Quality assurance during interstitial brachytherapy: in vivo dosimetry using MOSFET dosimeters

Melchert, Corinna; Soror, Tamer; Kovács, György

doi:10.5114/jcb.2018.76748

Cited by 15 publications

(19 citation statements)

References 6 publications

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“…Their study showed that the overestimations of MOSFET (uncorrected for energy response) to TPS dose values were 2-7% for the end-to-end measurements in HDR prostate and head and neck implantations. Inaccuracy of the MOSFET detectors (±4%) was reported, and the deviations between the planned and measured dose values were markedly influenced by the tube applicator geometry and the positioning of the patient during irradiation [33].…”

Section: Discussionmentioning

confidence: 99%

End-to-end test and MOSFET in vivo skin dosimetry for 192Ir high-dose-rate brachytherapy of chronic psoriasis

Tuntipumiamorn

Nakkrasae

Kongkum

et al. 2019

jcb

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PurposeThis study was performed using end-to-end testing and real-time in vivo skin dose measurements, using metal oxide semiconductor field effect transistor (MOSFET) dosimeters on our first chronic psoriasis patient treated with iridium-192 (192Ir) high-dose-rate (HDR) brachytherapy (BT).Material and methodsTreatment delivery was planned with the prescription dose of 1.8 Gy to a 3 mm depth for 12 fractions, using our custom-fabricated surface mold and Varian soft catheters. The optimal technique to provide an adequate and acceptable skin dose as well as its feasibility were evaluated by an end-to-end exercise using a perspex finger phantom. The accuracy and reliability of MOSFET dose measurement was explored with a thermoluminescence dosimetry (TLD) before being used in vivo to monitor skin doses during treatment delivery for each BT fraction.ResultsUsing custom-made surface mold (2.4 mm Med-Tec thermoplastic mask for hand fixation and 5 applicators attached to each finger for dose delivery), the optimal skin dose on the phantom was obtained without the need for additional bolus to increase thickness of applicator. We acquired mean skin doses at different skin depths from various dose-volume parameters of no-bolus and 3 mm-added bolus plans. They were 125% and 110% (1 mm), 120% and 108% (2 mm), and 114% and 106% (3 mm), respectively. There was excellent agreement between MOSFET and TLD for 192Ir HDR-BT within ±3% (mean 2.65%, SD = 2.05%). With no energy correction, MOSFET overestimated the Acuros BV surface doses by up to 7% in the phantom study and in the clinical case.ConclusionsWe demonstrated achievable HDR-BT for our first case of nail bed psoriasis. The end-to-end exercise was an efficient methodology to evaluate new feasibility for this technique. Real-time dose monitoring using MOSFET was an effective and reliable tool to ensure treatment quality and patient safety.

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Section: Discussionmentioning

confidence: 99%

End-to-end test and MOSFET in vivo skin dosimetry for 192Ir high-dose-rate brachytherapy of chronic psoriasis

Tuntipumiamorn

Nakkrasae

Kongkum

et al. 2019

jcb

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“…Dose veri cation measurements were performed using Gafchromic EBT3 lm (Ashland Specialty Ingredients, NJ, USA lot#09071703 and #04171901) and three MOSFET TM detectors to be described in the following section. The feasibility and e ciency of MOSFET detectors were con rmed in real-time invivo dosimetry for brachytherapy by previous researchers [20,21].…”

Section: Methodsmentioning

confidence: 98%

Validation of an Individualized Home-Made Superficial Brachytherapy Mould Applied for Non-Melanoma Skin Cancer

