Evaluation of LiF:Mg,Ti (TLD-100) for Intraoperative Electron Radiation Therapy Quality Assurance

Liuzzi, Raffaele; Savino, Federica; D’Avino, Vittoria; Pugliese, M.; Cella, Laura

doi:10.1371/journal.pone.0139287

Cited by 19 publications

(19 citation statements)

References 32 publications

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“…This result was in line with the well-known published results 22,23 and with the findings of our previous work. 14 In addition, a recent study was carried out by Bahreyni Toossi et al 24 about calibration of TLDs with 6-MV photon and 6-MeV electron irradiation but restricted to the dose range 0 to 2 Gy. The results of the study showed that for dose up to 120 cGy the TLD response is linear and for higher dose supralinear, for both types of radiation beams.…”

Section: Discussionmentioning

confidence: 99%

Dose–Response of TLD-100 in the Dose Range Useful for Hypofractionated Radiotherapy

et al. 2020

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Purpose: The aim of the study was to exploit the feasibility of thermoluminescent dosimeters (TLDs) in radiation therapy techniques in which high dose per fraction is involved. Methods: Dose–response of TLD-100 (LiF: Mg, Ti) was investigated in both 6-MV photon and 6-MeV electron beams. The element correction factor (ECF) generation method was applied to check the variability of the TLDs response. Two batches of 50 TLDs were divided into groups and exposed in the dose range 0 to 30 Gy. Regression analysis was performed with both linear and quadratic models. For each irradiation beam, the calibration curves were obtained in 3 dose range 0 to 8 Gy, 0 to 10 Gy, and 0 to 30 Gy. The best-fitting model was assessed by the Akaike Information Criterion test. Results: The ECF process resulted a useful tool to reduce the coefficients of variation from original values higher than 5% to about 3.5%, for all the batches exposed. The results confirm the linearity of dose–response curve below the dose level of 10 Gy for photon and electron beam and the supralinear trend above. Conclusion: The TLDs are suitable dosimeters for dose monitoring and verification in radiation treatment involving dose up to 30 Gy in a single fraction.

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Section: Discussionmentioning

confidence: 99%

Dose–Response of TLD-100 in the Dose Range Useful for Hypofractionated Radiotherapy

et al. 2020

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“…We experienced the latter problem when we tried to measure using two MOSFETs at the same time, as reported in the results section. The difficulty of inserting more than one MOSFET has also been identified elsewhere [ 24 ]. In addition, it has been pointed out that MOSFETs are presumably more difficult for the surgeon to initially handle because they have to be inserted with sterile components and attached onto the surgical bed [ 15 ].…”

Section: Discussionmentioning

confidence: 99%

“…However, in the 1990s, dedicated mobile linacs, characterized by output rates of 2 to 12 cGy per pulse, were developed and introduced [ 4 ]. The high dose-per-pulse reduces the irradiation time during the surgery because 10 Gy are typically delivered in less than 1 min [ 24 ].…”

Section: Discussionmentioning

confidence: 99%

Implementation of an intraoperative electron radiotherapy in vivo dosimetry program

