MOSFET detectors in quality assurance of tomotherapy treatments

Cherpak, Amanda; Studinski, Ryan; Cygler, Joanna

doi:10.1016/j.radonc.2007.10.025

Cited by 22 publications

(27 citation statements)

References 26 publications

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“…Thermoluminescent dosimetry (TLD), surface diodes, metal oxide semiconductor field effect transistor (MOSFET), radiochromic and radiographic films, and plastic scintillators have been used with varying results tied to the detector's integral buildup and perturbation effects. [6][7][8][9][10] Treatment planning systems have generally not been an accurate means to determine surface dose because it is uncommon for the beam model to be created with accurately measured and modeled surface dose data. The resulting calculated surface doses are typically higher than in reality.…”

Section: Introductionmentioning

confidence: 99%

Validation of OSLD and a treatment planning system for surface dose determination in IMRT treatments

Zhuang

Olch

2014

Medical Physics

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Section: Introductionmentioning

confidence: 99%

Validation of OSLD and a treatment planning system for surface dose determination in IMRT treatments

Zhuang

Olch

2014

Medical Physics

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“…In general, it is of extreme importance to calculate the PD down to the level of 0.1% of the central axis maximum dose (dmax) [8] and its determination has been the subject of extensive investigation [2,[9][10][11][12][13][14][15][16][17][18][19][20] . Metal oxide semiconductor field effect transistor (MOSFET) is used as a clinical dosimeter for radiotherapy beams, and mobileMOSFET seems to be the appropriate dose verification system [21][22][23][24][25][26][27][28][29][30] , since due to its small size it can be positioned very easily on the patient's skin, and can evaluate the delivered dose both at the target and at organs at risk [21] . This paper aims to assess the PD in high-energy photon beam radiotherapy as a function of the distance from the edge of the field, the depth, the field size and the energy of the photon beam, while the overall accuracy has been investigated by comparing the derived experimental results to corresponding ones obtained with an ionization chamber.…”

Section: Introductionmentioning

confidence: 99%

Peripheral dose measurement in high-energy photon radiotherapy with the implementation of MOSFET

Vlachopoulou

Malatara²,

Delis³

et al. 2010

WJR

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AIM:To study the peripheral dose (PD) from highenergy photon beams in radiotherapy using the metal oxide semiconductor field effect transistor (MOSFET) dose verification system. METHODS:The radiation dose absorbed by the MOS-FET detector was calculated taking into account the manufacturer's Correction Factor, the Calibration Factor and the threshold voltage shift. PD measurements were carried out for three different field sizes (5 cm × 5 cm, 10 cm × 10 cm and 15 cm × 15 cm) and for various depths with the source to surface distance set at 100 cm. Dose measurements were realized on the central axis and then at distances (1 to 18 cm) parallel to the edge of the field, and were expressed as the percentage PD (% PD) with respect to the maximum dose (dmax).The accuracy of the results was evaluated with respect to a calibrated 0.3 cm 3 ionization chamber. The reproducibility was expressed in terms of standard deviation (s) and coefficient of variation.RESULTS: % PD is higher near the phantom surface and drops to a minimum at the depth of dmax, and then tends to become constant with depth. Internal scatter radiation is the predominant source of PD and the depth dependence is determined by the attenuation of the primary photons. Closer to the field edge, where internal scatter from the phantom dominates, the % PD increases with depth because the ratio of the scatter to primary increases with depth. A few centimeters away from the field, where collimator scatter and leakage dominate, the % PD decreases with depth, due to attenuation by the water. The % PD decreases almost exponentially with the increase of distance from the field edge. The decrease of the % PD is more than 60% and can reach up to 90% as the measurement point departs from the edge of the field. For a given distance, the % PD is significantly higher for larger field sizes, due to the increase of the scattering volume. Finally, the measured PD obtained with MOSFET is higher than that obtained with an ionization chamber with percentage differences being from 0.6% to 34.0%. However, when normalized to the central dmax this difference is less than 1%. The MOSFET system, in the early stage of its life, has a dose measurement reproducibility of within 1.8%, 2.7%, 8.9% and 13.6% for 22.8, 11.3, 3.5 and 1.3 cGy dose assessments, respectively. In the late stage of MOSFET life the corresponding values change to 1.5%, 4.8%, 11.1% and 29.9% for 21.8, 2.9, 1.6 and 1.0 cGy, respectively. CONCLUSION:Comparative results acquired with the MOSFET and with an ionization chamber show fair agreement, supporting the suitability of this measurement for clinical in vivo dosimetry.

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“…24 Further complicating matters is that the TomoTherapy planning software itself may overestimate skin dose by anywhere between 3% and 13%. [25][26][27][28] Despite these limitations, adequate breast surface dose has been shown to be achievable utilizing TomoTherapy in clinical practice both at our institution, 29 as well as others. 30,31 Special care must be taken when treating patients with breast cancer having IMRT.…”

Section: Discussionmentioning

confidence: 93%

Acute Toxicity From Breast Cancer Radiation Using Helical Tomotherapy With a Simultaneous Integrated Boost

Wojcieszynski

Olson

Rong

et al. 2015

Technol Cancer Res Treat

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MOSFET detectors in quality assurance of tomotherapy treatments

Cited by 22 publications

References 26 publications

Validation of OSLD and a treatment planning system for surface dose determination in IMRT treatments

Validation of OSLD and a treatment planning system for surface dose determination in IMRT treatments

Peripheral dose measurement in high-energy photon radiotherapy with the implementation of MOSFET

Acute Toxicity From Breast Cancer Radiation Using Helical Tomotherapy With a Simultaneous Integrated Boost

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