Development of an in vivo MOSFET dosimeter for radiotherapy applications.

• Grant number: 13/24894-0
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: May 01, 2014
• End date: April 30, 2015
• Field of knowledge: Engineering - Electrical Engineering - Electrical, Magnetic and Electronic Measurements, Instrumentation
• Principal Investigator: Francisco Javier Ramirez Fernandez
• Grantee: Osmar Franca Siebel
• Host Institution: Escola Politécnica (EP). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

In radiotherapy, the maximum difference between the prescribed dose and the dose delivered to the patient must be ±5% based on the fact that some tumors exhibit steep dose response curves. For this reason, in vivo dosimeters are fundamental for radiotherapy, since they are the only devices that allow the dose to be monitored during the patient treatment. In this context, we have this postdoctoral research which consists in developing an in vivo dosimeter for radiotherapy applications using the MOSFET dosimeter that has being developed by the candidate on his doctorate. This MOSFET dosimeter was tested at the Centro de Pesquisas Oncológicas (CEPON), Florianópolis-SC, using 6MV and 15MV X-rays beams. The main results of these experiments were: radiation sensitivity 98,1mV/Gy, thermal dependence 0.5cGy/æC, angular dependence of 13%, energy dependence of 1,5%, linearity of 97,5%, and attenuation to the radiation beam of 0,14%. These results are promising; however the high angular dependence (13%) is an important disadvantage of this dosimeter. Hence one of the main goals of this postdoctoral project is to reduce this angular dependence with the development of a new sensor package. In addition to the design of a new package and consequent reduction of angular dependence, other activities to be accomplished in this postdoctoral are: improvement of the dosimeter reading system and performing more experiments with ionizing radiation.

Scientific publications

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

SIEBEL, O. F.; PEREIRA, J. G.; SOUZA, R. S.; RAMIREZ-FERNANDEZ, F. J.; SCHNEIDER, M. C.; GALUP-MONTORO, C.. A very-low-cost dosimeter based on the off-the-shelf CD4007 MOSFET array for in vivo radiotherapy applications. Radiation Measurements, v. 75, p. 53-63, APR 2015. (13/24894-0)