Measurement and effects of MOSKIN detectors on skin dose during high energy radiotherapy treatment

Alnawaf, Hani; Butson, Martin J; Yu, Peter K N

doi:10.1007/s13246-012-0153-1

Cited by 12 publications

(8 citation statements)

References 31 publications

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“…A measurement of the field factor at surface of the phantom was also performed to evaluate the capabilities of the detector to measure the surface dose as a function of the field size defined by the jaws. The silicon epitaxial diode was benchmarked against Gafchromic EBT3 film, the Attix ionization chamber, and the MO Skin , which are frequently used for interface measurements and described in several studies …”

Section: Methodsmentioning

confidence: 99%

“…The silicon epitaxial diode was benchmarked against Gafchromic EBT3 film, the Attix ionization chamber, and the MOSkin, which are frequently used for interface measurements and described in several studies. 16,[37][38][39][40] The films were calibrated using 1.5 9 1.5 cm² squares and scanned using a flatbed scanner (Epson 10000XL scanner; Epson America, Inc. Long Beach, CA, USA) 24 h after irradiation to allow for postirradiation development. The films were scanned in transmission mode with color correction turned off, at a resolution of 72 dpi and 48 bit RGB data format.…”

Section: G Output Factor and Surface Field Size Dependencementioning

confidence: 99%

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Development of a silicon diode detector for skin dosimetry in radiotherapy

et al. 2017

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Purpose: The aim of in vivo skin dosimetry was to measure the absorbed dose to the skin during radiotherapy, when treatment planning calculations cannot be relied on. It is of particularly importance in hypo-fractionated stereotactic modalities, where excessive dose can lead to severe skin toxicity. Currently, commercial diodes for such applications are with water equivalent depths ranging from 0.5 to 0.8 mm. In this study, we investigate a new detector for skin dosimetry based on a silicon epitaxial diode, referred to as the skin diode. Method: The skin diode is manufactured on a thin epitaxial layer and packaged using the "drop-in" technology. It was characterized in terms of percentage depth dose, dose linearity, and dose rate dependence, and benchmarked against the Attix ionization chamber. The response of the skin diode in the build-up region of the percentage depth dose (PDD) curve of a 6 MV clinical photon beam was investigated. Geant4 radiation transport simulations were used to model the PDD in order to estimate the water equivalent measurement depth (WED) of the skin diode. Measured output factors using the skin diode were compared with the MOSkin detector and EBT3 film at 10 cm depth and at surface at isocenter of a water equivalent phantom. The intrinsic angular response of the skin diode was also quantified in charge particle equilibrium conditions (CPE) and at the surface of a solid water phantom. Finally, the radiation hardness of the skin diode up to an accumulated dose of 80 kGy using photons from a Co-60 gamma source was evaluated. Results: The PDD curve measured with the skin diode was within 0.5% agreement of the equivalent Geant4 simulated curve. When placed at the phantom surface, the WED of the skin diode was estimated to be 0.075 AE 0.005 mm from Geant4 simulations and was confirmed using the response of a corrected Attix ionization chamber placed at water equivalent depth of 0.075 mm, with the measurement agreement to within 0.3%. The output factor measurements at 10 cm depth were within 2% of those measured with film and the MOSkin detector down to a field size of 2 9 2 cm 2 . The dose-response for all detector samples was linear and with a repeatability within 0.2%. The skin diode intrinsic angular response showed a maximum deviation of 8% at 90 degrees and from 0 to 60 degree is less than 5%. The radiation sensitivity reduced by 25% after an accumulated dose of 20 kGy but after was found to stabilize. At 60 kGy total accumulated dose the response was within 2% of that measured at 20 kGy total accumulated dose. Conclusions: This work characterizes an innovative detector for in vivo and real-time skin dose measurements that is based on an epitaxial silicon diode combined with the Centre for Medical Radiation Physics (CMRP) "drop-in" packaging technology. The skin diode proved to have a water equivalent depth of measurement of 0.075 AE 0.005 mm and the ability to measure doses accurately relative to reference detectors.

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Section: Methodsmentioning

confidence: 99%

Section: G Output Factor and Surface Field Size Dependencementioning

confidence: 99%

Development of a silicon diode detector for skin dosimetry in radiotherapy

et al. 2017

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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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“…The advantages of the MO Skin detector, such as being small in size with submicron dosimetric volume which provides excellent dosimetry spatial resolution, as well as the ability to provide real‐time reading and instant readout, make it suitable for in vivo skin dosimetry measurement. The MO Skin detector has been characterized and been used for dose measurement in megavoltage radiotherapy and brachytherapy (23‐30) …”

Section: Introductionmentioning

confidence: 99%

Characterization of MOSkin detector for in vivo skin dose measurement during megavoltage radiotherapy

Jong

Wong

Ung

et al. 2014

J Applied Clin Med Phys

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In vivo dosimetry is important during radiotherapy to ensure the accuracy of the dose delivered to the treatment volume. A dosimeter should be characterized based on its application before it is used for in vivo dosimetry. In this study, we characterize a new MOSFET‐based detector, the MOSkin detector, on surface for in vivo skin dosimetry. The advantages of the MOSkin detector are its water equivalent depth of measurement of 0.07 mm, small physical size with submicron dosimetric volume, and the ability to provide real‐time readout. A MOSkin detector was calibrated and the reproducibility, linearity, and response over a large dose range to different threshold voltages were determined. Surface dose on solid water phantom was measured using MOSkin detector and compared with Markus ionization chamber and GAFCHROMIC EBT2 film measurements. Dependence in the response of the MOSkin detector on the surface of solid water phantom was also tested for different (i) source to surface distances (SSDs); (ii) field sizes; (iii) surface dose; (iv) radiation incident angles; and (v) wedges. The MOSkin detector showed excellent reproducibility and linearity for dose range of 50 cGy to 300 cGy. The MOSkin detector showed reliable response to different SSDs, field sizes, surface, radiation incident angles, and wedges. The MOSkin detector is suitable for in vivo skin dosimetry.PACS number: 87.55.Qr

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Measurement and effects of MOSKIN detectors on skin dose during high energy radiotherapy treatment

Cited by 12 publications

References 31 publications

Development of a silicon diode detector for skin dosimetry in radiotherapy

Development of a silicon diode detector for skin dosimetry in radiotherapy

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

Characterization of MOSkin detector for in vivo skin dose measurement during megavoltage radiotherapy

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