Evaluation of the usefulness of a MOSFET detector in an anthropomorphic phantom for 6-MV photon beam

Kohno, Ryosuke; Hirano, Eriko; Kitou, Satoshi; Goka, Tomonori; Matsubara, Kana; Kameoka, S.; Matsuura, Tetsuya; Ariji, Takaki; Nishio, Teiji; Kawashima, Mitsuhiko; Ogino, Takashi

doi:10.1007/s12194-010-0084-z

Cited by 5 publications

(4 citation statements)

References 17 publications

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“…Different methodologies for skin dose measurement and detectors characterization have been reported in the literature: radiochromic films; thermoluminescent dosimeters (TLD), and other passive solid state dosimeters; diodes; metal oxide semiconductor field effect transistors (MOSFETs)‐based dosimeter, etc …”

Section: Introductionmentioning

confidence: 99%

Optimization of skin dose usingin‐vivoMOSFETdose measurements in bolus/non‐bolus fraction ratio: AVMATand a 3DCRTstudy

Dias

Pinto

Borges

et al. 2019

J Applied Clin Med Phys

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In‐phantom and in‐vivo three dimensional conformal radiation therapy (3DCRT) and volumetric modulated arc therapy (VMAT) skin doses, measured with and without bolus in a female anthropomorphic phantom RANDO and in patients, were compared against treatment planning system calculated values. A thorough characterization of the metal oxide semiconductor field effect transistor measurement system was performed prior to the measurements in phantoms and patients. Patients with clinical indication for postoperative external radiotherapy were selected. Skin dose showed higher values with 3DCRT technique compared with VMAT. The increase in skin dose due to the use of bolus was quantified. It was observed that, in the case of VMAT, the bolus effect on the skin dose was considerable when compared with 3DCRT. From the point of view of treatment time, bolus cost, and positioning reproducibility, the use of bolus in these situations can be optimized.

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Section: Introductionmentioning

confidence: 99%

Optimization of skin dose usingin‐vivoMOSFETdose measurements in bolus/non‐bolus fraction ratio: AVMATand a 3DCRTstudy

Dias

Pinto

Borges

et al. 2019

J Applied Clin Med Phys

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“…Metal‐oxide semiconductor field‐effect transistor (MOSFET) detectors may be used to achieve this goal. The MOSFET detector has been used as a pinpoint dosimeter for the dose verification of photons ( 1 – 5 ) and electrons (6) . Although the MOSFET detector has been used for proton beam dosimetry, ( 7 , 8 ) the relative response of the TN‐252‐RD MOSFET detector (Best Medical Canada, Ottawa, Canada) in the Bragg peak region was 26% lower than responses obtained with an ionization chamber, (7) presumably because the MOSFET detector strongly depends on the linear energy transfer (LET) of the proton beam.…”

Section: Introductionmentioning

confidence: 99%

In vivo proton dosimetry using a MOSFET detector in an anthropomorphic phantom with tissue inhomogeneity

Kohno

Hotta

Matsubara

et al. 2012

J Applied Clin Med Phys

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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 for a mono‐energetic proton beam in polyethylene was measured with the MOSFET detector. This curve was used to calculate MOSFET output distributions with the SMC false(SMCMOSFETfalse). The SMCMOSFET output value at an arbitrary point was compared with the value obtained by the conventional SMCPPIC, which calculates proton dose distributions by using the depth‐dose curve determined by a parallel‐plate ionization chamber (PPIC). The ratio of the two values was used to calculate the correction factor of the MOSFET response at an arbitrary point. The dose obtained by the MOSFET detector was determined from the product of the correction factor and the MOSFET raw dose. When in vivo proton dosimetry was performed with the MOSFET detector in an anthropomorphic phantom, the corrected MOSFET doses agreed with the SMCPPIC results within the measurement error. To our knowledge, this is the first report of successful in vivo proton dosimetry with a MOSFET detector.PACS number: 87.56.‐v

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“…The mobile MOSFET dose verification system [131415161718] was introduced by Best Medical, Canada that makes the dosimetric measurements faster and easier. The use of a MOSFET dosimeter has several advantages, such as small detector size that allows pinpoint measurements, lightweight that does not cause any harm to the patient, minimal power requirement, ease of use, and online readout.…”

Section: Introductionmentioning

confidence: 99%

“…the “threshold voltage”, is permanently altered by the absorption of radiation. [9131415161718192021222324]…”

Section: Introductionmentioning

confidence: 99%

Characteristics of mobile MOSFET dosimetry system for megavoltage photon beams

Kumar¹,

Sharma²,

Ravindran³

2014

J Med Phys

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The characteristics of a mobile metal oxide semiconductor field effect transistor (mobile MOSFET) detector for standard bias were investigated for megavoltage photon beams. This study was performed with a brass alloy build-up cap for three energies namely Co-60, 6 and 15 MV photon beams. The MOSFETs were calibrated and the performance characteristics were analyzed with respect to dose rate dependence, energy dependence, field size dependence, linearity, build-up factor, and angular dependence for all the three energies. A linear dose-response curve was noted for Co-60, 6 MV, and 15 MV photons. The calibration factors were found to be 1.03, 1, and 0.79 cGy/mV for Co-60, 6 MV, and 15 MV photon energies, respectively. The calibration graph has been obtained to the dose up to 600 cGy, and the dose-response curve was found to be linear. The MOSFETs were found to be energy independent both for measurements performed at depth as well as on the surface with build-up. However, field size dependence was also analyzed for variable field sizes and found to be field size independent. Angular dependence was analyzed by keeping the MOSFET dosimeter in parallel and perpendicular orientation to the angle of incidence of the radiation with and without build-up on the surface of the phantom. The maximum variation for the three energies was found to be within ± 2% for the gantry angles 90° and 270°, the deviations without the build-up for the same gantry angles were found to be 6%, 25%, and 60%, respectively. The MOSFET response was found to be independent of dose rate for all three energies. The dosimetric characteristics of the MOSFET detector make it a suitable in vivo dosimeter for megavoltage photon beams.

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Evaluation of the usefulness of a MOSFET detector in an anthropomorphic phantom for 6-MV photon beam

Cited by 5 publications

References 17 publications

Optimization of skin dose usingin‐vivoMOSFETdose measurements in bolus/non‐bolus fraction ratio: AVMATand a 3DCRTstudy

Optimization of skin dose usingin‐vivoMOSFETdose measurements in bolus/non‐bolus fraction ratio: AVMATand a 3DCRTstudy

In vivo proton dosimetry using a MOSFET detector in an anthropomorphic phantom with tissue inhomogeneity

Characteristics of mobile MOSFET dosimetry system for megavoltage photon beams

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