Batteryless NFC dosimeter tag for ionizing radiation based on commercial MOSFET

This paper reports the development, evaluation and validation of DosiTag, a dosimetric platform based on Near Field Communication (NFC) technology. The designed system comprises two main parts: a passive NFC sensing tag as the dosimeter unit, which includes a commercial P-channel MOSFET transistor as radiation sensor; and an NFC-enabled smartphone running a custom-developed application as the reader unit. Additionally, a cloud service based on the messaging protocol Message Queue Telemetry Transport (MQTT) has been implemented using a broker/client architecture to allow the storage and classification of the patient’s data. The dosimeter tag was designed using commercial low-power integrated circuits (ICs) and it can operate without any external power supply or battery, being supplied by the smartphone through the radio frequency (RF) energy harvested from the NFC link. The radiation dose is measured through the increase of the DMOS transistor source voltage using the smartphone as the reader unit. Two tag prototypes have been characterized with a 6 MV photon beam and radiation doses up to 57 Gy and 42 Gy, respectively. The achieved average sensitivity is (4.37 ± 0.04) mV/ Gy with a resolution of 2 cGy, which goes beyond the state-of-the-art of previous NFC dosimeters and places DosiTag as a low-cost promising electronic platform for dose control in radiotherapy treatments.Junta de Andalucía (Spain), projects numbers PI-0505–2017 FEDER/Junta de Andalucía- Consejería de Economía y Conocimiento Project B-TIC-468-UGR18Proyecto del Plan Nacional I + D: PID2019–104888GB-I00 and Proyectos I + D + i Junta de Andalucía 2018: P18-RT-3237H2020 ELICSIR project (grant No. 857558)Grant IJC2020-043307-I funded by MCIN/AEI/ 10.13039/501100011033European Union NextGenerationEU/ PRT