Clinical dosimetry using mosfets

Ramaseshan, R.; Russell, Stephen; O’Brien, P.

doi:10.1016/s0360-3016(96)00600-1

Cited by 145 publications

(114 citation statements)

References 7 publications

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“…( 1 , 3 , 4 ) In our clinical practice, we currently use a dual P‐channel enhancement mode type MOSFET.…”

Section: Methodsmentioning

confidence: 99%

“…Metal oxide semiconductor field effect transistor (MOSFET) dosimeters with plastic water buildup caps have been in use in our institution for some time to verify routine patient entrance

D_{max}

doses, and we have had excellent agreement with predicted doses as reported by other groups. ( 1 – 3 ) More recently, Thomson Nielsen, the manufacturer of MOSFETs, has introduced single, wide‐energy hemispherical buildup caps for patient dosimetry that have full buildup at

D_{max}

for all photon energies.…”

Section: Introductionmentioning

confidence: 99%

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In vivo prostate IMRT dosimetry with MOSFET detectors using brass buildup caps

Varadhan

Miller

Garrity

et al. 2006

J Applied Clin Med Phys

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The feasibility of using dual bias metal oxide semiconductor field effect transistor (MOSFET) detectors with the new hemispherical brass buildup cap for in vivo dose measurements in prostate intensity‐modulated radiotherapy (IMRT) treatments was investigated and achieved. In this work, MOSFET detectors with brass buildup caps placed on the patient's skin surface on the central axis of the individual IMRT beams are used to determine the maximum entrance dose (Dmax) from the prostate IMRT fields. A general formalism with various correction factors taken into account to predict Dmax entrance dose for the IMRT fields with MOSFETs was developed and compared against predicted dose from the treatment‐planning system (TPS). We achieved an overall accuracy of better than ±5% on all measured fields for both 6‐MV and 10‐MV beams when compared to predicted doses from the Philips Pinnacle 3 and CMS XiO TPSs, respectively. We also estimate the total uncertainty in estimation of MOSFET dose in the high‐sensitivity mode for IMRT therapy to be 4.6%.PACS numbers: 87.53Xd, 87.56Fc

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“…( 1 , 3 , 4 ) In our clinical practice, we currently use a dual P‐channel enhancement mode type MOSFET.…”

Section: Methodsmentioning

confidence: 99%

“…Metal oxide semiconductor field effect transistor (MOSFET) dosimeters with plastic water buildup caps have been in use in our institution for some time to verify routine patient entrance

D_{max}

D_{max}

for all photon energies.…”

Section: Introductionmentioning

confidence: 99%

In vivo prostate IMRT dosimetry with MOSFET detectors using brass buildup caps

Varadhan

Miller

Garrity

et al. 2006

J Applied Clin Med Phys

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“…Until recently, MOSFETs were mainly used in radiotherapy, 10 , 11 , 12 , 13 but are now being more commonly used in different fields of diagnostic radiology 14 , 15 , 16 , 17 , 18 . A drawback with MOSFET dosimeters is that they have limited sensitivity when compared with TLD dosimeters.…”

Section: Introductionmentioning

confidence: 99%

Characterization of MOSFET dosimeters for low‐dose measurements in maxillofacial anthropomorphic phantoms

