Light-dependent resistors as dosimetric sensors in radiotherapy

Román Raya, J., Ruiz García, I., Escobedo Araque, P. , Palma López, A. J., Guirado Llorente, D. and Carvajal, M. A. (2020) Light-dependent resistors as dosimetric sensors in radiotherapy. Sensors, 20(6), 1568. (doi: 10.3390/s20061568)

Abstract

Safe quality control of radiotherapy treatments lies in reliable dosimetric sensors. Currently, ionization chambers and solid-state diodes along with electrometers as readout systems are accomplishing this task. In this work, we present a well-known and low-cost semiconductor sensor, the light-dependent resistor (LDR), as an alternative to the existing sensing devices for dosimetry. To demonstrate this, a complete characterization of the response to radiation of commercial LDRs has been conducted in terms of sensitivity, reproducibility and thermal correction under different bias voltages. Irradiation sessions have been applied under the common conditions in radiotherapy treatments using a hospital linear accelerator. Moreover, the same electrometer used for the ionization chamber has also been successfully used for LDRs. In comparison with the sensitivity achieved for the ionization chamber (0.2 nC/cGy at 400 V bias voltage), higher sensitivities have been measured for the proposed LDRs, ranging from 0.24 to 1.04 nC/cGy at bias voltages from 30 to 150 V, with a reproducibility uncertainty among samples of around 10%. In addition, LDR temperature dependence has been properly modeled using the simple thermistor model so that an easy thermal drift correction of dose measurements can be applied. Therefore, experimental results show that LDRs can be a reliable alternative to dosimetric sensors with the advantages of low size, affordable cost and the fact that it could be adopted with minimal changes in routine dosimetry quality control since the same readout system is fully compatible.

• Item Type: Articles
• Additional Information: Funding: This research and APC were partially funded by Junta de Andalucía (Spain), projects number PI-0505-2017 and B-TIC-468-UGR18, and in part by the European Regional Development Fund (ERDF).
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Escobedo, Dr Pablo

Creator Roles

Escobedo Araque, P.: Methodology, Validation

• Authors: Román Raya, J., Ruiz García, I., Escobedo Araque, P., Palma López, A. J., Guirado Llorente, D., and Carvajal, M. A.
• College/School: College of Science and Engineering > School of Engineering > Electronics and Nanoscale Engineering
• Journal Name: Sensors
• Publisher: MDPI
• ISSN: 1424-8220
• ISSN (Online): 1424-8220
• Copyright Holders: Copyright © 2020 by the authors
• First Published: First published in Sensors 20(6):1568
• Publisher Policy: Reproduced under a Creative Commons license