Monte Carlo modeling of a High‐Sensitivity MOSFET dosimeter for low‐ and medium‐energy photon sources

Wang, Brian; Kim, Chan-Hyeong; Xu, Xintao

doi:10.1118/1.1688272

Cited by 38 publications

(26 citation statements)

References 22 publications

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“…MOSFET detectors have photon energy response [19][20][21] similar to the other silicon sensors which are driven by the photoelectric effect cross sections of silicon and the charge recombination in the gate oxide and packaging of the chip. This response, however, is well known to be nonlinear, especially for energies below 300 keV.…”

Section: Energy Dependencementioning

confidence: 97%

Absolute depth-dose-rate measurements for an Ir192 HDR brachytherapy source in water using MOSFET detectors

et al. 2006

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This article was originally published as Zilio. VO, Joneja, OP, Popowski, Y et al, Absolute depth-dose-rate measurements for an 192Ir HDR brachytherapy source in water using MOSFET detectors, Medical Physics, 33(6) Reported MOSFET measurements concern mostly external radiotherapy and in vivo dosimetry. In this paper, we apply the technique for absolute dosimetry in the context of HDR brachytherapy using an 192 Ir source. Measured radial dose rate distributions in water for different planes perpendicular to the source axis are presented and special attention is paid to the calibration of the R and K type detectors, and to the determination of appropriate correction factors for the sensitivity variation with the increase of the threshold voltage and the energy dependence. The experimental results are compared with Monte Carlo simulated dose rate distributions. The experimental results show a good agreement with the Monte Carlo simulations: the discrepancy between experimental and Monte Carlo results being within 5% for 82% of the points and within 10% for 95% of the points. Moreover, all points except two are found to lie within the experimental uncertainties, confirming thereby the quality of the results obtained.

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Section: Energy Dependencementioning

confidence: 97%

Absolute depth-dose-rate measurements for an Ir192 HDR brachytherapy source in water using MOSFET detectors

et al. 2006

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“…They reported the angular dependence for a photon beam was within 2-3%. Wang et al [13,14] simulated the angular dependence of the MOSFET response by the Monte Carlo method, and they evaluated the angular dependence as a function of photon energy. Figure 8 shows the angular dependence of the MOSFET response for 6 and 10 MV photon beams.…”

Section: Angular Dependencementioning

confidence: 99%

Dosimetric evaluation of a MOSFET detector for clinical application in photon therapy

Kohno

Hirano

Nishio

et al. 2007

Radiol Phys Technol

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Dosimetric characteristics of a metal oxide-silicon semiconductor field effect transistor (MOSFET) detector are studied with megavoltage photon beams for patient dose verification. The major advantages of this detector are its size, which makes it a point dosimeter, and its ease of use. In order to use the MOSFET detector for dose verification of intensity-modulated radiation therapy (IMRT) and in-vivo dosimetry for radiation therapy, we need to evaluate the dosimetric properties of the MOSFET detector. Therefore, we investigated the reproducibility, dose-rate effect, accumulated-dose effect, angular dependence, and accuracy in tissue-maximum ratio measurements. Then, as it takes about 20 min in actual IMRT for the patient, we evaluated fading effect of MOSFET response. When the MOSFETs were read-out 20 min after irradiation, we observed a fading effect of 0.9% with 0.9% standard error of the mean. Further, we applied the MOSFET to the measurement of small field total scatter factor. The MOSFET for dose measurements of small field sizes was better than the reference pinpoint chamber with vertical direction. In conclusion, we assessed the accuracy, reliability, and usefulness of the MOSFET detector in clinical applications such as pinpoint absolute dosimetry for small fields.

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“…MC simulations of deposited doses in the gate oxide by previous workers dealt with broad beams in free-air geometry, or in a solid water phantom [15], and mainly with the beam perpendicular to the surface ("front on"). Results agree well with experimental data.…”

Section: Simulation Modelmentioning

confidence: 99%

Edge-on face-to-face MOSFET for synchrotron microbeam dosimetry: MC modeling

Rosenfeld

Siegbahn

Brauer-Krish

et al. 2005

IEEE Trans. Nucl. Sci.

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Abstract-The dosimetry of X-ray microbeams using MOSFETs results in an asymmetrical beam profile due to a lack of lateral charged particle equilibrium. Monte Carlo simulations were carried out using PENELOPE and GEANT4 codes to study this effect and a MOSFET on a micropositioner was scanned in the microbeam. Based on the simulations a new method of microbeam dosimetry is proposed. The proposed edge-on face-to-face (EOFF) MOSFET detector, a die arrangement proposed here for the first time, should alleviate the asymmetry. Further improvement is possible by thinning the silicon body of the MOSFET.Index Terms-Charged-particle equilibrium (CPE), dose enhancement effects (DEEs), dosimetry, microbeam, MOSFET, radiotherapy, synchrotron.

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Monte Carlo modeling of a High‐Sensitivity MOSFET dosimeter for low‐ and medium‐energy photon sources

Cited by 38 publications

References 22 publications

Absolute depth-dose-rate measurements for an Ir192 HDR brachytherapy source in water using MOSFET detectors

Absolute depth-dose-rate measurements for an Ir192 HDR brachytherapy source in water using MOSFET detectors

Dosimetric evaluation of a MOSFET detector for clinical application in photon therapy

Edge-on face-to-face MOSFET for synchrotron microbeam dosimetry: MC modeling

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