et al. 2016

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BackgroundIntraoperative electron radiotherapy (IOERT) is a highly selective radiotherapy technique which aims to treat restricted anatomic volumes during oncological surgery and is now the subject of intense re-evaluation. In vivo dosimetry has been recommended for IOERT and has been identified as a risk-reduction intervention in the context of an IOERT risk analysis. Despite reports of fruitful experiences, information about in vivo dosimetry in intraoperative radiotherapy is somewhat scarce. Therefore, the aim of this paper is to report our experience in developing a program of in vivo dosimetry for IOERT, from both multidisciplinary and practical approaches, in a consistent patient series. We also report several current weaknesses.MethodsReinforced TN-502RDM-H mobile metal oxide semiconductor field effect transistors (MOSFETs) and Gafchromic MD-55-2 films were used as a redundant in vivo treatment verification system with an Elekta Precise fixed linear accelerator for calibrations and treatments. In vivo dosimetry was performed in 45 patients in cases involving primary tumors or relapses. The most frequent primary tumors were breast (37 %) and colorectal (29 %), and local recurrences among relapses was 83 %. We made 50 attempts to measure with MOSFETs and 48 attempts to measure with films in the treatment zones. The surgical team placed both detectors with supervision from the radiation oncologist and following their instructions.ResultsThe program was considered an overall success by the different professionals involved. The absorbed doses measured with MOSFETs and films were 93.8 ± 6.7 % and 97.9 ± 9.0 % (mean ± SD) respectively using a scale in which 90 % is the prescribed dose and 100 % is the maximum absorbed dose delivered by the beam. However, in 10 % of cases we experienced dosimetric problems due to detector misalignment, a situation which might be avoided with additional checks. The useful MOSFET lifetime length and the film sterilization procedure should also be controlled.ConclusionsIt is feasible to establish an in vivo dosimetry program for a wide set of locations treated with IOERT using a multidisciplinary approach according to the skills of the professionals present and the detectors used; oncological surgeons’ commitment is key to success in this context. Films are more unstable and show higher uncertainty than MOSFETs but are cheaper and are useful and convenient if real-time treatment monitoring is not necessary.

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“…The thermoluminescent response is not linear for large doses. At high doses, above 10 Gy, it exhibits a supralinear behaviour; this supralinearity has been one of the main drawbacks to their use in high-dose dosimetry (Liuzzi et al, 2020;Liuzzi, Savino, D'Avino, Pugliese, & Cella, 2015). For this reason, a smaller dose was given (with scaled monitor units from the original treatment plan) via the same treatment machine.…”

Section: Ta B L Ementioning

confidence: 99%

Feasibility study evaluating arrhythmogenesis and cardiac damage after heart‐base irradiation in mice: A brief communication

Elliott

Linder

Nolan

2020

Veterinary Medicine & Sci

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Radiation‐induced heart disease (RIHD) is a potential cause of morbidity and mortality in dogs undergoing thoracic irradiation. Arrhythmias and sudden death have been documented in dogs undergoing stereotactic body radiation therapy for heart base tumours. A study was proposed to interrogate the effect of different stereotactic‐like radiation prescriptions on RIHD development, including arrhythmogenesis and classical histological endpoints in a mouse model. A pilot study was performed initially. The heart base of CD1 (n = 3) and C57Bl/6J (n = 3) female mice were irradiated (12 Gy × 3, daily) with a clinical linear accelerator. No significant adverse effects were noted and each mouse survived the entire subsequent 3‐month observation period. At various time points, no arrhythmias were identified on ECG analysis. Cardiac histology (haematoxylin and eosin, and picrosirius red staining) was performed at 3 months. In a single CD1 mouse and two C57BI/6J mice, multifocal, minimal, peri‐vascular lymphoplasmacytic inflammation was noted within the irradiated proximal heart. In one mouse of each strain, a small, single focus of fibrinoid vascular necrosis was observed. Overall, there was no significant myocardial necrosis, atrophy or inflammation. Picrosirius red staining revealed no evidence of fibrosis in any mouse. Dosimetric verification indicated that the irradiation was successful and delivered as planned, with an average predicted‐to‐measured dose‐difference within 5%. While this study did not demonstrate significant arrhythmogenesis, certain modifications of the experimental mouse irradiation procedures are discussed which may enable more translationally relevant modelling of the canine cardiac response to SBRT‐like irradiation.

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Evaluation of LiF:Mg,Ti (TLD-100) for Intraoperative Electron Radiation Therapy Quality Assurance

Cited by 19 publications

References 32 publications

Dose–Response of TLD-100 in the Dose Range Useful for Hypofractionated Radiotherapy

Dose–Response of TLD-100 in the Dose Range Useful for Hypofractionated Radiotherapy

Implementation of an intraoperative electron radiotherapy in vivo dosimetry program

Feasibility study evaluating arrhythmogenesis and cardiac damage after heart‐base irradiation in mice: A brief communication

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