Monte Carlo Simulation of the Treatment of Eye Tumors with &lt;sup&gt;106&lt;/sup&gt;Ru Plaques: A Study on Maximum Tumor Height and Eccentric Placement

Brualla, L.; Zaragoza, Francisco J.; Sauerwein, W.

doi:10.1159/000362560

Cited by 15 publications

(12 citation statements)

References 36 publications

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“…The determination of 3-D dose distributions is a current field of research [16,17,18,19,20,21,22,23,24]. This study is based on Monte Carlo simulated dose distributions of 3 eye plaque types.…”

Section: Introductionmentioning

confidence: 99%

Dose Distributions and Treatment Margins in Ocular Brachytherapy with 106Ru Eye Plaques

et al. 2017

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Brachytherapy with ¹⁰⁶Ru eye plaques is the most common treatment modality for small to medium-sized uveal melanomas in Europe. So far, no standardized or widely accepted dose prescription protocol for the irradiation of intraocular tumors with ¹⁰⁶Ru eye plaques has been defined. For ¹²⁵I plaques, the minimum dose required for tumor control should be at least 85 Gy. Concerning ¹⁰⁶Ru plaques, the dose prescriptions at the University Hospital of Essen foresees minimum doses of 700 Gy to the tumor base and 130 Gy to the tumor apex. These dose prescriptions are expected to ensure sufficient treatment margins. We apply these dose prescriptions to different eye plaque types and tumor sizes and discuss the resulting treatment margins. These investigations are based on Monte Carlo simulations of dose distributions of 3 different eye plaque types. The treatment margin in apical direction has an expansion of at least 0.8 mm for all investigated eye plaques. For symmetrically formed eye plaques, the treatment margin at the base of the tumor goes beyond the visible edge of the plaque. This study focuses on the shape of 85-Gy isodose lines and on treatment margins for different eye plaque types and tumor sizes and shall help exchange knowledge for ocular brachytherapy.

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Section: Introductionmentioning

confidence: 99%

Dose Distributions and Treatment Margins in Ocular Brachytherapy with 106Ru Eye Plaques

et al. 2017

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“…Other researchers combined the point-kernel and the Monte Carlo method [10,11] . Finally, some studies have used Monte Carlo algorithms to simulate the radiation transport produced by eye applicators to determine the dose distribution [11][12][13][14][15][16][17] . Until very recently, the commonly used treatment planning system for 106 Ru plaques was based on simplified physical models of radiation transport where the emitter substance was as-sumed to be homogeneously distributed over the surface of the plaques and the anatomy of the eye was approximated to a homogeneous water sphere.…”

Section: Introductionmentioning

confidence: 99%

Monte Carlo Estimation of Absorbed Dose Distributions Obtained from Heterogeneous 106Ru Eye Plaques

Zaragoza¹,

Eichmann²,

Flühs³

et al. 2017

Ocul Oncol Pathol

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Background: The distribution of the emitter substance in ¹⁰⁶Ru eye plaques is usually assumed to be homogeneous for treatment planning purposes. However, this distribution is never homogeneous, and it widely differs from plaque to plaque due to manufacturing factors. Methods: By Monte Carlo simulation of radiation transport, we study the absorbed dose distribution obtained from the specific CCA1364 and CCB1256 ¹⁰⁶Ru plaques, whose actual emitter distributions were measured. The idealized, homogeneous CCA and CCB plaques are also simulated. Results: The largest discrepancy in depth dose distribution observed between the heterogeneous and the homogeneous plaques was 7.9 and 23.7% for the CCA and CCB plaques, respectively. In terms of isodose lines, the line referring to 100% of the reference dose penetrates 0.2 and 1.8 mm deeper in the case of heterogeneous CCA and CCB plaques, respectively, with respect to the homogeneous counterpart. Conclusions: The observed differences in absorbed dose distributions obtained from heterogeneous and homogeneous plaques are clinically irrelevant if the plaques are used with a lateral safety margin of at least 2 mm. However, these differences may be relevant if the plaques are used in eccentric positioning.

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“…This phantom has been used in previous works [16, 29, 30]. The computerized tomography scan has 256 × 256 × 59 voxels of 0.03125 × 0.03125 × 0.1 cm 3 size.…”

Section: Methodsmentioning

confidence: 99%

“…Also, most of them approximate the anatomy of the eye to a homogeneous water sphere where the anatomical structure of the eye and its corresponding structures at risk are not accounted for. Although some of the most recent works [15, 16] take into consideration the structures at risk, they still assume that the radioactive emitter substance is homogeneously distributed. Finally, Zaragoza et al [20] determined the dose over a water phantom using a fine-grain probability map emission of the emitter substance previously measured over a specific CCA (CCA1364) and a CCB (CCB1256) eye plaque.…”

Section: Introductionmentioning

confidence: 99%

Monte Carlo Simulation of the Treatment of Uveal Melanoma Using Measured Heterogeneous <sup>106</sup>Ru Plaques

et al. 2018

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Background/Aims: Ruthenium plaques are used for the treatment of ocular tumors. The aim of this work is the comparison between simulated absorbed dose distributions tallied in an anthropomorphic phantom, obtained from ideal homogeneous plaques, and real eye plaques in which the actual heterogeneous distribution of ¹⁰⁶Ru was measured. The placement of the plaques with respect to the tumor location was taken into consideration to optimize the effectiveness of the treatment. Methods: The generic CCA and CCB, and the specific CCA1364 and CCB1256 ¹⁰⁶Ru eye plaques were modeled with the Monte Carlo code PENELOPE. To compare the suitability of each treatment for an anterior, equatorial and posterior tumor location, cumulative dose-volume histograms for the tumors and structures at risk were calculated. Results: Eccentric placements of the plaques, taking into account the inhomogeneities of the emitter map, can substantially reduce the dose delivered to structures at risk while maintaining the prescribed dose at the tumor apex. Conclusions: The emitter map distribution of the plaque and the computerized tomography of the patient used in a Monte Carlo simulation allow an accurate determination of the plaque position with respect to the tumor with the potential to reduce the dose to sensitive structures.

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Monte Carlo Simulation of the Treatment of Eye Tumors with <sup>106</sup>Ru Plaques: A Study on Maximum Tumor Height and Eccentric Placement

Cited by 15 publications

References 36 publications

Dose Distributions and Treatment Margins in Ocular Brachytherapy with 106Ru Eye Plaques

Dose Distributions and Treatment Margins in Ocular Brachytherapy with 106Ru Eye Plaques

Monte Carlo Estimation of Absorbed Dose Distributions Obtained from Heterogeneous 106Ru Eye Plaques

Monte Carlo Simulation of the Treatment of Uveal Melanoma Using Measured Heterogeneous <sup>106</sup>Ru Plaques

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