A very-low-cost dosimeter based on the off-the-shelf CD4007 MOSFET array for in vivo radiotherapy applications

Autor(es)

Siebel, O. F. ^[1] ; Pereira, J. G. ^[2] ; Souza, R. S. ^[3] ; Ramirez-Fernandez, F. J. ^[1] ; Schneider, M. C. ^[4] ; Galup-Montoro, C. ^[4]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Sch Engn, BR-05508010 Sao Paulo, SP - Brazil

^[2] Ctr Pesquisas Oncol CEPON, BR-88034000 Florianopolis, SC - Brazil

^[3] Inst Nacl Canc INCA, BR-20230010 Rio De Janeiro, RJ - Brazil

^[4] Univ Fed Santa Catarina, Dept Elect Engn, BR-88040900 Florianopolis, SC - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Radiation Measurements; v. 75, p. 53-63, APR 2015.
• Citações Web of Science: 5

Resumo

Purpose: This paper presents a low-cost MOSFET dosimeter suitable for in vivo radiotherapy applications. We analyze different methods to extract the threshold voltage and how this extraction is affected by the dose dependence of slope factor and carrier mobility. Also, we discuss fundamental aspects of the basic building blocks of a MOSFET dosimeter, namely, the radiation sensor, the reader circuit and temperature desensitization. Methods: Experiments with ionizing radiation (6 MV X-ray beams) were carried out at the Centro de Pesquisas Oncologicas (CEPON) using linear accelerators to test the MOSFET dosimeter. Results: The main performance parameters of the dosimeter prototype are radiation sensitivity about 100 mV/Gy (sensor's sensitivity is around 6.7 mV/Gy), thermal dependence of 0.5 cGy/degrees C, reproducibility is about 2.6%, and radiation beam attenuation of 0.14%. Conclusions: The MOSFET dosimeter described in this article, which combines a simple and accurate readout procedure with a small size, low-cost, cable/battery-free sensor and very little attenuation of the radiation beam is a very appealing option for in vivo dosimetry. (C) 2015 Elsevier Ltd. All rights reserved. (AU)

• Processo FAPESP: 13/24894-0 - Desenvolvimento de um dosímetro in vivo a MOSFET para aplicações radioterápicas.
• Beneficiário: Osmar Franca Siebel
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado