutrons sensitive SRAM memories. Control Software. Grupo de Investigación en Radio-física de la Universidad de Santiago de Compostela (Dr. Faustino Gómez): Definition of the monitor specifications regarding the radiotherapy environment. Validation of the performance of the monitor in terms of its sensitivity and detection spectra. Grupo de FÍSICA MÉDICA de la Universidad de Sevilla (Pr. Francisco Sánchez Doblado): - Calibration of the data provided by the neutrons monitor (NEUTOR) in relation with the working conditions of the linear accelerators used in radiotherapy. - Relationship between the measurements (quantity of neutrons) detected by the NEUTOR during one single radiotherapy session and the y real dose received by the patient. - Calculation of the real risk of generation of future secondary cancer due to the neutrons dose received during the treatment.

8 Phase 1 PHASES and TECHNICAL ACTIVITIES Specifications and detectors selection. Hardware y software design.. Prototype manufacturing. Calibración model. Phase 2 Determination of the neutrons spectrum (detector sensitivity). Development and manufacturing of a test FANTOMA. Verification and correlation with the figures (neutron counts) provided by NEUTOR. Development of the algorithm for the calculation of the effective dose. Development of the algorithm for the calculation of the biological damage and risk of induction of secondary cancers.

9 RESULTS An equipment that is able to detect in real time the number of neutrons passing through a given area in the radiotherapy room during one treatment session has been developed and validated.. The real distribution of the flux of neutrons in any place of the radiotherapy room during one treatment session has been determined departing from the measurements of the neutrons detector. The effective dose of neutrons received by a patient submitted to a radiotherapy sessions has been determined for all possible treatment conditions. From the above, it is possible now to determine the dose due to neutrons ina treatment and to estimate the increase in the risk of production of a secondary future cancer. All this information will be of high utility at the time of establishing the best treatment taken into account not only the possibilities of success but also other future consequences.

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