Light-Dependent Resistors as Dosimetric Sensors in Radiotherapy Román-Raya, Juan Ruiz García, Isidoro Escobedo Araque, Pablo Palma López, Alberto José Guirado Llorente, Damián Carvajal Rodríguez, Miguel Ángel Dosimetry Radiotherapy Light-dependent resistor Dose rate Thermal characterization The authors would like to acknowledge to the staff of the Hospital Universitario Clínico San Cecilio, Granada, Spain, for their support and use of the facilities. We also thank the reviewers for their useful and constructive comments and suggestions which have improved this paper. 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. 2020-06-03T07:21:15Z 2020-06-03T07:21:15Z 2020-03-11 info:eu-repo/semantics/article Román-Raya, J.; Ruiz-García, I.; Escobedo, P.; Palma, A.J.; Guirado, D.; Carvajal, M.A. Light-Dependent Resistors as Dosimetric Sensors in Radiotherapy. Sensors 2020, 20, 1568. [doi:10.3390/s20061568] http://hdl.handle.net/10481/62340 10.3390/s20061568 eng http://creativecommons.org/licenses/by/3.0/es/ info:eu-repo/semantics/openAccess Atribución 3.0 España MDPI