When in vivo proton dosimetry is performed with a metal-oxide semiconductor field-effect transistor (MOSFET) detector, the response of the detector depends strongly on the linear energy transfer. The present study reports a practical method to correct the MOSFET response for linear energy transfer dependence by using a simplified Monte Carlo dose calculation method (SMC). A depth-output curve f...

The dosimetry of very small electron fields can be challenging due to relative shifts in percent depth-dose curves, including the location of dmax, and lack of lateral electronic equilibrium in an ion chamber when placed in the beam. Conventionally a small parallel plate chamber or film is utilized to perform small field electron beam dosimetry. Since modern radiotherapy departments are becomin...

The radiation positioning system (RADPOS) combines an electromagnetic positioning sensor with metal oxide semiconductor field-effect transistor (MOSFET) dosimetry, enabling simultaneous online measurement of dose and spatial position. Evaluation points can be determined with the RADPOS. The accuracy of in-vivo proton dosimetry was evaluated using the RADPOS and an anthropomorphic head and neck ...

This note investigates temperature effects on dosimetry using a metal oxide semiconductor field effect transistor (MOSFET) for radiotherapy x-ray treatment. This was performed by analysing the dose response and threshold voltage outputs for MOSFET dosimeters as a function of ambient temperature. Results have shown that the clinical semiconductor dosimetry system (CSDS) MOSFET provides stable do...

We have investigated the feasibility of using a set of multiple MOSFETs in conjunction with the mobile MOSFET wireless dosimetry system, to perform a comprehensive and efficient quality assurance (QA) of IMRT plans. Anatomy specific MOSFET configurations incorporating 5 MOSFETs have been developed for a specially designed IMRT dosimetry phantom. Kilovoltage cone beam computed tomography (kV CBC...

This work presents different techniques to increase the sensitivity of commercial MOSFET (no RADFET) to demonstrate their potential as dosimetry sensors with electrons beams (for IORT) and gamma radiation. Different models of commercial MOSFET were irradiated in unbiased and biased mode, to select the best candidate and configuration for each type of radiotherapy.

Background: Intracavitary brachytherapy plays a major role in management of cervical carcinoma. Assessment of dose received by OAR’s therefore becomes crucial for the estimation of radiation toxicities in HDR brachytherapy. Objective: Purpose of this study is to evaluate the role of in vivo dosimetry in HDR brachytherapy and to compare actual doses delivered to OAR’ s with those calculate...

The accuracy of a MOSFET dosimetry system with respect to peripheral therapeutic doses from high-energy X-rays has been evaluated. The results have been compared with ionisation chamber measurements in the same peripheral regions of the beam. For 6 MV and 18 MV X-ray beams, the MOSFET system in the high-sensitivity mode produces reproducibility of dose measurement with relative standard deviati...

We experimentally evaluated the proton beam dose reproducibility, sensitivity, angular dependence and depth-dose relationships for a new Metal Oxide Semiconductor Field Effect Transistor (MOSFET) detector. The detector was fabricated with a thinner oxide layer and was operated at high-bias voltages. In order to accurately measure dose distributions, we developed a practical method for correctin...

Metal oxide semiconductor field effect transistor (MOSFET) detectors have recently been introduced to radiation therapy. However, the response of these detectors is known to vary with dose rate. Therefore, it is important to evaluate how much variation between the treatment prescribed dose and the dose that is actually delivered to the patient using high-energy photon or electron beams under co...