Authors:
M. A. Carvajal
1
;
J. Banqueri
1
;
A. J. Palma
1
;
A. M. Lallena
2
;
M. Vilches
3
and
D. Guirado
3
Affiliations:
1
University of Granada, ETSIIT and CITIC-UGR, Spain
;
2
University of Granada, Spain
;
3
University Hospital San Cecilio, Spain
Keyword(s):
Radiation sensor, Dosimeter, MOSFET, Radiotherapy, Portable instrument.
Related
Ontology
Subjects/Areas/Topics:
Biomedical Engineering
;
Biomedical Instrumentation
;
Biomedical Instruments and Devices
;
Biomedical Sensors
Abstract:
A portable dosimeter based on unbiased MOSFET sensor is presented. Its main characteristics are an extended linearity range and a notable thermal drift reduction using a unique p-channel MOSFET (pMOS) unbiased during the irradiation period, allowing the location of the sensor without wires for patient comfort and easy-to-use. Both features have been obtained with novel procedures of dose reading and signal processing applied to low-cost commercial pMOS. In this work, a full description of the electronics of the dosimetry system and the signal processing techniques are drawn. The system has been tested with photons from 60Co and the complete technical specifications have been obtained. Among them, we can emphasize: i) dose sensitivity of around 25 mV/Gy; ii) linearity range of more than 50 Gy, with intermediate calibration each 15 Gy, for each sensor; iii) thermal drift below 3 mGy/ºC; iv) resolution below 1cGy; and v) total uncertainty of ± 9 mGy in the temperature range from 19 ºC t
o 36 ºC . We believe that the proposed dosimeter could be a novel and feasible low-cost alternative to previous commercial dosimetry systems for radiotherapy monitoring in clinical applications.
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