Jaberi¹,

Siavashpour²,

akha³

et al. 2021

Preprint

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Purpose: This study was conducted to evaluate the effect of a Brachytherapy (BT) customized mold (Condensation silicone elastomer (Protesil TM )) thickness ,on dose distribution pattern in deeper lesions used for nonmelanoma skin cancers (NMSC).Material and Method: MOSFET TM and GAFCHROMIC TM EBT3 film dosimeters were used for the different thicknesses of a Brachytherapy (BT) customized mold (up to 20 mm), skin dose and dose in different depths were evaluated.Result: The received dose to the surface is overestimated by TPS.Skin dose can be reduced from 250 to 150% of prescription dose by increasing mold thickness from 5 mm to 20 mm. There was a 7.7% difference in calculated dose by TPS and measured dose by MOSFET. Film dosimetry data was unreliable. There was a good agreement between film dosimetry, MOSFET detector, and TPS results, in the depth of 5mm<.Conclusion: Any individualized material chosen to use for making the customized surface BT mold should be validated at BT departments. Protesil TM can be selected as feasible material to make any form of superficial molds. For thicker NMSC lesions up to 20 mm using thicker molds up to 20 mm can be. Even for 10 mm lesions, by changing mold thickness from 5 mm to 20 mm, skin dose would reduce. Protesil TM can be used to make an individualized superficial BT mold. By increasing the mold thickness, lesions can be treated without overexposing the skin surface and skin dose reduced by increasing mold thickness. So, superficial BT can be recommended as an appropriate treatment option for NMSC lesions with some consideration.

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“…Table 2 provides an overview of the reported clinical studies of IVD for brachytherapy. Most (20/27) of the studies reported on integrated dose from point detectors (e.g., thermoluminescent dosimeters [41] , [42] , [43] , [44] , [45] , metal-oxide semiconductor field-effect transistors (MOSFETs) [46] , [47] , [48] , optically stimulated luminescence detectors [49] , diodes [50] , [51] , [52] , glass detectors [53] , plastic scintillators [54] , and alanine dosimeters [52] , [55] ) for different treatment sites. These studies reported maximum deviation between measured and planned dose ranging from a few percent to more than 100%.…”

Section: Methods For Ivdmentioning

confidence: 99%

“… MR scans acquired just before and after the treatment. Reported uncertainty 5.0% (k = 1) 2018 Melchert et al [46] BR, TH, HN MOSFET 12 ≈ 56.0% Dosimeters inserted into catheters/needles. A long interval between needle implantation and imaging can reduce positioning uncertainties due to edema.…”

Section: Methods For Ivdmentioning

confidence: 99%

In vivo dosimetry in brachytherapy: Requirements and future directions for research, development, and clinical practice

Fonseca

Johansen

Smith

et al. 2020

Physics and Imaging in Radiation Oncology

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Brachytherapy can deliver high doses to the target while sparing healthy tissues due to its steep dose gradient leading to excellent clinical outcome. Treatment accuracy depends on several manual steps making brachytherapy susceptible to operational mistakes. Currently, treatment delivery verification is not routinely available and has led, in some cases, to systematic errors going unnoticed for years. The brachytherapy community promoted developments in in vivo dosimetry (IVD) through research groups and small companies. Although very few of the systems have been used clinically, it was demonstrated that the likelihood of detecting deviations from the treatment plan increases significantly with time-resolved methods. Time-resolved methods could interrupt a treatment avoiding gross errors which is not possible with time-integrated dosimetry. In addition, lower experimental uncertainties can be achieved by using source-tracking instead of direct dose measurements. However, the detector position in relation to the patient anatomy remains a main source of uncertainty. The next steps towards clinical implementation will require clinical trials and systematic reporting of errors and nearmisses. It is of utmost importance for each IVD system that its sensitivity to different types of errors is well understood, so that end-users can select the most suitable method for their needs. This report aims to formulate requirements for the stakeholders (clinics, vendors, and researchers) to facilitate increased clinical use of IVD in brachytherapy. The report focuses on high dose-rate IVD in brachytherapy providing an overview and outlining the need for further development and research. ☆ During the 1st ESTRO Physics Workshop celebrated in November 2017 in Glasgow, Scotland, a task group was created to stimulate the wider adoption of in vivo dosimetry for radiotherapy. The members of this task group, authors of this report, were selected on the basis of their expertise to contribute relevant input to the area of study and their long-term experience in the clinical implementation of in vivo dosimetry systems.

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Quality assurance during interstitial brachytherapy: in vivo dosimetry using MOSFET dosimeters

Cited by 15 publications

References 6 publications

End-to-end test and MOSFET in vivo skin dosimetry for 192Ir high-dose-rate brachytherapy of chronic psoriasis

End-to-end test and MOSFET in vivo skin dosimetry for 192Ir high-dose-rate brachytherapy of chronic psoriasis

Validation of an Individualized Home-Made Superficial Brachytherapy Mould Applied for Non-Melanoma Skin Cancer

In vivo dosimetry in brachytherapy: Requirements and future directions for research, development, and clinical practice

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