Technical Note: Monte Carlo study of106Ru/106Rh ophthalmic plaques including the106Rh gamma spectrum

Hermida-López, M.; Brualla, L.

doi:10.1002/mp.12248

Cited by 7 publications

(7 citation statements)

References 22 publications

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“…In order to find the cause of the isodose disagreement between film measurements and MC calculations in the low-dose region, some simulations were carried out, including the Ru/Rh-106 gamma spectrum, obtaining results similar to those of Hermida-López et al [ 34 ], who reported an insignificant contribution of the gamma spectrum for clinical depths (below 10 cm). Besides gamma contribution, there are at least two other factors that may have a significant impact on the isodose distributions: (a) The measurement depth as to film measurements and (b) the inactive rim size parameter as to MC simulations.…”

Section: Discussionmentioning

confidence: 75%

Modified Geometry of 106Ru Asymmetric Eye Plaques to Improve Dosimetric Calculations in Ophthalmic Brachytherapy

Miras

Terrón

Bertolet

et al. 2022

JPM

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Ru/Rh asymmetric plaques for ophthalmic brachytherapy have special geometric designs with a cutout intended to prevent irradiation of critical ocular structures proximal to the tumor. In this work, we present new geometric models for PENELOPE + PenEasy Monte Carlo simulations of these applicators, differing from the vendor-reported geometry, that better match their real geometry to assess their dosimetric impact. Simulation results were benchmarked to experimental dosimetric data from radiochromic film measurements, data provided by the manufacturer in the calibration certificates, and other experimental results published in the literature, obtaining, in all cases, better agreement with the modified geometries. The clinical impact of the new geometric models was evaluated by simulating real clinical cases using patient-specific eye models. The cases calculated using the modified geometries presented higher doses to the critical structures proximal to the cutout region. The modified geometric models presented in this work provide a more accurate representation of the asymmetric plaques, greatly improving the agreement between Monte Carlo calculations and experimental measurements. Lack of consideration of accurate geometric models has been shown to be translated into notable increases in dose to organs at risk in clinical cases.

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Section: Discussionmentioning

confidence: 75%

Modified Geometry of 106Ru Asymmetric Eye Plaques to Improve Dosimetric Calculations in Ophthalmic Brachytherapy

Miras

Terrón

Bertolet

et al. 2022

JPM

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“…Such conditions would certainly aid in the volatilization and dispersion of otherwise nonvolatile ruthenium species. For a facility undertaking the purification of fission products from spent nuclear fuel for commercial gain, it is hard to ignore the potential profit afforded by obtaining 106 Ru in high-specific activity, considering its long-standing medical use in the development of brachytherapy plaques for the treatment of eye cancer (53,54). For this application, it is commonly electrodeposited from solution onto silver, along with the addition of carrier RuCl 3 (54,55).…”

Section: Discussionmentioning

confidence: 99%

“…For a facility undertaking the purification of fission products from spent nuclear fuel for commercial gain, it is hard to ignore the potential profit afforded by obtaining 106 Ru in high-specific activity, considering its long-standing medical use in the development of brachytherapy plaques for the treatment of eye cancer (53,54). For this application, it is commonly electrodeposited from solution onto silver, along with the addition of carrier RuCl 3 (54,55). Since this requires a highly soluble form of 106 Ru, it makes sense to invoke a reductive technique that generates polychlorinated Ru(III/IV) species with a high degree of radiopurity and aqueous solubility, rather than the vast majority of passivation techniques that ultimately produce the highly insoluble RuO 2 .…”

Section: Discussionmentioning

confidence: 99%

Identification of a chemical fingerprint linking the undeclared 2017 release of ¹⁰⁶ Ru to advanced nuclear fuel reprocessing

Cooke

Botti

Zok

et al. 2020

Proc. Natl. Acad. Sci. U.S.A.

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The undeclared release and subsequent detection of ruthenium-106 (106Ru) across Europe from late September to early October of 2017 prompted an international effort to ascertain the circumstances of the event. While dispersion modeling, corroborated by ground deposition measurements, has narrowed possible locations of origin, there has been a lack of direct empirical evidence to address the nature of the release. This is due to the absence of radiological and chemical signatures in the sample matrices, considering that such signatures encode the history and circumstances of the radioactive contaminant. In limiting cases such as this, we herein introduce the use of selected chemical transformations to elucidate the chemical nature of a radioactive contaminant as part of a nuclear forensic investigation. Using established ruthenium polypyridyl chemistry, we have shown that a small percentage (1.2 ± 0.4%) of the radioactive106Ru contaminant exists in a polychlorinated Ru(III) form, partly or entirely as β-106RuCl3, while 20% is both insoluble and chemically inert, consistent with the occurrence of RuO2, the thermodynamic endpoint of the volatile RuO4. Together, these findings present a clear signature for nuclear fuel reprocessing activity, specifically the reductive trapping of the volatile and highly reactive RuO4, as the origin of the release. Considering that the previously established103Ru:106Ru ratio indicates that the spent fuel was unusually young with respect to typical reprocessing protocol, it is likely that this exothermic trapping process proved to be a tipping point for an already turbulent mixture, leading to an abrupt and uncontrolled release.

