Characterization of a MO<i>Skin</i> detector for <i>in vivo</i> skin dose measurements during interventional radiology procedures

Safari, M. J.; Wong, Jeannie Hsiu Ding; Ng, Kwan Hoong; Jong, Wei Loong; Cutajar, Dean L; Rosenfeld, Anatoly B.

doi:10.1118/1.4918576

Cited by 11 publications

(6 citation statements)

References 52 publications

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“…The derived MOSFET sensitivity was 14.88 and 15.77 mV/cGy for measurement with and without bowtie filter, respectively. This indicated a minimal sensitivity variation within 6% for blank and filtrated beam qualities, which is consistent with the previous finding [22]. The possible reason is that the filtration changes the energy spectrum and the high atomic number material in the sensitive volume of the MOSFET (silicon oxide) tends to over respond to the low energy x-rays due to photoelectric absorption effects.…”

Section: Discussionsupporting

confidence: 90%

“…The physical performance of this dosimeter was well documented in the literature for external beam radiotherapy [27, 28], interventional radiology procedures [22] and diagnostic radiology dosimetry [16, 17]. …”

Section: Methodsmentioning

confidence: 99%

“…As adding the filtration would change the X-ray spectrum which may vary the MOSFET sensitivity [22], the calibration was conducted for F0 and F1 filter, respectively. The half value layers (HVL) of the primary X-ray beam at different conditions were determined by using the ion chamber.…”

Section: Methodsmentioning

confidence: 99%

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Assessment of female breast dose for thoracic cone-beam CT using MOSFET dosimeters

et al. 2017

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Objective: To assess the breast dose during a routine thoracic cone-beam CT (CBCT) check with the efforts to explore the possible dose reduction strategy.Materials and Methods: Metal oxide semiconductor field-effect transistor (MOSFET) dosimeters were used to measure breast surface doses during a thorax kV CBCT scan in an anthropomorphic phantom. Breast doses for different scanning protocols and breast sizes were compared. Dose reduction was attempted by using partial arc CBCT scan with bowtie filter. The impact of this dose reduction strategy on image registration accuracy was investigated.Results: The average breast surface doses were 20.02 mGy and 11.65 mGy for thoracic CBCT without filtration and with filtration, respectively. This indicates a dose reduction of 41.8% by use of bowtie filter. It was found 220° partial arc scanning significantly reduced the dose to contralateral breast (44.4% lower than ipsilateral breast), while the image registration accuracy was not compromised.Conclusions: Breast dose reduction can be achieved by using ipsilateral 220° partial arc scan with bowtie filter. This strategy also provides sufficient image quality for thorax image registration in daily patient positioning verification.

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Section: Discussionsupporting

confidence: 90%

Section: Methodsmentioning

confidence: 99%

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Assessment of female breast dose for thoracic cone-beam CT using MOSFET dosimeters

et al. 2017

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“…This approach has been applied when using radiation detectors known to be energy dependent when used under kV photon beams. 22 , 33 The energy dependence of the radiation detectors calibrated under the clinical beams would be much lesser within the energy range used. Brown et al 34 reported a relative sensitivity of 3% for EBT3 film used under 25–35 keV monochromatic beams.…”

Section: Discussionmentioning

confidence: 99%

Evaluation of skin dose and skin toxicity in patients undergoing intraoperative radiotherapy for early breast cancer

