Evaluation of a microMOSFET radiation sensor for the monitoring of in vivo dosimetry during total scalp radiotherapy

The present study is to introduce the in vivo dosimetric verification in field abutment regions during total scalp radiotherapy by using standard MOSFET and microMOSFET sensors. Both types of MOSFET sensors were evaluated for linearity analysis, and angular dependence. The in vivo dosimetry verification in field abutment regions was first carried out in a Rando-head-phantom, and lateral photon-electron technique was employed. Both two types of MOSFET sensors were used to phantom study. The microMOSFET sensors were used alone on a patient. Good linearities were observed for the both types of MOSFET sensors in dose ranges 0-200 cGy. The angular dependence of MOSFET sensors were small that could be negligible in this work. The doses estimated from microMOSFETs provided acceptable accuracy in this work, which were under 4.7% respect to the doses calculated from treatment planning system. MicroMOSFET sensors are good candidates for immediate dose monitoring during total scalp radiotherapy.