Koivisto

Wolff

Kiljunen

et al. 2015

J Applied Clin Med Phys

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The aims of this study were to characterize reinforced metal‐oxide‐semiconductor field‐effect transistor (MOSFET) dosimeters to assess the measurement uncertainty, single exposure low‐dose limit with acceptable accuracy, and the number of exposures required to attain the corresponding limit of the thermoluminescent dosimeters (TLD). The second aim was to characterize MOSFET dosimeter sensitivities for two dental photon energy ranges, dose dependency, dose rate dependency, and accumulated dose dependency. A further aim was to compare the performance of MOSFETs with those of TLDs in an anthropomorphic phantom head using a dentomaxillofacial CBCT device. The uncertainty was assessed by exposing 20 MOSFETs and a Barracuda MPD reference dosimeter. The MOSFET dosimeter sensitivities were evaluated for two photon energy ranges (50–90 kVp) using a constant dose and polymethylmethacrylate backscatter material. MOSFET and TLD comparative point‐dose measurements were performed on an anthropomorphic phantom that was exposed with a clinical CBCT protocol. The MOSFET single exposure low dose limit (25% uncertainty, normalk=2) was 1.69 mGy. An averaging of eight MOSFET exposures was required to attain the corresponding TLD (0.3 mGy) low‐dose limit. The sensitivity was 3.09±0.13 mV/mGy independently of the photon energy used. The MOSFET dosimeters did not present dose or dose rate sensitivity but, however, presented a 1% decrease of sensitivity per 1000 mV for accumulated threshold voltages between 8300 mV and 17500 mV. The point doses in an anthropomorphic phantom ranged for MOSFETs between 0.24 mGy and 2.29 mGy and for TLDs between 0.25 and 2.09 mGy, respectively. The mean difference was −8%. The MOSFET dosimeters presented statistically insignificant energy dependency. By averaging multiple exposures, the MOSFET dosimeters can achieve a TLD‐comparable low‐dose limit and constitute a feasible method for diagnostic dosimetry using anthropomorphic phantoms. However, for single in vivo measurements (<1.7 mGy) the sensitivity is too low.PACS number: 87.50.wj

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“…It is constructed with a natural human skeleton which is cast inside soft tissue simulating material. Two tissue-simulating materials comprise the phantom head: the RANDO ® soft tissue material (0.997 g/cm 3 ), designed to have the same absorption as human tissue at the normal radiotherapy exposure levels, and the skeleton (1.61 g/cm 3 ).…”

Section: Rando Phantom Modelmentioning

confidence: 99%

“…There are not many studies that use MOSFET measures to validate Monte Carlo simulations, normally these kind of validations are done using TLD dosimeters, whose error tend to be greater and measures are more tedious to carry out [2], [3].…”

Section: Introductionmentioning

confidence: 99%

Use of MOSFET dosimeters to validate Monte Carlo radiation treatment calculation in an anthropomorphic phantom

Juste

Miró

Abella

et al. 2015

Radiation Physics and Chemistry

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Radiation therapy treatment planning based on Monte Carlo simulation provide a very accurate dose calculation compared to deterministic systems. Nowadays, Metal-OxideSemiconductor Field Effect Transistor (MOSFET) dosimeters are increasingly utilized in radiation therapy to verify the received dose by patients.In the present work, we have used the MCNP6 (Monte Carlo N-Particle transport code) to simulate the irradiation of an anthropomorphic phantom (RANDO) with a medical linear accelerator. The detailed model of the Elekta Precise multileaf collimator using a 6 MeV photon beam was designed and validated by means of different beam sizes and shapes in previous works.To include in the simulation the RANDO phantom geometry a set of Computer Tomography images of the phantom was obtained and formatted. The slices are input in PLUNC software, which performs the segmentation by defining anatomical structures and a Matlab algorithm writes the phantom information in MCNP6 input deck format.The simulation was verified and therefore the phantom model and irradiation was validated throughout the comparison of High-Sensitivity MOSFET dosimeter (Best medical Canada) measurements in different points inside the phantom with simulation results. On-line Wireless MOSFET provide dose estimation in the extremely thin sensitive volume, so a meticulous and accurate validation has been performed.The comparison show good agreement between the MOSFET measurements and the Monte Carlo calculations, confirming the validity of the developed procedure to include patients CT in simulations and approving the use of Monte Carlo simulations as an accurate therapy treatment plan.

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Clinical dosimetry using mosfets

Cited by 145 publications

References 7 publications

In vivo prostate IMRT dosimetry with MOSFET detectors using brass buildup caps

In vivo prostate IMRT dosimetry with MOSFET detectors using brass buildup caps

Characterization of MOSFET dosimeters for low‐dose measurements in maxillofacial anthropomorphic phantoms

Use of MOSFET dosimeters to validate Monte Carlo radiation treatment calculation in an anthropomorphic phantom

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