Wong

Zaili

Malik

et al. 2021

J Applied Clin Med Phys

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This study aims to evaluate in vivo skin dose delivered by intraoperative radiotherapy (IORT) and determine the factors associated with an increased risk of radiation-induced skin toxicity.Methodology: A total of 21 breast cancer patients who underwent breastconserving surgery and IORT, either as IORT alone or IORT boost plus external beam radiotherapy (EBRT), were recruited in this prospective study. EBT3 film was calibrated in water and used to measure skin dose during IORT at concentric circles of 5 mm and 40 mm away from the applicator. For patients who also had EBRT, the maximum skin dose was estimated using the radiotherapy treatment planning system. Mid-term skin toxicities were evaluated at 3 and 6 months post-IORT. Results:The average skin dose at 5 mm and 40 mm away from the applicator was 3.07 ± 0.82 Gy and 0.99 ± 0.28 Gy, respectively. Patients treated with IORT boost plus EBRT received an additional skin dose of 41.07 ± 1.57 Gy from the EBRT component. At 3 months post-IORT, 86% of patients showed no evidence of skin toxicity. However, the number of patients suffering from skin toxicity increased from 15% to 38% at 6 months post-IORT. We found no association between the IORT alone or with the IORT boost plus EBRT and skin toxicity. Older age was associated with increased risk of skin toxicities. A mathematical model was derived to predict skin dose. Conclusion:EBT3 film is a suitable dosimeter for in vivo skin dosimetry in IORT, providing patient-specific skin doses. Both IORT alone and IORT boost techniques resulted in similar skin toxicity rates.

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“…The increased interest in small-animal radiation biology research has resulted in a requirement for improvements in the standardized dosimetry of pre-clinical irradiations [1], [2,3]. In vivo dose measurement can be accomplished using devices like MOSFET-based dosimeters [4][5][6], Gafchromic films [7], or silica-based fibres as thermoluminescent dosimeters (TLDs) [8][9][10][11][12][13][14]. Computational techniques using mathematical models of systems can also be used to calculate radiation doses.…”

Section: Introductionmentioning

confidence: 99%

Absorbed dose calculation for a realistic CT-derived mouse phantom irradiated with a standard Cs-137 cell irradiator using a Monte Carlo method

et al. 2023

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Computed tomography (CT) derived Monte Carlo (MC) phantoms allow dose determination within small animal models that is not feasible with in-vivo dosimetry. The aim of this study was to develop a CT-derived MC phantom generated from a mouse with a xenograft tumour that could then be used to calculate both the dose heterogeneity in the tumour volume and out of field scattered dose for pre-clinical small animal irradiation experiments. A BEAMnrc Monte-Carlo model has been built of our irradiation system that comprises a lead collimator with a 1 cm diameter aperture fitted to a Cs-137 gamma irradiator. The MC model of the irradiation system was validated by comparing the calculated dose results with dosimetric film measurement in a polymethyl methacrylate (PMMA) phantom using a 1D gamma-index analysis. Dose distributions in the MC mouse phantom were calculated and visualized on the CT-image data. Dose volume histograms (DVHs) were generated for the tumour and organs at risk (OARs). The effect of the xenographic tumour volume on the scattered out of field dose was also investigated. The defined gamma index analysis criteria were met, indicating that our MC simulation is a valid model for MC mouse phantom dose calculations. MC dose calculations showed a maximum out of field dose to the mouse of 7% of Dmax. Absorbed dose to the tumour varies in the range 60%-100% of Dmax. DVH analysis demonstrated that tumour received an inhomogeneous dose of 12 Gy-20 Gy (for 20 Gy prescribed dose) while out of field doses to all OARs were minimized (1.29 Gy-1.38 Gy). Variation of the xenographic tumour volume exhibited no significant effect on the out of field scattered dose to OARs. The CT derived MC mouse model presented here is a useful tool for tumour dose verifications as well as investigating the doses to normal tissue (in out of field) for preclinical radiobiological research.

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Characterization of a MOSkin detector for in vivo skin dose measurements during interventional radiology procedures

Cited by 11 publications

References 52 publications

Assessment of female breast dose for thoracic cone-beam CT using MOSFET dosimeters

Assessment of female breast dose for thoracic cone-beam CT using MOSFET dosimeters

Evaluation of skin dose and skin toxicity in patients undergoing intraoperative radiotherapy for early breast cancer

Absorbed dose calculation for a realistic CT-derived mouse phantom irradiated with a standard Cs-137 cell irradiator using a Monte Carlo method

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