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“…The considered emitting energy spectrum was the one corresponding to the beta transitions from 106 Rh to 106 Pd, which is provided in ICRU Report 72 14 . The photon component produced by transitions to the ground state of 106 Pd was ignored as it is not relevant for clinical purposes 15 …”

Section: Methodsmentioning

confidence: 99%

A Monte Carlo dose calculation system for ophthalmic brachytherapy based on a realistic eye model

et al. 2021

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Purpose There is a growing trend towards the adoption of model‐based calculation algorithms (MBDCAs) for brachytherapy dose calculations which can properly handle media and source/applicator heterogeneities. However, most of dose calculations in ocular plaque therapy are based on homogeneous water media and standard in‐silico ocular phantoms, ignoring non‐water equivalency of the anatomic tissues and heterogeneities in applicators and patient anatomy. In this work, we introduce EyeMC, a Monte Carlo (MC) model‐based calculation algorithm for ophthalmic plaque brachytherapy using realistic and adaptable patient‐specific eye geometries and materials. Methods We used the MC code PENELOPE in EyeMC to model Bebig IsoSeed I25.S16 seeds in COMS plaques and 106Ru/106Rh applicators that are coupled onto a customizable eye model with realistic geometry and composition. To significantly reduce calculation times, we integrated EyeMC with CloudMC, a cloud computing platform for radiation therapy calculations. EyeMC is equipped with an evaluation module that allows the generation of isodose distributions, dose–volume histograms, and comparisons with Plaque Simulator three‐dimensional dose distribution. We selected a sample of patients treated with 125I and 106Ru isotopes in our institution, covering a variety of different type of plaques, tumor sizes, and locations. Results from EyeMC were compared to the original plan calculated by the TPS Plaque Simulation, studying the influence of heterogeneous media composition as well. Results EyeMC calculations for Ru plaques agreed well with manufacturer’s reference data and data of MC simulations from Hermida et al. (2013). Significant deviations, up to 20%, were only found in lateral profiles for notched plaques. As expected, media composition significantly affected estimated doses to different eye structures, especially in the 125I cases evaluated. Dose to sclera and lens were found to be about 12% lower when considering real media, while average dose to tumor was 9% higher. 106Ru cases presented a 1%–3% dose reduction in all structures using real media for calculation, except for the lens, which showed an average dose 7.6% lower than water‐based calculations. Comparisons with Plaque Simulator calculations showed large differences in dose to critical structures for 106Ru notched plaques. 125I cases presented significant and systematic dose deviations when using the default calculation parameters from Plaque Simulator version 5.3.8., which were corrected when using calculation parameters from a custom physics model for carrier‐attenuation and air‐interface correction functions. Conclusions EyeMC is a MC calculation system for ophthalmic brachytherapy based on a realistic and customizable eye‐tumor model which includes the main eye structures with their real composition. Integrating this tool into a cloud computing environment allows to perform high‐precision MC calculations of ocular plaque treatments in short times. The observed variability in eye anatomy among the selected ...

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Technical Note: Monte Carlo study of¹⁰⁶Ru/¹⁰⁶Rh ophthalmic plaques including the¹⁰⁶Rh gamma spectrum

Cited by 7 publications

References 22 publications

Modified Geometry of 106Ru Asymmetric Eye Plaques to Improve Dosimetric Calculations in Ophthalmic Brachytherapy

Modified Geometry of 106Ru Asymmetric Eye Plaques to Improve Dosimetric Calculations in Ophthalmic Brachytherapy

Identification of a chemical fingerprint linking the undeclared 2017 release of ¹⁰⁶ Ru to advanced nuclear fuel reprocessing

A Monte Carlo dose calculation system for ophthalmic brachytherapy based on a realistic eye model

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Technical Note: Monte Carlo study of106Ru/106Rh ophthalmic plaques including the106Rh gamma spectrum

Cited by 7 publications

References 22 publications

Modified Geometry of 106Ru Asymmetric Eye Plaques to Improve Dosimetric Calculations in Ophthalmic Brachytherapy

Modified Geometry of 106Ru Asymmetric Eye Plaques to Improve Dosimetric Calculations in Ophthalmic Brachytherapy

Identification of a chemical fingerprint linking the undeclared 2017 release of 106 Ru to advanced nuclear fuel reprocessing

A Monte Carlo dose calculation system for ophthalmic brachytherapy based on a realistic eye model

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Technical Note: Monte Carlo study of¹⁰⁶Ru/¹⁰⁶Rh ophthalmic plaques including the¹⁰⁶Rh gamma spectrum

Identification of a chemical fingerprint linking the undeclared 2017 release of ¹⁰⁶ Ru to advanced nuclear fuel reprocessing